Sheer and Blackout Curtains Together: How to Layer Them on One Window

The usual order is sheer behind, blackout in front. The sheer is the layer that stays drawn through the day, so it sits nearest the glass, where it filters the sun before it reaches anything else. The blackout curtain is open for most of the day and stacks at the sides, framing the sheer; at night it closes over it. From the room you see a soft, light window by day and a solid curtain by night, and the blackout's own lining faces the glass and takes the sun.

The reverse order, blackout behind and sheer in front, has a place too. With the blackout nearest the glass, it can sit tighter to the window and inside any returns, which helps darkness, and the room always sees the sheer: drawn over the closed blackout at night, the window still looks soft rather than solid. The cost is practical. The sheer in front gets handled every time someone reaches for the blackout, and in a room used by children or guests the front layer takes the knocks.

For most Goan bedrooms we fit the usual order, because it is easier to use. For a room where darkness is everything, such as a shift worker's bedroom or a nursery, the reverse order on a ceiling track, or a blackout roller blind in the window recess behind both curtains, is worth considering. Our guide to blackout curtains for a bedroom explains where light gets round any blackout layer.

A double curtain rod for sheer and blackout is the familiar version: two poles on shared brackets, with rings or eyelets. It looks traditional and suits a room where the hardware is part of the design. For darkness it is the weakest option, because a curtain hangs below its rod and light spills over the top of both layers; even a good blackout curtain on a rod leaves a bright band on the ceiling at dawn.

A double track, with two channels in one slim profile, is the working choice for most bedrooms. It draws more smoothly, carries a heavy lined blackout curtain without sagging between brackets, and the headings sit in front of the track so it barely shows. Wall-fixed on brackets, it suits most retrofits. Ceiling-fixed, it puts the top of the blackout curtain against the ceiling, which is what the US Department of Energy recommends for draperies: hang them close to the window, put a cornice at the top or place the drapery against the ceiling, seal the sides and overlap in the centre.

On a false ceiling the track must fix into timber or metal backing above the board, not the board alone, and on an old timber ceiling into the joists. If neither ceiling nor wall above the window can take a fixing, a pelmet box carrying the tracks is the fallback. Our curtain tracks page covers profiles and gliders for each weight of curtain.

Two layers need two lines of clearance. The sheer has to hang clear of everything on the window: the handles and locks of an aluminium sliding window, the bolts on old timber shutters, a window grille, the sill and any air-conditioner pipe running past the frame. The blackout curtain then has to hang clear of the sheer's folds. If either is tight, the curtains rub, drag and wear at the leading edges, and the sheer catches on the handle every time it moves.

Measure it rather than guess. Hold a tape square to the wall and measure from the wall to the furthest thing that projects into the room; that sets the line of the back channel, plus the depth of the sheer's folds. The front channel sits forward of that by the depth of the blackout's folds. A lined pinch-pleat curtain makes deeper folds than a sheer on a wave heading, so it needs more room. A standard double bracket may be enough; on windows with deep handles or a grille, extended brackets or a ceiling track set further from the wall solve it.

Plan the returns at the same time. A return is the end of the curtain turned back to meet the wall, so light cannot escape down the sides. With two layers, the front blackout return has to wrap round the end of the sheer channel, so it is longer than on a single curtain. Ask for the track ends or brackets to allow it.

Fullness is the ratio of fabric width to track width. Our fabric calculator uses 2.25 times for a pinch-pleat heading, 2.2 times for wave and eyelet, and 2.5 times for pencil pleat. Each layer gets its own fullness, and both are measured on the same track length.

The stack is the depth of fabric that gathers at each side when a curtain is open, and it decides how long the track must be. Our track planner works it out from the window width, the fabric and the heading. Take a 150 cm bedroom window with a lined blackout pair in pinch pleat. The planner gives a track of about 275 cm, about 61 cm past the window on each side, so the open blackout clears the glass. On that 275 cm track, the blackout needs about 275 × 2.25, roughly 6.2 m of finished fabric width, before hems.

The sheer shares the track length. In a wave heading on a 275 cm channel it needs about 275 × 2.2, roughly 6.05 m of finished width, and by the planner's rules its stack comes to about 31 cm each side, well inside the blackout's 61 cm. So the open sheer hides behind the open blackout, and the glass stays clear. If the blackout is also made in a wave heading, the planner's track drops to about 240 cm, 45 cm each side, and the sheer's stack on that track is about 27 cm. The lesson in both cases: the blackout layer sets the track length, and the sheer fits inside it.

Motorised double tracks carry a motor on each channel, so the two layers can move independently. The question is which layer you will actually move. The US Department of Energy reports that 75% of home window coverings stay in the same position every day; a motor is what turns a curtain that stays put into one that is used. In bedrooms, the blackout layer is the usual choice: it closes from bed at night and can open slowly a few minutes before the alarm. On a west-facing window, a motorised sheer set to draw itself at midday and open at sunset keeps the room shaded while the house is empty.

If both layers will be moved daily, motorise both; if the sheer stays drawn most of the time, motorise the blackout and leave the sheer on a hand-drawn channel. A motor also removes cords from the window, which matters in a child's room: the US Consumer Product Safety Commission's advice is that the safest option where young children are present is to go cordless.

Plan the power before the walls are finished. Each wired motor needs a socket or a fused connection close to the end of the track, usually at ceiling height, and the cable has to be chased into the wall or run inside a false ceiling. The Building America Solution Center recommends pre-wiring windows for motorised shading during construction. In Goa, think about power cuts too: most curtain motors allow a gentle hand-draw when the power is off. Our motorised curtain tracks page covers controls and options.

Both curtains are measured from the same track, so fix its position first: on the ceiling, or on the wall as high as the room allows. Then take the track length from the planner, or from the window width plus the stack on each side, and measure the drop for each layer from the track to the floor at several points across the window. Old Goan floors are rarely level, and a drop taken at one corner can be wrong at the other.

Finish both curtains just clear of the floor, about a centimetre, so they do not collect dust and damp in the monsoon. Many workrooms make the sheer a fraction shorter than the blackout, so it never shows below the front curtain's hem. If the face fabric of either layer is linen or cotton, remember that natural fibres can relax in very humid air; a linen-look polyester sheer behind a polyester-backed blackout holds its length more reliably through the rains.

Look after the pair through the monsoon. A blackout curtain left closed all day against a window running with condensation traps damp air against the glass and the lining. The US Environmental Protection Agency advises drying condensation on windows quickly when you see it. On dry spells, open both layers in the morning, let air reach the glass and the fabrics, and close the blackout again only at night. Our blackout curtains are made with linings that suit humid rooms.