Delta Membranes

Flood resilience: innovative measures and practices that reduce flood damage to homes

Building Products Index Ltd September 23, 2026 Waterproof Membranes, waterproofing Leave a Comment

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This project was designed and delivered by Delta’s Technical Team in collaboration with Shield Waterproofing and Preservation, a Delta Registered Installer. The objective was to successfully deliver innovative flood resilience (“PFR”) measures that would not only meet, but exceed recognised standards and codes of practice.

The privately owned detached house was built in 2007. The property flooded in 2023 and again in 2024 after poorly designed, insurance-funded retrofit works failed. These repeat incidents caused significant stress for the homeowner and damaged their trust in construction professionals and contractors.

Property Flood Resilience (PFR) strategies include measures that reduce flood damage and enable a flooded building to be recovered and reoccupied more quickly. These measures are typically grouped into resistance measures, which limit the amount of water entering a building; resilience measures, which reduce damage to the building fabric; and recoverability measures, which support faster, safe reoccupation. An effective PFR strategy may combine all three approaches to prevent water entry or limit the amount of floodwater that is able to enter the building.

PFR products can be either permanent or temporary. Permanent products are installed in-situ and remain ready to protect a building at all times, with no action needed when flooding occurs. Temporary products are stored away and deployed only when a flood is expected.

The Property Flood Resilience (PFR) design and installation featured here followed key principles of flood resistance, resilience, and recoverability, in line with best-practice guidance including BS 85500:2025 Flood resilient construction – improving the flood performance of buildings, CIRIA C790 (2020): Code of practice for property flood resilience, and the PCA Code of practice for the recovery of flood damaged buildings (2013).

Methodology

Following the six stages/standards of PFR:

Hazard Assessment
Property Survey
Options for Development and Design
Construction
Commissioning and Handover
Operation and Maintenance

All potential flood sources must be identified and assessed. At this property, the key sources were surface water, infrastructure failure, overland flow, and groundwater rising beneath the house. The homeowner’s experience was also considered. Together, these inputs informed a comprehensive risk assessment based on Environment Agency flood maps, geotechnical reports, drainage surveys, and utility layouts, using the widely recognised source–pathway–receptor methodology.

The second stage involved a comprehensive physical survey of the property, including its construction materials and details, supported by data from the structural engineer and coordinated by Robinson & Hall, the client’s representative.

The third stage used codes of practice and British Standards as a framework for developing options and PFR design proposals. It also involved meetings with the client, his representative, the structural engineer, the main contractor, and related trades such as M&E to ensure an integrated solution could be delivered within budget and project constraints.

The fourth stage involved detailed discussions with the client, main contractor, and design team on the key principles of flood resistance, resilience, and recoverability, including how water exclusion and controlled water entry strategies would work together. These discussions were essential to set realistic expectations for PFR performance and to agree the balance between cost, benefit, and risk.

The fifth stage involved coordinating all trades and stakeholders to develop an installation programme that clearly defined responsibilities and sequencing, ensuring the works could be delivered on time and within budget.

This flood resilience project, and the PFR solutions designed and installed, are entirely original and innovative.

Using our extensive knowledge in structural waterproofing and risk assessment for below-ground structures, Delta Membranes worked with the design and installation teams to apply expertise in design standards, forms of waterproofing, product application methods, water exclusion and water management, behaviours of diverse building materials when subjected to water ingress, and residual contamination risk to meet the flood resilience needs of an above-ground building. This approach combined creative thinking with technical rigour to ensure compliance with CIRIA C790 and BS 85500:2022.

As described, the core design rationale combined water exclusion measures to keep the building dry during shallow, short-duration floods with water entry measures and the potential consequences during deeper, longer-duration floods.

The water exclusion measures broadly comprised:

Pre-applied fully bonded Type A waterproofing membrane beneath new concrete floor slabs.
Type A crystalline slurries to internal faces of all internal and external walls.
Curved fillets of repair mortar at all structural junctures.
Sealing around all service penetrations through the structure, such as pipes, cables, drains etc.
Closing off all wall cavities and thresholds at door reveals and other locations of structural discontinuity.
Use of sealants, resins and other products to close off any other potential pathways.
None return valves (NRVs) where appropriate.

The water entry measures broadly comprised:

Design and installation of an internal water management and pumping system, based upon a typical Type C cavity drainage system that one would find in a basement.
Use of resilient floor insulation bonded down to the new floor slabs, and other materials which are also “recoverable” in that they do not change form or properties, or support bacterial growth when immersed in flood water, and would therefore not need to be stripped out.
Use of hydrophobic additives to cement screeds, for example, to ensure they would not break down when immersed.
Use of “sacrificial” materials – materials which would need to be removed in the event of a flood, for example, to access hidden voids for cleaning and sanitisation behind, but which can be quickly and easily replaced post-flood.
Elimination of hidden voids which could otherwise harbour trapped contaminated flood water and pose a health risk.
Enhancing the access and serviceability of voids which could not be eliminated (eg. increased frequency of inspection ports in perimeter drainage channels).

