Our Projects

Our cellar conversions, retrofits and new build basements have transformed many homes, creating valuable extra space — even in areas where extending traditionally would be impossible.

Interested in finding out more about how we work? Arrange a visit, contact us to find out more on 01727 370 874 or hello@stalbansbasement.co.uk.

Basement Construction & Single Storey Extension – Watford

  • Front basement lightwell
  • Stairway and living room
  • Bathroom
  • Basement stairway and shower room

Our clients required flexible space for their growing family and wanted their children to enjoy their own independence in larger bedrooms within the newly created basement space. Moving was deemed too expensive and their children were settled in the local school just a few minutes’ walk away.

The requirement for more space was further achieved with an extension on the ground floor to create a functional family sized kitchen with a central island providing working, dining, and flexible space. The kitchen was integrated seamlessly with the garden to create alfresco dining whilst a series of rooflights flooded the space with natural light all year round.

At the front entrance of the property a patterned black and white Victorian walkway was created guiding you to the new spaces at the back of the house where we also succeeded in incorporating a utility room and much needed ground floor WC!

The basement includes two bedrooms and a shower room. The bedrooms are each served by ample natural light from large lightwells at the front and rear of the property. Underfloor heating was installed throughout to create a warm ambience finished with wooden floors throughout, and tiles in the modern bathroom.

A unique feature of this project was the installation of art print deco panels into the basement shower room and refurbished first-floor bathroom to create a unique, interesting, and fun-filled décor.  

Type Info
Project Basement Extension, single-storey extension, and internal alterations
Area 90m²
Project Time 6 months

New build basement shell – St Albans

An experienced St Albans builder appointed us to provide the basement shell to a new build house. The builder required St Albans Basement’s technical expertise to deliver the substructure and handover ready for the follow-on works.

The basement was waterproofed by a drain cavity membrane system combined with Sika waterproof concrete, both fully guaranteed.

We provided the builder with peace of mind and delivered the expertise required from below ground. We de-risked the project for the builder enabling them to progress with the new house construction, which is what they do best!

Type Info
Project New build basement shell
Area 200m²
Project Time 14 weeks

Cellar Conversion – St Albans Old Conservation Area

  • The extended kitchen now has an infill glass roof and cantilevered bi-fold doors to create a functional room filled with light and space.
  • The cellar is entered via a newly-created staircase in the open plan living area, blending the new with the old and creating a feature from the bespoke ironmongery.
  • The newly converted cellar with increased head height is a perfect home office and offers the flexibility of a guest bedroom when needed.
  • The modernised bathroom is now a calm and relaxing space.

Situated within the old conservation area, where space is at a premium, our client’s brief was to create an open plan feeling throughout, and to make full use of the property’s footprint by converting the disused cellar.

The open plan living room now has a bespoke staircase which provides access to both the upper and lower floors of the property. A fire suppression system gives peace of mind that the new living spaces, both above and below ground are fully compliant with building regulations and fire safety rules.

The newly created multi-functional space in the cellar, which was once a disused storage area, now has full height ceilings and is ideal as a home office, media room or an occasional guest bedroom.

The rear ground floor was extended with an infill glass roof and the kitchen was reconfigured bringing the outside space in for alfresco dining. Cantilevered bi-fold doors were added to enjoy uninterrupted views of the landscaped rear garden creating a space perfect for entertaining.

Upstairs the bathroom was fully refurbished to create a relaxing and calm space. A feature herringbone tiled wall complements the double ended roll top bath and freestanding floor mounted mixer tap. A frameless shower cubicle is in keeping with the overall modern, minimal ambiance. 

Type Info
Project Cellar conversion, single-storey extension and whole house renovation
Area Whole property - 170m²
Project Time 6 months

Basement excavation, shell and core – Trumpington, Cambridge

A Cambridgeshire developer appointed us to construct a 200sqm basement shell and wider house foundations. 

Working alongside the developer’s construction team, we provided specialist basement experience to complete the substructure works.

The completed space will be used as a gym and wine cellar. Application of external waterproofing was requested to allow the client to finish the basement with an industrial look.

Type Info
Project Gym and wine cellar
Area 200m²
Project Time 16 weeks

New Build Basement – St Albans

  • The newly created basement is entered via a custom-made staircase, in keeping with the original period of the property, with bespoke mouldings and cornices.
  • The newly-built basement has a bright, airy feel with high ceilings and an external window to let in fresh air.
  • Making the most of areas without natural daylight, the utility room has plenty of storage and functionality.
  • The spacious, bright bedroom within the basement has another external window to allow fresh air to circulate the space and natural light to flood in.

This beautiful period home in the heart of St Albans gains plenty more space for our client’s growing family.

A newly-excavated basement runs the full length of the property, blending seamlessly with the existing house. Sympathetic renovation ensures new space complements the existing building’s character, and that it complies with St Albans’ stringent conservation area rules.

