Hello - I'm about to have some construction done in a part of my house that has a sliding glass door on one side of the room. The construction is gonna cause a lot of dust, so ideally we'd like to just seal that room off from the rest of the house for the duration of the project, and have the workmen and materials go in and out through the sliding door. The problem is...the door only locks from the inside right now. (And we can't just leave it unlocked when the guys leave for the day, otherwise someone can just walk into the house from the outside and, if they wanted to, slice through the plastic where we have sealed things off, and have their run of the house.) Does anyone know of an external lock we could add to our slider? Thank you!