Installation

All existing/flood-damaged finishes were removed to reveal the underlying structure and allow installation.

A new ground-bearing reinforced concrete slab was designed by the structural engineer. This included Delta DualProof, a fully and permanently bonded, Pre-Applied, Type A waterproofing membrane, beneath it. Delta DualProof is a continuous pre-applied fully bonded barrier protection waterproofing membrane system which is installed on blinded hardcore prior to steel reinforcement being set out and the new concrete being poured. It’s tough and unique profile features an integrated layer of fleece on the upper face. Delta DualProof keys with the new concrete to form an inseparable bond with such that the DualProof membrane and structure become fully integrated. This means that water ingress through any minor and un-noticed damage or defects typically caused by general building site conditions remains isolated to that specific area instead of being able to track between membrane and structure, so dramatically reducing risk of any water getting through.

The perimeter Delta Drainage Channel network was recessed within 50mm deep 100mm wide channel chases formed within the Delta Glass insulation zone, following all wall/floor juncture construction joints, so as to protect the full perimeter of the building, and to accept and drain away any flood water at the most vulnerable points of potential ingress.

External ground levels slope down towards the house, increasing the force of flow and exposing the front elevation to the greatest surface water flooding. A Delta dual packaged pumping station was installed internally near the front door to help manage this risk.

Delta Water Based Epoxy Resin offers waterproofing and protection for sand & cement screeds, mortar beds, concrete or masonry. It applies like paint, works in damp conditions, and dries to a tough, non-toxic, easy-to-clean surface.

Delta MS 500 is a robust Type C cavity-drainage membrane protection system designed for demanding conditions. It combines strength, durability, functionality, and ease of installation, making it well suited to applications where structural integrity is critical.

A Type C “drained protection” cavity drainage system can be a practical solution for both new-build and refurbishment projects. It consists of two main elements: internal cavity drainage membrane linings applied to the internal faces of the structure which act as a drainage space and a vapour barrier to accept and de-pressurize water ingress from outside the structure, and a maintainable internal basement drainage and pumping system, which acts to collect and control water from behind the cavity drainage membranes and pump it out to higher external surface water drainage or above flood design level, via an air gap . BS 8102:2022 (Protection of Below Ground Structures Against Water Ingress – Code of Practice) defines Type C waterproofing as a protection system that manages water penetrating the outer shell of a building by collecting it in a cavity between the external wall and an internal lining or wall.

The Type C System forms a flexible dimpled inner membrane lining to the walls and floor which acts as physical barrier to capillary dampness and salt contamination, and also enables seepage to be collected and managed to a packaged pump station. To enhance flood resilient performance, Delta has tailored the Type C system in such a way that it will also accept water from upon the internal finishes on the internal or “dry” side of the membranes. In accordance with the water entry strategy, this acts to minimise internal flood levels and passively drains any flood water attempting to rise above floor level to a packaged pump system to be pumped out to above external flood level, also simplifying de-contamination and recovery post-flood.

Related Products:

Delta MS 500
Delta Plugs
Delta Water Based Epoxy
Delta DualProof
Delta Perimeter Drainage Channel
Delta Dual V6
Koster KB Flex 200
Koster KBE Liquid Film
Koster NB1 Grey
Koster Repair Mortar Plus
Koster MS Joint Sealant
Koster Mortar Tight Cement Additive
Delta Glass Floor Insulation
PC56 Adhesive

Case Study Results

The human impact of this project was also significant. The design team together with Delta Registered Installers, Shield Waterproofing and Preservation recognised the long-term psychological and financial effects of flooding suffered by the homeowner and actively paired empathy with professional expertise and practical support.

The project delivered a highly innovative and entirely unique PFR solution that successfully identified and responded to all project constraints, and earned the respect and admiration of everyone involved, especially the client.

DAMP PROOFING, RESTORATION, AND WATERPROOFING PROCESSES

Building Products Index Ltd May 24, 2026 Waterproof Membranes, waterproofing Leave a Comment

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Converting a public house into two luxurious dwellings

Overview

Delta Registered Installers, Prism Construction successfully restored a dilapidated former public house into two modern properties, despite initial concerns from the structural engineer about potential collapse of two sections.

This scope of this project was converting an abandoned and damp structure into two modern, dry dwellings, ensuring a complete transformation from neglect to contemporary living spaces.

The trend of converting pubs into residential properties presents substantial opportunities. These structures hold immense potential for transformation into highly desirable residential spaces.

The building’s original solid brick construction was in excellent condition, highlighting the era’s high-quality craftsmanship. This building presents a complex layout with varying ground levels along its frontage and side elevations, adjacent to the road.

Plans include raising the first floor for more headroom, replacing timber floors affected by wet rot, and addressing the solid concrete plank floor in unit two, which is slightly below ground level to the front elevation

Ensuring comprehensive waterproofing or damp proofing for any subterranean structure is essential to maintain and protect a building’s structural integrity.

