Can I install a keyed lock in my sliding patio door if it didn't come with one?Roger E., Katy, Texas You have two options: You can get a general retrofit kit from an outfit like Swisco.com (it bills ...

Single-cylinder deadbolts (keyed on one side) will work fine for most situations. Double-cylinder deadbolts (keyed on two sides) are a good idea if you have a window near the deadbolt. For safety ...