Rooflight and skylight installation in Lawford

Establishing what applies

Three questions, in order, before any product is discussed.

Is it listed? If so, listed building consent is required for a rooflight on any slope, front or rear, visible or not. The listing covers the whole building. There is no small works exception, and doing the work without consent is a criminal offence rather than a planning irregularity.

Is it in the conservation area, and is there an Article 4 direction? A conservation area on its own does not remove permitted development for rooflights on a house. A direction does. It is a short enquiry to the council and it changes the whole shape of the job.

Is it a flat? Flats and maisonettes have no permitted development rights at all, designation or not, so any rooflight needs an application and usually the freeholder’s consent.

Where none of those apply, a rooflight is permitted development provided it projects no more than 150mm beyond the plane of the roof and does not sit above the highest part of it.

The older housing

Steep pitches, cut roofs with rafters and purlins, clay plain tile and slate. Good roofs for a skylight installation once the designation question is settled: the pitch does much of the weathering work and an opening can usually be formed without a structural trimmer.

The unknowns are what is underneath. A roof never stripped may have no underlay, in which case the weathering is built around the opening rather than lapped into a membrane. And decayed rafter ends are a realistic possibility on an older property, which is why an honest quotation names a contingency with an indication of cost rather than producing an invoice for it afterwards.

The twentieth century housing

Where most of our Lawford work is. Concrete interlocking tiles, pitches around 30 to 35 degrees, cut roofs on the earlier properties and trussed rafters on the later ones.

The cut against trussed distinction sets the price more than the choice of window does. Rafters with a purlin and clear space between is cut, and a wide opening is ordinary carpentry. Triangular frames with diagonal webs joined by flat pressed steel plates is trussed, and opening width is limited to the 600mm truss spacing unless a designed trimmer is installed by an engineer.

A photograph looking up inside the loft answers it without a visit, which saves an appointment.

Estuary exposure

Properties toward the Stour take weather off the water, and the specification should account for it without going to the lengths an open coast position requires.

Stainless fixings rather than plated, which cost very little more and do not bleed rust down a roof in five years. A generously sized flashing kit of the correct profile with a well lapped underlay collar, because driving rain is pushed under a covering rather than running down it. And on an exposed position, aluminium clad timber rather than bare timber, since the cladding takes the weather and the timber stays dry behind it.

What we fit here

Roof windows into rear slopes for loft rooms and landings. Flat roof rooflights and lanterns over rear extensions, where the kerb detail decides whether the installation lasts. Sun tunnels into internal bathrooms and hallways in the older cottages. And replacement work, which is a growing share everywhere as units fitted in the 1980s and 1990s reach the end of their sealed unit life.

On any replacement, photograph the data plate on the sash first. From that we can usually tell you what the unit is, whether the size is still made and what the job costs, without anyone visiting.

Access

Generally good, with off street parking on most roads and space to stand a tower at the rear. Tighter in the older village lanes, where frontages sit closer to the road and scaffold may need a highway licence.

Four situations, and telling them apart

Condensation on the glass. Appears on cold mornings, worst in deep winter, forms evenly across the inner face, and bears no relation to whether it rained. Clears as the day warms. Not a fault, and no work on the window will fix it.

A genuine leak. Follows rain, and usually rain driven from one particular direction. Arrives at one point rather than spread evenly. Leaves a mark that is still there when everything has dried.

Misting inside the sealed unit. If the moisture is between the two panes and cannot be wiped off either face, the perimeter seal has failed. That is a unit at the end of its life, which happens at fifteen to twenty five years, rather than an installation problem.

Water on the reveal rather than the glass. This one usually is a fault, and the cause is almost always a missing insulation collar. The collar closes the gap between frame and structure, and without it the reveal is cold enough to condense. It is a separate order line on any quotation, it is the first thing dropped from a cheap one, and the symptom does not appear until months later when nobody connects the two.

Ventilation is the actual fix

Where condensation is the diagnosis, moving air solves it and nothing else does.

An opening at the highest point of a room lets warm moist air leave, and as it goes it draws drier air in through anything open lower down. That is stack ventilation and it clears a room in minutes where a wall window alone takes hours. It only works if something at low level is open as well: a rooflight on its own in a sealed room moves very little.

Where the unit is above easy reach, a motorised opener with a rain sensor is worth the premium, because a window that closes itself when it starts raining is a window that actually gets left open. Where running mains cable through a finished ceiling would mean lifting floors and chasing walls, a solar powered opener needs no connection at all and goes in within a couple of hours.

What we will tell you before charging for a visit

Send a photograph of where the water appears and, if you can do it safely, one of the outside of the unit. Say whether it follows rain or cold mornings, and whether it can be wiped off.

Between those we can usually tell you which of the four situations you are in, and two of them do not need anybody to come out at all.