When specifying a retrofitted waterproofing solution, considerations should include site contamination, head heights, and retaining walls.

Methodology

A thorough structural survey is essential for any pub-to-residential conversion. Experts assess building integrity, evaluate load-bearing walls, and identify structural challenges that may impact the process. Working in collaboration with the Structural Engineer and Developers, Delta’s Technical Team provided expert advice and guidance throughout the project. Delta tailored a waterproofing design to meet specific project requirements.

BS 8102:2022 categorises waterproofing into four performance grades: 1a, 1b, 2, and 3. These grades specify the required waterproofing standards to match client expectations. For example, while commercial or industrial environments may allow some dampness (Grades 1a and 1b), residential areas necessitate complete dryness (Grade 3).

The new timber floors must be isolated. Delta’s Technical Team suggests using Delta High Performance DPC. The plank floor will experience lateral dampness from high ground levels. Once the structure is stabilised, the floor should ideally be replaced with an isolated timber floor. Waterproofing options were also discussed.

A ‘Type C’ Waterproofing System was selected as a maintainable waterproofing solution to the existing basement to ensure a Grade 3 habitable environment was achieved.

BS 8102:2022 outlines three primary waterproofing methods: Type A (Barrier), Type B (Structurally Integral), and Type C (Drained). For habitable spaces, a combination of two methods is preferred, known as combination protection. These systems should possess different performance characteristics to reduce the risk of a common failure cause.

Type A

Delta’s Technical Team recommended two coats of Koster NB1 be applied to the front face of the brickwork and LGF slab before the installation of the proposed “Type C” cavity drained protection system.

Preparation of the substrate prior to the application of Koster NB1 is essential. Typically, where Type A tanking is carried out internal 90 degree angles should be filleted with Koster Repair Mortar Plus. Any voids should be filled and loose masonry adequately pointed with Koster Repair Mortar Plus.

This in effect provided a “Type A” form of waterproofing in addition to the proposed internal “Type C”, with the principle of designing out risk.

It is essential to treat all new concrete, including the basement slab and walls, with a free lime treatment. Koster Polysil TG 500 was spray applied to prevent free lime build-up.

Free lime and mineral salts leaching from concrete can cause Type C Drained Protection Systems to fail. According to BS 8102:2022 Section 10.2.1.2, these substances deposit within cavity drainage systems, perimeter channels, and especially sump chambers, leading to blockages and potential system failure.

Type C

Delta’s Type C, Cavity Drained Protection System (CDM) supports slight movement and vibration without affecting structural dynamics. It permits moisture or water to travel behind the membrane in a controlled drainage system, requiring minimal substrate preparation.

Walls above external ground level can be affected by rising dampness. Therefore, using a cavity drain membrane (CDM) as a damp-proofing medium was essential. Delta’s Technical Team advises lining all walls with the Type C system. With combination waterproofing (Type A and C) only required for retaining walls.

Delta MS 500 was installed on walls, with Delta MS20 laid on the floor and joined to the MS 500 wall membrane. Delta FM was deployed to the concrete plank at first floor level to protect against lateral capillary held moisture.

Delta drainage channel was inserted adjacent all retaining walls and taken to non return valves to evacuate via gravity due to the topography of the site.

The existing solid staircases were retained and prepared prior to the application of Koster NB1.

Where insulation is provided a vapour control layer is recommended on the warm side of the insulation.

All installed with great dealing and expertise.

Products Used

Delta MS 500
Delta MS 20
Delta Cornerstrip
Delta Tape
Delta Qwikseal Plugs
Delta FM
Delta Drainage Channels
Koster Repair Mortar Plus
Koster NB1
Koster Polysil TG500

Case Study Results

Our clients were highly impressed with Delta’s technical approach. Structural waterproofing requires a technical and design-driven strategy, which Delta effectively delivered.

Delta Membranes Type C cavity drain membrane system Type C waterproofing system Waterproof membranes waterproofing

Sympathetic waterproofing solution to historic structure

Building Products Index Ltd November 26, 2025 Membranes, Waterproof Membranes Leave a Comment

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Overview

The former Bradford Odeon Cinema, saved from demolition by a local campaign, has been transformed into an exciting music venue, newly named “Bradford Live”. Built in 1930, the cinema hosted famous acts like the Beatles and the Rolling Stones in the 1960s before being left derelict for 23 years.

The venue will feature a main auditorium, smaller spaces for corporate events, weddings, and graduations, and will host business conferences, awards ceremonies, comedy shows, and family entertainment.

Construction started in 2021, with many original features, such as the ballroom’s art deco ceiling, being restored.

Delta Registered Installers, Timberwise (UK) Ltd having worked with the main contractor previously, were called upon to give assistance on a dry rot outbreak and to design a custom, robust waterproofing solution for the large underground basement.

The scope of the project was to provide a Grade 3 environment to a large existing large basement which will feature multiple bars, toilets, seating areas along with further excavation for lift pits, etc.

This complex project required a specialist to provide an efficient, compliant, and future proof approach.

