How high and how wide should a curtain pole go?

Almost every curtain pole in Britain is fitted too low and too narrow, which makes the window look smaller, loses daylight to the stacked-back fabric, and gives the room a slightly squashed proportion nobody can quite name. The corrections are simple and they are all geometry rather than taste.

What you'll need

• Tape measure and pencil
• Long spirit level
• Cable and pipe detector

Step by step

1. Go 150 to 200mm above the window opening.This lifts the eye and makes the window and the room read taller. It also lets the top of the drawn curtain sit above the glass so no daylight is lost behind fabric. In a low-ceilinged room, go higher still — up to just below the ceiling or the cornice — which is the single most effective thing you can do to make a room look taller.
2. Extend 150 to 250mm past each side.This is the stack-back allowance and it is the number most often got wrong. It exists so the gathered curtain sits on the wall rather than over the glass when it is open, which recovers a surprising amount of daylight and makes the window look wider.
3. Choose the drop deliberately: floor or sill, not in between.Either 10 to 15mm clear of the floor, or 100 to 150mm below the sill. Halfway down the wall between the two always looks accidental. Floor length reads as more generous; sill length is more practical over a radiator or a window seat.
4. Set the projection so nothing catches.The brackets must hold the pole far enough from the wall that the fabric clears the sill, the window handle and any radiator below by at least 40 to 50mm. Check with a handle in the open position, not closed.
5. Fit the centre bracket on anything over about 1.5m.This is the part most often left in the box. Without it, the pole bows visibly in the middle within weeks, and lined curtains are heavy enough to bend a wooden or thin metal pole permanently.
6. Allow enough fabric width.Total curtain width about double the pole length for proper fullness, more for a light fabric. Curtains that are only slightly wider than the window hang flat and look mean however well the pole is positioned.
7. Check what is above the window before drilling.There may be a concrete lintel, a steel lintel, a timber lintel or plasterboard with a void, and each demands a different fixing. Cables also run horizontally above windows to switches, so scan the whole line and treat the reading as one input rather than proof.

Tips

• In a room with a low ceiling, taking the pole right up near the ceiling and the curtains down to the floor is the cheapest way to add apparent height that exists.
• Measure the drop from the top of the pole's eyelet or ring, not from the pole itself — the rings add 20 to 40mm.
• If two windows on one wall are at slightly different heights, set both poles from the same line, not from each window. The eye reads the pole line, not the window heads.

Common mistakes

• Fitting the pole just above the window frame — It makes the window look shorter, and the stacked-back fabric then covers the glass at the top as well as the sides.
• Buying a pole the width of the window — There is nowhere for the open curtains to go except over the glass, so the room is darker with the curtains open than it needs to be.
• Leaving the centre bracket out because the pole looks fine without it — Lined curtains are heavy. A pole over 1.5m sags within weeks and the bow is permanent in timber.
• Hanging curtains that end halfway down the wall — Neither floor length nor sill length. It is the one drop that always looks like an error.

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