20 diy pergolas with free plans that you can make this ... plans: myoutdoorplans. 2. easy diy 15 minute pergola. believe it or not you can have a pergola in your backyard in under an hour. this one just takes about 15 minutes! it’s pretty cheap and super easy to build. a pergola is a structure that doesn’t have a roof so it’s a pretty easy build to begin with.