Cavity Drainage Membranes as a Waterproofing Solution

Cavity Drainage Membrane

Cavity Drainage Membranes as a Waterproofing Solution

Cavity drainage membranes are primarily used as part of a water management solution where water is directed to a suitable drainage system or a sump for future discharge. These systems are particularly effective in remedial applications where access to the source of water ingress is difficult.

Another significant advantage is a possibility of application over existing substrates (including those of questionable quality) with a minimum of preparation and disturbance. Also, cavity drainage membrane systems do not result in significantly increased stresses in the substrate.

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 that penetrates the external shell of a structure, by collecting this water ingress in a cavity formed between the external wall and an internal lining/wall.

A ‘Type C’ Waterproofing System is a maintainable waterproofing solution for new-build basements, refurbishment and retrofit projects. The Type C System comprises of two key components, a Cavity Drainage Membrane and Basement Drainage system.

It should be noted that using a combination of Waterproofing Types A, B, and C can offer optimal structural protection against water ingress.

Developing a robust waterproofing design can be a challenging task. Therefore, it is recommended that a Waterproofing Design Specialist is appointed as part of the design team at the planning stage. SURFASOLOGY offer waterproofing design services – Certificated Surveyors in Structural Waterproofing with an extensive waterproofing experience. 

In addition to this, we carry a Professional Indemnity Insurance to provide you, our client, with certainty and peace of mind.

We are delighted to announce that SURFASOLOGY is working closely with Delta Membrane Systems, which provides us with an unlimited access to latest technological developments and world-class solutions.

*Image supplied courtesy of Delta Membrane Systems Limited – www.deltamembranes.com

Signature Product

MS 500 Fire Retardant Cavity Drain Membrane

Type C protection system that combines the benefits of a comprehensive waterproofing system with Euroclass fire retardant protection.

Delta MS 500 Fire Cavity Drainage Membrane

*Image supplied courtesy of Delta Membrane Systems Limited – www.deltamembranes.com

Delta MS 500 Fire Retardant is a new 8mm studded Type C, Cavity Drainage Membrane that has been manufactured with DELTASAFE, a new innovative fire-retardant property which enables Delta MS 500 Fire Retardant to achieve a Euroclass rating of B-S2, d0 in accordance with EN 13501-1:2018.

This Fire-retardant High-Density Polyethylene (HDPE) cavity drainage membrane has an 8mm studded clear profile. Suitable for use on the internal faces of walls and floors as a water management system for the protection of below ground structures against the potentially adverse effects of ground water ingress.

Fire 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 a building 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. Find out more here.

Fire Retardant Waterproofing

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.

Read the full article here

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Delta CPD Seminars (RIBA Approved)

  • BS 8102:2022 – Waterproofing Below Ground Structures
  • Waterproofing Existing Basements
  • Structural Waterproofing Podium Decks and Buried Roofs
  • Flood Resilience
  • Cold Applied Waterproofing
  • Waterproofing – The Use of a Concrete Combinations Type A, B and C

Delta Membrane Systems Limited, a leading manufacturer and supplier of waterproofing systems in the UK, recognises that professional development is a continuous journey.  They are dedicated to assisting you in advancing your career.

Delta’s team of technical specialists regularly provides six RIBA Approved, double points CPDs to architects, engineers, and construction practitioners throughout Ireland.  For reserving a spot in any of Delta’s RIBA Approved seminars, a direct email can be sent to [email protected] (quoting Surf1 – CPD) or head to their website www.deltamembranes.com/training-categories/riba-approved-cpd-seminars/.  The seminars are an excellent opportunity for professionals to expand their knowledge in a variety of subjects.

Cavity Drainage Membrane

SURFASOLOGY offer comprehensive consultancy services supported by the Professional Indemnity Insurance. These services include:

  • CSSW Waterproofing Specialist Services
  • In-House Design Support
  • On-Site Surveys 
  • Technical Reports
  • Independent Expert Witness

For more information, please visit our website or give us a call on 01 832 1005.

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Jamie Smyth

Quantity Surveyor

Jamie brings our team a wealth of knowledge in project costs management, from the cost and risk analysis to the preparation and submissions of tenders and valuations.


Jamie has spent over ten years working as a Quantity Surveyor with a background in the construction industry (from residential build to pharma projects). He has been involved in all aspects of construction collaborating with small builders and large contractors on projects of varying sizes and scale. All this contributed to his thorough understanding of the requirements and priorities when performing his tasks of a Quantity Surveyor.


On a personal note, Jamie enjoys playing soccer and is a true golf fanatic. He enjoys travelling and fine dining.

Dear Customers,

High performance Resin Flooring Solutions by Sherwin Williams are now available from SURFASOLOGY.

We offer seamless, resinous flooring systems that combine durability and design aesthetics. The product line covers a multitude of industries and areas of application, such as industrial & manufacturing, pharmaceutical & healthcare, food & beverage.

Are you currently working on a flooring project and looking for a solution? For advice and guidance, please contact us on 01 832 1005 or [email protected].

Your SURFASOLOGY Team