- FROM SWANSEA:
- 6.32 miles, road
- COUNCIL:
- City and County of Swansea
- HOMES:
- roof by roof
Rooflights and skylights fitted in Three Crosses
Three Crosses weather reaches every roof at a different angle, and the angle picks the glass.
Free survey / fixed written quote / Building Control notification handled / 10-year workmanship guarantee
What a Three Crosses roof asks of its glass
Rain meets a roof at whatever angle the roof happens to have, and for a rooflight that angle is the first fact worth knowing. A steep slope throws water off quickly. A shallow one lets it linger. A flat one lets it settle, and settled water is where the trouble starts.
That is why the makers talk about pitch before they talk about anything else. Two VELUX products are defined by angle. The flat roof dome is meant for roofs from level to 15°, and for 10° to 20° the maker offers its low-pitch roof window instead. Together they cover the gentle end of the scale, while a steeper slope takes an ordinary roof window set in the plane of the tiles or slates.
On a flat roof with a kerb-mounted rooflight, the kerb itself should have a fall. Manufacturers of flat rooflights typically recommend one, and Rainclear's installation guide advises a kerb sloping by 5° or more, which keeps pooling low. On a roof lantern, the rain runs down pitched glass onto an upstand, and from the upstand onto the roof around it.
Inside the house the weather arrives as moisture. A shower, a kettle and a drying rack all send damp air up to the coolest surface in the room, and in a room with a rooflight that is often the glass. Glazing chosen to meet Approved Document L (Wales) keeps the inner pane warmer than a poor unit would, and a working vent or extractor lets the damp air leave.
Ventilation settles the matter for replacements. Replacement windows come with a ventilation condition in Approved Document F (Wales): the home should breathe at least as well afterwards, so trickle vents in the old window call for vents no smaller in the new one. The condition covers a roof window as it covers a wall window.
Glass with a self-cleaning coating is an option for the outside. Pilkington includes roof-lights among the applications for Pilkington Activ, which uses daylight to loosen dirt before rain rinses it off.
Rooflights in Three Crosses face the same weather as anywhere else around Swansea, so the practical difference lies in how each house is built. The roof angle, the room below and the way up to the glass tell us more than the postcode does. Whether the glass will be reached from inside with a pole, or from a ladder outside, shapes the choice of opener and of finish.
| Dwelling | Roof angle | Matching glass |
|---|---|---|
| Houses with a pitched roof | pitched | roof window in the plane of the slope |
| Roofs with a shallow pitch | low pitch | window made for low pitches |
| Garage and porch roofs | flat or close to it | flat rooflight or dome |
| Kitchen extensions | flat | lantern or kerb rooflight |
| Landings and halls | loft above | sun tunnel |
- WELSH NAME:
- Y Crwys
- FROM SWANSEA:
- west
- BY ROAD:
- 6.32 miles
Three Crosses, Y Crwys, and the places around it
Three Crosses, in Welsh Y Crwys, lies west of Swansea, 6.32 miles by road. Planning decisions here go to City and County of Swansea Council, and the village sits well inside the area we work in around the city.
Close by are Gowerton, Penclawdd, Loughor and Crofty, each with a page of its own, and we fit and replace rooflights in all of them, along with roof windows, lanterns and sun tunnels.
The shape of the roof decides what the glass can be, so it is worth getting the vocabulary straight. Approved Document L defines a roof window as a window installed in the same orientation as the surrounding roof and in plane with it. A rooflight is a glazed unit installed out of plane with the roof surface, on a kerb or an upstand, and the document adds that it is sometimes called a skylight. That difference matters because Welsh energy limits are written separately for each, and because the two shed water in different ways.
A roof window follows the slope, so rain runs straight over its frame and down the tiles beyond it. A rooflight stands proud on its kerb, so the water has to be led around it. The flashing does that work on a window and the kerb detail does it on a rooflight. A sun tunnel works differently again, with a small dome on the roof that rain slides straight off.
An electric opener suits glass that sits out of reach. VELUX's solar and electric roof windows carry a sensor that closes the sash when rain falls, which suits a landing or loft room left aired while the house is empty.
Which of these suits a given house cannot be read off a map. The three products are fitted and replaced by us, and the choice comes after the survey.
Two terms the rules keep apart
- Roof window
- a window set at the same angle as the roof around it and in its plane
- Rooflight
- a glazed unit installed out of plane with the roof surface, on a kerb or upstand; also called a skylight
- PLANNING:
- Swansea Council
- BOUNDARIES:
- checked per address
- LISTED HOUSES:
- consent needed
Permission, protected land and paperwork
City and County of Swansea Council handles any rooflight application made for a Three Crosses house, and it is the body to ask about the land. The route depends on the land under the house. A new rooflight in the roof slope of a house inside a conservation area, the Gower AONB, Bannau Brycheiniog National Park or a World Heritage Site needs planning permission, and the council can tell you whether an address falls on any of that land. Three Crosses is outside the Gower AONB.
