How far can you span a pergola?

Asked By: Mouha Mcgrory | Last Updated: 2nd May, 2020
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22 feet

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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.

39 Related Question Answers Found

What size board can span 20 feet?

Max. Live Load 30 lbs/ft2 (1436 N/m2)
Maximum Span (ft - in)
Nominal Size (inches) Joist Spacing Center to Center (inches) Lumber Grade
2 x 10 12 20' - 3"
16 18' - 5"
24 15' - 0"

Which direction should pergola slats run?

Thinking of two different approaches to a pergola. From a functional standpoint, ideally you want the slats perpendicular to the sun (running north/south) to provide the most shade. Not knowing which way north is, it's a toss up.

Can you hang a swing from a pergola?

Even with all the cross bracing, the pergola will remain stable unless the kids decide to hook a truck to it and try to pull it over. A swing set is 'A frame' to prevent it tipping over yes. If you don't want to make the pergola 'A frame' and look tacky, then yes bury the 6x6s in concrete.

What size should pergola rafters be?

Standard Pergola Rafter Spacing
The measurements are 12 inches and 16 inches off center rafter-to-rafter. This is a centerline measurement from the center of the board, so about three-quarters of an inch from the side of the board on its narrowest face.

How much weight can a 2x12 beam hold?


One 2x12 can support about 180 lbs. per foot or about 2,100 lbs. total for a 12' span.

How far can a double 2x8 span without support?

When supporting joists that span 12 feet with no overhang beyond the beam, a double ply beam can span in feet a value equal to its depth in inches. A double 2x12 beam can span 12 feet; a (2) 2x10 can span 10 feet and so on.

How far can you span a 2x6 without support?

In general terms, joists spaced 16 inches on center can span 1.5 times in feet their depth in inches. A 2x8 up to 12 feet; 2x10 to 15 feet and 2x12 to 18 feet.

How far will a double 2x8 span?

The current floor joists are 2x8 and span the 24 feet, but there is a wall mid way.

Why does my pergola wobble?


The wobble appears to be stemming from within the anchor, mostly in the direction where the anchor does NOT wrap around the post; the two open sides. I thought after fastening the beams and rafters, plus a pair of knee/y-braces to each corner, things would stabilize.

What size pergola do I need?

A pergola structure can be as wide as you like, as long as it's built with enough beams to support the roof. The minimum height of a pergola should be no lower than 7'6” to provide enough head room, though most projects call for a range of 8-10' in height.

How much weight can a pergola hold?

They hold as much as 250 pounds.

What is the longest wood beam?

The largest wood beams ever tested are being studied at the Forest Products Laboratory (FPL). Made of Douglas-fir, the glued laminated (glulam) beams each measured 72-feet-long and weighed in at 6,000 pounds.

How much weight will a 2x12x20 support?


You'd need some maths to figure out specifics but those 2x12's would hold around 150 pounds per foot x length x spans but then at some point you get into mode of rupture or elastics, dead weight live weight.

How deep should a pergola post hole be?

Dig holes in the locations for the pergola's posts, making each hole at least 12 inches in diameter and the depth of one-third the height of one post. If, for example, each post is 12 feet tall, then make each hole 4 feet deep. In that example, the pergola will be about 8 feet tall.

Can a pergola be freestanding?

Freestanding pergolas have at least four posts and like their name says, stand without being attached to any other structure or wall. The advantage of freestanding pergolas is there are no limitations on total size, height, or orientation. There are however always limits to the span of the beams.