Methodology

Timberwise (UK) Ltd collaborated with architects and the project team to provide a straightforward, effective approach. Their waterproofing design ensured a robust and suitable system that integrated seamlessly with the structure, adhering to BS 8102:2022 standards, Approved Documents, and industry Best Practice Guidance. This design emphasised continuity, proper sequencing and installation, and future maintenance and serviceability.

Timberwise (UK) Ltd specified a Delta Type C system. A Type C waterproofing system, or cavity drain membrane system (CDM), effectively manages water ingress by creating a drainage cavity within the structure, directing water to a sump and pump or external drain. Key benefits include flexibility for both new and existing properties, a ‘failsafe’ design that doesn’t rely on external barriers, and reversible installation suitable for historic buildings. The system’s discreet internal finishing and under-cover installation allow work to proceed regardless of weather conditions and reduce susceptibility to minor installation defects compared to surface barriers.

Before installation of the Delta Type C system, all existing walls and new concrete slab were treated with Koster Polysil TG 500 anti-lime inhibiter to seal the surfaces and reduce the leaching of ‘free lime’ which could cause blockages behind the membranes.

Attention was given to all wall/floor junctions and fillet seals were created. Angles are potential stress points for waterproofing systems. These crack endangered areas require special attention.

Delta PT, a high-density polyethylene (HDPE) cavity drain membrane which features a plastic mesh welded to its dimpled surface, serves as an impermeable damp proofing base for plaster or shotcrete, and functions as a water control and drainage membrane. Delta PT was securely fixed to the internal walls using specialist fixing plugs, with Delta MS20 installed to floors.

Below the floor membrane perimeter drainage channels were sited within rebates allowing for suitable drainage of any future water ingress and this being diverted to suitable discharge point (on this occasion a mechanical pump system).

To ensure the Type C system was fully maintainable, inspection ports were located at every major change of direction.

The basement drainage system features four Dual Delta Pumping Stations, each with an individual high level water alarm (HLA) and battery backup systems to keep pumps running in event of mains power outage.

All floors and drainage elements were tested to ensure these would drain as the system was designed and BS 8102:2022 requirements were met.

A new lift pit waterproofing detail has been integrated into the elevator system, featuring a preformed liner sandwiched between concrete, enabling lift engineers to drill internally without compromising the waterproofing system.

The need to service and maintain the drainage elements of type C waterproofing systems is paramount to long-term success. Timberwise (UK) Ltd, incorporated inspection ports in the perimeter channel and installed the sump pump in a location that allows easy access for periodic servicing.

After the Type C System was installed the all-important final integrity testing was undertaken to exercise the waterproofing system in worst case scenario.

Products Used

Delta PT
Delta MS 20
Koster Polysil TG 500
Delta Tape/Cornerstrip
Delta Drainage Channel
Delta Packaged Pumping Stations
High Level Alarms
Battery Backups

Case Study Results

The former Bradford Odeon Cinema has been transformed from an unused derelict building back to its former glory for many theatrical and musical performances to be enjoyed once again.

The project was delivered on time and to budget.

The client was delighted with Timberwise (UK) Ltd’s ability to collaborate throughout the build process, adapting to phasing and sequencing to provide a robust waterproofing solution.

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Tensile and Compressive Loads – Structural Waterproofing

Building Products Index Ltd September 25, 2025 Membranes Leave a Comment

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Tensile and compressive stress and strain are two common types. Tensile stress increases an object’s length, while compressive stress decreases it. These stresses help determine a material’s elastic modulus, indicating its stiffness.

Tensile and compressive loads are key in mechanics and engineering. Tensile load stretches materials, causing elongation. Compressive load compresses materials, causing them to shorten.

Tensile Strength

Tensile strength in structural waterproofing products is important to resist cracking and tearing under stress, preventing water penetration and ensuring a structure’s longevity. High tensile strength is vital in areas prone to movement, where the waterproofing solution must withstand stretching and elongation without failing.

Tensile strength is measured by conducting a tensile test, also known as a tension or pull test, on a material sample. This test involves applying a gradually increasing tensile force to the sample until it breaks, while simultaneously measuring the force and deformation of the material. The maximum force the material withstands before breaking, divided by its original cross-sectional area, determines its tensile strength.

There are three types of tensile strength: Yield strength (A) is the stress a material can handle without permanent deformation. Ultimate strength (B) is the maximum stress it can endure. Breaking strength (C) is the stress level at the point of rupture.

A third-party tensile strength test evaluates a material’s resistance to breaking untder tension. Conducted by independent labs, it provides an unbiased assessment of mechanical properties. Results verify the material’s suitability for high-stress applications.

Not all third-party construction product testing is the same. The goal is to ensure product performance and compliance, but standards, processes, and rigor vary between testing bodies.

It’s important to follow manufacturer’s instructions for safety, optimal performance, and longevity of products and equipment. This prevents accidents, injuries, and damage, while maximising efficiency and meeting warranty requirements.

