Instant
01 · Ask
Ask the AI a follow-up
Got more questions about dormer Roof Construction? Describe the bit you're unsure about — the AI explains options, sequencing and what to ask the roofer.
Build a dormer roof.
Box, gable or hipped dormer — added to a pitched roof to gain headroom and light in a loft conversion.
✓ Updated May 2026✓ Free quotes✓ Vetted pros
20,000+UK homeowners
50,000Quotes sent
Keep going
Hire a roofer. Without the leak in year two.
You've read the brief on dormer Roof Construction. Now lean on us to find the right roofer — and stay in control of the job.
Free
02 · Read the brief
Walk in informed
Costs, timelines, pitfalls and the right questions to ask before any roofer starts on dormer Roof Construction.
60 seconds
03 · Compare
Compare 3 roofer quotes
Itemised quotes from up to 3 local roofers on dormer Roof Construction — so you can compare like-for-like, not lump sums.
✦
Get roofer quotes Ready when you are
Enter your postcode and get free quotes from local pros.
Top tips
Hiring a roofer, without the regret.
Four moves that separate a smooth job from a nightmare.
Permitted development misinterpreted
Many homeowners assume "permitted development" means no application — Lawful Development Certificate (£103) is still recommended.
Cheek leaks
Junction between dormer cheek and original roof is the highest-risk leak area. Insist on proper flashing and lead detail.
Thermal bridging
Old detail at cheek-to-roof junction creates a cold bridge. Modern detail uses thermal blocks at this junction.
Wrong material
Modern dormer on a heritage house looks anachronistic. Match cladding to existing roof.
Costs & timeline
Know what it costs. Know when it ends.
Indicative UK ranges and a typical week-by-week schedule.
Cost range
By job type
Inc. VAT · 2026
Source: NMT quotes
Source: NMT quotes
Small flat-roof dormer2m × 2m
£5.5k–£14k
Standard flat-roof dormer3m × 2.5m
£8k–£22k
Pitched-roof dormerHeritage style
£12k–£28k
L-shaped large dormerMaximum space
£20k–£45k
Eyebrow/curved dormerHeritage/listed
£15k–£40k
Tile cheek cladding per m²Matching house
£50–£120/m²
!
Quote spread is typically ± 18% — always get 3 quotes.
Timeline
Semi-detached full re-roof · week by week
Typical
4 phases · 3 wk
4 phases · 3 wk
W1
W2
W3
Scaffold erection
Strip + felt + battens
Tile + ridge + verge
Flashings + snags
!
Schedule slips on dependencies — pad each phase by 10–20% for real-world delays.
At a glance
Infographic · VideoThe Roofer briefing.
Infographic
Roofer quick-view
Video guide
Roofer explained
Dormers expand loft conversions, add natural light, and create headroom. Expect to pay £7,500–£35,000 for a UK dormer roof depending on size, style, and whether it's part of a loft conversion. Adds 10–15% to property value typically.
What Does the Work Involve?
The dormer is structurally framed onto the existing roof — usually a flat-roof dormer (cheapest), pitched dormer (heritage), gable dormer (most space), or eyebrow dormer (curved heritage style). Cheek walls built up; roof framed; weather membrane applied; window installed; cladding (tile, slate, lead, zinc) fitted to cheeks; roof covering matching house style. Internal lining, insulation and finishing.
Typical Costs
| Item | Low (£) | High (£) | Notes |
|---|---|---|---|
| Small flat-roof dormer | 5,500 | 14,000 | 2m × 2m |
| Standard flat-roof dormer | 8,000 | 22,000 | 3m × 2.5m |
| Pitched-roof dormer | 12,000 | 28,000 | Heritage style |
| L-shaped large dormer | 20,000 | 45,000 | Maximum space |
| Eyebrow/curved dormer | 15,000 | 40,000 | Heritage/listed |
| Tile cheek cladding per m² | 50 | 120 | Matching house |
| Lead cheek cladding per m² | 120 | 250 | Heritage |
| Zinc/cladding modern | 150 | 350 | Modern architectural |
How Long Does It Take?
