The window decides the blind more often than the room does. A sliding door needs something that stacks sideways; a skylight needs a blind that works against gravity; an arched window cannot take a rigid headrail at all. This section works through each opening and what it can actually accept.
Start With the Opening
- Sliding and patio doors — wide spans, constant traffic, and a blind that must not foul the door as it moves.
- Skylights and roof windows — out of reach, working against gravity, and the hottest glass in the house.
- Bay, corner and arched windows — angles and curves a single headrail cannot follow.
- Large and floor-to-ceiling windows — where weight, sag and the maximum single-blind width start to govern.
- Small and narrow windows — where stack height eats the glass and standard mechanisms will not fit.
Three Measurements That Decide Everything
| Measurement | What it rules out | Threshold |
|---|---|---|
| Reveal depth | Recess fitting | Under 55 mm rules out a recess-fitted roller; under 70 mm rules out a 50 mm venetian |
| Width | A single blind | Past roughly 2,400 mm most blinds split into two on a shared headrail |
| Drop | Manual operation | Past about 2,400 mm a manual chain becomes awkward and motorisation starts to make sense |
Take all three before you shortlist anything. The method, including the three-point rule for out-of-square openings, is in how to measure for blinds.
When the Window Beats the Preference
People usually arrive with a type in mind and a window that will not take it. A 63 mm timber venetian on a 600 mm bathroom window gives you nine slats and a stack covering a quarter of the glass. A roller on a 3,600 mm patio door needs a tube so long it visibly sags. In both cases the opening has already made the decision.
Get a Free Measure & Quote in Cape Town
Window Blinds Cape Town measures on site, which removes the guesswork on depth, square and span entirely. Call 081 411 8471, or see what blinds cost.
Get a Free Measure & Quote in Cape Town
Window Blinds Cape Town measures, manufactures and installs across the metro. Call 081 411 8471 for a free on-site measure and quote, or browse the other blind guides.