To create an additional 120m² of space, we excavated beneath the original house and added a single-storey rear extension. The property is now a 5-bedroom, 4-bathroom home with front and rear light-wells adding natural daylight to the new floor.

The basement has created space for a generous double bedroom, bathroom, utility room, and a substantial multi-use space which the client uses as a second living area, home office, playroom, and gym. On the ground floor the property now has a brand-new open plan kitchen and dining area, opening on to the rear garden.


Type Info
Project Double bedroom, bathroom, utility room, home office, playroom, gym
Area Basement: 90 m², Whole Property: 30 m²
Project Time Basement: 7 months, Property: 9 months

Basement excavation, shell and core – Welwyn

A private home owner commissioned us to undertake the basement, substructure foundations and ground floor construction of their project.

The basement waterproofing was a drain cavity membrane system combined with Sika waterproof concrete, both fully guaranteed.

We delivered the substructure works ready for the client’s new timber frame home to sit above, working closely with the client’s design team to deliver the basement’s shell  ready for the client’s future use — to include a golf simulator.

Type Info
Project Basement excavation, shell and core
Area 95m²
Project Time 16 weeks

Basement excavation – Clarence Park, St Albans

  • The warmth of the natural materials used created a welcoming hallway feeding the new spaces created.
  • The adjacent alleyway permitted the integration of high level windows providing an added touch of natural light to the inner rooms.
  • A sympathetic lightwell was incorporated to the front fenestration to to provide natural light to the space and fire escape provision.
  • The valuable parking space was retained by adding a bespoke reinforced lightwell grill suitable for parking on in necessary.

Overlooking the popular open spaces of Clarence Park, within a short walk from St Albans City station, our client’s property was ideally situated.

Originally a cramped disused cellar, St Albans Basement was commissioned to excavated beneath the original property to create an additional 50 of living space. The new extended basement now contains a bathroom, utility room, bedroom and multi-use room.

The project was sympathetically executed to retain the character of the upper floors of the house. Our client favoured the warm finish of natural wood and the bespoke staircase was commissioned to blend the existing house with the new space.

Lightwells were added to the main rooms to ensure the property benefitted from natural light. Reinforced lightwells were commissioned to ensure that our client retained use of their off street parking, a rare gem in St Albans.

Type Info
Project Bathroom, utility room, bedroom and multi-use room
Area 50m²
Project Time 4 months

Basement Construction – St Albans’ Old Conservation Area

  • The double-storey staircase adds to the feeling of space and light with bespoke ironmongery and carpentry.
  • Light and airy basement bedroom with an external window to let in fresh air. The room also has floor-to-ceiling bespoke cabinetry to maximise storage.
  • Making the most of areas without natural daylight, the utility room has plenty of storage and functionality.
  • The basement wet room features underfloor heating and we managed to create an external window allowing fresh air to circulate and natural light to flood in.

What was a small two-bedroom character cottage in the heart of St Alban’s Old Conservation Area has now been sympathetically transformed into a four-bedroom, three-bathroom family home.

In a space restricted area where every inch of room matters, our brief was to maximise and modernise the living space without compromising the character of the property to create a beautiful family home.

We excavated beneath the original property and added a double-storey rear extension. The project created an additional 1000 sq ft. creating a four-bedroom, 3-bathroom property with a rear full depth light-well.

Our client has the benefit of living in a dynamic period property with the advantages of a modern-day specification including cinema room, bespoke wine storage, underfloor heating, a wet-room. Other features include large rear Crittal doors in the family kitchen leading to the landscaped rear garden, creating an environment perfect for summer entertaining.

Type Info
Project Basement excavation, double-storey extension, complete house renovation and rear garden landscaping
Area Basement: 80m², Whole Property: 180m²
Project Time Basement: 6 months, Whole Property: 10 months

Basement Construction – St Albans

  • The master bedroom features an en-suite with wet room
  • The master bedroom features French doors leading out to a light well with a courtyard area
  • The third bedroom serves as a nursery
  • Above ground, the kitchen and dining area have been created to bring maximum daylight through the roof windows

This Victorian end-of-terrace property situated in St Albans within a conservation area provided little opportunity to extend externally. We were tasked with turning its ground floor and basement into a home suitable for a growing family, with substantial living space, a premium finish and modern features.

Extending the property created two new double bedrooms, one with en-suite and a full-length light well, a nursery and also provided a family bathroom. Above ground, we extended and renovated the ground floor, turning the property into a space that’s perfect for a growing family.

The home is now a modern, light-filled family space with many premium features including underfloor heating, a wet room and bespoke storage. The kitchen has a bi-folding aspect to the rear landscaped garden, featuring a glass light well.

Type Info
Project Three bedrooms, one with en-suite, bathroom, kitchen/diner, lounge
Area 100m²
Project Time 8 months