A blackout Roman blind can give you a beautifully dark bedroom, but never quite 100 per cent. This guide explains where the light gets in, the one lining question that separates a quality blind from a cheap one, and the simple addition that gets you complete darkness without giving up the look you love.
By Katherine Brown · Updated 20 October 2026 · 6 minute read
Quick answer: Fitted inside the window recess, a blackout-lined Roman blind gets you to around 95 per cent darkness, never quite 100.
Any honest maker will tell you the same. The walls of the recess block light at the sides, which helps enormously, but the blind can never sit completely flush against them.
When we do a consultation and people want blackout, the first thing we really need to establish is how black. How much blackout do they really need? That is the most important thing to establish, because people may start off by saying it’s got to be completely black, otherwise I can’t sleep.
But that takes us down a different path, and your hardware options are then fewer. For example, sometimes people will say, ‘I have to have complete darkness, but I’d really like a curtain pole.’ Well, the two don’t go together, because a curtain pole will always let in an element of light.
There are things you can do to help that. You can position the pole as high as possible above the window, and that will help. Curtains can be returned to the side of the wall, as you would on a track as well. But if it’s for complete blackout, or for a baby’s bedroom, we wouldn’t advise using a curtain pole. In that instance, a track is so much better. And if you want to enhance that even further, use a track with a covered lath and fascia, or a track with a pelmet.
There are other tricks we can play. If somebody really wants a pole, we can add a blackout roller blind behind. We can use zipped blinds as well, where a roller blind is zipped into channels at the sides and at the bottom, and has a cassette at the top. They’re a great piece of kit.
We often use those alongside Roman blinds, where people want a Roman blind but they want blackout. A Roman blind, by its very nature, unless it’s set into a recess, will always let light in at the sides. So we often use a zipped blind behind it for that purpose.
So there’s a whole series of questions we need to go through with people to find the absolute right blackout solution for them.
‘You will get a better level of blackout in the recess, but no blind can be fitted totally snug, otherwise the fabric would rub on the sides. So you are looking at around 95 per cent. If chinks of light around the edges would annoy you, it is not for you.’
How much that last five per cent matters depends on where you sleep. If light falls across the bed in your line of sight, you will notice it. If it doesn’t, you may never see it.
It is worth getting right. The NHS advice on insomnia puts a dark, quiet bedroom near the top of its list, and names curtains and blinds as the way to get there.
Katherine’s Key Takeaway
Before you choose anything, think about where the bed sits in relation to the window. A blind can be 95 per cent perfect, but if the light falls straight across your pillow, that last five per cent is the bit you will notice.
Quick answer: The blind hangs about three centimetres in front of the window, and light slips down each side through the gap between the fabric and the wall.
Most people assume light comes through the stitching or the channels that hold the rods. It doesn’t. The headrail on a manual Roman blind is around three centimetres deep, front to back, and more if the blind is motorised. The fabric hangs from the front of that headrail, so the whole blind sits forward of the window, and light creeps in down each side.
That is how every Roman blind is built, not a flaw in the making. It is also why fitting inside the recess helps so much: the recess walls close off the gap.
Quick answer: For a truly dark room and a beautiful blind, choose a blackout lining and interlining made up as separate layers, not a cheaper bonded lining.
A sheer or unlined Roman blind gives no blackout at all. For a bedroom you want a proper blackout lining with interlining: a soft, felt-like layer between the face fabric and the lining. Interlining:
Katherine’s workroom lines and interlines as standard. There is one question that tells you whether you are being offered a quality blind or a shortcut.
‘A lot of cheaper blinds use a blackout bonded lining, where the interlining is fused to the blackout lining. It is quicker and cheaper to make, but put it next to a blind that is properly lined and interlined and you will see the difference straight away.’
Cheaper suppliers use bonded lining for speed: one ready-made layer to attach rather than two built up by hand. The trade-off shows in the finished blind. A properly lined and interlined Roman has more body, hangs with more weight and holds its folds far better.
One exception: if you love the relaxed, scooped look of a soft Roman and have chosen a heavy face fabric, Katherine will sometimes leave the interlining out so the bottom of the blind falls into a soft curve. It is a judgement made fabric by fabric.
Katherine’s Key Takeaway
Ask any maker one question: is it blackout lined and interlined, or blackout bonded? The answer tells you in seconds whether you are buying real quality or a shortcut.
Quick answer: For blackout alone, inside the recess usually wins because the walls cover the side gaps. But the right choice depends on the window.
