Frequently Asked Questions:

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Why should I build a basement?

It is an effective way of gaining more space without the cost and hassle of moving home, and can add significant value to your property.

What do most people put in their new basements?

What most London properties lack is sufficient living space and a basement conversion can provide a complete new floor level, providing multiple rooms that can be used for any purpose. From a Media Room, Playroom, Games Room, Gymnasium/Sauna, Guest Bedroom, Nanny Suite, Swimming Pool, Utility or a combination of any of these – the possibilities are endless.

Must there be an existing cellar?

No, in most instances we can construct a basement where there is no cellar.

How much head height can I have?

We consider 2.4M (8’0″) to be a minimum comfortable ceiling height, but in most cases it can be as high as you want, although, of course, this will affect the cost. 

Is it possible to create a basement of more than one level?

Yes, although this is dependant upon ground conditions and the location of the property

Can I live in the property while the building works are in progress?

The majority of our clients remain in their homes during their basement conversion. As with any construction work, there will be some noise and debris but this is reduced through covering of exposed areas and only working during normal office hours.

We excavate in the front garden, where the window and light well will be and then construct a secure covered hoarding around the area.  Our ability to tunnel under the property means that you are able to remain in residence with minimum disruption.

Do we have to use your architect or engineer?

NO, we are happy to work with the client’s architects, engineer or interior designer. Alternatively we can supply or suggest a number of potential professionals to you.  We can simply provide a structural shell or handle everything from the design and planning to the construction and fit out.

Does a basement conversion require planning permission?

Basement planning permission is required when forming lightwells and creating new habitable space with basements. If you have not employed an architect then we are happy to take you through the planning stage. 

I live in a conservation area, would this prohibit me from having a basement constructed?

Very rarely, although it may have some affect on the design of the lightwell.

Do I need to advise my neighbours about the proposed basement construction?

Yes, Party Wall awards are generally required and we will arrange for a Party Wall Surveyor to act on your behalf.

Is it possible to take a basement construction beyond the footprint of the house?

Yes, we can continue the construction of a basement below front or rear gardens, including paved driveways, ground conditions and permissions allowing.

How long does a basement conversion take?

Once you get planning permission and the party wall awards ar in place the dig should take approx. 3-6 months.  Dependant upon the size of the area and the extent of the works.

Are there any guarantees on the work?

Lowndes Lumb are able to offer 12 year insurance backed latent defect cover in respect of structural works. The waterproofing works are also covered by our 10-year guarantee and the cavity drain membrane waterproofing system is covered by a 30 year product guarantee.

What kind of insurances do Lowndes Lumb carry?

We carry the very highest level of insurance, details available upon request.

Do I have a choice of fittings and finishes?

Yes. As part of the design phase we will endeavor to agree a specification for all of these items up-front.  Our experienced fit-out teams will ensure that your new basement is carefully finished to your spec.

How much will it cost?

The cost will depend on your precise requirements and specifications. As a rule of thumb, structural costs are generally £1,700-£2,500 per m² and fit-out costs are around £750-£800 per m².

Areas we cover

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