Loft conversions in Oxford and Oxfordshire

A loft conversion adds a bedroom, office or living room without touching the garden. We handle the structure, the floor, insulation, heating, stairs, windows and the finish, so you deal with one team and one programme. The photos on this page are from a recent conversion where we laid an acoustic subfloor, installed underfloor heating, fitted timber flooring and kept the oak beams exposed, and from dormer roof work on other jobs.

What type of loft conversion suits your house?

• Roof-light (Velux) conversion. Windows set into the existing roof slope, so the roofline stays as it is. It suits lofts that already have enough head height, and it is usually the least disruptive option.
• Rear dormer. A box built out from the back of the roof, with a vertical wall and a window. It adds head height and floor area, and is common on Victorian terraces and semi-detached houses.
• Hip-to-gable. Where the side of the roof slopes in (a hipped roof, typical of 1930s semis), the side is built up into a vertical gable wall to make room for a staircase and a full-size room, often with a rear dormer as well. We advise at the site visit whether the roof allows it.
• Dormer repairs. Repairs and re-fitting of existing dormers.

Do you need planning permission for a loft conversion?

Most loft conversions are permitted development, which means they need no planning application. When we checked the rules in September 2026, a loft conversion on a house stayed within permitted development if:

• the extra roof space is no more than 40 cubic metres on a terraced house, or 50 cubic metres on a semi-detached or detached house;
• nothing is higher than the highest part of the existing roof;
• there is no dormer on the roof slope that faces the road at the front;
• there are no balconies or raised platforms;
• any side-facing windows are obscure-glazed and fixed shut below 1.7 metres from the floor;
• dormers are set back from the eaves, usually by about 20 centimetres.

These rights do not apply in a conservation area, so a dormer or hip-to-gable conversion there always needs planning permission. They do not apply to flats either. In Jericho and Osney, Article 4 directions also control rooflights on roof slopes that face the street. Our Oxford planning guide lists Oxford’s 18 conservation areas and links to the official rules.

Stairs, head height and fire safety

• Head height. Most lofts with about 2.2 metres or more from the top of the ceiling joists to the ridge can be converted. We measure at the site visit.
• The new floor. The existing ceiling joists are not strong enough for a room, so a new floor structure goes in, often with steels, sized by a structural engineer.
• The staircase. It usually rises above the existing stair. Building Regulations allow slightly less headroom on a loft stair than on a normal one, which often makes the difference.
• Fire safety. A loft room turns a two-storey house into a three-storey one, so the stairway down to the front door becomes the escape route. Doors onto it are usually upgraded to fire doors and mains-powered, linked smoke alarms are fitted.
• Sound. Acoustic boarding in the new floor keeps noise from the loft away from the rooms below.

Building Regulations and party walls

Every loft conversion needs Building Regulations approval, whether or not it needs planning permission. The structure, stairs, fire safety, insulation and ventilation are checked during the work, and you get a completion certificate at the end. Keep it with the deeds, because a buyer’s solicitor will ask for it.

In a terraced or semi-detached house the new steels usually sit in the party wall with the neighbours, so the Party Wall etc. Act 1996 applies. The neighbours get notice two months before that work starts, and can agree in writing or appoint a surveyor.

How a loft conversion runs

1. A site visit to check head height, roof structure and access, then a written quote.
2. Drawings, structural calculations and approvals.
3. Scaffolding goes up, the roof is opened for any dormer or gable wall, and it is made watertight again.
4. The new floor structure and steels go in, then insulation and stud walls.
5. The staircase is fitted.
6. First fix plumbing, heating and electrics, then plastering.
7. Flooring, carpentry and decoration, the final Building Control inspection, and we walk through the finished room with you.

Most of the work happens from the scaffolding and inside the loft, so the rest of the house stays in use until the staircase goes in.

What customers say

“We contacted Harry for a quote for our loft extension and received a prompt response. We chose Oxford Direct Builders, and everything was completed smoothly and to a high standard. The team was professional, kept the house clean every day, and delivered excellent results. Highly recommended.”

Orgito, May 2026, loft extension

Adding space downstairs as well? See our house extensions page.