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Basement Conversion & Damp Proofing

Space is at a premium in London and basement construction is on the rise. Many districts in London forbid extending a property upwards but allow extending it downwards via the basement. Basement conversions are a great way to create extra living space in built-up areas where outdoor space for extensions is limited. You will not only add so much more habitable space but also significantly increase the value of your property.

One of our main building services is basement conversion, specialising in designing, excavation, construction, new build, waterproofing, fit-outs and all other basement conversion requirements.

Our team members have the skills and experience that general builders don’t. We undertake all the works for you, both above and below ground such as kitchen extensions/side returns, loft conversions and even whole house refurbishment. However, if you have a current team we are pleased to undertake only the specialist groundworks if you wish. We will include all excavation and removal of soil, reinforced concrete and steelworks, together with all temporary and permanent propping works, followed by the waterproofing and drainage.

One of the most critical aspects of a successful basement is to make it damp proof and there are different ways to make it so. In our projects, we use two main methods of damp proofing: 

  • Cavity drain membrane systems. These are usually used for larger areas or complete basement conversions. They are strong, versatile, studded Polyethylene membranes that we fix to walls and ceilings, using special waterproof fixings, loose laid over floors and joined together, creating a complete system. In principle a cavity drain membrane system allows moisture or running water to travel behind the membrane within a controlled drainage system. The moisture then is directed into special drainage channels and into a pump station, to be pumped out to a designated place. A cavity drain system requires minimal preparation and disturbance to an existing substrate. When the installation is complete, insulation can be installed and the membrane can either be dry-lined or plastered directly onto, creating new, warm dry rooms for years to come.
  • Structural waterproofing (Tanking). This method of damp proofing, commonly known as tanking, can either be used on small localised areas or complete basements or cellars. It comprises of a special cementitious, waterproof system that is applied to structures that are below ground, to block the incoming damp. Once the old plaster has been removed and the walls are prepared, we apply a gauged waterproof scratch coat of render. Once this has dried, we apply three slurry coats of the structural waterproofing system, allowing each coat to cure before applying the next. Another waterproof coat of render is then applied, prior to plastering to a smooth finish.

As a registered Cavity Drain Membrane System installers, all our works are covered by a 30-year product guarantee giving you absolute peace of mind. We are highly skilled with broad experience in the construction industry and we can also assist you with other legal requirements such as:

  • Planning permission. For basement excavation or dig out, planning permission is required, mainly to any means of escapes or light wells that are to be installed. This is because they affect the exterior appearance of the property. Fortunately, planning permission is almost always granted as it does not change the exterior appearance of the property above pavement level.
  • Building regulations will be required if you are changing the basement to habitable living space. This includes the means of escape, the thermal values, etc. If it is simply to be used for storage though, this may not be required. We can assist you with building regulations and planning permissions. Please contact us and we will be happy to visit and discuss your options.
  • Party wall agreements. A party-wall agreement is a legal agreement with your neighbours to commence building work which affects the jointly owned wall between the properties.

Feel free to contact us on

020 8579 2832

or drop us an email 

contact@agmaconstruction.com

and we will be happy to visit and discuss your options.

Why choose us?

You can rest assured that Agma Construction Ltd is the correct company for you. With over 10 years of experience in the construction industry, we have references from numerous existing and previous clients, architects and engineers we have been working with, who will put your mind at ease. We will go that extra mile to make sure there are no stones unturned and that you, the customer, are happy with every aspect of the job from start to finish.