Bifold door panels are only supported on the side that connect to the rollers; the other side has no support which means that panels can drop or sag over time due to the weight of glass. The primary identifying feature of a dropped bifold door is that it rubs on the sill or floor*. Therefore, it’s important to glaze bifold doors properly. The method to do this is known as heel and toe which aims to brace the glass diagonally corner to corner using setting blocks. This distributes the weight of the glass towards the side connected to the rollers (shown in the pictures below as hinge side).
Below is step-by-step guide to heel and toeing our bifold doors properly. If you haven’t done this before it’s recommended that you seek professional help from a qualified glazier or from Nu-Line Windows.
* Other signs: the bifold door may be difficult to lock at the handle or there might be a gap at the top of the door (although these two points, more often then not, mean that the door has not been adjusted properly yet or the bifolds need readjusting once a new building has settled over time).