A loft conversion is one of the few big building jobs that often doesn’t need planning permission at all. But “often” is doing some work in that sentence. Fulham’s terraces and semis have set limits worth knowing before you start on the design.
Permitted development volume limits
Most houses carry what’s called permitted development rights. These let you add a set amount of roof space without a planning application. A terraced house is capped at 40 cubic metres. A semi-detached or detached house gets a higher limit of 50 cubic metres. That’s according to Resi’s guide to permitted development for loft conversions. Since Fulham has a lot of terraced housing, the 40 cubic metre figure applies to most of our loft conversion enquiries in SW6.
Within that allowance, there are design conditions too, not just a volume cap. A dormer’s front wall generally needs to sit at least 20cm back from the original eaves wall. Side-facing windows have to be obscure-glazed. A side window below 1.7 metres from the floor also needs to be non-opening. None of this is unusual. It’s standard practice on most loft conversions. But it does shape what the finished extension can look like.
What always needs full planning permission
Certain changes fall outside permitted development entirely, no matter how generous the volume allowance is. Extending the roof on the front of the house needs a full application. So does changing the roof’s height in any way, under the rules Resi sets out. Loft work on a flat or maisonette needs one too, since these rights generally apply to houses only. And if a past planning condition has already removed your permitted development rights, which isn’t rare on newer developments, you’ll need permission as well.
Conservation areas and listed buildings
Conservation areas add another layer. The planning system treats them as more sensitive locations, so the usual permitted development allowances get cut back or removed. A dormer that would sail through elsewhere in Fulham may need an application inside a conservation area boundary. Listed buildings need separate listed building consent too, whatever the roof volume involved. Not sure if your street sits inside a conservation area? Your council’s planning pages will have a map showing this. It’s worth five minutes before you pay for drawings.
Why a lawful development certificate is worth having
Even when a loft conversion clearly counts as permitted development, it’s wise to apply for a lawful development certificate from the council. It isn’t compulsory, but it gives you clear proof that the finished conversion was legally built without planning permission.
That matters when you come to sell, since a buyer’s solicitor will usually ask for exactly this kind of paperwork. We build the certificate into the timeline on every loft conversion we quote, alongside the separate building regulations sign-off.
Getting a Fulham loft right from the start
Every Fulham loft conversion we look at starts with the same two questions. Is this within the volume allowance? And does the site sit in a conservation area? Getting that answer early avoids redesigning a scheme halfway through. Usually we can tell within a single site visit. Once the planning route is confirmed, we talk through layout, staircase position, and whether a simple rooflight conversion or a full dormer suits your roof better.
Planning a loft conversion in Fulham, Putney, or Hammersmith? Get in touch for a free site visit. We’ll tell you plainly whether your project needs an application before you spend money on drawings.