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The Basement Conversion Process

Full Basement conversion, London

Our initial meeting is at your home to discuss your requirements, intended use for the basement, and to do a preliminary check of the area. We supply a quote based on your design ideas and the survey of your home.

We can provide architect details based on your requirements who will create detailed drawings for planning consent and for our construction team to follow throughout the project. As part of the pre application planning process we recommend carrying out any necessary investigations, such as tree reports, noise surveys, and flood risk assessments to ensure that your planning application is completed in full. This saves time during the planning process and ensures that we are prepared for any eventualities once we begin excavating.

Basement Design

We work with experienced architects as well as structural engineers who will ensure your basement is totally safe and structurally sound. We can offer any level of design input you require either by our experienced design partners or input from ourselves based on past experience. We would be very happy to work extensively with your appointed professionals if you would prefer.

Basement Tanking

Basement tanking (or waterproofing) involves applying waterproof coating or membranes to the outside of your basement conversion to keep it dry and comfortable. This doesn’t just prevent damp or mould from developing – it actually ensures that your basement is structurally sound. If a conversion is improperly waterproofed, the brick work can decay and the interior can also be damaged, in a worst-case scenario this can involve flooding.

Installing Waterproofing

With a wealth of experience, our team is confident in the materials and techniques that they use to tank basement conversions. In some instances, a pumping system is required while excavating and building the exterior of the basement to keep the area dry and remove ground water, grey water, or effluent. Once the tanking has been installed, these pumps may no longer be necessary and the membrane system will prevent water from filtering through into your basement or damaging the exterior walls.

Keeping the Basement Waterproof

In some instances, we have to install a permanent water pump if natural drainage isn’t possible. The pump will remove water that accumulates in a designated pit and redirect it to a main drain. These pumps are run off the main electricity supply and have a battery back up in case of a power outage – they should not have a significant impact on your electrical bill.

Guaranteed Work

Our quality and product guarantees extend to our waterproofing systems, which are also guaranteed by the manufacturers. We used the same suppliers for many basement conversions in London, and only ever use proven and tested products for such an important aspect of the build.

Party Wall Agreements

Party Wall agreements are an essential part of planning your basement conversion. Due to the architecture in Central London, it’s almost always necessary to put a party wall agreement in place – most properties require two to ensure that both adjacent neighbours are protected.

The Party Wall Act 1996

There are two main parts of the Party Wall Act that are relevant to basement conversions ; Section 2 applies to work that is done to a wall (including underpinning, cutting away projections, and downward extensions), while Section 6 applies to excavation work within 3 or 6 meters of a shared wall. The statutory notice period is 1 month, but it is best to tell your neighbours as soon as possible to ensure that your party wall agreement doesn’t hold up work.

Putting an Agreement in Place

Once you have presented your neighbour with a notice, they can either consent to the works, or dissent and appoint a surveyor. If a surveyor is appointed, you will be responsible for the fees and not the dissenting neighbour. This process can take several months, so our recommendation is to always approach your neighbours in person and discuss this in person before presenting notices or appointing surveyors. In most instances, an amicable agreement can be reached quite quickly.

We work with a highly experienced party wall surveyor and can provide a referral if necessary.

Changing Your Basement Design

We recommend that you approach your neighbours to casually discuss the work before the design process is completed – if a surveyor is appointed you may need to rethink certain aspects of your design and pay for it to be amended. For example, if your underpinning is thicker than the wall above it, it will restrict your neighbour’s use of their own basement space and this will need to be amended (surveyors will not accept these designs). While our team work to pre-empt any issues and create a basement conversion that does not encroach upon your neighbours’ space, some objections can not be predicted.

Basement Conversion Staircase, London

Wine Staircase, Basement Conversion, London

Basement Fit Outs

The fit out is the final stage of creating your basement conversion, and essentially means making the interior space habitable. This step is completed by our team of builders, decorators, and can involve an interior designer if you prefer, that we would be happy to work with.

Our design team will discuss the fittings and finishes that you would like well before the project nears completion, and most aspects of the final finish will be agreed during the design process. This ensures that we have the correct information for the installation of stair cases, addition of power sockets, and have information about varied flooring materials, raised platforms, or items that are built in to your basement conversion.

Pre-Decoration Finish

The fit out is completed before the final decoration to create a secure shell space within your new basement. A sub floor is created with screed to create a level surface, and under-floor heating is added at this stage if it is something that was specified in your design.

Electrical work is incorporated before it is plastered – our design team recommend that you decide on the positioning of your electronics before this phase so that we can conceal as many wires as possible.

Once the flooring and walls have been completed, our carpenters and joiners hang doors, lay flooring, and add decorative finishes. Bathrooms, kitchens, and entertainment rooms will receive a second fix at this stage before the decorators begin their work.

Fit Out Documentation

Hatch Construction’s fit outs are completed to the highest specifications, and come with a number of guarantees on our work, your satisfaction, and the products that we use in your basement. As part of the final completion, there are a number of certificates and documents that need to be completed for the basement to be signed off.

The documentation includes:

  • Electrical Certificates
  • Gas Safety Certificates
  • Drainage layouts
  • Structural guarantees
  • Plans for the building
  • Technical documents for equipment installed
  • Manufacturers’ instructions and guarantees for appliances