Outside the recess, her rule of thumb is to take the blind to the sill width and around 15 centimetres above the window, so it just covers the top of the glass when raised. Any higher and you see blind, then wall, then window.
Fabric width matters too. Most fabrics are 135 to 140 centimetres wide, so if going to the sill width would need an extra width of fabric and a seam, it is often more sensible to fit to the frame instead.
Quick answer: Fit a zipped or cassette roller blind inside the recess behind the Roman. It seals the edges for complete darkness while the Roman stays on show.
This is the answer for anyone who wants real darkness but doesn’t want curtains. Behind the Roman sits a plain blackout roller blind whose fabric runs in channels down each side and tucks into a cassette at the top. Sealing the edges blocks exactly the light a Roman on its own cannot. People call these zipped blinds or cassette blinds: they mean much the same thing.
‘If you don’t like curtains but want really good blackout, a zipped roller blind behind the Roman is such a good idea. They are not terribly expensive, they are a really good bit of kit, and they give you complete blackout, as long as the recess is deep enough.’
There is even a dual version with an insect net and a blackout blind in one: net down during the day so you can open the window without letting flies in, blackout at night.
If you need to sleep through full daylight, for example after night shifts, a Roman blind is rarely the whole answer. Katherine would steer you towards layering, and towards blackout curtains, which give the deepest darkness of all.
Katherine’s Key Takeaway
If you love a Roman blind but need genuine darkness, you do not have to compromise on the look. A zipped blind behind it gives you both, provided the recess is deep enough to take it.
Quick answer: Every blind we make meets the UK child-safety standard. In a child’s bedroom, though, the safest choice is a blind with no chain at all.
The Roman headrails Katherine uses have a small wheel the chain runs over, which releases under a sudden downward pull so the chain cannot become a choking hazard. That is why it should never be screwed tight to the wall. The chain is also set 1.5 metres above the finished floor. Roller blinds don’t have the release wheel, so their chains are fitted at the same height with a retainer fixed to the wall.
The Royal Society for the Prevention of Accidents (RoSPA) goes further for children’s rooms. It advises against any looped cord or chain in a child’s bedroom, suggests a cordless blind when buying new, and recommends keeping the cot away from the window. A motorised Roman blind removes the chain altogether, and battery motors keep the headrail neat with no wiring.
What Our Clients Say ★★★★★
Black-Out For Our Son’s Nursery
‘Great service from Katherine and her team, the curtains were made to measure and provided the black-out effect needed for our son’s nursery, plus they look smart too.’
Charlie C, Google review
Quick answer: From around £500 to £1,000 for a standard window. The blackout lining itself adds only about £1 per metre.
The cost sits in the making, not the lining. A Roman blind done properly is enormously time-consuming: a single blind can take one person a full day to make by hand. That craftsmanship, with the quality of the fabric, is what you are paying for and what you see in the finished blind. For more on what drives the price, see what affects the cost of bespoke curtains and blinds.
What Our Clients Say ★★★★★
Real Expertise And Quality
‘Katherine made four gorgeous roman blinds for my bedroom. Her service is not cheap, but you are paying for real expertise and quality and I feel the pricing was fair.’
Catherine J, Google review
No. A blackout-lined Roman blind fitted in the recess reaches around 95 per cent, with a little light at the sides. For complete darkness, add a zipped roller blind behind it, or choose curtains.
Yes. The blackout comes from the lining behind the fabric, not the face fabric, so you can choose almost any pattern or colour.
A lined and interlined blind has separate layers built up by hand for a better look and feel. A bonded blind fuses the layers together to save time and cost.
Every blind is made to the UK safety standard, with a chain that releases under a downward pull, set 1.5 metres off the floor. For a nursery, RoSPA advises a cordless blind, and a motorised Roman removes the chain entirely.
Yes. The interlining in a quality blackout Roman blind adds real insulation, helps with draughts and softens outside sound.
Katherine Brown began her career project managing major house renovations, giving her a rare mix of creative design ability and deep technical understanding of construction, hardware, motorisation and installation. For the last decade, Katherine and her team have delivered bespoke window dressings and soft furnishings for homes across London and the Home Counties, including large heritage properties, complex architectural spaces and full-house projects where every room demands a tailored approach.
She works with some of the UK’s most respected interior designers as well as private homeowners, and her work is recognised for its precision, considered detailing and a calm, collaborative design process rooted in trust and craftsmanship.
