Loft conversion drawings from £589 in total, survey included
Rooflights, a rear dormer or a hip-to-gable: we measure your roof space, work out which of those routes the roof allows and draw the set. It is £439 for the drawings plus the £150 survey.
- £439 drawings + £150 survey (£589 total)
- Roof measured in person
- Free redraws until approval
How much are loft conversion drawings in London?
Our fee is £439 for the drawings and £150 for the measured survey, £589 in total, and there is no VAT to add. A rooflight-only loft often needs no planning application at all, so the first thing we settle is whether you need a certificate, a planning application or neither. Whichever route fits, you get the same dimensioned set.
What the £589 buys
- A roof-space survey: ridge height, floor-to-ridge, purlin and rafter sizes where visible, and the stair position below
- Existing and proposed plans for the new floor and the floor beneath it, with the stair shown
- Front, rear and side elevations showing the dormer or rooflights against the existing roof
- A roof section, with the volume calculation that tells us if the work stays inside the permitted limits
- A site plan and location plan for the application or certificate
- Submission and every reply to the planning officer, with free redraws until approval
Which kind of loft does your roof allow?
The roof shape decides more than the budget does. A hipped roof usually needs a hip-to-gable to gain a usable rear dormer, and that changes the side elevation, which a neighbour sees. A butterfly or flat roof behaves differently again, and a house that has had its roof raised before may have used up its volume already.
We measure the existing roof space, work out the cubic volume of the original and what you want to add, and tell you which route applies before you spend on anything else. The limits are set by Class B of the 2015 Order: 40 m³ on a terrace, 50 m³ otherwise.
- Rooflights only: often permitted development, no more than 0.15 m proud of the slope
- Rear dormer: permitted development if volume, ridge and eaves limits are met
- Hip-to-gable: counted in the same volume, and usually drawn with a rear dormer
- Front dormers, balconies and anything in a conservation area: planning application
Certificate or planning application?
Even where the work is permitted, a Lawful Development Certificate is worth having. It is the council’s written view that the loft is lawful, and a buyer’s solicitor will ask for it years later (gov.uk guidance, paragraph 002). Our lawful development certificate service is priced from £539 in total. If the roof does not qualify, the same drawings go in as a householder application instead.
Some boroughs add their own design rules even to permitted lofts, and Brent, for example, asks that no dormer rises above the original ridge (Brent SPD, para 3.6.2). We draw to the stricter of the two tests, so a refusal on design grounds is less likely.
Building control for a loft is a different job
Turning a loft into a bedroom is building work whichever planning route you use. The council or an approved inspector must approve it, and for most lofts that means full plans, with a decision in five weeks, or two months by agreement (gov.uk). They check the new floor, the stair, the escape route and the insulation. We prepare that set as building regulations drawings, and the survey is not charged twice.
Where steel beams must sit in a shared wall, the Party Wall etc. Act 1996 asks for notice at least two months before the work starts. Read how this fits with the rest of the job on our extensions and lofts page.
The limits on a permitted loft
- 40 m³
- The most a roof enlargement may add to a terraced house under permitted development. GPDO 2015, Sch. 2 Part 1, Class B.1(d)(i)
- 50 m³
- The same limit for a semi-detached or detached house, counted from the original roof space. GPDO 2015, Class B.1(d)(ii)
- 0.2 m
- The edge of a dormer nearest the eaves must be set back at least 0.2 m, measured along the roof slope, so far as practicable. GPDO 2015, Class B.2(b)(i)
- 1.7 m
- A side-facing window in the new roof must be obscure-glazed and non-opening unless its opening part is more than 1.7 m above the floor. GPDO 2015, Class B.2(c)
- 0.15 m
- A rooflight under Class C may protrude no more than 0.15 m from the plane of the original roof slope. GPDO 2015, Class C.1(b)
- Article 2(3)
- In a conservation area a dormer or other roof enlargement is not permitted development, so you need a planning application. GPDO 2015, Class B.1(f)
- £548
- The council fee for a householder planning application, where the loft needs one, from 1 April 2026. National fee schedule from 1 April 2026, published by Bradford Council
- 5 weeks
- The usual time for a council to decide a full-plans building regulations application, or 2 months if you agree. gov.uk, Building regulations approval: how to apply
Loft conversion questions
Do I need planning permission for a loft conversion in London?
Not if the work stays within the Class B limits and the house is not a flat or in a conservation area. Volume is measured from the original roof, so an earlier dormer counts. We check the address and the volume before we quote.
Source: GPDO 2015, Class B
Can a flat have a loft conversion under permitted development?
No. Class B applies to dwellinghouses, and flats and maisonettes are not dwellinghouses for this purpose, so a flat’s loft needs a planning application and the freeholder’s consent.
Source: GPDO 2015, Class B
Does the council fee come on top of the £589?
Only if your loft needs an application. A householder application costs £548, paid to the council. A rooflight-only loft with no application has no such fee.
How much headroom do I need?
It depends on the stair and the room use, and it is the first thing our survey tests. We measure floor-to-ridge in the loft and tell you before you commission anything whether a conversion works.
Do you handle the building regulations as well?
Yes, as a separate fixed fee. You pay the £150 survey once for the house, so the second set is the drawings fee alone.
Other services people book with this one
Find out what your roof will allow
Tell us the postcode, the roof type and whether you want a dormer. We check the volume limits and any conservation area, then send a fixed fee.