What are blockout curtains made of?
Updated
Blockout (blackout) curtains are made of a face fabric plus a layer that stops light. The layer is either a coating on the back of the fabric, called self lined or coated blockout, or a separate blockout lining hung behind it. The colour at the front is a style choice, and the coating or lining does the blocking.
What is the layer that blocks the light?
A blockout curtain blocks light in one of two ways. A self lined fabric, often called a coated blockout, has a blocking coating on the back of the face fabric, such as acrylic, silicone or TPU, so the curtain is one layer. A separate lining is its own fabric, hung behind the face fabric. Both stop light passing through the cloth.
| Feature | Self lined blockout | Separate blockout lining |
|---|---|---|
| Layers | One fabric with a coated back | Two fabrics, the face fabric and the lining |
| Weight | Lighter than a curtain with a separate lining, with less to stack | Adds weight and thickness |
| Seams | Stitching leaves tiny pinholes of light along seams and hems | Covers the pinholes |
| Care | Many must not be machine washed, tumble dried or ironed on the coated side | Follow the care instructions for each fabric |
Even so, large self lined blockout curtains are among the heavier curtains, so they settle and hang lower over time. A separate lining suits fabrics that are not made with a coating, such as linens and many decorative weaves.
At Speedy Blinds a separate lining is joined to the curtain at the heading, fastened at the sides and left to hang free at the bottom, sitting slightly inside the face fabric so it does not show from the room.
Do blockout curtains have to be black, and what do they look like?
No. Blockout (blackout) describes what the layer does, not what colour it is. The colour you see in the room is the colour of the face fabric, and what blocks the light is the coating or lining behind it.
From the room it looks like a curtain in the fabric you chose. The back faces the window, so from outside you see the coated back or the lining. If that matters to you, ask your retailer to show you the back of the sample.
What do room darkening and semi blockout mean?
Dense woven fabrics, often called triple weave or dim out, darken a room without a coating, but they usually let a little light through. Room darkening and semi blockout usually describe fabrics that reduce light without fully stopping it.
What a particular fabric does is worth checking, so ask to see it against a window. No curtain seals a window completely, and light can still show around the edges.
Ask your curtain retailer whether the curtain is self lined or has a separate lining, what the back looks like, how much light the fabric lets through and how to care for it. They take the measure and place the order with the workroom.
Other ways people ask this
What are blockout curtains?
Curtains that stop light passing through the fabric, either with a coating on the back of the fabric or with a separate blockout lining. No curtain seals a window completely, so some light can still show around the edges.
Is blackout lining black?
Blockout describes what the lining does, not its colour. Ask your retailer to show you the lining you would get.
What is the difference between blockout and room darkening curtains?
Blockout stops light passing through the fabric. Room darkening reduces it, and how much depends on the fabric, so ask to see it against a window.
What are semi blackout curtains?
Curtains in a fabric that reduces light but does not stop it. Ask your retailer how much light the fabric lets through.
How do blackout curtains look from outside?
From outside you see the back of the curtain, which is the coated back of the fabric or the lining, because it faces the window.
This answer is general information. For your own windows, your retailer's advice and your order with them come first.