FAQ

Q:	A:
1) Why would I have a garden basement? 2) How long does it take? 3) How much does it cost 4) Is planning permission required? 5) Do I need an existing cellar? 6) Will you convert my existing cellar? 7) How do you charge for your services? 8) What about natural light? 9) What can I use a basement for? 10) Are basements safe? 11) How does the waterproof concrete system work? 12) Why not just have an above-ground extension? 13) What happens to the excavated ground? 14) Can I stay in my home during the work? 15) Do I need to inform my neighbours? 16) How disruptive is the work? 17) How big and how deep can I go? 18) Is it economically viable? 19) Are your basements guaranteed?

1) Why would I have a garden basement?
2) How long does it take?
3) How much does it cost
4) Is planning permission required?
5) Do I need an existing cellar?
6) Will you convert my existing cellar?
7) How do you charge for your services?
8) What about natural light?
9) What can I use a basement for?
10) Are basements safe?
11) How does the waterproof concrete system work?
12) Why not just have an above-ground extension?
13) What happens to the excavated ground?
14) Can I stay in my home during the work?
15) Do I need to inform my neighbours?
16) How disruptive is the work?
17) How big and how deep can I go?
18) Is it economically viable?
19) Are your basements guaranteed?

The advantages and reasons for having a Sub-terranea basement are listed in detail on our advantages page with the main reasons including:

A lack of suitable housing options.
A need for more space.
A desire to preserve views from your existing home.
A need to preserve garden space.
Insufficient site area to accommodate a conventional extension.
Restrictive planning constraints.
The opportunity to maximise the value of your home.

This depends on the size and nature of the project. Generally, once planning and building regulation approval are in place, the excavation and creation of the basement shell takes approximately two to three weeks with the internal fit-out and external remedial works taking a further eighteen weeks.

This depends on the size, specification and nature of the project.

Though building underground can cost more than constructing the equivalent accommodation above ground, recent advances in pre-fabricated building techniques has made basement construction far more economical than in the past.

Economies of scale can be achieved by building larger basements.

To give an idea of cost, a Sub-terranea basement shell together with foundation can be constructed from around £55-£65 per sq. ft. (£600-£700 per sq. m.). This figure excludes architectural design, planning and project management fees. Also excluded are costs relating to ground preparation and internal & external finishing, both of which are dependent on ground conditions and overall project specification.

Generally, yes. But as part of our service we prepare and submit the application on your behalf to the Local Authority. Please refer to our planning page for more information.

Absolutely not. To access most Sub-terranea garden basements, we create an above ground link with stairway down. However, should your property already have a cellar or finished basement level, this can provide an access into your new basement.

No. We specialise in the creation of new-build basement space built to current building regulations and benefitting from a full insurance-backed guarantee. We would only consider embarking on cellar conversion work if it was purely to serve as an access or minor part of a substantial new build project.

We operate using fixed price charges for all of our three levels of service which are paid in stages as a project progresses. We focus on delivering an excellent service, fair and open with an end product which represents value for money to our clients.

Many rooms don't require natural light to perform their function examples being: home cinemas, gyms, saunas and wine cellars etc. For rooms that would benefit from natural light, Sub-terranea designs can incorporate glazed roof lights, structural glazing, light wells or sunken terrace areas.

Pretty much anything. Modern basements are warm, dry and light being just as usable as the rest of your home.

Within the UK, there are over 10,000 new-build basement-related projects constructed each year and if you travel further afield to Germany, Scandinavia, Canada and the States you find that up to 90% of properties have basements. Basements are playing an increasingly important role in creating both safe and usable accommodation. The design and construction of Sub-terranea basements is overseen by a qualified team of design professionals with a project manager assigned to supervise each stage of the construction process. All Sub-terranea basements are designed and constructed so as to exceed current building regulations.

The waterproof concrete used in Sub-terranea basements is a proven patented Swedish system which has been produced and used in the UK for basement construction since 1999. The system has gained certification by the Building Research Establishment in Certificate No 086/01 and has been used by numerous house-builders throughout the UK.

All too often above-ground extensions are restricted, either through insufficient site area, the need to maintain sufficient garden space, planning restrictions or neighbour objections to the height or mass of a proposal. These restrictions don't effect a garden basement and so the advantages can be very significant. Sometimes, homeowners want to increase their home to an extent which simply wouldn't be allowed above ground. A garden basement can bridge the gap between the role of the planning system / neighbour concerns with the needs and wishes of those who wish to extend their home.

As with all projects which involve an element of excavation, including new houses with basements or apartment blocks with underground parking, any excavated material is removed by specialist companies in accordance with current regulations. Where possible, we seek to re-use excavated material for on-site landscaping. Alternatively, subject to Local Authority agreement, we export surplus material to local building projects where the introduction of additional earth is required.

Yes and this is one of the advantages of a Sub-terranea basement, as the construction process is fast and confined to a specific area, separate from your main living area.

It is a good idea to do so. In most cases it is beneficial to explain to your neighbours the nature of your proposal and indicate the projected time-scale of the project. Given the subterranean nature of the proposal, most neighbours should recognise that you are going to considerable lengths to minimise the above ground impact. Following a site survey and depending on the proximity of neighbouring structures, we will advise you of any obligations you may have under Party Wall Act legislation.

We minimise the inconvenience and the most disruptive part of the project (the excavation and shell construction) is completed within a short period of time. Furthermore, the fact that construction work is confined to one area, separate from your property, means that construction will not impact on your main living area.

Structurally, there isn't really any restriction on depth and there are examples of residential basements which go down as much as five-storeys accommodating anything from an indoor tennis court to a 10 metre - high climbing wall. These are quite extreme projects but demonstrate what is possible with subterranean design. Notwithstanding this, there are advantages for having a simple single-storey construction. With regard to overall volume, this, to some extent, depends on the location of your property. In reality, each site will offer different opportunities and we tailor our designs specifically to meet site characteristics and the individual requirements of our clients.

Generally yes. Providing you are extending a property which is in a desirable location, you can expect the value of your property to reflect the added facility that you property would enjoy. Prime locations command prime values and improving your main home represents one of the few tax-free investments you can make. In addition to the economic benefit, there is also a considerable value in terms of the lifestyle benefits which can be derived from creating the perfect home in the ideal location.

Each basement is protected by a 10-year guarantee to the benefit of the client or any subsequent owner of the property. Furthermore, this policy is insured by Guarantee Protection Insurance Limited who, as a body authorised and regulated by the FSA, provide insurance cover for work and guarantees within specialist areas of building and construction.