Full-Width Rear Dormers in Northamptonshire
We design, build and weatherproof full-width rear dormers for homeowners across Northamptonshire, working from first survey through to building control sign-off.
Full-Width Rear Dormers — indicative geometry
Full-Width Rear Dormers for Northamptonshire homes
Because Northamptonshire is largely Victorian and Edwardian terraces, interwar semi-detached houses and post-war bungalows, the roof pitches and span widths we meet are fairly predictable, and that makes feasibility a quick conversation rather than a guess.
A full-width rear dormer runs from party wall to party wall, squaring off the entire rear slope. On a standard terrace or semi it typically converts 12–18m² of crawl space into full-height room — enough for a double bedroom and an en-suite. Set back 200mm from the eaves and 500mm below the ridge, it usually falls inside permitted development on a house that has not been extended before.
Key specification
| Typical projection | 4.0m – 8.0m wide |
|---|---|
| Set-back | 200mm from eaves, 500mm below ridge |
| Structure | Steel ridge beam plus floor steels |
| Roof finish | GRP, EPDM or single-ply membrane |
Planning and building control in Northamptonshire
Getting the consent route right at the start saves months. We establish whether it is permitted development, a lawful development certificate or a full application on the first visit.
Building regulations approval is separate and always required. We submit the application, book the inspections around the programme and hand you the completion certificate at the end — the document a buyer's surveyor will ask to see.
Why homeowners in Northamptonshire use us
The completion certificate is part of the deliverable, not an afterthought. It is the document that makes the space count when you come to sell.
Send us the address and roughly what you are hoping to gain, and we will come back with a realistic answer rather than an optimistic one.
Other dormer work in Northamptonshire
- Dormer Cladding in Northamptonshire
- Dormer Window Repairs in Northamptonshire
- Gable-Fronted Dormers in Northamptonshire
- L-Shaped Dormers in Northamptonshire
- Cat Slide Dormers in Northamptonshire
- Velux to Dormer Conversions in Northamptonshire
- uPVC Dormer Windows in Northamptonshire
- Sash Dormer Windows in Northamptonshire
FAQs
Full-Width Rear Dormers in Northamptonshire — FAQs
Can you match my existing roof tiles?
Usually. Most common clay and concrete profiles are still in production or available reclaimed, and we source a match at survey stage so you see it before work starts. Where a discontinued profile cannot be matched exactly, we normally recommend taking tiles from a less visible slope for the dormer and using the closest new match on the hidden elevation.
Can you convert an existing Velux loft to a dormer?
Yes, and it is usually a shorter job than starting from scratch because the floor, staircase and services already exist. We verify the existing floor structure and any previous building control approval first, then cut and form the dormer into the finished room. Expect the room to be out of use for three to five weeks.
How disruptive is a dormer build?
Less than people expect, because most of the work happens above your ceilings and is reached from the scaffold. The noisy phases are opening up and installing steels, typically two to four days. Once the staircase is cut in there is dust and traffic through the house, and we sheet and protect the route for that period.
Do dormer windows need to be fire escape windows?
In a loft conversion, at least one window in each habitable room generally needs to meet escape requirements — a clear opening of at least 0.33m², minimum 450mm in both height and width, with the bottom of the opening between 800mm and 1100mm above floor level. We specify the opening lights to meet this as standard.
Do I need planning permission for a dormer window?
Rear dormers on a house often fall under permitted development, provided the dormer is set at least 200mm back from the eaves, sits below the ridge line, uses materials similar in appearance to the existing house, and stays within the volume allowance — 40m³ for a terrace, 50m³ for a semi or detached. Front-facing dormers, flats and maisonettes, listed buildings, conservation areas and any property with an Article 4 direction all need a full planning application. We check the constraints on your specific address before we quote.
Find out what your roof will take
A free measured survey in Northamptonshire tells you what is achievable, what it needs, and what it costs — before you commit to anything.