Rooflight and skylight installation in Myland

What a trussed roof allows

The trusses sit at 600mm centres and each one is an engineered unit in which rafter, ceiling tie and webs work together. A rooflight narrow enough to sit between two of them, touching neither, goes in with no structural work at all. That is the straightforward job and it is what most Myland enquiries turn into.

Anything wider means cutting a truss member, which changes how the roof carries load, and it needs a structural trimmer designed by an engineer rather than judged by a fitter. It is routine work and it is the point at which the quotation steps up. Knowing that before setting a budget avoids an unpleasant surprise.

It also means the loft is not convertible in the ordinary sense. Webs cross the middle of the space, and clearing them means replacing the roof structure rather than boarding it out. On these estates, daylight work happens in extensions rather than in the main roof.

Warranties and covenants

Two things specific to new build, and both are simple to deal with if they are checked first.

The structural warranty. Where a property is still inside its cover period, forming a new opening in the roof can affect it. That is not a reason to avoid the work. It is a reason to check the terms and to keep documentation showing the installation was carried out to the manufacturer’s instructions. We provide a written specification naming the unit, the flashing kit and the detailing, plus a ten year guarantee on the workmanship, which is what a warranty provider asks for if the question arises.

Covenants in the deeds. Developers frequently restrict alterations to elevations facing the street. These are private contractual restrictions rather than planning ones, they are enforceable, and they are much easier to read before the work than to argue about after.

Planning itself is usually straightforward. There is no conservation designation over the modern estates, so permitted development normally applies: a rooflight is permitted provided it projects no more than 150mm beyond the plane of the roof and does not sit above the highest part of it.

Shallow pitch, and getting the light in

Pitches here run between 25 and 30 degrees, which is comfortably above any manufacturer’s minimum but shallow enough to change two things.

Water sheds more slowly, so more of the weathering job falls on the flashing kit. The correct deep profile kit for an interlocking tile is essential rather than preferable, and substituting a flat kit intended for slate leaves voids under the tile profile that water finds within a season. It is the most common fault we find on other people’s work and it is invisible once the job is finished.

The reveal is longer and shallower, which blocks a surprising amount of the light the window collects. Splaying it, cutting back at an angle at head and sill rather than boxing it square, opens the beam and makes a modest unit feel much larger. It costs a little more in plastering and it is the best value decision available on a roof of this pitch.

The older core

Around the church and the older stretches of Mile End Road the picture is different: traditional cut roofs with rafters and purlins, steeper pitches, and coverings including slate and clay plain tile.

Cut roofs give real freedom. Openings can be formed or widened with ordinary carpentry, wide rooflights are possible, and lofts convert properly. The trade off is age: more variable timber, less predictable underlay, and a genuine possibility of decay around an old opening. Any honest quotation on a property of that age names a contingency rather than pretending it cannot happen.

There are listed buildings in the older part of the parish. A listing removes permitted development entirely and listed building consent is required for a rooflight on any slope regardless of visibility.

Access

Excellent on the new estates. Off street parking, wide roads, open frontages and space to stand a tower at the rear. Most single storey extension work needs no scaffold at all, which keeps the price noticeably below the terraced parts of town.

Tighter around the older core, where parking is limited and side access is not guaranteed.

What to send us

A photograph of the roof, one looking up inside the loft, and for an extension one showing where the flat roof meets the house. The loft photograph settles cut against trussed, which is the question that decides the price.

Flat rooflights or a lantern

On a modest kitchen extension, two or three flat roof rooflights in a row light a long room more evenly than one large unit ever will, cost less, and sit lower from outside.

On a larger extension with a flat ceiling and normal head height, a lantern gives volume the room does not otherwise have, and collects light from more than one direction so it stays bright as the sun moves round rather than having one good hour. It needs the structure below to carry it and it can look out of proportion on a small extension.

Sizing and overheating

Glazed area somewhere around 15 to 20 percent of floor area gives a bright room without turning it into a greenhouse. The common mistake is jumping straight to the largest unit that fits.

A great many Myland rear elevations face south or west, and a large rooflight on those orientations without solar control glass produces a room that is unusable on a July afternoon. The glass costs a modest premium at the point of order and a great deal to change afterwards, because the labour and access are identical either way.

The second half of the answer is an opening at the highest point so accumulated heat can leave. On a motorised unit with a rain sensor, night purge happens without anyone thinking about it.

Maintenance

Keep the perimeter clear. Leaves and silt collect around a kerb, water sits against the seal, and standing water is what kills a flat roof unit early. Check the outlet the roof drains to, because a perfect fall discharging into a blocked gulley is a pond. Clean the gasket on any opening unit once a year, since grit on a compression seal stops the sash seating and gets reported as a leak.