Double roller blinds give you the flexibility to switch between filtered daylight and complete privacy using two separate fabrics in one system. However, to make sure they fit and operate properly, the measurements need to be taken correctly. Unlike a standard roller blind, a double roller blind requires enough recess depth to accommodate two rollers and their brackets.
In this guide, Home Decisions explains the simple checks you can do at home before ordering, including how to measure the width, drop, and, most importantly, the recess depth. You’ll also learn which measurements are useful to note down and which details our professional fitters will confirm during a free measuring visit, helping you choose the right solution for your windows with confidence.
Before You Measure: The One Check That Catches Most Problems
Most measuring guides start with width. The check that prevents the most problems is depth.
Measure your recess depth from the surface of the glass to the front edge of the window frame. That figure tells you immediately whether a recess fit is possible, or whether a face fix is needed.
A single roller blind cassette needs approximately 60 to 75mm. A double roller on one bracket needs considerably more.
| Blind type | Minimum recess depth | If shallower than this |
| Single roller blind | ~60-75mm | Usually still recess-fits with a slim cassette |
| Double roller blind (standard bracket) | ~110-130mm | Face fix required |
| Double roller blind (slimline stacked bracket) | ~90-100mm | Borderline — measuring visit needed |
These are approximations, not specifications. The only accurate way to confirm your recess depth is a measuring visit. But the check above tells you which conversation to have when you get in touch.
How to Measure for Double Roller Blinds: Step by Step
Work through these six steps before you contact us. You do not need to be exact on every figure — the fitter takes precise measurements on the day. What you need is enough information to have a useful conversation about fabric, bracket type and fit.
- Measure the recess depth from the glass face to the front edge of the frame. Compare against the table above before you go further.
- Measure the recess width from reveal wall to reveal wall. Take the measurement in three places at the top, middle and bottom of the recess and note the smallest figure. Recesses in Victorian and Edwardian windows often taper slightly; modern uPVC frames are usually more consistent.
- Measure the drop from the top of the recess to where you want the blind to stop. Decide whether that is the window sill, a point below the sill, or the floor.
- Decide whether both rollers need the same drop. This step does not appear in most measuring guides, but it comes up on almost every fitting. The blackout and sunscreen rollers on the same bracket are ordered as separate units. In a bedroom, the blackout roller may need to reach the floor for complete darkness, while the sunscreen roller only needs to reach the sill. If the drops are different, note both measurements separately.
- Note your window type. Tilt-and-turn windows need handle clearance checked before the bracket can be positioned. Bay windows need each section measured independently. Flag either of these when you contact us so the fitter knows what to expect.
- Take a photo of the window and the recess. A clear photograph of the full reveal, including the frame depth, is more useful than measurements alone when choosing between bracket types.
Width and Drop Deduction Reference
| Fit type | Width to order | Drop to order | Notes |
| Recess fit | Recess width minus 10mm | Top of recess to stopping point | Deduction allows blind to run freely |
| Face fix | Window width plus 50-100mm each side | From bracket mounting point to stopping point | Overhang reduces light bleed at the edges |
| Bay window (each section) | Each section measured independently | Recess or face fix per section | Fitter aligns cassette heights across sections |
What If the Recess Is Too Shallow? Face Fix Explained
If your recess depth is under approximately 90mm, a face fix is the correct solution. The double bracket mounts on the face of the window frame or on the wall above the window, outside the recess entirely. The two rollers still sit on one bracket and still operate independently. The function is identical to a recess fit; only the mounting position changes.
For a face-fix double roller, the width of the blind is ordered wider than the window opening, typically 50 to 100mm beyond the frame on each side. That overhang blocks the light that would otherwise creep around the edges. The fitter determines chain placement on the day, taking into account furniture, curtain tracks and door positions near the window.
This scenario is common in 1980s and 1990s uPVC builds, where reveals tend to be shallower than in Victorian and Edwardian houses in Ilford, East Ham and Stratford. If you are not certain whether your window is deep enough, that is what the free measuring visit is for.
Bay Windows: Why Each Section Is Measured Separately
A bay window cannot be treated as a single opening for a double roller blind. Each section of the bay is measured and ordered as an independent unit, with its own bracket set. In a three-section Edwardian bay, a common window type across the service area that means three separate pairs of rollers, aligned so the cassette heights sit level across all sections.
The fitter handles that alignment on the day. What you should know before ordering is this: some light gap at the angled joins between sections is unavoidable.
The fitting method minimises those gaps, and the result is substantially better than a single face-fixed roller stretched across the whole bay, but the gaps do not disappear entirely. That is worth knowing before you decide on fabric opacity for the blackout roller.
