Basement and Cellar Conversions

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There are various methods to help create a prefect living space by performing a basement conversion. Cementious tanking and epoxy systems can be used to achieve a conversion but ideally cavity drain membrane applications far exceed performance and potential lifetimes.

Which should I choose?

Cementious systems / epoxy systems are great option for when areas are limited and drainage cannot achieved.

Why use these options?

This is a single component, polymer modified cement "tanking" system for walls and floors. It provides an effective way to damp proof brickwork, concrete or any cementitious substrate.

Is every application the same?

Dependant on the surface the application needs to be correctly prepared. This includes:

• Surfaces being free from loose materials.

• Floors by direct application.

• Wall applications should be applied within a sandwich approach between the sand/cement render coats.

Please note Fillet Seal is a pre-packed, cement based and polymer modified product for use to form a "floor to wall junction seal" during waterproofing works when using cementitious slurry coatings and renders. Fillet Seal helps to ensure a smooth transition between horizontal and vertical surfaces which minimises the risk of leaving gaps or holes unsealed during the waterproofing works.

Which properties would benefit from having this treatment?

Basement areas, with outer external ground levels often higher than levels internally, can result dampness by lateral penetration.

Additionally with high cost properties the recommendation of such treatments are considered very cost effective within cellar areas if they are to form part of the living space. In order to protect this area this would include internal remedial structural water proofing and associated damp proofing works and re-plastering.

What happens during the DPA inspection?

The DPA surveyor will investigate the area specified, and conclude a number of options for the property to eliminate dampness. Dependant on findings a variety of options may be provided including a cementatious type chemical vertical membrane or ‘tanking’ application, or perhaps a cavity drain membrane system, which is becoming more popular, involving less initial destruction and preparation works.

What happens when the work is taking place?

When providing the application a series of schedules will take place as follows:

1. Removal of plasters or renders The cementatious systems normally requires plasters and renders to be removed back to the original masonry, and it may also be necessary at the same time to consider incorporating within the cementatious system (or the cavity drain membrane system) a chemically injected damp proof course depending on the external ground levels or adjoining property levels which will be taken into consideration by the DPA surveyor during his inspection.

2. Application of render coat Generally cementatious systems require a render coat of washed sand and cement to be applied to the prepared clean brick or stone masonry with the cementatious membrane applied to the surface of the new render as per the manufacturers recommendations in a minimum of two coats (green on green) with suitable overlap detailing between the vertical membrane of the walls with any proposed horizontal membrane depending on floor construction or proposals.

3. Instalment of sump pump (situation dependant) The cavity drain membrane systems provides an alternative to conventional cementatious tanking systems. Cementatious systems work by holding the water back within the wall structure, the cavity drain membrane system works on the principal of allowing water to continue to penetrate the structure, but controlling the dampness in the air gap and diverting it to a suitable drainage point. Depending on circumstances this could involve the installation of a suitable sump pump which may incorporate a backup and failure warning system. This system does not allow pressure to build up against the internal construction, and the air gap behind the membrane allows the structure to breath ‘and to some extent dry’. Membranes are of plastic, type, and are fixed to the masonry using special damp proof seal plugs, sealing tape and rope, with overlap detailing at junctions, which involves minimal preparation required to the substrate. It is often a requirement when installing cavity drain membrane systems however as mentioned earlier, to incorporate within the programme the installation of a drainage sump pump system which may include a backup pump and failure warning alarm.

The DPA Cavity Pump Systems

The cement based systems including sika and cementitious applications should only be used on cellars and basements that are not at risk of flooding. In the event of this context the most beneficial option is the application of a DPA membrane system.

Water Based Epoxy Coating

• Two coat system comprising primer and top coat.

• Epoxy based waterproof coating for walls and floors.

• Suitable for use as a damp proof finish.

• Water based formulation safe for use in confined spaces.

 Product can be used as a damp proof membrane where none exists or the original has failed, or as a tanking layer in a "sandwich" construction between sand and cement renders. It is also suitable for use as a durable finish.

Product can be applied to most building substrates and to damp surfaces. When fully cured product resists petrol, oil and mild chemicals. Application can be by brush or roller.

What is a water vapour suppressant?

It is a solvent free, two part epoxy resin coating, typically used as a surface damp proof membrane and a water vapour suppressant.

This a great option as a water and water proof barrier for situations beneath raised access floors, in plant rooms and bundled areas.

It is also a great choice for application on damp surfaces, such as sand/cement and cement floors subject to rising damp or containing residual construction moisture. Product can be used as a general purpose coating for surfaces subject to foot and light wheeled traffic. Product can be applied using a brush or medium pile roller onto sound, clean surfaces.

NB: New concrete subfloors or sand/cement screeds should be left for a minimum of seven days to cure before applying this product.

Want a Dry Basement or wish to create greater living space? Why not contact us today for a highly competitive quotation.

Our principle members can provide extensive Basement Conversion services in London and the South East. We are the only Association that offers a full Basement Conversion service as follows:

• Initial survey and design
• Construction ready drawings
• Planning permission
• Geotechnical Surveys
• Party Wall Surveys 
• Underpinning calculations 
• Engineering drawings 
• Building control services 
• Supply of membrane products 
• Supply of contractors 
• Contractor supervision 
• Provide full Basement indemnity guarantees for ten years

All the above comprehensive services are conducted by our principle members (In London and South East only). 

We are the only Association whose members are qualified to undertake such technical skills. This service is unique to the DPA and saves thousands of pounds to clients budgets. We conduct on average 20 basement conversions per month. 
 

Requesting a survey is a simple process, call us free on 0207 118 0039 or request by Clicking Here

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