Wilsden skylights and rooflights for village terraces and loft rooms

Front slope or back

The back slope is the easier slope on a terraced row. It faces the garden or a back lane, and a window there leaves the street view alone. The front slope is a different question, particularly where several neighbours have kept the roof unbroken, and we point out the choice before it is settled.

One window or two

A single window sized to the room usually serves better than two small ones. It lights the floor from one position, needs one opening cut, and leaves more of the slate in place. Where the attic runs the full width of a row house, a pair can balance the room, and we judge on site which makes sense.

The look of the frame

A conservation rooflight is slim, normally black, and lies close to the covering. On a grey roof it recedes. So it is the unit we show first on older stone buildings. A standard roof window is a fair choice on a rear slope that nobody sees.

Inside the attic

The rafters in an old terrace roof vary in size and spacing, and old timbers are rarely identical. We measure the actual spacing and note the position of any purlin or collar, because the frame has to land in a gap that the timbers allow or be trimmed into one.

Sound timbers first

Before a frame is ordered, we check the rafters round the opening for rot and woodworm, and the slates for the condition they are in. A frame set into weak timber is a weak frame, so a rafter in poor order is dealt with when the opening is framed, and we say so if the covering above needs attention first.

Light down the attic wall

An attic ceiling slopes, so the window sits in the sloping part and a short lined well carries the light down. The well can be square or splayed. A splayed well, wider at the bottom, spreads daylight further into the room and is the usual choice where the attic is narrow.

On fitting day

The slates round the opening are lifted and kept, the frame goes in with its flashing, the slates go back and the attic reveal is plastered. We notify Building Control about this attic window too.

Why the bathroom and landing differ

A landing is a corridor, and daylight should land on the floor and the treads. A bathroom is a small box where privacy matters, so the light should arrive from above through a frosted diffuser in the ceiling, which needs no blind.

Running a tube past obstacles

A rigid tube sends daylight further with less loss than a flexible one on the same route. When the bathroom is not directly under the dome, we plan a short angled run with the fewest bends. Every bend dims the result, so the tube takes the straightest line the roof allows.

Sizing the openings

A landing window only needs to be as large as the stair is long, since the light falls down the flight. A bathroom tube is measured by its diameter and chosen to the size of the room: a larger tube for a bathroom with a bath and a shower, a smaller one for a cloakroom. The sizes are agreed on the survey and the quote names them.

Where the loft floor comes in

A tube has to cross the loft, and the loft floor in an old terrace may be boarded, lath-and-plaster, or bare joists with deep insulation between. We find out which on the survey and plan the route and the lining around it, so that the tube is kept warm and the ceiling below is not disturbed more than the opening needs.

A window and a tube together

There is nothing to stop both going in. The landing gets a window in the slope above it and the bathroom gets a tube, each sized to its room. The two openings can be cut together, so the roof is opened once, and the written quote then covers both rooms.

What a lower U-value means

A U-value measures how fast heat leaks through a material. The lower the figure, the less escapes. An old single-glazed unit leaks heat fast, and a modern sealed double or triple glazed unit with a warm-edge spacer loses far less.

Coatings for hot rooms

A south or west facing room can overheat in summer. Glass with a coating that cuts solar gain admits less heat, and we specify it where the room faces the afternoon sun.

Condensation on the inside

If the old unit drips with moisture in winter, the cause may be a cold frame rather than a failed seal. A thermally broken frame helps, since rooflight condensation on a cold frame is warm air meeting a cooler surface.

Keeping the old size or going bigger

A like-for-like swap keeps the opening as it is. A bigger unit means cutting the kerb and the roof deck back, so the work is larger. It can be worth it where the old rooflight was small for the room, and we note the size the roof could carry. The replacement is fitted by us and the old unit is taken away.

Roof access

A single rooflight on an extension is reached from a ladder or from the main roof, and the old unit comes out in one piece. The opening is covered before we leave the roof, so the room is never left open to the weather overnight. If rain is forecast while the unit is out, the work waits for a drier spell, and the old unit stays in place.

Fitting it in one go

An existing opening and kerb usually carry the new unit with little extra work, so the replacement is quick. We check the kerb on the survey, and if it has rotted or sagged, we rebuild it while the unit is out.