Builders and extensions in Stevenage

How an extension in Stevenage runs from drawing to handover

We start with the drawings, the structural calculation and the building control notice, then a programme you can hold us to. Groundworks and the shell take the first half of the job, the roof and glazing come next, and fit-out finishes it. Payments are staged against completed stages, so you never pay for work that has not happened.

Foundations and ground conditions around SG1 and SG2

Nothing gets priced properly until a trial hole is dug. Clay, made ground and nearby trees all change the depth, and the inspector signs the excavation before concrete goes in. If the ground turns out worse than the trial hole suggested you get the photographs, the revised figure and a decision to make before the digger moves again.

Roofs, lanterns and where extensions actually leak

Flat roofs fail at the upstands and the lantern kerb, not in the middle. Warm-deck build-ups, kerbs formed in timber and dressed properly, and single-ply or GRP taken well up behind the cladding — that is the difference between a room you use and a stain you argue about.

One team from footings to final coat

Groundworkers, bricklayers, carpenters, plumbers, electricians, plasterers and decorators are all in-house or people we have used for years. Gabriel runs the site himself, which keeps the programme honest and gives you one number to call.

Neighbours, access and parking in Stevenage

Stevenage is about fifty minutes north-west from our base. Before we start we agree skip and delivery arrangements, check whether a party wall notice is needed, keep the site swept and the road clear, and give the neighbours a date range in writing. Good access saves more time on a SG1 and SG2 job than any amount of extra labour.

New town housing and standard layouts

Much of Stevenage is new town housing with repeating layouts, which is genuinely useful: we have built the same rear and side combinations several times, so the drawings, the steel sizes and the programme are predictable and the price does not carry a large unknown.

Old Town properties

The Old Town end is a different job entirely — older brickwork, softer mortar and conservation considerations on some streets. Extensions there get lime-compatible mortar where it matters and brick matched from a reclaim yard rather than the nearest merchant pallet.

Garages, side infills and permitted development

A side infill between the house and the boundary is often the best value extension in SG1, and frequently permitted development. We check the specific plot against the current rules and, where a lawful development certificate is worth having, arrange it so a future sale is not held up.

What does an extension cost in Stevenage?

A 3m by 4m single-storey rear extension in Stevenage is typically £38,000 to £52,000 finished, a side return infill £30,000 to £45,000, and a two-storey extension from £65,000. Kitchens and glazing are quoted separately.

Do I need planning permission?

Many single-storey rear extensions fall under permitted development, but it depends on the property, the plot and whether you are in a conservation area. We will tell you honestly at the survey and arrange drawings and an application if you need one.

How long does the build take?

Six to ten weeks for a single-storey rear extension, twelve to sixteen for two storeys, and three to five weeks for a garage conversion. You get a written programme with stage dates before we break ground.

How are payments handled?

Staged against completed work — footings, shell, roof, first fix, plaster, completion — never a large deposit up front. Materials for a stage are ordered against that stage's payment.

Do you deal with building control?

Yes. We lodge the notice, book every inspection and hand you the completion certificate along with the electrical certificate at the end.

Can we stay in the house during the work?

Almost always. The new structure is built outside the existing wall and the opening is only formed near the end, so the disruption is concentrated into a short window we plan with you.

What if the ground is bad?

We dig a trial hole before quoting to reduce the risk, but if the inspector calls for deeper foundations you see the measurement and the revised figure before any extra concrete is poured.

How far ahead are you booking in SG1 and SG2?

Larger builds are running about 8-12 weeks ahead. Drawings and approvals usually take that long anyway, so it is worth starting the conversation early.