Rooflights and skylights in Caldicot

In June the sky is light well before most alarms go off, and a bedroom in the roof is the first room to notice. A roof window lies in the slope, level with the tiles, so it takes in the whole sky above the bed. That is a pleasure at midday and a nuisance at five in the morning.

A blackout blind is the answer, and it is chosen along with the window rather than afterwards, so the two are measured and priced together. Fresh air matters as much as darkness: a sash that opens lets a warm loft clear before bedtime, and it does the same job again at first light if the room has heated up overnight.

If the loft is becoming a bedroom, the window takes on a second job as the way out in a fire. Approved Document B (Wales) sets size and height rules for an escape window, and it makes allowance for a roof window that a wall window does not get. Where the rafters fall decides what can be fitted, so the position and the sash size are worked out together on the survey. We do not choose a size from a catalogue and hope the roof agrees.

The stairs belong in the same conversation. Converting a loft can bring fire protection for the stairway into the job, and we raise it early so that the price of a window is never mistaken for the price of the whole conversion.

Cutting a new opening in a slope usually means altering the roof structure, so Building Regulations approval will generally be needed. Where the work is notifiable, we handle the Building Regulations notification with local authority building control or a registered building control approver. On the planning side, our Welsh planning guide explains when a roof window can go in without an application.

For the choice of window itself, the comparison of pivoting and top-hung sashes shows how the two behave in a bedroom.

The opening of the Severn Bridge in 1966 furthered the growth of the community. Whatever a house's age, a roof window has a working life of its own, and the signs that it is ending are easy to read: a milky patch between the panes, a sash that sticks, a seal that lets the draught in.

There are two kinds of fix. If the glass has misted but the frame is sound, the sealed unit can be the only part that changes. Swapping just the glass and keeping the frame falls outside the energy rules, as Approved Document L (Wales) puts it, whereas a like-for-like swap of the whole window is still building work. To work out which case you are in, read the short answer on swapping only the glazing of a VELUX.

If the frame is the problem, the whole window comes out and a new one goes in. The size code helps here. VELUX gives each roof window a code, printed on a metal plate along the sash top, called the type sign, readable whenever the sash is lifted. Send a photograph of it and the survey starts with the right size in mind. Our guide to VELUX size codes explains how to read it.

The energy figure in the guidance is a target for the whole window. Approved Document L (Wales) says a new or replacement roof window in an existing home should have a U-value no worse than 1.4 W/m²K, or a Window Energy Rating of Band B.

The glazing is worth a conversation while the old window is out. VELUX lists safety lamination among its options, which means a laminated inner pane, for rooms where an accidental break is a worry. It also lists an easy-to-clean coating and rain noise reduction, and the choice on offer varies by window and by glazing variant.

Air matters too. If trickle vents sit on the old window, its replacement should carry vents no smaller than those, which you or an automatic control can work. We look at that on the survey, so a swap does not leave the room more airtight than it was.

Where the opening is sound, a window of the same size in the same place avoids much of the structural work. Where it is not, we look at the rafters around it before the quote is written.