Rooflight and skylight installation in Dovercourt

The Victorian and Edwardian properties

Steep pitches, cut roofs with rafters and purlins, slate or clay tile. Good roofs for a skylight installation: the pitch does much of the weathering work, openings can usually be formed without a structural trimmer, and the headroom gain from a roof window is generous.

Many are three storey or have been divided into flats. Height means scaffold rather than a tower, which is a real line on the quotation. And a flat has no permitted development rights at all, so a rooflight in one needs a planning application and the freeholder’s agreement, whatever the roof is like.

Underlay is the usual unknown on a roof of this age. Where there is none, the weathering is built around the opening rather than lapped into a membrane. Normal, more work, and it belongs in the quotation.

Interwar and post war housing

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

Establish which you have before asking for a quotation, because it decides more about the price than the choice of unit does. Rafters running eaves to ridge with a purlin partway up and clear space between them is a cut roof: a wide opening is ordinary carpentry and the loft is convertible. A repeating pattern of triangular frames with diagonal webs joined by flat pressed steel plates is trussed: a unit narrow enough to sit between two trusses at 600mm centres needs no structural work, and anything wider needs a designed trimmer and an engineer.

Profiled interlocking tiles need a deep flashing kit rather than the flat kit used on slate. A flat kit leaves open voids under the tile channels where it crosses them, and water gets under within a season. It is the most common installation fault we find on other people’s work, it is invisible once the job is finished, and it is where cheap quotations economise.

Coastal specification

The same three adjustments that apply anywhere on this coast, none expensive at the point of order and all difficult to add later.

Stainless fixings rather than plated, because salt air corrodes plated fixings within a few years. A durable factory finish, with aluminium clad timber suiting exposed positions particularly well. And weathering detail sized for driving rain rather than for rainfall, because wind driven water is pushed under a covering rather than running down it.

Sealed units also tend toward the shorter end of the fifteen to twenty five year range in coastal positions, which is worth knowing when deciding between repairing an old unit and replacing it.

Bungalows

There are a lot of them here and they are a genuinely different proposition.

The roof area is large relative to the rooms, so daylight can go where it works best rather than where it fits. Every room is under the roof, so internal bathrooms and hallways can have a sun tunnel, which is the cheapest daylight in this trade. And access is easy, because single storey eaves are reachable from a tower on almost every plot, which removes the line that most often surprises people on a quotation.

Vaulting a ceiling is the most transformative thing that can be done to a bungalow room, and rooflights in the pitched plane are what make it work. It needs structural attention, because the ceiling joists in a cut roof are usually acting as ties holding the feet of the rafters together, and removing them without a ridge beam or collar arrangement lets the roof spread. Where the roof is trussed, vaulting means replacing the structure and it is a much larger project.

Permissions

Straightforward for most Dovercourt houses. 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, with additional obscure glazing and opening restrictions on side elevations facing a boundary.

The exceptions are individually listed buildings, which need consent regardless of slope or visibility, and flats and maisonettes, which have no permitted development rights.

Access

Generally good. Driveways and front gardens on most of the interwar and post war roads, with space to stand a tower at the rear. Tighter in the older seafront streets, where parking is limited and scaffold may need a highway licence.

When the size is obsolete

Normal for anything of that age and entirely solvable. Three routes.

Adapt the opening to the nearest current size, usually within 40mm or 60mm, packing out or trimming back and making good the reveal. Invisible when finished, and it leaves a standard size for the next thirty years. This is the usual answer.

Find another manufacturer at the old dimension, which suits an opening that is genuinely awkward to alter.

Reframe to a current size, which makes sense where several windows are being standardised or the timber needs replacing anyway.

What nobody should do is force a unit into an opening it does not fit and pack the difference. It survives about a year before the packing settles, the frame goes out of square and the sash stops closing properly.

The glass upgrade you get anyway

A unit fitted twenty five years ago has no low emissivity coating, no argon, an aluminium spacer and no solar control. The replacement has all four as standard, so the room will be warmer in winter, cooler in summer and quieter in rain without paying extra for any of it.

Where the window faces south or west, adding solar control glass at this point costs a modest premium because the labour and access are already being paid for. Coming back for the glass alone later costs nearly as much as the whole replacement.