Altherm bi-folding doors allow for a dramatic wide opening. The trusted and reliable Altherm bi-fold system copes easily with a large opening span. The weight is carried bottom-rolling on a sill where it has maximum support, which makes the moving panels glide easily.
Our ultra-convenient lay-back bi-fold doors swing back against adjoining walls. They don’t project out or obstruct decks and walkways (available in 2-panel, 2+1 and 2+2 configurations).