11 road miles west-north-west of Bournemouth
skylights & rooflights in corfe mullen
Post-war houses along the Wareham Road make up the larger, newer half of Corfe Mullen, with an older village in the Stour valley, and we measure each roof, whichever half it belongs to, on site.
one parish, two kinds of street
- Wareham Road housingMostly post-war houses on the plateau, with tiled roofs and lofts.
- Single-storey homesA hall in the middle of the plan and nothing above it but a loft.
- Older village cottagesAround the lanes to the north, with irregular timbers.
- Extended housesRear kitchens and garden rooms with flat roofs.
the record to pull for a Corfe Mullen house
- planning authority
- Dorset Council
- conservation area
- Sleight Lane area: check the address
- road miles
- 11
Nearby
corfe mullen, plateau and valley
a large village built mostly in living memory
Dorset Council's own planning documents describe Corfe Mullen as two parts: an older village in the Stour valley to the north and a larger, more recent area on a high plateau along the Wareham Road. The roofs follow the same split.
A valley village and a plateau of newer streets
Most of the housing went up in the later twentieth century, and that sets the roofs we expect.
The older village lies in the Stour valley, near the junction of the Blandford Road with the A31. The much larger, more recent part runs along either side of the Wareham Road on high ground, and the census shows the population almost doubling between 1971 and 1981. That growth was filled in street by street, so many Corfe Mullen closes have houses of one date, one tile and one roof shape.
A roof of that kind is helpful to survey. The rafters tend to be regular and the covering is a modern tile, so the questions are practical ones: how deep the loft is, whether the roof is built from trusses, and what the owner wants to light. In the older lanes the answers are less tidy, and we measure more points on the slope before we name a size.
In houses of that period the rooms that call for more light are a landing over the stairs, a bathroom without a window and a rear bedroom in the loft. Each can be lit from the roof directly above it, and each needs a different reading before a size is chosen: the landing wants a clear drop, the bathroom a short shaft, the loft bedroom a headroom check at the sill.
North of the plateau, in the older lanes, the picture is looser. Cottages and farmhouse-style buildings were altered over many years, and an extension of one date may sit beside a roof of another. There we plan for surprises under the tiles and allow time to open the roof and look.
Dorset Council has been the planning authority here since 2019. Before that the village sat under East Dorset District Council, so older letters in a file may carry that name. Fitting a VELUX window or a roof window in a loft room is the commonest request we expect, and the cost of it varies with the roof construction, the size, the access, the finish inside and whether the window opens.
Prices only mean something once a roof has been measured.
What moves the cost of a roof window on a Corfe Mullen house
- Roof constructionCut rafters take a trimmer and approval. A trussed roof limits the size to the gap between frames.
- Window sizeA wider window needs more timber work, and a taller one needs a longer flashing kit.
- AccessA driveway and a low eave keep scaffold simple. A tall house or a tight close needs a tower.
- Finishes insideA boarded reveal and plaster to match the room add work after the glass is in.
- Opening or fixedAn opening model costs more than a fixed one and helps ventilate the room.
Checking a Corfe Mullen address with Dorset Council
A conservation area sits in the older north-west of the village, and Green Belt covers much of the surrounding land.
Dorset Council's planning documents place the village's conservation area around Sleight Lane and Brog Street, in the older north-west part, away from the Wareham Road housing. The same papers note that the village sits within the South East Dorset Green Belt and that nearby heathland is protected. The Green Belt and the heathland are no reason to expect trouble with a rooflight, but each is a reason to look an address up before assuming either way.
A conservation area is the one most likely to affect a rooflight, because councils can restrict them there through an Article 4 direction. We never name a direction for a street. Dorset Council's website and its planning register show what applies to a particular house, and our planning guide explains the rules in full, so the steps keep to how to check.
The heathland protections that the council's papers describe are written about the effect of additional housing close to the heath. If your address is near protected land and you are unsure how the policy reads for a rooflight in an existing roof, put the question to the council in writing and keep the reply with the survey sheet.
Older buildings bring one more check. Roofs of old cottages and outbuildings can hold bat roosts, which are legally protected. If you have seen bats in or around the roof, mention it when you book, because that advice has to come before any work.
Checking a Corfe Mullen house before you plan a rooflight
- Find the conservation mapDorset Council publishes conservation area boundaries on its website. Search the full address, since a boundary can follow the back of a plot instead of the road.
- Look the house up on the heritage listIf the house is on the list, the listing covers the roof and consent is required before work. The national list is searchable by address.
- Read the planning historyThe council's planning register lists past applications at your address. If the house was built or extended with conditions, the decision notice states them.
