Rooflight and skylight installation in Sudbury

Timber framed buildings with Georgian faces

A recurring situation here. A property presents a brick or rendered Georgian frontage to the street with a considerably older timber framed structure behind it. That matters for two reasons.

The frame is frequently part of what is listed. Rafters, purlins and tie beams may be original and historically significant, so an opening is positioned to avoid them rather than cut through them. The survey establishes where a rooflight can go before anybody discusses what it should be, and made to measure sizes are often the answer rather than an indulgence.

And the building moves. It has been moving for centuries and it will continue to, so the fixing has to allow for seasonal movement. A modern unit clamped rigidly into a frame that flexes is under stress it was not designed for, and it shows up years later as a failed seal or a distorted frame.

Consent

Listed building consent is required for a rooflight on a listed building, always, on any slope, whether or not it can be seen. The listing covers the whole building inside and out. There is no rear elevation exception and no small works threshold, and carrying out the work without consent is a criminal offence rather than a planning irregularity, which surfaces on sale.

In the conservation area, permitted development for rooflights on an unlisted house survives unless an Article 4 direction removes it. In a town centre of this quality that is worth confirming rather than assuming either way.

Flats and maisonettes have no permitted development rights at all, and Sudbury has a good number of subdivided older properties. Any rooflight in a flat needs an application and the freeholder’s consent.

What gets approved

A conservation rooflight: sitting low against the plane of the covering rather than standing proud, upright rather than wide in proportion, with a central glazing bar, in matt black. The profile matters more than everything else combined, and the manufacturer’s section drawing is the document that answers the officer’s real question.

Where an existing modern rooflight or plastic dome is being replaced with a conservation unit, say so explicitly in the application. That is a heritage improvement and framing it that way is both true and useful.

The Victorian terraces

The silk weaving expansion left a good deal of nineteenth century terraced housing. Steep pitches, slate or clay plain tile, narrow plans, and frequently an internal bathroom or hallway with no external wall.

That is exactly what a sun tunnel is for. A rigid mirrored tube brings genuine daylight into a room that has never had any, for a fraction of the cost of anything else, and the roof component is small and low enough to be effectively invisible from the street.

Specify rigid rather than flexible, because a flexible foil tube scatters light at every fold and delivers roughly a third of what a rigid tube of the same diameter gives. Size by diameter, since output goes with area, so 350mm passes about twice the light of 250mm. And insulate the tube where it crosses the cold loft, or condensation forms inside it and arrives at the diffuser looking exactly like a leak.

The later housing

Ordinary work. Concrete interlocking tiles, pitches around 30 to 35 degrees, cut roofs on the earlier properties and trussed rafters on the later ones, off street parking and space to stand a tower.

Cut or trussed decides the price more than the choice of unit does, and a photograph looking up in the loft answers it without a visit.

Access and coverage

Tight in the town centre: narrow streets, frontages on the pavement, limited parking, and in places no side access to the rear. Scaffold on the highway needs a licence and time to arrange. Straightforward on the twentieth century roads.

We cover Sudbury from Colchester and plan it as full days. If there is more than one thing that needs doing, say so at the enquiry stage, because access is a fixed cost shared across everything done on the same visit.

Cut roof or trussed rafters

Rafters running from eaves to ridge with a horizontal purlin partway up and clear space between them is a traditional cut roof. Forming or widening an opening is ordinary carpentry, wide rooflights are possible, and the loft is convertible.

A repeating pattern of triangular frames with diagonal members crossing the middle of the space, joined by flat pressed steel plates, is trussed rafters. Rafter, ceiling tie and webs act as one engineered unit, so cutting any member sends load somewhere it was not designed to go.

With trusses at the usual 600mm centres, a unit narrow enough to sit between two of them needs no structural work at all. Anything wider needs a designed trimmer and an engineer, which is routine and which is where the price steps up.

A photograph looking up inside the loft settles it without an appointment and is the single most useful thing you can send.

Coverings

Slate and clay plain tile on the Victorian terraces, concrete interlocking tile on most of the later housing, and pantile on some Suffolk properties.

Each needs its own flashing kit and they are not interchangeable. Interlocking tiles and pantiles are profiled and need a deep kit; a flat kit designed for smooth slate leaves open voids under the profile where it crosses, and water gets under within a season. Because it enters below the flashing it appears inside as a leak that seems to come from nowhere.

It is the most common installation fault we find on other people’s work. Ask any quoting installer which kit is specified for your covering by name and part number.

Extensions

Common across all periods and where a good deal of the work is. The kerb decides whether the installation 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. Ask directly whether it is insulated.

Replacement work

A growing share, because a lot of units went into Sudbury during the 1980s and 1990s and sealed units last fifteen to twenty five years.

Photograph the data plate on the sash before doing anything else, rather than measuring. 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. Obsolete sizes are normal and solvable, usually by adapting the opening to the nearest current size and making good the reveal.