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There are no grooves or ‘v’ lines running along Altherm profiles, and we’ve paid close attention to shapes and proportions across all our ranges.

Bi-fold windows

For a dramatic wide-span opening, Altherm bi-folds are hard to beat. They can be built in a range of configurations - all capable of stacking to one end of the frame.

The innovative lay-back bi-fold allows clear decks, with panels folding flat against walls. This option is available in 2-panel and 2+2 configurations. Our unique, bottom-rolling bi-folds ensure the weight is carried on the sill where it has maximum support, which makes the moving panels glide easily.

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Bi fold desktop 01
Bi fold desktop 01
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