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What is the maximum window height that a roller blind can cover?
Category: All,Technical
By: John James

Floor to ceiling glass is increasingly common in offices and residential apartments and roller blinds that are capable of covering the entire height are favoured by specifiers, interiors designers and facilities managers.  The maximum drop that any particular roller blind is capable of achieving is determined by a number of factors. This post explains what to look out for.

The maximum drop of a roller blind must be considered in conjunction with the width of the roller blind. For any roller blind with a width of more than 1m requiring a drop of more than 2m, the roller tube should be a minimum of 40mm diameter. This will ensure the tube does not bow under the weight of the fabric causing unsightly ripples or ‘smiles’ in the fabric.

The first factor to consider is the size of the roller blind brackets. The drop of the blind will be limited to the amount of space available for the roller tube and fabric when it is rolled up. Most large roller blind systems such as the ShadeTech RBXL range allow a maximum roll-up diameter of 110mm, this allows for an approximate drop of 6m based on using a screen fabric with a thickness of 0.6mm.

The next issue to consider is the type of roller blind fabric. Some fabrics are more dimensionally stable than others which helps them to roll up straight. Treveria type fabrics have a tendency to run off on one side when being rolled up and on a long –drop blind can snag against the bracket causing the fabric to fray. Thin polyester fabrics tend to curl at the edges over the length of a blind more than 3m tall. Anti-glare screen fabrics such as Betascreen 20, Betascreen 70, Betascreen 90 etc are not only weighty and stable, they are also available in wide widths which means any roller blind under 3m wide can be made without the need for joins in the fabric regardless of what the drop of the blind is.

If you require roller blinds with a greater drop than 6m on your project then the Draper Flexshade 2 (max. height 9m) and Draper Colossal (max. height 12m) electric blinds are worth considering.

Specifying roller blinds for a project? Our blog Performance considerations for solar shading fabrics on blinds could be useful.

About the author

John James Marketing Director