Frequently Asked Questions

Basement construction isn’t the type of project that most take on regularly so we are sure you have questions about what is involved and how we work. We hope to answer some of the questions we are most often asked here.

If you have any questions that aren’t answered here please call us on 01727 370 874, email us at or use our contact form to get in touch, we’ll be happy to answer any of your queries.

Where do you operate?

We’re based in St Albans and offer our services to St Albans, London and the surrounding area.

Why choose St Albans Basement over other companies?

We pride ourselves on working with professionalism, integrity and attention to detail. We are awarded Chartered Status by the Chartered Institute of Building, this means we’re bound to a professional code of conduct and gives recognition to the high standards we work to.

We’re the only basement construction specialist with Chartered Building Company status in the UK, recognition of the high level of quality and value for money we deliver throughout out projects.

What types of projects does you take on?

We construct new basements, including extension of existing spaces, refurbish existing cellars. We also provide traditional building services including extensions, renovations and refurbishments.

We manage many of our projects from start to finish, providing and overseeing architectural design, engineering, planning, fit-out and interior design.

What types of clients do you work with?

We work with homeowners and also offer services to industry professionals including architects and engineers.

Do you take on building work other than basements?

Yes, we offer above-ground works, including complete renovations and extensions and are happy to work on projects without a below-ground element.

How much will my project cost?

The cost of basement construction or other forms of building work varies from project to project, depending on the size and complexity. We can give you a guideline estimate to help you determine the feasibility of your project.

How long does basement construction take?

Construction time depends on the extent of work carried out but generally speaking a standard basement conversion takes between 12–24 weeks.

Do you offer a full basement package?

Yes. We can provide either the full basement package including interior finishes or just shell and core – basement excavation, underpinning, structural slab, waterproofing and floor screed.

See our services page or contact us for further information on the services we offer.

Do I need to have an existing cellar?

No, we can create basement spaces where there is no existing cellar.

Can I stay in my property while work is in progress?

Yes, our construction method enables formation of your basement space whilst you live in your property. We create a means of access within your front garden and ensure our hoarding secures this area.

Do I need planning permission?

Planning permission is required to convert basements into habitable living accommodation, or when constructing features that change the external appearance of properties.

Do I need to advise my neighbours?

Yes, you will generally require a Party Wall Award under the Party Wall Act 1996 if your work requires fixing into/altering a party wall and/or you are excavating within 3m of a party wall.

I’m concerned about disruption in my neighbourhood, can this be minimised?

We keep clean, safe sites and make works as unintrusive as possible. Our hoardings are tasteful, on-street work is kept to the minimum possible and we only work within hours specified by local authorities.

How do you waterproof basements?

We carry out an analysis through visual inspection, inspection of drawings (where applicable) and potentially intrusive investigation i.e. trial hole excavation.

Typical waterproofing details consist of a membrane system with associated sump and pump and/or Caltite waterproof concrete forming part of the basement structure.

What insurance and guarantees do you provide?

Our company insurance is comprehensive and designed specifically for the works we carry out. Details are available upon request.

We are able to offer a 12-year insurance-backed latent defect cover on our structural works. Waterproofing works are also covered by a 30-year product guarantee and we provide our own company guarantees.

There’s further information on our insurance and guarantees on the site or you can contact us to find out more.

Can I pass insurance and guarantees on to purchasers of my property?

Following construction we will provide you with an Operation & Maintenance Manual which contains insurance and guarantee documentation, this should be given to purchasers of your property.

Do you provide a written contract?

Yes. When working directly with a client we provide our own contracts, alternatively on larger projects we are usually party to a contract administered by the project architect.

Can I see a completed home extension?

Yes, we encourage you to see our work. Please contact us to arrange a site visit.

Do you provide references and project visits?

Yes. We can provide references from clients and industry professionals alike. We can arrange site visits to our ongoing projects on request.

Do I need to arrange Local Authority permissions?

An architect will need to arrange Local Authority permissions, draw up plans, make applications and liaise with the council.

How long does it take to get planning permission?

The statutory period for a council to decide upon a planning application is 8 weeks. This is the same for planning permission and lawful development.

Do I need to apply for building regulations for my work?

If you are carrying out a basement extension, traditional extension or internal renovation, building regulations will be required.

How long does it take to draw up plans for my extension?

It takes approximately 2-4 weeks to conduct the survey, draw up the plans and get them registered with the local authority.

How quickly can work progress?

Works can generally commence within 2-4 weeks of all permission being obtained and your instruction.

Who supervises the work?

A project manager will be appointed to your project along with a site foreman to manage the day to day works as they progress.

Want to know more?

Call us on 01727 370 874, email us at or use our contact form to send us a message.