Tensile strength is vital for crack bridging products as it measures the material’s resistance to breaking under tension. It enables the material to span and seal cracks without fracturing. High tensile strength is essential to withstand the stress and strain from crack movement, preventing further damage and water ingress.

Compressive Strength

Tension is a force that pulls objects apart, while compression is a force that pushes objects together.

Compressive strength measures a material’s ability to withstand forces that crush or squeeze it. It represents the maximum stress a material can endure before fracturing or deforming significantly under compression. Essentially, it gauges how well a material resists being pushed together.

Compressive strength is vital for building materials, especially those supporting loads. It’s essential in concrete foundations, columns, walls, bricks, masonry, and insulation used in floors and roofs.

Foundations transfer the weight of buildings into the ground. Concrete, often used for foundations, undergoes compressive strength tests to ensure it can bear the load.

Columns are vertical structural members, often made of reinforced concrete, that support beams and floors. Their compressive strength is crucial to prevent buckling under heavy loads.

Load-bearing walls must withstand forces from above. Bricks, concrete blocks, and some insulation types need enough compressive strength for this purpose. Floors and roofs must support the weight of people, furniture, and materials. Insulation in these areas needs strong compressive strength to avoid being crushed and losing its insulating properties.

Using materials with good compressive strength is vital for keeping a structure’s integrity.

Compressive strength of a membrane refers to its ability to withstand crushing or deformation under compressive force. It’s a crucial mechanical property, especially for membranes used in construction, insulation, filtration and waterproofing applications, where they may be subjected to significant loads.

Always follow the manufacturer’s guidelines for any construction or waterproofing product you use, regardless of general advice offered.

Manufacturer guidelines vary based on product types, materials, intended use, and regulations. These differences affect recommended installation, maintenance, and usage procedures due to each manufacturer’s unique processes and standards.

Ask Questions

We encourage you to ask questions about our products and services. Transparency and honesty are our core values. Enquiring helps us learn, understand, and grow. It allows us to gather information, clarify doubts, and gain deeper insights. By asking questions, we engage in critical thinking and problem-solving, essential for personal and professional development. This fosters communication, collaboration, and open dialogue, leading to better decision-making and problem-solving.

Training

Manufacturer training is vital for implementing best practices, enhancing skills, and boosting career opportunities. It keeps you updated with industry trends and new technologies, making you more competitive. Training also improves job performance, productivity, and confidence, leading to higher job satisfaction and personal growth.

Always Happy to Help

Delta’s office and field Technical Teams offer expert assistance to identify the ideal waterproofing system for your project, ensuring it meets your specific requirements precisely. For any inquiries about our products, we provide honest and accurate answers at all times.

Reach us at 01992 523 523 or drop us an email at info@deltamembranes.com.

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Value Engineering in Structural Waterproofing

Building Products Index Ltd July 20, 2025 Waterproof Membranes, waterproofing Leave a Comment

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Value engineering is a method to deliver essential project functions at the lowest cost. It substitutes materials and methods with cheaper alternatives without losing functionality. Focused on functions rather than physical attributes, value engineering is also known as value analysis.

Value engineering reviews products in the design phase to cut costs and boost functionality, enhancing product value. It aims to produce items cost-effectively without compromising their purpose. The concept of Value Engineering began at General Electric Co. during World War II. During the war, there were shortages of skilled labour, raw materials, and component parts. Lawrence Miles and Harry Erlicher at G.E. sought suitable substitutes.

Aligning Value Engineering with Structural Waterproofing

Messrs Miles Erlicher defined product value as the ratio of function to cost. Function is the work an item is designed to perform, and cost covers its life cycle expenses. Increasing product value involves enhancing function or reducing cost. Value engineering includes analysing costs related to production, design, maintenance, and replacement.

Product value = Function

__________

Cost

Waterproofing requires a tailored design approach, as there is no one-size-fits-all solution. So, to achieve value engineering in structural waterproofing, consideration should be given to product, Product performance characteristics, installation, future maintenance and worst-case scenario, refitting flawed or failed systems.

Waterproofing is vital for maintaining the integrity and value of a structure. Poor workmanship, wrong materials, lack of preparation, or missed details during installation can cause failed waterproofing systems, leading to water damage and expensive repairs. Addressing waterproofing issues early ensures a structure stays in great condition. Although waterproofing costs only 2-5% of a building’s total expense, to rectify failed or flawed waterproofing, can account to nearly 80% of all construction-related problems.

Effective structural waterproofing relies on precise product selection and proper installation methods from the start.

Waterproofing Design

Waterproofing design is essential in construction, employing various methods and materials to prevent water ingress. Effective waterproofing design enhances building longevity and safeguards structures against water damage.

Three key stages to successful waterproofing: design, specification, and installation.

The waterproofing designer will assess “value” and incorporate this into their design. Not all waterproofing products/materials are equal. Different products offer varied qualities and features, so it’s important to choose the right one for the project.

A Waterproofing Design Specialist must know various waterproofing systems and BS 8102:2022. They should understand water sources, their interaction with structures, and soil flow. Structural principles and geotechnical knowledge are essential for working with engineers and interpreting soil reports.

