New dormer window installation and leaking dormer repair across Stratford-upon-Avon and Warwickshire. Correct waterproofing, conservation area guidance and planning advice. Free surveys and quotes.
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Most dormer problems are at the join — where the dormer cheeks and flat or pitched top meet the main roof, the lead and the covering have to be detailed correctly or water tracks in.
When it is not the answer: If your dormer only needs its flat top re-covered or a lead detail re-dressed, that is a targeted repair — you do not need the whole dormer rebuilt. Read the full guide.
Dormer windows create three separate waterproofing challenges simultaneously: the flat or pitched roof over the dormer structure, the cheek flashings on the vertical sides, and the apron flashing at the base where the dormer meets the main roof slope. All three interfaces must be correctly specified and executed for the dormer to remain watertight over its design life. A poorly waterproofed dormer is one of the most persistently problematic roofing situations we encounter — intermittent leaks that are hard to locate and easy to incorrectly repair.
We install new dormer window structures and carry out targeted waterproofing repairs on existing dormers across Stratford and Warwickshire. For new dormers on conservation area properties in Stratford's Old Town, we advise on planning requirements before any structural work begins — a dormer added without the appropriate consent can require costly removal. For leaking existing dormers, we assess all three potential failure points systematically before proposing any remedial work.
A new dormer installation begins with assessment of the structural rafter arrangement in the existing roof, planning status confirmation, and specification of the dormer size and roof covering. For rear dormers on standard Stratford semis outside conservation areas, this is typically a straightforward permitted development project. For conservation area properties or larger loft conversion dormers, planning and structural engineer input is required before the roofing work begins.
The most common dormer repair we carry out in Stratford is lead cheek flashing failure on older dormers. The lead flashing on the vertical cheeks of a dormer must be dressed over the tile or slate surface below and wedged into the timber cheek cladding above. Original lead on dormers built in the 1960s and 1970s is now typically at or past end of life. We re-dress with code 4 lead to correct lap dimensions and wedge into a proper chase rather than surface sealing, which is the correct long-term repair.
Free quotes — no call-out fees — honest advice.
We assess the dormer construction, the flat or pitched top, the cheeks and the junction with the main roof.
A fixed price naming the covering — EPDM, GRP or lead — the cladding and the insulation.
We confirm any planning or conservation requirement before work begins.
We build or re-cover the dormer, dress the leadwork at every junction and insulate to standard.
We make good, weatherproof the dormer and hand over the guarantee.
| Job | Typical duration |
|---|---|
| Re-cover a dormer flat top | 1 day |
| Re-clad dormer cheeks | 1–2 days |
| New dormer construction | 1–2 weeks |
| Leadwork to junctions | 1 day |
Fitting and re-covering are scheduled for dry conditions since the dormer is briefly open; we never leave it exposed overnight.
Dormer work needs scaffold for safe access to the cheeks and top and to control the opening; it is itemised in the quote. Scaffold is specified for: new dormers and cheek re-cladding — anything needing sustained access at height - always itemised in your written quote, never a hidden extra, and we arrange it.
Victorian terraces off the Alcester Road and the Old Town lanes usually mean rear-access scaffold and permit-controlled pavement space, while the post-war Bishopton and Clopton estates give straightforward front access with room for a skip on the drive. Pavement scaffold and skip permits go through Stratford-on-Avon District Council; allow a few working days on streets like Sheep Street, Chapel Street, Church Street where space is tight.
| Job | Typical range | Notes |
|---|---|---|
| Re-cover dormer flat top (EPDM/GRP) | £800–£1,800 | Per dormer, membrane dependent |
| Re-clad dormer cheeks | £600–£1,500 | Lead, tile-hung or cladding |
| Leadwork to junctions | £300–£750 | Per dormer, code 4/5 lead |
| New dormer construction | £4,000–£10,000 | Structure, covering and glazing |
| Insulation upgrade | £400–£1,000 | Added at re-cover |
Worked example: Re-covering a leaking flat-topped dormer in GRP and re-dressing the lead cheeks on a Tiddington Road semi came in around £1,650.