Standalone dormer construction: 3–6 weeks. As part of loft conversion: typically included in 8–12 week conversion timeline.
DIY or Professional?
Professional only. Structural calculations required. Building Regs notification mandatory. Working at Height regulations.
Choosing the Right Tradesperson
A specialist loft conversion company or general builder with dormer experience. Architect/structural engineer for the design. Confirm matching materials with existing roof.
UK Regulations
Building Regs full notification: structural, thermal (Part L), fire escape (Part B), drainage if relevant. Planning permission: most dormers are permitted development under specific limits — but anything visible on the front elevation usually needs full planning. Listed buildings always need consent.
Common Problems
- Permitted development misinterpreted: Many homeowners assume "permitted development" means no application — Lawful Development Certificate (£103) is still recommended.
- Cheek leaks: Junction between dormer cheek and original roof is the highest-risk leak area. Insist on proper flashing and lead detail.
- Thermal bridging: Old detail at cheek-to-roof junction creates a cold bridge. Modern detail uses thermal blocks at this junction.
- Wrong material: Modern dormer on a heritage house looks anachronistic. Match cladding to existing roof.
Frequently Asked Questions
Do I need planning permission?
Rear elevation: usually permitted development. Front elevation: usually full planning required. Conservation areas: usually planning. Listed: always consent. Get a Lawful Development Certificate to confirm.
Best dormer style?
Flat-roof: maximum internal space, cheapest, modern look. Pitched: heritage character, more period. Gable: most space and headroom, biggest impact on appearance.
How much value does a dormer add?
Quality dormer conversion: 10–15% to property value, plus a usable extra room. ROI typically 50–80% of build cost.
Can I build a dormer on a bungalow?
Yes — popular for adding a master bedroom upstairs. Increases living space without extending the footprint.
Dormer or skylight?
Dormer: maximum headroom and usable floor area. Skylight: cheaper (£800–£3,500), more light but no extra headroom. Most lofts have both.
How does a dormer impact resale?
Positively — adds usable square footage, increases bedrooms count (if conversion), boosts kerb appeal. Buyer concerns: heat loss potential and waterproofing (verify quality install).
This guide was written with AI assistance and is intended for general information only. Prices are estimates based on UK averages and may vary by region. Always get at least three quotes and consult a qualified professional before starting any work.
NEWAI Trade Assistant
Got more questions
about roofer?
Ask follow-ups in plain English. The AI explains options, sequencing and what to ask the roofer — so you walk in informed.
I'm planning a job. Should I be looking for a roofer?
Sounds like a job for roofer. Tell me what you're trying to do — I'll walk you through costs, timeline and what to ask before they start.
FREE QUOTES60 SECONDS
Keep reading
VIEW ALL ROOFER GUIDES →More roofer guides.
Guide
Chimney sealing
Chimney stacks are among the most exposed elements of a UK property, constantly battling high winds, driving rain, and freeze-thaw cycles. Over time, the mortar...
READ GUIDE →GuideRoof Leak Repair Guide
A leaking roof is more than just a nuisance; it is a direct threat to your home’s structural integrity. In the UK’s damp climate, even a minor drip can quickly ...
READ GUIDE →GuideChimney Installation Guide
Installing a new chimney is a significant structural upgrade for any UK home, whether you are adding a traditional masonry stack or a modern twin-wall flue syst...
READ GUIDE →GuideRoof Replacement Process Overview
Replacing a roof is one of the most significant investments a UK homeowner can make in their property. Beyond simply keeping out the rain, a new roof ensures st...
READ GUIDE →GuidePitched Roof Shingle Installation Guide
Pitched roof shingles, often made from bitumen (felt) or cedar, offer a lightweight and cost-effective alternative to traditional clay tiles or slate. In the UK...
READ GUIDE →GuideRoof Tile Repair Guide
Roof tile repair is a critical maintenance task for UK homeowners, especially given our unpredictable weather. Even a single cracked or displaced tile can allow...
READ GUIDE →