Multi-point patio door lock

A patio door is a large panel held by one small catch. A multi-point lock replaces the whole latch mechanism with hook bolts that engage the frame at three heights, so force applied anywhere along the panel is resisted at a point near it rather than at a single central catch.

Keyed on both faces with a thumbturn option, for sliding panels 1-3/8 to 2 inches thick. This is a replacement mechanism, not an add-on, and fitting it means routing the stile — we would call a joiner for it unless you have done one before.

Fitting and care. This replaces the whole latch mechanism and needs the stile routed to take the gearbox — measure the existing lock case and the backset before ordering, and if you have not fitted one before, this is the item in the catalogue we would send a joiner to. Once fitted, check all three hooks engage with the door closed and the handle fully lifted. Re-check after the first summer, because a panel that has expanded will show up as one hook not seating. Dry lubricant on the hooks yearly.