Rooflight and skylight installation in Witham

The historic core

Steep pitches, cut roofs, clay plain tile and slate, and a real chance that the property is listed or in a conservation area.

Establish the designation before anything else. Listed building consent is required for a rooflight on a listed building on any slope, front or rear, visible or not, and there is no small works exception. In a conservation area, permitted development for rooflights survives on a house unless an Article 4 direction removes it, which is a short enquiry to the council rather than something to assume in either direction.

Where consent is needed, the unit that gets approved is a conservation rooflight: low profile, upright in proportion, central glazing bar, matt black. Include the manufacturer’s section drawing with the application, because how far the unit stands above the covering is the question the officer actually cares about.

The coverings here are demanding. Old clay plain tiles are brittle and a proportion will break on removal, and matching weathered handmade tile is difficult. The usual answer is to take sound tiles from a hidden slope and put the replacements there.

The post war expansion

This is where most of our Witham work is. Concrete interlocking tiles, pitches around 30 to 35 degrees, cut roofs on the earlier blocks and trussed rafters on the later ones.

These houses take a roof window well and the work is straightforward. Two things decide the price. Whether the roof is cut or trussed, which sets how wide the opening can be without a designed trimmer. And access, which on most of these roads is easy because there is off street parking and space to stand a tower.

A substantial part of the work now is replacement rather than new. A lot of units went into this housing in the 1980s and 1990s and sealed units last fifteen to twenty five years. Photograph the data plate on the sash before doing anything else and we can usually price it without a visit.

Extensions

Rear extensions are common across every band and flat roof skylights over them are steady work.

The kerb is what decides whether it lasts. At least 150mm of upstand, the deck falling away from it so water cannot pond against the seal, and rigid insulation on the outer face of the kerb itself. That last item appears on almost no quotation and matters more than the glass specification does, because an uninsulated timber kerb punches straight through the roof insulation around the whole perimeter of the opening.

Where the extension is large enough, a lantern gives height and shape that a flat unit cannot, and collects light from more than one direction so the room stays bright as the sun moves. It needs the structure to carry it and a properly built kerb, and on a small extension it can look out of proportion.

Orientation

Worth deciding deliberately rather than defaulting to whichever slope faces the garden.

North facing gives even, cool, glare free light all day with no solar gain, and should be specified for thermal performance alone. South and west want solar control glass as standard, and west is frequently worse in practice than south because low afternoon sun arrives when the building has already been warming for hours. East gives shorter, cooler morning gain, which suits a kitchen and is difficult over a bedroom.

Coming out to Witham

We work across this part of Essex from Colchester and Witham is comfortably within range. Distance does not appear as a line on the quotation; what it affects is how we plan the day. Larger jobs and multiple units suit that better than a single small item, so if there is more than one thing to do, say so at the enquiry stage.

The reliable way to spend less

Do several at once. Access is a fixed cost shared across everything done in the same visit, so two units replaced together cost meaningfully less than two replaced a year apart.

That matters more than it sounds, because units fitted at the same time fail at about the same time. If two of three have misted, the third is not far behind, and doing it while the access is up costs a fraction of doing it separately later.

What the quotation will itemise

The unit with manufacturer, model, size code and glazing specification. The flashing kit and which profile. The insulation collar as a named line. Access and who provides it. Making good, to what standard, and whether decoration is included. Disposal. Building Control where the work is notifiable. And the contingency for decayed timber.

A quotation that says roof window supplied and fitted with one number against it is not comparable with anything. Where ours is higher than another, the breakdown will usually show you why.

Guarantee

Ten years on our workmanship, covering the weathering, the flashing, the frame fixing, the insulation collar and the making good. Alongside that sits the manufacturer’s warranty on the product, which is separate cover from a separate party.

Most rooflight problems are installation problems, which is why the first matters more. Where a unit fails under a manufacturer’s warranty on a job we did, we handle that claim rather than leaving you to argue with a manufacturer about a product we chose and fitted.

Getting it right

Rigid rather than flexible. A rigid mirrored tube reflects 98 percent or better at each bounce. A flexible foil concertina reflects perhaps 80 percent and scatters light at every fold, and over a run from roof to ceiling that difference is most of the light. We fit rigid wherever the route allows it.

Diameter decides output. It goes with area rather than width, so a 350mm tube passes roughly twice the light of a 250mm one rather than forty percent more. 250mm suits an internal WC or small ensuite, 350mm a landing or a decent bathroom, 530mm a room you actually live in.

Two beat one. Two smaller tunnels spaced apart read as ambient daylight; one larger tunnel reads as a spotlight in the middle of the ceiling.

Insulate the tube and seal the ceiling ring. A metal tube through a cold loft collects condensation, and water running down it arrives at the diffuser looking exactly like a leak. Sealing the ring airtight stops warm room air getting into the tube in the first place.

What it will not do

It is not a rooflight. There is no view, no ventilation and no sense of sky, and after dusk there is nothing. Most units take an optional light fitting inside the diffuser so the same ceiling opening does both jobs.

What it gives you, on a dull afternoon in a windowless bathroom, is enough soft daylight not to reach for the switch. For the money that is a good proposition, and it is why we recommend it over a rooflight on a fair number of jobs where a rooflight would have cost three times as much.

Maintenance

Less than anything else we fit. Clean the roof dome when the gutters are done, because the whole product depends on collecting light. Check the flashing every few years after a storm. Twist off the ceiling diffuser occasionally and wipe its upper face.

What eventually fails is the dome: polycarbonate yellows under ultraviolet over fifteen to twenty years and is a replaceable part, while a glass dome costs more initially and does not degrade. The mirrored tube itself has nothing to wear out.