Delta Technical Team

Delta’s Technical Team can help you find value engineering solutions for your waterproofing project. For all your project requirements, Delta’s Technical Team is a dependable resource. Offering expert advice, comprehensive support, and timely practical assistance, we cater to your specific needs. Contact us today to optimise your project’s performance and cost efficiency.

Tel: 01992 523 523 or drop us an email at info@deltamembranes.com.

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Value Engineering – Waterproofing

Building Products Index Ltd June 30, 2025 Waterproof Membranes, waterproofing Leave a Comment

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Aligning Value Engineering with Structural Waterproofing

Product value = Function

_________

Cost

Waterproofing requires a tailored design approach, as there is no one-size-fits-all solution. So, to achieve value engineering in structural waterproofing, consideration should be given to product, product performance characteristics, installation, future maintenance and worst-case scenario, refitting flawed or failed systems.

Effective structural waterproofing relies on precise product selection and proper installation methods from the start.

Waterproofing Design

Three key stages to successful waterproofing: design, specification, and installation.

Delta Technical Team

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What is a ‘Cavity Drain System’?

Building Products Index Ltd April 29, 2025 Membranes, Waterproof Membranes, waterproofing Leave a Comment

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Type C, Cavity Drainage Waterproofing – Delta Membranes

Waterproofing Below Ground Structures RIBA Approved CPD

Technical Drawings Type C – Drained Protection – Delta Membranes

A “cavity drain system” is a structural waterproofing solution that isolates internal wall and floor finishes from water, water vapour and dampness. This article explores cavity drain systems and cavity drain products.

Structural waterproofing is a term which covers materials and/or techniques to stop water from entering a building, especially below-ground, by creating a barrier against groundwater or other water sources. Buildings globally depend on structural waterproofing systems.

A cavity drain system, or Type C, waterproofing system, protects below-ground structures (or any structure that is wholly or partially earth retained from water ingress by allowing water into enter into the structure (via ‘a cavity’) and safely draining it away. A cavity drain system manages water entering a structure through external walls or floors, directing it behind a membrane into a controlled drainage system. This system safely diverts water to a disposal point, like a package pumping station.

Cavity drain systems are also known as Cavity Drained, CDM, Type C, Cavity Drainage and Cavity Protection. BS 8102:2022 ‘Protection of below ground structures against water ingress. Code of practice’ classifies Type C as “Drained cavity construction” and “Cavity Drained Protection.”

Key Components

Key components of a ‘cavity drain system’ are high-density polyethylene internal drainage membranes. These membranes are loose laid in flooring application, whilst being attached to the wall with surface plugs in vertical installations.

Water entering the structure is channelled into drainage systems (made up from basement drainage channels and collected in a submersible pumping station before being discharged at a suitable point. Additional key elements of a basement drainage system are high water level alarms and battery backups.

Cavity Drain Systems

A cavity drain system is fully maintainable, and an ideal solution for both new-builds, refurbishments, and historic buildings and structures. A cavity drain system offers a host of benefits, from easy and fast installation to ability to accommodate minor structural movements.

Cavity drain systems are highly effective and considered one of the safest and most reliable waterproofing methods.

Crossover

Certain cavity drain membranes can also provide protection in other fields. Such as AT 800, AT 800 is a cavity drain membrane that meets BS 8102:2022 and BS 8485:2015+A1:2019 standards, offering waterproofing and ground gas protection in one application. This membrane provides drainage protection in Type C waterproofing (Grade 3 environment) and acts as a barrier against Carbon Dioxide, Radon, and Methane gases. It also features high adhesion for applying flame retardants.

MS 500 Fire Retardant is an 8mm studded cavity drain membrane that achieves a Euroclass rating of B-S2, d0 (EN 13501-1:2018) and is suitable for internal walls and floors, protecting below ground structures from groundwater ingress with increased Fire Safety.

Need help with cavity drain systems?

For all your project requirements, Delta’s Technical Team is a dependable resource. Offering expert advice, comprehensive support, and timely practical assistance, we cater to your specific needs. Reach us at 01992 523 523 or drop us an email at info@deltamembranes.com.

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The Former Magistrates’ Court – Type C Waterproofing

Building Products Index Ltd October 21, 2024 Membranes, Waterproof Membranes, waterproofing Leave a Comment

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Casestudies – Delta Membranes

Technical Drawings (Structural Waterproofing) – Delta Membranes

Structural Waterproofing Product Data Sheets – Delta Membranes

Overview

The Future High Streets Fund (FHSF) is a program initiated by the government aimed at revitalizing underperforming high streets. The Former Magistrates’ Court is set to undergo a significant transformation, becoming a vibrant centre for cultural and creative endeavours. The new design will incorporate diverse workspaces and production areas to accommodate a variety of creative industries. The evolution of this site will not only involve the establishment of innovative working environments but also foster community interaction through entertainment events and social gatherings.

The building, steeped in 143 years of history, has stood unoccupied for the last two decades. This extensive period of vacancy has added another layer to renovation approaches.

