Skylight Blinds for Roof Glass and Lanterns

We measure the opening from inside the room, but what matters is where the blind will fix. On a factory-made roof window, the blind usually fits to the frame itself, just inside the glazing bead, and the exact width between the frame sides at the top and the bottom decides the channel length. On a site-built lantern, the blind often fixes to the plaster of the light well instead, and plaster walls are rarely parallel, so we measure at several points along each side.

We also record the depth of the light well, the angle of the glass, the position of any opening handle or vent, and what the ceiling is made of. A tensioned blind pulls on its fixings constantly, so the head and the foot must go into something solid. Old timber ceilings, thin gypsum board and laterite that crumbles at the surface all need a different fixing plan.

Almost every skylight blind above head height is motorised, because a blind that needs a ladder is a blind that stays in one position. There are three ways to power it. A rechargeable battery motor sits inside the roller and is topped up with a cable every few months; a small solar panel can be added on the outside face of the glass to keep it charged; and a wired motor runs from a mains supply brought to the head of the blind.

In Goa, power cuts settle the question for many houses. A battery or solar motor keeps working when the supply drops, which matters in a loft bedroom on a summer afternoon. A wired motor needs either an inverter circuit or acceptance that the blind will stay where it is until power returns. Our motorised blinds page compares the motors, remotes and wall controls in more depth.

For heat, the face that looks at the sky is what counts. A white, pale or metallised outer face reflects more of the sun back out through the glass; a dark face absorbs it and warms the air under the ceiling. A lower-openness fabric cuts more glare, a more open one keeps a view of the sky. In a living room we usually choose a reflective-backed screen fabric; in a bedroom, a blackout fabric with a pale outer side.

The air at the top of a room is the warmest and wettest in the house, and during the monsoon a skylight can run with condensation for days. A blind pressed against cold, wet glass will mark and, if it is a natural fibre, grow mildew. We specify fully synthetic fabrics overhead, leave a small air gap between fabric and glass where the system allows, and suggest opening the blind on dry spells so the glass and the fabric both dry out.

Leaks are the other concern. A skylight that seeps at a corner will find the blind before it finds the floor. Before fitting, we look for water staining on the light well and the frame. If there are signs of a leak, the skylight should be resealed before the blind goes in, or the new fabric will carry the stain within a season.

Near the coast, the weak points of a skylight blind are metal: the guide wires, the springs, the tension fittings and the screws into the frame. Salt carried in the air settles high up where it is never wiped away, and plain steel parts rust and stain the fabric. We use stainless steel wires and fixings and anodised or powder-coated aluminium channels as standard in sea-facing houses.

Motor heads and battery packs need the same thought. A motor in a closed cassette is far better protected than one left open in a damp roof void, and in a house that stays shut through the monsoon, a battery should be charged before it is left and checked when the owners return.