Loft conversions & extensions in St Albans

Yes. We come to your home, measure up and talk through what you want, at no cost. You get a clear quote afterwards, and there is no obligation to go ahead with it.

Often not. The government’s permitted development rules let you add up to 40 cubic metres of roof space on a terraced house and 50 on other houses, no higher than the existing roof, with no dormer on a front slope facing a road. In a conservation area, roof extensions need planning permission, so we check your address first.

Likely, going by the council’s own record. Government planning statistics show St Albans council decided 980 homeowner planning applications between July 2025 and June 2026 and approved 87% of them. Three Rivers council decided 617 and approved 91%. Many lofts and rear extensions need no application at all, because they fall within permitted development.

Yes. A loft conversion counts as a “material change of use”, so building regulations apply: they check the new floor is strong enough and the house stays stable. Extensions are covered too. The application is made for you, and you get a completion certificate at the end, which you may need when you sell.

If the work cuts into, or sits on, a wall you share with a neighbour, the Party Wall Act says you must give them written notice between two months and a year before starting. They must reply in writing within 14 days if they consent. A party wall agreement is separate from planning permission and building regulations.

MyJobQuote’s 2026 cost guides put a Velux loft at £15,000 to £35,000, a rear dormer at £30,000 to £60,000 and a hip-to-gable at £40,000 to £65,000. Costs in London and the South East run roughly 15 to 35% higher. The figure that counts is your quote after the free survey.

On site, a Velux loft usually takes 4 to 8 weeks, a dormer or hip-to-gable 6 to 8 weeks and a mansard 8 to 10 weeks, according to MyJobQuote’s 2026 guides. Drawings, any planning application and building regulations approval come first, so allow extra time before work starts.

Homebuilding & Renovating’s 2026 guide puts a single-storey extension at £2,200 to £3,300 per square metre and a double-storey at £2,000 to £3,200, before VAT. A side return runs £2,800 to £3,800 per square metre. Costs in London and the South East run roughly 15 to 35% higher. The figure that counts is your quote after the free survey.

On site, 2026 guides from MyJobQuote and Homebuilding & Renovating put a single-storey or double-storey extension at 10 to 18 weeks, and a single garage conversion at 2 to 4 weeks. Drawings, any planning application and building regulations approval come first, so allow extra time before work starts.

It can. Nationwide found in October 2025 that adding a large double bedroom and a bathroom to a three-bedroom, one-bathroom house, by loft conversion or extension, can add as much as 24% to its value. How much yours gains depends on the house, the street and the finish.

Usually, yes. Most of the work is done from scaffolding and through the roof, so the trades mainly come inside when the new stairs go in. Expect dust and noise for those weeks. If the loft is too low and the ceiling below has to come out, there’s more upheaval downstairs.