Costs
How Much Does a Loft Conversion Cost in West London? (2026 Guide)
29 July 2026
Loft conversion cost is one of the first questions every homeowner asks us, and we love talking through it - the honest answer is that it depends mostly on the type of conversion your roof allows. Here's a friendly, realistic 2026 breakdown for typical West London terraces and semis.
Rooflight (Velux) conversion - the simplest and usually most affordable option, adding windows into the existing roof slope without changing its shape. A lovely choice if you want a lighter-touch project.
Dormer conversion - the most popular conversion we build in West London. A box-shaped addition built out from the rear roof slope, adding lovely extra headroom and floor space. This is usually the sweet spot between cost and the amount of genuinely usable room you end up with.
Hip-to-gable conversion - extends a hipped (sloped) roof end out to a vertical gable wall, common on semi-detached properties. A bit more structural work than a dormer, and often combined with a rear dormer for maximum space.
Mansard conversion - the most spacious option, replacing most of one roof slope with a near-vertical wall. Delivers wonderful amounts of usable space, and the highest budget of the four.
What tends to move the price beyond the base conversion type: whether an en-suite is included, the number of structural steels your roof needs, staircase relocation, and finish level.
The only way to get a genuinely accurate figure for your own roof is a friendly, free site survey - roof pitch, joist spans and staircase position all affect what's possible, and therefore what it costs. We're always happy to pop round, have a look and talk it all through with you.
Frequently asked questions
How long does a loft conversion take?
Most rooflight and dormer conversions take 6-10 weeks from start on site to a finished, ready-to-use room. Hip-to-gable and mansard conversions typically take 10-14 weeks due to the extra structural work involved.
Will a loft conversion add value to my West London home?
Loft conversions are consistently one of the best-loved home improvements in London, particularly where they add a genuine extra bedroom with en-suite - and beyond the value, most families tell us it's simply become their favourite room.
Can I stay in my home while the loft is converted?
Yes, most families do - we keep noise and disruption to sensible hours and always leave the site tidy at the end of each day.
Thinking about your own project?
Book a free site visit and we'll talk through scope, timeline and a fixed price.
Speak with us