Extensions built start to finish

Many single storey rear extensions fall under permitted development and need no planning application, but the limits on depth, height and how close you build to the boundary are strict, and they are tighter on a flat, in a conservation area or where permitted development rights have been removed. Double storey work usually does need permission. We will tell you which category your job falls into before you spend anything, and a lawful development certificate is worth having even when permission is not required.

No, and you generally need to think about both. Planning is about whether you may build it, and building regulations are about whether it is built safely and properly: foundations, structure, insulation, fire safety, drainage and ventilation. An extension almost always needs building regulations approval even when planning permission is not required. We build to the approved details and book the inspections at each stage.

A straightforward single storey rear extension is commonly eight to twelve weeks on site once the foundations are in and materials are ordered. Two storey work and anything involving significant structural alteration to the existing house runs longer. Weather during groundworks and lead times on windows and steel move the programme more than the building work does, and you get a realistic schedule with the quotation rather than an optimistic one.

In most cases yes. The extension is built as a shell outside the existing wall for the bulk of the programme, and the disruptive part is the week or two when we break through and connect the two together. We plan that stage with you, keep the house sealed and dust-screened, and make sure the kitchen or bathroom you rely on stays usable for as long as possible.

We work to a set of drawings from an architect or a technician, and if you do not have any yet we will point you at the right person and work with them from the start. Structural calculations for steels and beams come from an engineer. We handle the building control notices and inspections as part of the job so nothing gets missed.

On a measured scope after a site visit and a look at the drawings, broken down by stage so you can see what the groundworks, the structure, the roof, the fit-out and the finishes each cost. Anything we cannot know until the ground is open, such as the depth the foundations need to go, is flagged as a provisional item up front rather than appearing as a surprise later.