Oh, shade, how I love thee

June 6, 2012 1:02 PM

Building a pergola.. Ideas welcome, but a construction question - is there a reason why every plan I see says to set the posts, then put up the cross-beams? What is wrong with assembling two posts with cross beams already attached, then lifting that up and setting in your post-holes?

Lifting a 2x6x12 beam 10 feet in the air and trying to attach it to two posts seems silly to me. Is there something I'm missing? Is there some good reason for not building your two 'walls' and putting them up assembled?

Then proceeding as usual for the rest of the beams that would attach the two walls and make your 'roof'?

I understand you want to make sure your posts are plumb, but wouldn't it be more likely to be square if it's already assembled and bolted to support?

Finally - any really cool designs you have seen? I'm looking at a 10' x 10' area, using 4 6x6x12's as the posts. 2 2x6x12 cross beams on each post 'wall', then another 2 going the other way (so 8 beams in all). Then 2x4 slats. Sort of like this.

posted by rich to Home & Garden (6 answers total)

Assuming the surface you're building on isn't perfectly level, it's easier to set the posts plumb and then make the beams level than it is to measure the difference in elevation from one corner to another and build the sides accordingly before putting them up.
posted by jon1270 at 1:10 PM on June 6, 2012 [2 favorites]

It's the way it's done for good reason. MUCH easier to adjust a two by six than a deep hole, especially if you just poured concrete into it. The Bolts and Cuts can be precise, the holes cannot.
posted by French Fry at 1:16 PM on June 6, 2012 [1 favorite]

Having had to bury 4 posts for a shed (ie not a whole lot of experience) I'm guessing the instructions want you to set the posts first because your holes may not all be the same depth. Once the posts are set you just cut the tops until they are level.

If your were to make the thing first and put it into holes you'd end up stressing the pergola as some of the posts would be held up by the pergola itself and not the ground.
posted by any portmanteau in a storm at 1:18 PM on June 6, 2012

Yeah, what jon1270 said.

You'd have to be history's greatest measurer* to get your "wall," which isn't really a wall since the posts aren't connected at the bottom and will be all floppy-like as you try to set them in the holes and raise your beam, to get your two posts and a beam close to square and plumb.

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*And history's most accurate post-hole digger.
posted by notyou at 1:20 PM on June 6, 2012

Best answer: Lifting a 2x6x12 beam 10 feet in the air and trying to attach it to two posts seems silly to me.

Not if you're building it right. The trick is to have it so the crosspieces can be lifted into place and rested in position while you secure them to the posts. This is where joist hangers and similar framing brackets are a huge help, but you can also accomplish the same thing by temporarily attaching scraps of wood to either carry the weight of the crosspiece or restrict it's lateral movement while you're permanently attaching it to the posts.
posted by RonButNotStupid at 1:33 PM on June 6, 2012 [2 favorites]

Seconding what ronbutnotstupid says. I would also suggest that you use a laser level for this project.
posted by mareli at 6:00 AM on June 7, 2012