Delta Registered Installers, Timberwise (UK) Ltd, were appointed as the Waterproofing Specialists to undertake the waterproofing design and installation of the subterranean space.

The basement, spanning a substantial 70m in length and 6.3m in width, required renovations. The comprehensive works encompass several rooms including a Plant room, I.T room, and Music rooms, each with its unique requirements and design considerations. This project promises to enhance the utility and functionality of these spaces, benefiting the entire establishment.

The waterproofing design was specified around identifying water sources and eliminating them, along with considering the structure design, a continuous system, sequencing, and installation. It also factors in future maintenance and serviceability, all in compliance with the standards set by BS 8102:2022. This standard, known as the Protection of below ground structures against water ingress, is the code of practice that governs the waterproofing industry.

Methodology

For this project a specialist system was required to provide an efficient, compliant, and future proof approach.

Working closely with the developer, Timberwise (UK) Ltd suggested incorporating Delta’s Type C, Fire Retardant, fully maintainable Cavity Drained System.

Delta MS 500 Fire Retardant is a robust Type C, Cavity Drained Protection system, designed to withstand demanding conditions. It holds a Euroclass fire rating of B-S2, d0 (EN 13501-1:2018), an indication of its superior fire resistance. Delta MS 500 Fire Retardant does not compromise on its strength, durability, functionality, or workability. This makes it an excellent choice for applications where both fire safety and structural integrity are paramount.

The ‘Type C’ Waterproofing System serves as a practical waterproofing solution for both new constructions and renovation projects. It incorporates two essential elements: a Cavity Drainage Membrane and a Basement Drainage system. BS 8102:2022 (Protection of Below Ground Structures Against Water Ingress – Code of Practice) defines Type C waterproofing as a protection system. This system manages water that penetrates the outer shell of a building, collecting the water in a cavity created between the exterior wall and an internal lining/wall.

Before the Delta Type C, Cavity Drained system was put in place, all junctions between floors and walls were meticulously attended to. In the context of building structures, ‘junctions’ refer to the points or surfaces where different elements or components intersect. In terms of waterproofing design, these junctions are often perceived as “weak points”. They necessitate thorough detailing to guarantee a robust approach and ensure the effectiveness of the waterproofing system.

The previous flooring consisted of blue bricks, which were replaced by the main contractor. The new design incorporated rebates for drainage channels and sump chambers within the freshly installed concrete floor slab. This upgrade was meticulously planned and executed to enhance the functionality of the basement drainage system.

Before the Delta MS20 floor membrane was installed, a comprehensive flood test was carried out on the basement slab to ensure its integrity and suitability for the application. The flood testing process involves completely filling the basement slab with water and closely monitoring for any leaks or signs of water seepage.

Delta PT, was applied in the vaulted sections located directly beneath the structure. This specific installation permitted direct finishes.

Products Used

Delta Amphibia (lift pit)
Delta PT
Delta MS 500 Fire Retardant
Delta MS 20
Delta Drainage Channel
Delta Dual V3 Packaged Pumping Station
Delta Dual V4 Packaged Pumping Station

Case Study Results

Adopting a future-proof strategy is a proactive way of ensuring a structures longevity. The project was successfully completed within the set timeline and budget constraints. This showcases Timberwise (UK) Ltd’s commitment to efficiency and financial responsibility.

Delta Membrane Systems Ltd Delta Membranes structural waterproofing Type C Cavity Drained System type C waterproofing Waterproof membranes

CPD Approval for Delta Membrane Systems Limited

Building Products Index Ltd July 22, 2024 Membranes, waterproofing Leave a Comment

View the Delta Membranes entry on BPindex

RIBA approved CPD Seminars – Delta Membranes

Technical – Delta Membranes

Video Suite – Delta Membranes

Delta Membrane Systems Limited is delighted to announce their ‘Waterproofing – The Application of Concrete Combinations Type A, B, and C Systems for Continual Professional Development (CPD)’, has received endorsement from the Royal Institute of British Architects (RIBA). This seminar represents a significant chance for industry professionals to broaden their understanding of waterproofing technology.

Delta’s Waterproofing – The Application of Concrete Combinations Type A, B, and C Systems presentation delves into the realm of design specialisations, specifically focusing on waterproofing design. The specialist’s toolbox includes a variety of elements and considerations, all meticulously developed to form a robust solution. This presentation is designed to equip Architects, Designers, and Specifiers with a comprehensive understanding of the factors a waterproofing design specialist considers to formulate a robust solution that aligns with the standards of BS 8102:2022 and BS 8500-1:2023. This deep dive into design methodology offers a unique perspective into the rigorous process behind waterproofing design.

This approval underscores Delta’s ongoing commitment to professional growth and knowledge expansion in the field of waterproofing solutions. We believe this seminar will significantly contribute to your professional development and assist in maintaining your CPD requirements.

