Vertical Blinds Product Characteristics

The number of slats/louvres is determined by the width of the blind. For this reason, some blinds in adjacent windows which may seem to be of equal size may have a different number of slats due to slight dimensional differences between window sizes. When the louvres are fully retracted, they will stack to one or both sides. The wider the blind, the bigger the stack. 

For a vertical blind to operate correctly, the louvres (fabric strips) must have clearance from the window sill or floor. This allows the louvres to traverse correctly, and to rotate from the open to the closed position. The industry accepted clearance gap is expected to be between 5mm to 15mm. This gap is measured at the shortest point of the window, so if the sill or floor is not parallel to the blind’s fixing point the gap could be greater.

Fabrics that are made from cotton or have a high cotton content can take on moisture and shrink. For this reason, these fabrics are not suitable for high moisture environments. Slight cupping of the fabric may occur; this is typically due to changes in humidity levels. If the back of the fabric is different to the front of the fabric, when the fabric is folded to create the pocket at the top and bottom of the louvre, this will show the opposite side of the fabric. If the fabric is translucent, there will be darker areas where the louvres overlap. Where fabrics are stitched, there will be pin-holes in the fabric. These will allow light to pass and will be more obvious on darker/opaque/blackout fabrics. The number of louvres used to make a vertical blind is calculated and rounded up; this may result in blinds of similar sizes having a noticeably different overlap in the louvres.

When the louvres are fully closed, there will always be a slight gap between the slats due to the header at the top of the louvre and the weight at the base.

Vertical blinds with opaque fabrics provide a good degree of dim-out but there will be light coming around the extremities of the blind and where the slats close. This is more apparent with blinds fitted inside a reveal than those fitted outside. Due to their product specification, vertical blinds do not offer blackout.

When fitted in a bay window, there will be some gaps where the neighbouring blind headrails meet each other. The size of any gap will depend on several factors including; the shape of the bay, the style of the window and the specification of the blind system. Similarly, at the edge of the bay there may be light gaps/ potential loss of privacy depending on the angle of the bay and the adjoining walls. On some bay windows it is possible to have a track bent to the shape of the windows, eliminating the gaps explained above.

To allow for operating clearance, the width of the blind must be narrower than the width of the reveal. If there are any obstructions in the reveal, for example tiles at the base or a dado rail, the blind will need to be made to accommodate the narrowest width.

A vertical blind is made square however in reality reveals are often not. The head of the window or sill may not be level and the distances between the side walls throughout often vary. The distance from the edge of the reveal to the window may also vary, so blinds will either be fitted to run parallel to the window or to the edge of the reveal. 

There is a wide range of motorised solutions available for your comfort and convenience and each system will have its own characteristics. Some points to consider are: 

• Speed and alignment: Blinds in the same installation may not travel at the same speed and may not line up if stopped during the travel of the blinds due to mechanical and electrical tolerances. 

• Noise: Being operated by a motor, some noise will be emitted. Quiet motors may be available. 

• Wiring: Some surface wiring may be required. Where 240V mains power is involved, a competent person will be required to provide a power feed unless the blinds can be powered from a plug inserted into an existing socket. 

• Motor protection: For safety reasons, most motors are fitted with a thermal cut-out to protect them from getting too hot (usually from over-use). When cooled sufficiently, the motor will start working again.

Where a smart home hub is used the signals to the blinds may get occasionally interrupted by other wireless devices in the home such as smart speakers or doorbells. This can affect the operation, or seamless operation of the blind.

All blinds with cords or chains could pose a risk of strangulation to young children. The BBSA recommends inherently safe products (Safe by Design). If you choose a product with additional child safety devices, these must be securely fitted as required. For further information on window blind safety visit: www.makeitsafe.org.uk