- Raise it when we visitAt the survey we go through the same records and note what each one showed, so you hold the findings in writing. If an application is needed, Dorset Council handles it.
Lofts on the plateau: trusses, headroom and the right size
Houses built in the later twentieth century commonly have roofs made of factory trusses.
Many houses built in the later twentieth century have trussed roofs. A truss is a factory-made triangular frame, and the roof is a row of them standing at regular spacing. The members inside each truss are part of its strength, so we do not cut them to fit a window. The aim on these roofs is to pick a window that sits between two trusses, or to use a design approved through Building Regulations when something wider is wanted.
Loft conversions on these houses tend to arrive as a dormer or a row of roof windows in the rear slope. A row of windows keeps the work within the plane of the roof and brings light along the whole room. A dormer follows different planning rules, so the planning guide is the place to start. Where heat loss matters, the page on energy-efficient rooflights covers the glass options.
Bungalows on the plateau have a hallway and often a bathroom with no outside wall. When the loft is shallow and the run is short, a sun tunnel fits. Elsewhere the roof window with a shaft suits a wider hall.
Escape is the other thing to settle early. Where the rooms in the roof belong to a single-storey home, a roof window of the right size and sill height can be the way out. A loft room above two storeys needs a protected stair instead, so the layout is drawn before the window is chosen.
One example house on the plateau shows the readings we would write down.
Replacing a rooflight that has been in since the first owners
Houses that were new a few decades ago now have rooflights at the end of their life.
Corfe Mullen grew quickly, and many of its houses now have a rooflight that has been in the roof for decades. Frames age, seals fail and glass fogs. The question for the owner is whether to replace the whole unit, or only the sealed glass unit if the frame is sound. Our guide to misted and failed rooflight replacement explains how we tell the two apart on a survey.
The two jobs sit under different rules. A whole new rooflight or roof window is notifiable as a controlled fitting, and a unit fitted to an existing home has to reach 2.2 W/m²K as a rooflight, or 1.4 W/m²K as a roof window. Swapping just the sealed glass in a frame that is still sound needs no notification.
Glass ages in a particular way. A sealed unit holds air or gas between two panes, and once the seal goes, moisture gets between them and leaves a permanent haze. That cannot be wiped away, and it is the clearest sign that the unit needs replacing. Condensation on the inside of a window is a different matter and says nothing about the seal.
Flat roofs behind the houses need the same measured approach. Kitchens built out at the back often hold an old flat unit, and a flat rooflight with a new kerb is the likely replacement. The survey records the fall, because water has to run off a flat unit.
Myth
Replacing a rooflight is the same job as fitting a new one.
The opening is already there, so it looks as though a new unit simply goes in. What is being swapped changes the rules that apply.
Fact
A whole unit and a glass unit are treated differently.
Replacing the frame and glass is notifiable and must meet the current thermal figures. A sound frame that only needs fresh sealed glass falls outside notification. Cutting a brand new opening in the roof alters the structure and needs approval.
Sizes that fit: reading a VELUX code against your rafters
The first letter in a size code is the width and the digits are the height.
Roof window sizes are written as a code such as MK04, with the width in the first letter and the height in the digits. At rafters 600 mm apart, only the narrowest codes come close to fitting between two rafters, and most sizes mean trimming at least one. A tall, narrow window brings light deep into a bedroom, while a wide one suits a landing.
Broadstone and Upton are the nearest towns, and a survey in either runs along the same lines. A few common codes are listed with their sizes.
The code is only a starting point. The maker rates every model for a span of pitches, and the flashing kit has to suit the tile profile, so the survey reads the slope and the covering before a code is written on the order. If the rafters are not where a drawing says, the code can change on the day of the survey and the order follows the measurement.
| Code | Width | Height |
|---|---|---|
| CK02 | 55 cm | 78 cm |
| MK04 | 78 cm | 98 cm |
| MK06 | 78 cm | 118 cm |
| PK06 | 94 cm | 118 cm |
| SK06 | 114 cm | 118 cm |
faq
questions from Corfe Mullen households
Is there a conservation area in Corfe Mullen?
Dorset Council's planning documents place one around Sleight Lane and Brog Street. Check your full address on the council's map; we confirm it again when we visit.
Can I put a roof window in a trussed loft?
Yes, if the window fits in the gap between two trusses. Anything wider needs a structural design approved through Building Regulations.
My old rooflight has misted. Do I need a whole new one?
Only if the frame is failing. If the frame is sound, the sealed glass unit alone can be replaced. We tell you which at the survey.
Does the Green Belt stop me fitting a rooflight?
Green Belt policy is mainly about new buildings and large extensions. Dorset Council's website is the place to confirm how it applies to your address.