To reduce light gaps around blackout blinds, start with accurate made-to-measure fitting and choose a blind system suited to the window. Blackout fabric may prevent light from passing through the material, but light can still enter through gaps around the sides, top, or bottom of the finished blind.
This distinction is important when choosing blackout blinds for bedrooms, nurseries, shift workers or home cinemas. Blackout refers to the material; it does not automatically guarantee that the entire room will be completely dark.
Why Do Blackout Blinds Leave Gaps?
Free-hanging blinds need space to operate correctly. On a roller blind, the fabric is typically narrower than the full headrail or mechanism, leaving a small gap on each side. Window recesses can also be uneven or out of square. Handles, vents, tiles and projecting sills may stop the blind from sitting close to the glass. Vertical blinds have separate fabric vanes, so some light can remain between the drapes or around the outer edges.

Choose Made-to-Measure Blackout Blinds
Made-to-measure blinds are manufactured for the dimensions of your individual window. Accurate sizing helps minimise unnecessary space and produces a neater finish than choosing the nearest standard blind width. Professional measuring is particularly valuable for bay windows, shallow recesses and frames with large handles. The surveyor can check whether the blind has enough room to operate and identify anything likely to affect coverage.
We offer blackout materials in styles including roller, cellular and Roman blinds. The best option depends on the room, window design and level of darkness required.
Should the Blind Sit Inside or Outside the Recess?
An inside-recess blind creates a tidy, integrated appearance. However, the blind must fit within the opening, and the necessary operating clearance may allow a slim line of light around the sides. An outside-recess blind can overlap the window opening, potentially covering more of the surrounding area. This requires enough unobstructed wall space and must not interfere with radiators, shelving or furniture. Neither fitting position is always best. The right choice depends on recess depth, window handles and your preferred appearance.
Can Perfect Fit Blinds Reduce Edge Light?
Perfect Fit blinds clip into compatible uPVC window and door frames and sit close to the glazing. The blind moves with the frame, providing a neat installation without drilling. At A1 Blinds, we offer Perfect Fit roller, pleated and Venetian options. A blackout roller or pleated material may provide stronger room darkening than some loosely fitted alternatives, depending on the frame and product specifications.
Choose the Right Blackout Style
Blackout roller blinds are compact and practical, making them popular for bedrooms. Roman blinds provide a softer decorative look and can include a blackout lining, whereas cellular or pleated blinds sit neatly at the glazing and may provide additional thermal benefits.
Our Linear Nightshade range is designed for strong blackout performance and thermal insulation. The product information describes the result as near-total darkness rather than guaranteeing that every room will be completely light-free.

Layer Blinds with Curtains
Pairing blackout blinds with lined curtains can cover light that remains around the edges. Curtains also add softness and another insulating layer at the window. Layering is particularly useful in children’s rooms, shift workers’ bedrooms and home cinemas. The blinds provide convenient daily control, while the curtains can be closed when a darker environment is needed. Any chains or cords must be installed with the correct child safety devices. Cord-free Perfect Fit or motorised blinds may be preferable in nurseries.
Get a Better-Fitting Blackout Blind
The most effective way to stop light gaps around blackout blinds is to match the material, blind style and fitting position to the individual window. Made-to-measure fitting can minimise gaps, but complete darkness should only be promised after the whole system has been assessed.
Book a free A1 Blinds home consultation to discuss blackout fabrics and the most suitable room-darkening option for your property in North Yorkshire.





