First time post here, thank you for such a great resource! I've done a lot of research but am hoping I can get some help building a pretty large pergola.

I'm trying to be my own master contractor and hire subcontractors to build a long freestanding pergola with no post in the middle. My plan is to have an architect draw up plans, but before I started spending money I'm trying to see if this is even a viable project that a pretty handy person can manage. Basically am I crazy for attempting this?

Property details - main structure is a duplex - there is a detached four car carport/garage 12' from the back of the main structure. - trying to cover the space between the garage and the house with a slight hang over both structures.

Project details: - 24' L x 14' W. - I am hoping that a steel beam could span the length with no post. a) What's the max length span? It would be preferable to go greater than 24'L. b) Any guesstimates on what a beam this size would weigh? - Would 8" x 8" wood post be strong enough? a) how deep do footings need to go and how close can footing be to house foundation?

  • Hello, and welcome to Home Improvement. A diagram of exactly what you're hoping to do would really help us. And, you should probably take our tour so you'll know how best to participate here. – Daniel Griscom Oct 2 at 1:22
  • Welcome, Luke. You'e asked several distinct questions here. We're not a discussion forum. Please do take the tour Daniel suggested and then revise your post to just ask one clear thing. Post other questions if you like. – isherwood Oct 2 at 13:30
  • Is the 24' length parallel to the existing structures? Could it be supported by the buildings? (This is non-trivial, as you'd have to go right through the cladding into the studs or beams of the house) – Chris Cudmore Oct 2 at 13:32
  • Thank you for the tour recommendation. Now that I know how the site works a little better I think I can search it a little better. Chris- I was trying to avoid attaching it to the house, just because I don't want to go through the brick and a roofer advised against using roof risers on the roof. – Luke Stone Oct 4 at 2:51

I wouldn't bother with an architect.

Hire a structural engineer if anyone.

You want a 24' long beam, probably two? with just some minimal loading from open air beams that sit on the two 24'L beams? A quick diagram would help.

24' is long but I've done wood PSLs 5.25"x11.75" that open air span more than that and support floor and roof loads.

  • Thank you for your reply. I think I'm going to research the site a little better for my specific problems and then maybe come back with more specific questions. – Luke Stone Oct 4 at 2:55

That sounds like a good plan

Steel can span hundreds of feet: they use it to make bridges and other large structures.

You can probably meet your goal with a cold formed steel beams (the cheapest kind of steel)

You can either consult a structural engineer or use a framing handbook to determine the sizes of the structural members and footings needed for your project in your location.


I would consider an "engineered wood " beam ; several 2 X 6 or 2 X 8 ,etc, glued together like plywood. I have commonly seen these in modern ( since about 1960) churches . Although often on a angle they are longer than 50 ft. For steel you need to have transitions between steel and wood. Of course a steel beam would be much smaller than laminated wood.

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