Waterproofing and Damp Proofing in Housing Management

Delta Membrane Systems Limited’s Technical Director, David J Symes, explores the challenges experienced by housing providers in today’s ever evolving market.

Availability of affordable housing is key to accommodating the United Kingdom’s ever increasing population, not only in building newer homes but in ensuring the restoration and maintenance of existing buildings.

Social housing (Housing Association and Local Authority) provides accommodation for around 4 million tenants in the United Kingdom; the upkeep of these homes is essential.

The Government pledged in April 2017 to unlock Brownfield land to accommodate our housing shortage.  73 Local authorities across the United Kingdom will pilot, under new legislation, registers of Brownfield sites available for housing locally.  These new registers will help house builders identify suitable Brownfield sites instantly, therefore unlocking land for thousands of new homes.

The government has pledged 1 million more homes and to get planning permission in place on 90% of suitable Brownfield sites for housing.

Brownfield land is a word specifically used to describe land which has previously been used for commercial or industrial purposes with suspected or known contamination (such as pollution or soil contamination) or land which has been in close proximity to pollution, hazardous waste or soil contamination.  There are over 66,000 hectares of Brownfield sites in England, one third of these are in the high-growth areas of greater London, the South East and East.

To safely build on Brownfield land considerations need to be given to how the land was previously used.  All Brownfield sites prior to developing will need to be assessed by an experienced environmental consultant before they can be redeveloped. This involves an analysis of the soil, groundwater and surface water through testing for hazardous compounds and will ensure that appropriate measures are taken to reduce identified risks and liabilities.

With continued challenges to build on Brownfield land, technologies have advanced with the introduction of Gas Proof Membranes.

Gas Proof Membranes protect buildings and structures by offering a barrier to dangerous chemicals and ground gases.

Legislations such as Building Standards BS8485:2015, BRE 211.2015, CIRIA 665, CIRIA 735, CIRIA 748 and NHBC Standards have all taken into consideration what protection will be essential for building on Brownfield land.  Gas Proof Membranes can cater for the harshest of Brownfield conditions, protecting against the ingress of Hydrocarbon Vapours, Radon, Methane, Carbon Dioxide, Ground Gas and Volatile Organic Compounds (VOC).

The demand for maintaining the country’s ever growing housing stock is continual.

Preservation of older properties has taken on greater significance in recent years. Concrete structures over time deteriorate.  Properties which have experienced long term exposure to snow, frost, ice and rain will require repair and maintenance.  Concrete repair solutions can repair and protect a structure, whilst managing and controlling corrosion, strengthening the structures whilst offering a cost effective solution.

Multi-tenanted structures will have additional features to consider – besides the frontage, maintenance of balconies, terraces and walkways are vital.   With a wide array of application techniques and detailed knowledge of the causes of deterioration to concrete, a Waterproofing Design Specialist should be consulted to advise cost effective solutions available.

Damp can damage much more than a building’s appearance, it creates unhealthy conditions for occupants. Over time damp will lead to the deterioration of plaster and masonry whilst promoting timber decay.   Inappropriate treatments for damp will cause further harm to older structures.

Damp proof barriers, such as Delta PT , Delta FM and Epoxy Resin satisfy most site conditions whilst offering a sympathetic approach.   Incorporating a damp proof membrane to a structure suffering with damp issues minimises reoccurrence or structural damage.

Additional attention may need administering during the design stage to maintain the aesthetic and structural integrity of the structure/building.  The waterproofing design should offer sympathetic application.

Damp proof membranes offer a further compromise, for when lime renders are inadequate in given situations, for example on below ground structures, on structures that have heavy salt contamination and on structures that cannot be effectively repaired and waterproofed sympathetically and adequately from the outside (for example where there are architectural features that cannot be waterproofed).  Damp proof membranes may be used in conjunction with a chemical damp proof course or as is often the case in listed buildings used as the sole means of providing an effective barrier which complies with BS 6576:2005.

Understanding the basic construction of older buildings differs from that of new ones and this knowledge will assist in avoiding misguided remedies.

A Waterproofing Design Specialist provides expertise in structural waterproofing. Waterproofing Design is a complex task; every construction project is different and will require diversities. A Waterproofing Design Specialist should attend site, undertake site investigations, produce reports and manage documentation in relation to the design, ensuring at all stages that sufficient protection is designed into the project. Getting the design correct prior to construction will save significant costs!

A Waterproofing Design Specialist should have:

• CSSW as a minimum standard of qualification
• Be able to list the principal considerations for a robust waterproofing design
• Offer knowledge on waterproofing systems available
• An in-depth understanding of BS8102:2009 and its requirements
• Desk top study & risk assessment knowledge – these should form part of any Designers Report and Waterproofing Design
• An understanding of sources of water (such as how it flows through the soil and interacts with the structures)
• Structural knowledge
• Knowledge of Ground Gases
• Geotechnical knowledge (to be able to understand the implications of a soil report)
• The ability to produce a Design Report, Method Statements and Waterproof Design drawings.

Delta Membrane Systems Limited offer CSSW training and examinations at their fully functional training facilities in Epping Essex, hosted by the PCA. All of Delta’s Technical Team are CSSW qualified surveyors and registered to the “Waterproofing Design Register”.  Our Technical Team would be delighted to help with your waterproofing designs/projects.

Our article can be seen in Housing Management and Maintenance.