Skylight and rooflight fitting in Cymmer, Neath Port Talbot

Cymmer, in Welsh Cymer, is a small village in the community of Cymer and Glyncorrwg, in Neath Port Talbot. It is set on a hillside in the Afan Valley, near the point where the River Afan and the River Corrwg come together. The name translates as the joining place of two rivers, and from there the Afan carries on to the sea at Aberavon and Port Talbot. The ground around it is densely forested upland, cut by steep-sided valleys.

In 2001 Cymmer had a population of 2,883. Among the places that give the village its character are The Refreshment Rooms, a pub in the preserved Rhondda and Swansea Bay Railway station, and a working men's club called The Coronation Club.

From Swansea the road distance is 17 miles, towards the east, well within the 30 miles we work to. We also fit rooflights in Croeserw, Abergwynfi, Glyncorrwg and Maesteg.

A hillside village raises one practical question before any other: how does the roof sit on the slope, and what is above and around it? What we can offer is general. Roofs on sloping ground differ a great deal, and so does the amount of sky each room can see, so one house may want a roof window where its neighbour wants a sun tunnel.

The community of Cymer and Glyncorrwg takes in more than the village itself, so the survey starts from your own address and the roof over it. Tell us the street and the room, and say what the glass overhead is doing at the moment.

That is why the first step is a free survey. The visit shows which way the slope faces, how much of the roof is shaded, and where a window or a sun tunnel can go. A fixed written quote follows once the visit is done.

Planning decisions for a house in Cymmer rest with Neath Port Talbot Council. Whether a rooflight on a house needs an application depends on what is proposed and how the house stands, and the planning guide to skylights in Wales lists the conditions. It is the page to open before a window is chosen.

Four starting points differ. Flats and maisonettes are excluded from householder permitted development. The council may have removed those rights with an Article 4 direction, and a condition tied to a house's original permission can do the same. A listed house needs listed building consent where a rooflight would change what makes it special, applied for through the local planning authority.

If you are unsure, ask the council. A Lawful Development Certificate puts the answer on record.

Building Regulations are another thing again. Making a new opening in the roof for a rooflight will generally call for approval. You pick between the council's building control team and a registered building control approver. Notifiable work gets notified through us. An exchange of one old roof window for a similar new one falls under building work as well, with the new unit expected to meet the current energy figure.

Those figures are worth stating once. Under Approved Document L (Wales), a roof window should have a U-value no worse than 1.4 W/m²K, or sit in Window Energy Rating Band B. A rooflight should be no worse than 2.2 W/m²K. They are guidance values, and the survey notes which one applies to your unit.

A lantern is a special case. Adding one to a flat roof that stands already normally means a planning application, as the lantern rises well above the roof. Where a lantern forms part of a brand-new extension, we put that question to the council.

Ventilation comes into a swap as well. The guidance says a replacement window should leave a room's ventilation no poorer than before, so any trickle vents in the old frame are matched in the new one. In a bedroom, a roof window is an escape window only when it was specified as one, and our roof window Building Regulations page goes through those rules.

Begin with a bedroom under a pitched roof. A roof window lights it from above and opens for air. On a shallow roof, VELUX offers a low-pitch model for pitches of 10 to 20 degrees, so the slope of the roof helps choose the window.

A room that is left empty all day may deserve a motor. The electric opening rooflight option brings a sensor that, on VELUX solar and electric models, closes the window when it begins to rain. A bedroom aired in the morning can then be left to look after itself.

A landing or an inner hall has no outside wall to give it daylight. A sun tunnel takes light from a dome on the roof and delivers it through a tube. Rigid or flexible tubes are both available, and the route past joists and pipes picks between them.

On a rear extension, glass set on a kerb lights a kitchen. If the roof is flat, compare flat roof rooflights with roof lanterns, which put pitched glass above the room. VELUX gives its flat roof dome a design range of 0 to 15 degrees of roof pitch, a reminder that a roof which looks flat may still carry a slight fall.

Trees and shade have a say in glass choice as well. Self-cleaning glass is worth a look here: Pilkington names roof-lights among the places for Pilkington Activ, a coating that uses daylight to break dirt down, with rain doing the rinsing. On a roof that catches leaves, that is worth asking about, though a clear outlet matters just as much.

Kitchens bring their own steam. A rooflight over a hob or a sink sits right where the vapour rises, so the choice between an opening unit and a fixed one is partly a choice about how the room is aired. An opening unit lets the air out directly, and a fixed one leans on the extractor. Where the rooflight is out of reach, the electric kind saves a stepladder and a pole.

When a unit has misted between the panes, the seal around the glass has failed. Misted rooflights can be sorted by a new sealed unit or by a new rooflight, depending on the frame.

Ready to start? Send the room and the roof through the quote form, or ring 01792 929062. We back finished work with a 10-year workmanship guarantee in writing.