You only need spacer blocks if you have trim or molding around the window, and where you are mounting the blinds outside the window. Spacer blocks push your blinds away from your wall or door. You need spacer blocks when your trim or molding might keep your blinds from hanging straight down when mounted directly on the wall or door.

So, you insert a spacer block between the wall and the installation brackets to push them away from the wall enough so your blinds can hang straight. One spacer block will push your blinds or shades about 3/8 of an inch away from the wall. You can stack two spacer blocks on top of each other to get 3/4 of an inch.

Remember, you only use spacer blocks with outside mount blinds. Inside mount blinds do not need spacers.