# How far can you span a pergola?

Considering this, how far can a 2x12 span for a pergola?

There's not quite enough information here to give a definitive answer, but for decks, a rule of thumb is when supporting joists that **span** 12 feet, a double ply beam **can span** in feet a value equal to its depth in inches. Thus, a double **2x12** beam **could span** 12 feet - with 20' beams, posts at 10' might look the best.

Also Know, how far apart should pergola posts be? Spacing the rafters 16 to 20 inches **apart** is common. The most important rule in spacing is to keep the **distance** consistent between all the rafters. Install the front and rear rafters first, fastening them to the face of the support **posts** above the girder.

Regarding this, how far can a 2x10 span for a pergola?

A 4x4 **does** make a good knee brace when 6x6 posts are used. Also a **2x10 can span** 13'9" when being used as a deck joist so I am not sure why it couldn't easily carry 14 feet on a **pergola** which is going to halve 75 percent less load on it.

What size lumber can span 20 feet?

Re: **20** foot clearspan beam **size** In that case, you need something like a 12-16" GLULAM or LVL to **span** the **20**' and **can** use simple 2x8-10 dimensional **lumber** 16"OC as floor joists.