Velux (Rooflight) Loft Conversions

A Velux loft conversion fits Velux windows, or any other make of roof window, into your existing roof slope, then adds insulation, a floor and a staircase to turn the loft space into living space. It leaves the shape of the house exactly as it is from the street. With Excellence Living a velux loft conversion starts from £40,000 + VAT, the least expensive loft conversion we build, because it needs the fewest structural changes. The condition is headroom: it only works where the space under your ridge is already generous, because nothing is being added to the roof. Where it is not, a dormer conversion from £55,000 + VAT is the honest answer instead.

What a Velux (rooflight) loft conversion actually is

Velux is a brand of roof window rather than a type of conversion, and homeowners use the name for all of them. The work itself is a rooflight conversion: Velux windows set into the existing roof slope, the loft’s existing structure strengthened where the calculations require it, insulation brought to current standards, a new floor, a compliant staircase, and the room finished. Because it requires fewer structural changes than a dormer, it is usually completed faster than any other type of loft conversion work we do, and it is the most cost effective.

What it does not do is change the outside of your home. No box projecting from the rear roof, no new gable wall, no alteration to the ridge. The volume you convert is the volume you already have.

Most of the extra living space becomes a main bedroom, a home office, or a guest bedroom with an en-suite shower room. Natural light is why an unused attic converted this way feels bigger than the floor area suggests: Velux windows sit in the plane of the sloping roof, so daylight falls across the room rather than through one wall. Clever storage in the eaves turns the low corners into usable space.

Is my loft tall enough for a rooflight conversion?

Stand under the ridge and measure to the underside of the rafters. There is no Building Regulations minimum head height for a habitable room, whatever a lot of guidance online says. The standard that does bite is headroom over the staircase: 2 metres, relaxed for a loft conversion to 1.9m at the centre and 1.8m at the side. Our loft conversion building regulations guide sets out the rest.

What we look for in practice is around 2.2m under the ridge today, because the new floor build-up and the insulation above your head both take some of what you measure. With that, a rooflight loft conversion works. Below it, you need a dormer or a hip to gable conversion, because dormer conversions and mansard conversions add the height rather than work around it.

Will the roof structure and the floor take it?

The existing ceiling joists were built to hold a ceiling, not a room, so the floor has to carry more weight than it was designed for. A structural engineer assesses the load-bearing requirements and specifies the reinforcement, usually new beams spanning between the load-bearing walls. That is the main structural element of a velux loft conversion project, and it sits inside the price.

Insulation and ventilation are planned at the same time. A room directly under the existing roof structure will overheat without the right ventilation strategy and glazing, and the same detailing is what delivers the energy efficiency and the energy savings afterwards.

> Not sure which one your roof is? We measure the height and tell you what is possible before you spend anything on drawings. No obligation. No sales pressure. We come to you. Book a free feasibility visit, or open the cost calculator first.

Rooflight loft conversions in Bristol and North Somerset

Bristol’s housing stock splits fairly neatly on this question. The Victorian and Edwardian terraces through Bedminster, Southville, Easton, Bishopston and Totterdown were built with steep pitches, and steep pitches produce volume, so many loft conversions here are rooflight loft conversions. Where a rear outrigger runs off the back it sits lower, so the main roof is where the room goes.

The interwar and postwar semis around Horfield, Filton, Brislington and Downend are a different proposition: shallower pitches, and on later estates trussed roofs with neither the height nor the clear span. A dormer is the honest recommendation there.

Conservation areas change the paperwork rather than the structure. Clifton, Redland, Montpelier and Cotham all carry conservation status, and several Bristol streets sit under Article 4 directions that withdraw permitted development rights. Planning permission for a Velux window on a street-facing slope is then settled by application rather than assumed.

We have built in exactly that situation. For Tim and Debra Bennet, in a conservation area in Backwell, North Somerset, we installed new steelwork to enlarge an existing loft, reinsulated it, redesigned the floorplan, and fitted a Velux Cabrio balcony window system. Read the Backwell loft project in full.

What a Velux loft conversion costs

Velux loft conversion costs with Excellence Living start from £40,000 + VAT. That is a starting point rather than a cost range, because a starting point is a promise we can keep, and because the average costs quoted nationally vary depending on labour and material costs in each region.

The published additions are listed separately: multiple rooms from £10,000+, an en-suite from £8,000+, a premium finish from £8,000+, a signature finish from £18,000+. Every figure is net and carries VAT on top.

> “This is an indicative range based on your answers. Your actual cost depends on your property’s structure, access, and final specification. A free feasibility visit gives you a detailed, fully specified quote so you know exactly what’s included and why.”

Access moves the total more than homeowners expect: a terraced street with permit parking and no side passage means every load goes through the house. Our loft conversion cost guide for Bristol sets loft conversion costs out type by type.

On programme, many loft conversions take between 8 and 14 weeks from the start of construction, and a velux roof conversion sits at the shorter end. That is build time, excluding design, planning permission and Building Regulations approval.

Rooflight or dormer: the roof decides, not the budget

Decide what the roof can carry first, then what to spend.

A velux conversion, from £40,000 + VAT. The headroom is already there, you want the outside left alone, and you want the shortest build. A small velux loft conversion is often all a single room needs.

A dormer conversion, from £55,000 + VAT. The headroom is not there, or the floor area under it is too small to plan a room around. Dormer conversions add a flat ceiling and full standing height across most of the new space. Our dormer loft conversion guide covers it.

Bungalows are their own case: generous roof volume, whilst the staircase still has to be found within the floor plan below. See our bungalow loft conversion guide, the guide to which type suits your Bristol home, and how much value a loft conversion adds.

Planning permission and Building Regulations

In general terms, a rooflight loft conversion is the type least likely to need planning permission, because the existing roof structure does not change and Velux windows sitting close to the roof plane usually fall within permitted development. That is the national position, not a guarantee for your address.

Rules vary depending on the property and the council. Listed buildings, conservation areas, Article 4 directions and flats sit outside the general case. As loft conversion specialists in Bristol we confirm the position at survey and make any application needed.

Building Regulations apply whatever the planning position: staircase design and headroom, insulation, fire safety with an escape route, and the structural calculations. Our loft conversion planning permission guide covers both.

Getting a price for your loft

There are two ways to get a number. The loft conversion cost calculator gives you an indicative figure in about a minute. The free feasibility visit tells you whether your roof will take a rooflight loft conversion at all.

Every decision is captured in a detailed scope of works before work begins, and your dedicated Site Manager owns every stage through to handover. We will contact you within 2 working days. Our loft conversions page covers the wider service.

Frequently asked questions