In this informative presentation, we are collaborating with SMR Projects Limited, a leader in the field of Type B structural waterproofing design and specifications for below-ground structures. Our focus is to provide a comprehensive insight into two harmonious methodologies. SMR Projects Limited’s expertise in the field fortifies the value of this presentation.

Both Delta and SMR unite innovative products with highly skilled waterproofing design specialists. Both organisations have an in-house team of technical consultants to support our customers by providing comprehensive, reliable, and expert advice, identifying, and mitigating risk and establishing opportunities for added value.

Proudly part of the RIBA CPD Providers Network. Members whose materials are thoroughly vetted by RIBA, notably, this content is worth twice the usual CPD points for RIBA Chartered Architects. For easy access and navigation, all the materials are fully indexed on ribacpd.com.

Delta’s seminars are designed to last for about 60 minutes, this duration includes time for enquiries and discussions. Additionally, attendees will receive an attendance certificate, which allows them to accrue points for continuous professional development.

Delta’s CPD presentations are offered in several accessible formats. Available in person for a more traditional, interactive experience. Alternatively, they’re available as private webinars, which are conducted on digital platforms like Teams or Zoom. For those who prefer flexibility, Delta’s presentations can also be accessed as recorded versions “on Demand”, allowing for self-paced learning.

Enhance your knowledge with our ‘Lunch while you Learn’ program. This engaging initiative allows you to combine nourishment for your body and mind at the same time.

Delta Membrane Systems Limited is a manufacturer and provider of specialist structural waterproofing solutions, covering Types A, B and C waterproofing, combination waterproofing, damp proofing, flood resilience and ground gas protection.

To find out more information about Delta’s CPD seminars, email: info@deltamembranes.com

Fire Retardant Waterproofing

Building Products Index Ltd June 26, 2024 Waterproof Membranes, waterproofing Leave a Comment

View the Delta Membranes entry on BPindex

Technical Drawings – MS Fire Type C Drained Protection – Delta Membranes

Delta Fire Retardant, Type C Waterproofing – Delta Membranes

Comparison Test of Delta MS 500 Fire – Delta Membranes

Fire retardants serve a crucial role in fire safety measures, fire retardant materials possess the unique characteristic to slow down or even halt the spread of fire. This key feature makes them an essential element in fire safety management.

Typically, the concepts of water management and fire safety are not concurrently considered due to their contrasting nature and effects. Though it may initially appear far-fetched, upon closer inspection, it is not as irrational as it may first seem.

Waterproofing refers to the technique of preventing water from penetrating a structure and controlling the flow of water and water vapor within and out of the structure. Type C waterproofing integrates two key elements for optimal functionality: Cavity Drainage Membranes and Basement Drainage Systems. These components work in unison to ensure efficient water management in structures.

Type C Cavity Drainage Membranes tend to be crafted from High-Density Polyethylene (HDPE); a tough, durable plastic material known for its high strength-to-density ratio. This material offers excellent resistance to impact, moisture, and chemicals, ensuring long-lasting performance and reliability. However, polyethylene possesses flammable characteristics. It can easily catch fire under certain conditions, due to its chemical composition. When exposed to certain conditions, plastic can undergo a transformation where it starts to melt and subsequently produce droplets. This occurrence is crucial to consider when dealing with plastic materials.

The Euro class system is an analytical tool that evaluates various fire-related characteristics. These include ignitability, the rate at which flames spread, heat emission, smoke generation, and the likelihood of producing flaming droplets or particles. Products achieving A1 and A2 classification are defined as non-combustible under Regulations.

The Euro class system is designed to unify standards throughout the European Union. It systematically classifies products into seven distinct fire reaction classes, from A1 to F, with F being the most combustible. This classification is determined through a specific test or a combination of tests. This professional framework ensures a consistent approach to product safety standards.

The system offers an extended classification, usually linked to fire response classes D through B. This classification relates to smoke production, ranging from s1, indicating minimal or no smoke, to s3, which signifies considerable smoke. It also categorises flaming droplets or particles, from d0 representing no presence, to d2 signifying a significant amount. This information is crucial in understanding the behaviour and potential hazards of fires.

The Delta MS 500 Fire Retardant is a product that carries the BBA certification. This seal of approval signifies that this fire-retardant waterproofing system meets the rigorous standards set by the British Board of Agrément. The certification is an assurance of quality, reliability, and safety in fire retardation.

Flame retardants play a critical role in enhancing safety measures in homes or buildings. Their primary function is to delay the spread of fire, thereby providing occupants with crucial extra time to evacuate and firefighters with additional time to intervene. Moreover, they contribute significantly to preventing property damage, not only from the fire itself, but also from potential water damage arising from automated sprinklers or fire control efforts by local authorities.

Delta Registered Installer Network

The Delta MS 500 Fire Retardant system, is accessible exclusively via the Delta Registered Installer Network. This network is a trusted source for acquiring this high-quality fire retardant.

Always Happy to Help

Delta Membranes Delta MS 500 Fire Retardant Euroclass fire rating Fire Retardant Waterproofing Type C Cavity Drainage Membranes Waterproof membranes

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