Our bifolds come with offset flush bolts as standard which allow you to lock door panels securely into place. The image below shows the typical location of these flush bolts (located inside the building). Our standard offset flush bolt is shown in the bottom left image. These sit flush in the frame and are located at the top and bottom of the required panels. Our second and third option is shown in the bottom right corner. This is known as the dual twin bolt lock which can come with a key or be keyless. The dual twin bolt operates in the same way as the standard offset flush bolt, but allows operation of both bolts in one mechanism. Usually the twin bolt lock is located halfway up the bifold, whereas the standard flush bolt are located at the top and bottom of the panel. Whenever we do a bifold quote we always attach a copy of our bifold options brochure which shows these and other price options. All bolts are usually only available in satin chrome or black.
When the bolts are set to the closed position the weather seals naturally push slightly against the door panels in order to seal them well against weather. Flipping the bolts to the open position without relieving the pressure can make the bolts stiff to open and could damage the dual twin bolt mechanism. It is really simply to relieve the pressure on the door panels though, just pull the door panels slightly towards you with the hinge set handle and flip the bolts open like normal. To close the bolts the same thing should be done, but in reverse. This will allow for easy bolt operation.
Location of bolts on a typical bifold
Standard offset flush bolt Twin bolt lock (key or keyless)