No deposit on re-covers under £500; staged payment on new dormers. VAT shown separately.
Our workmanship is guaranteed for 10 years; GRP and EPDM dormer tops carry 20–25-year manufacturer warranties, and dressed lead lasts far longer.
If a fault appears in covered work, we come back and put it right. No quibbling, no re-charge.
A flat dormer top laid to BS 6229 with correctly dressed code 4/5 lead at the cheeks is what keeps a dormer dry — the failed-junction leaks we are called to are almost always poor original detailing, not a failed window. — to BS 6229 and the Lead Sheet Training Academy
We detail the dormer-to-roof junction to Lead Sheet Training Academy standards and lay the flat top to BS 6229 falls. In the damp Avon Valley that junction is the make-or-break detail, which is why we lead it properly rather than relying on sealant.
Re-covering is contained and quiet; a new dormer involves internal work, dust and a week or two of scaffold, and we sheet the room and clear up daily. You do not need to stay home for external work - we just need power and access agreed in advance.
The Avon Valley's damp makes a fully impermeable dormer top — GRP or EPDM — and correctly lapped lead at the cheeks especially important against wind-driven rain. The Avon Valley's humidity slows drying times through autumn and speeds moss growth on shaded, north-facing slopes near the watermeadows.
Covering CV37, CV35, CV36, B49, B50 and surrounding postcodes.
“Rear dormer had been leaking intermittently for three years — two previous roofers had patched it without diagnosing correctly. These lads found the cheek flashing failure immediately, re-dressed in lead correctly and the leak has completely stopped.”
“New small box dormer for a loft conversion. They confirmed permitted development status, specified lead flat roof and tile cheeks matching the main roof. Watertight and visually correct. Good outcome.”
“Dormer flat roof on a 1970s property had failed felt. GRP replacement in one day. They also re-dressed the apron flashing at the same visit which was the actual leak source. Very thorough diagnosis.”
Most rear dormer window additions on residential properties in Stratford fall within permitted development rights if they meet specific dimensional limits: the dormer cannot exceed the height of the existing roof, cannot be on the principal elevation, and must be set back from the gable ends and the eaves. Properties in Stratford's conservation area, listed buildings, and certain Article 4 Direction areas require a planning application before any dormer can be added. We advise on planning status in every survey.
A single rear dormer window on a standard Stratford semi-detached typically costs £5,000 to £12,000 depending on size, specification and whether a full loft conversion is involved. A box dormer providing additional headroom for a loft conversion is at the higher end. A smaller "shed" dormer for a roof light alternative is at the lower end. We provide free surveys and fully itemised quotes for all dormer and roof alteration work.
Yes. Leaking dormers are one of the more common repair calls we receive in Stratford. Dormers have multiple waterproofing interfaces — cheek flashings on the vertical sides, an apron flashing at the base, and a ridge or flat roof above — any of which can fail independently. We assess the specific failure point and repair only what is failing, rather than defaulting to a full strip and rebuild. Free assessments available for all Stratford dormer repairs.
For dormers on Stratford properties within the conservation area, the dormer roof covering must typically match the main roof or use a sympathetically related material. On non-conservation properties, a small dormer flat roof is usually specified in lead (the traditional material) or GRP fibreglass for its seamless weatherproofing. Dormer cheek cladding is typically tile, slate or hanging tile to match the main roof. We advise on the appropriate specification for each property in the free survey.
A properly designed and constructed rear dormer that creates a usable loft bedroom with adequate headroom typically adds value to a Stratford property. The added value depends on the local market, the quality of the conversion and whether planning consent was properly obtained. We focus on the roofing and weatherproofing elements of dormer additions — structural and interior conversion work is outside our scope but we work alongside conversion specialists regularly.
No call-out fees. No obligation. Local roofers covering Stratford and Warwickshire since 2003.
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