I have this large patio (Ignore the mess) to which I want to add to put a pergola (with clear roofing to stop the rain). I would love the pergola to be on the left side of the patio and leave the right side open.. I plan on doing this myself but I've never built one before. I'm not sure the best way to approach this.. as you can see the left and right walls come in at an angle so its not square… I'm unsure of two things.. how to tackle that angle and should I fix the pergola to the back wall or just have posts in where the flower bed is? Would I even get beams long enough to reach the font of the patio.. how much of a slope is needed for the rain
by k-eastwood
1 Comment
Do not attach a roof ledger to that back block wall. You have no idea what the structural load rating of that property wall is and waterproofing it is a headache you do not need. Go fully freestanding. Sink your back posts right into that elevated sleeper bed to keep your patio footprint clear but make sure you dig down past the loose dirt and pour proper concrete footings. For that weird boundary angle on the left do not try to build an angled trapezoid pergola. Build a perfect rectangle. You can just let the roof overhang the angled gap or leave a wedge of open air. Trying to cut compound angles on heavy timber for your first build is a guaranteed way to ruin expensive wood.
Since you are adding a clear roof you need a pitch to shed water and leaves. A standard slope is about a quarter inch of drop for every foot of depth. You will easily find beams long enough to span that distance if you go to a dedicated local lumber yard instead of the big box hardware stores.
Before you start digging holes take a picture of that corner and run it through the GardenDream web app. It is a solid design tool that lets you overlay realistic hardscapes on your exact space so you can see exactly how a perfectly square pergola will look sitting next to an angled wall. It works as a great safety net so you can lock in your post heights and visual footprint before spending a dime. Once the structure is built get some shade tolerant vines in that back bed to climb the posts and tie the whole thing together.