For a house with no such designation, the conditions that can bring a rooflight within permitted development are set out in our Wales planning guide for skylights. Those rights belong to houses. A flat or maisonette has none, and a council can withdraw them across an area by issuing an Article 4 direction. A condition written into the first permission for a house can remove them too.
Listed houses have a different system. A rooflight that would affect a listed building's character as a building of special architectural or historic interest needs listed building consent, applied for through the local planning authority. Starting work without consent may amount to a criminal offence. Cadw has said that replacing traditional windows with uPVC on a listed building will not normally be acceptable, and its page on listed building consent covers the detail.
Listed building consent covers work inside as well as outside, including historic fixtures, fittings and details, so even minor work can need it. Cadw is the Welsh Government's historic environment service, and its records of listed buildings are published in Cof Cymru.
Where it is unclear whether permitted development applies, the planning team will give its view, and a Lawful Development Certificate makes that view official.
Building Regulations follow their own rules. Approval generally has to be obtained for a brand-new rooflight, as the roof is usually altered and must then bear the added load. In Wales you can choose between the council's building control service and a registered building control approver. For notifiable work we handle the Building Regulations notification through whichever of the two applies.
Paperwork in the order it is easiest to do
- Find out the land type Ask the council whether the address is on protected land.
- Ask about the permission If it is, a rooflight in the slope needs a planning application.
- Settle building control Pick the council's service or a registered approver.
- KERB FALL:
- 5 degrees or more
- LANTERN UPSTAND:
- 150 mm minimum
- ROOF WINDOW:
- U-value 1.4
Rooflight, lantern or dome for a flat or shallow roof
A flat or shallow roof has more choices than a pitched one, and each carries its own conditions. Over a flat roof, a flat roof rooflight rests on a kerb that has to be built with a fall. A dome is made for roofs from level up to 15°. A roof lantern comes with its own recommendations for the roof below it, and the maker's own paperwork is the source.
Brett Martin's technical bulletin sets the minimum height of the builder's upstand at 150 mm and suggests building it level. A pitch of up to 5° is tolerated, though Brett Martin warns that this will likely look lopsided, a point worth settling before the roof is built.
The energy figures differ too. Under Approved Document L (Wales), a new or replacement roof window should reach 1.4 W/m²K or Window Energy Rating Band B, and a rooflight, being a unit on a kerb or upstand, should reach 2.2 W/m²K. Lanterns are not named in the document, so for a new extension planned with a lantern, the council is asked to confirm.
A loft room under a pitch is simpler. A roof window goes into the slope, and a window with moisture sealed between its panes can be replaced through our misted rooflight replacement. For a room with no roof of its own, such as a hall below a loft, a sun tunnel brings in light from above.
All of this starts with a free survey. After it comes a fixed written quote, and once fitted the work is covered by our 10-year workmanship guarantee in writing. Call 01792 929062 to book, or use the online form.
| Roof angle | Product | Where it comes from |
|---|---|---|
| 0° to 15° | flat roof dome | VELUX design range |
| 10° to 20° | window made for low pitches | VELUX design range |
| level | upstand for a lantern | Brett Martin advice |
| 5° or more | kerb fall, flat rooflight | Rainclear advice |
Questions from Three Crosses
Which roof angles does a low-pitch roof window suit?
VELUX's figures give the low-pitch window a range of 10° to 20°, and the dome a range from level to 15°. The ranges overlap, so a roof near 12° could take either, and the survey measures the real angle before a product is chosen. Beyond 20° an ordinary roof window is the natural choice.
How tall should the upstand under a roof lantern be?
Brett Martin sets 150 mm as the minimum height of the builder's upstand, and suggests building it level. A lantern can sit on up to 5° of pitch, though the maker warns that this will likely look lopsided. Settling the upstand before the roof is built saves rework.
Who do I ask about a rooflight on a house in Three Crosses?
City and County of Swansea Council, for planning. For Building Regulations you can pick the council's building control service or a registered building control approver. The council can also say whether an address is on protected land.
Does a lantern on a flat roof I already have need planning permission?
Normally it does. Its height above the roof normally takes a lantern outside permitted development, as our Wales planning guide for skylights explains. The council gets the question at survey.
Is Three Crosses on your patch?
It is. Three Crosses lies west of the city, 6.32 miles by road, and comfortably within our service radius across Swansea, Neath Port Talbot, Carmarthenshire and Bridgend. The same cover extends to the neighbouring places named above.
What follows the survey?
A fixed written quote comes next, then the work, then our 10-year workmanship guarantee given in writing. To start, send the form and say which room the glass is for. If you would rather talk it through, ring 01792 929062 and describe the room and the roof above it.
Nearby towns we also cover
Bulletin Three Crosses
Book your free survey
- Survey:
- before we price
- Quote:
- fixed, in writing
- Guarantee:
- 10 years on our workmanship, in writing
No obligation. Building Control notification handled where the work is notifiable.