Rooflight and skylight installation in Great Wigborough

Ground movement, which is a real consideration here

The heavy clay soils across this part of Essex shrink and swell with the seasons, and buildings on them move. That is not a defect and it does not stop a rooflight going in, but it changes how the work is detailed.

Older buildings here have generally been moving for a very long time and have found their own equilibrium. What matters is not correcting that movement but allowing for it.

Nothing is assumed from a drawing. Every dimension is measured off the building at the position the unit will actually occupy, because a rafter spacing measured at one end of a slope may be different at the other, and a roof that has settled is not square.

The frame is set square regardless. A unit fitted twisted to match a sagging roof gives a sash that catches at one corner and never closes properly. Packing and trimming absorb the difference; the window itself sits true in both directions.

Fixing allows for seasonal movement. A rigid modern unit clamped hard into a structure that flexes is under stress it was not designed for, and it shows up years later as a failed seal or a distorted frame.

Where a building shows signs of active rather than historic movement, that is a question for a structural engineer before it is a question for us, and we will say so rather than fitting a window into a moving opening.

Exposure

Properties standing in open ground on the marshland edge take considerably more wind than a house in a village street, and salt carries inland on the wind from the estuary.

Stainless steel fixings rather than plated, which cost very little more and do not stain an exposed roof. A correctly profiled, generously lapped flashing kit rather than a universal one, because driving rain is pushed under a covering rather than running down it and gravity does very little of the weathering work here. And wind loading checked against the site on larger units and anything that opens.

Farms and converted buildings

Most of the older property here is agricultural in origin, and those are their own category.

The first question is what the roof is actually made of, since historic timber, twentieth century lightweight trusses and steel frames all occur, and the answer decides whether a heavy unit such as a lantern needs structural work.

The second is what the original permission said. Conversions are frequently granted with conditions about rooflights, or with permitted development rights removed by condition, and those run with the property regardless of who owns it now. Reading the permission first saves a wasted application or an enforcement problem.

Consent

Listed building consent is required for a rooflight on a listed building, always, on any slope, whether or not anyone can see it, and the parish has a number of listed farmhouses and cottages.

Where a property is unlisted and outside any designation, permitted development normally applies: no more than 150mm projection beyond the plane of the roof and not above the highest part of it.

Coverings

Handmade clay plain tile and peg tile on the older buildings, pantile on several of the agricultural ones, and concrete interlocking tile on the twentieth century housing.

Pantiles need their own deep flashing profile and are unforgiving of a universal kit. Handmade clay is the most demanding of all: small, double lapped, irregular and brittle, with a proportion breaking on removal whatever care is taken. Matching weathered tile is difficult, and the usual answer is to take sound tiles from a hidden slope so the visible elevation stays consistent.

Access and coverage

Excellent on site, with space around almost every property for a tower or scaffold on private land and no highway licences to arrange. The constraint is more often getting a delivery vehicle with a large unit down a single track lane, which is worth establishing at survey.

Because the parish is small and we come out from Colchester, we plan work here as full days. Access is a fixed cost shared across everything done on the same visit, so mention everything that needs doing at the enquiry stage rather than one item at a time.

What we would advise against

A universal flashing kit. On open ground with wind driven rain, that is the single most consequential economy a quotation can make, because the flashing is doing almost the whole weathering job rather than gravity.

Plated fixings. They corrode and stain, and once a fixing has gone the flashing it held is loose. Stainless costs very little more.

Forcing a modern unit into an old opening and packing the difference. On a building that has already moved, this fails faster than anywhere. Adapt the opening properly or order to fit.

Triple glazing as a default. Real but modest thermal gain, at the cost of weight, daylight transmission and a good deal of money. Solar control glass where it faces the sun, a properly insulated kerb and a sealed vapour control layer do more for how a room feels.

Getting a price

A photograph of the roof, one looking up inside the loft, and the address. For a replacement, the data plate on the sash. From those we give an indicative range by email, then a fixed written itemised price after survey.

Because the parish is small and we come out from Colchester, we plan work here as full days. Access and travel are fixed costs shared across everything done on the same visit, so mention everything that needs doing at the enquiry stage.