What the Fitter Handles on the Day
The steps above give you enough to have a productive first conversation and make fabric choices with confidence. The rest is handled during the measuring visit:
- Precise bead-to-bead width measurement with professional tools
- Recess depth confirmation and bracket selection (standard or slimline stacked)
- Chain placement decision — which chain goes on which side, based on your room layout and how you use the window
- Bracket positioning and visual alignment across bay sections
- Handle clearance check on tilt-and-turn windows
- Fabric and opacity recommendation based on room orientation, privacy requirements and whether you need different drops on the two rollers
- Motorised double roller blinds discussed if relevant — motorisation removes the chain placement question entirely
Measuring a double roller blind doesn’t have to be complicated. Taking a few basic measurements at home gives you a good starting point, but details such as recess depth, bracket selection, handle clearance, and the final fitting measurements are best checked by a professional to ensure everything fits and operates smoothly.
At Home Decisions, we provide a free measuring service across East London and Essex, confirming every detail before your blinds are made. That means you can choose your fabrics with confidence, avoid costly measuring mistakes, and enjoy a made-to-measure installation that looks great and performs exactly as it should for years to come.
Book your free measuring visit and we will cover everything above during the visit. We serve Rainham, Barking, Romford, Hornchurch, Ilford and the wider East London and Essex area.
Frequently Asked Questions About Measuring Double Roller Blinds
Do double roller blinds need a deeper recess than single roller blinds?
Yes. A single roller blind cassette typically needs around 60 to 75mm of recess depth. A double roller blind on one bracket needs around 90 to 130mm, depending on the bracket type. If a recess is shallower than this, a face fix is used instead, mounting the bracket outside the recess on the window frame or wall above.
Can both rollers in a double blind have a different drop length?
Yes. The blackout and sunscreen rollers on the same bracket are manufactured and measured as separate units. In a bedroom, the blackout roller may reach the floor for complete darkness while the sunscreen roller stops at sill height. Both drop lengths are specified independently when ordering, even though both rollers sit on the same bracket.
How do I measure the width for a double roller blind?
Measure the recess width from reveal wall to reveal wall at the narrowest point, taking readings at the top, middle and bottom of the recess and using the smallest figure. For a recess fit, the blind is made approximately 10mm narrower than this measurement so it runs freely. For a face fix, the blind is made wider than the window opening to reduce light bleed at the edges.
Can double roller blinds be fitted outside the recess?
Yes. This is called a face fix. The double bracket mounts on the face of the window frame or wall above the window rather than inside the recess. It is the correct solution when the recess is too shallow for both cassettes. The blind functions identically to a recess-fit installation; only the mounting position is different.
What does the double bracket look like and how does it work?
A double bracket is a single mounting unit that holds two independent roller tubes side by side, or front to back on a slimline version. Each roller has its own operating chain and works independently. Both blinds sit within one bracket, which keeps the installation compact compared to mounting two separate brackets in the same recess.
Can you fit double roller blinds in a bay window?
Yes, but each section of the bay is measured and fitted as a separate unit. A three-section bay needs independent double bracket sets for each section, as the brackets cannot span the angled joins between sections. The fitter aligns the cassette heights across all sections on the day. Some light gap at the angled joins is unavoidable, though fitting reduces it significantly.
Do double roller blinds operate with two separate chains?
Yes. Each roller has its own operating chain. The fitter decides which chain goes on which side of the window based on room layout, furniture position and ease of daily use. On some installations both chains are positioned on the same side of the window, staggered in length, so both are accessible without reaching across the blind.
What should I do if my window recess is not deep enough for a double roller?
Book a free measuring visit. The fitter will confirm the recess depth with professional tools and either confirm the window can take a slimline stacked bracket or specify a face-fix setup. Recess depth is the one measurement most buyers cannot assess accurately at home, and confirming it is exactly what the measuring visit is designed to do.
Is a double roller blind the same as a day and night blind?
No. A double roller blind is two independent rollers, typically blackout and sunscreen, on one bracket operated by separate chains. A day and night blind is a single roller with alternating sheer and opaque fabric stripes on one tube, adjusted by rotating the tube rather than raising or lowering it. They are different products with different mechanisms and different functions.
Do double roller blinds work on tilt-and-turn windows?
Usually yes, but handle clearance must be checked before the bracket is positioned. A tilt-and-turn window opens inward and the handle arc must remain unobstructed when the window is in use. The fitter checks clearance during the measuring visit. Where handle clearance is very limited, perfect fit blinds that clip directly into the frame may be a better option for that window.
