Hot Topics: Paver and Pergola Problems on the Patio

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As we feature decks and patios at the start of the sunny season, the forum is also buzzing with outdoor spaces. In just one of the patio related threads, new homeowners get to laying pavers and putting up a pergola, and the other members point them in the right direction.

Original Post: Young Couple Building Patio and Pergola

Adam Kirby Member

My wife and I are in the process of building a 450 square foot paver patio adjacent to our existing concrete slab. I'm sure we'll have many questions regarding that but my question now is regarding the pergola we are planning.

We just finished the excavation for the patio to approximately 9 inches. We are planning on building a 12x12 pergola and my question is about the posts. I'm planning on cementing the posts in the ground. (I know that isn't the best for posterity but we’re only going to be in this house a couple of years and it appears to be the most cost effective.) My question is how far below ground do I need to cement the 6x6's since they will also be in at least 6 inches of compacted crusher run and in between the pavers?
We live in Columbia SC and frost heave isn't an issue. Thanks in advance.

Highlights from the Thread

BridgeMan45 Member

Your local building department (the people who will issue the building permit you'll need) will have minimum requirements for embedment of the pergola columns. Or they may even require minimal concrete footings under each column.

Pilot Dane Group Moderator

The general rule of thumb for a free standing post or a fence post is to bury 1/3 of it in the ground. So a 12-foot post would have 4 feet underground and 8 feet sticking above ground. While that's proper, I very rarely see anything done much deeper than about 30 inches, since that's what most manual post hole diggers can do and is about the time your arms are tired and you say "that's good enough."

Adam Kirby Member

Thanks for all of the replies. I'm waiting on the building department to get back to me and I'll keep y'all "posted"(I know, terrible pun).

Also, does anyone have experience getting pavers flush with an existing slab? I'm planning on compacting the base extra well next to the slab and I'm hoping that will get it.

Pilot Dane Group Moderator

Add up the thicknesses of everything going into your patio; pavers, sand & base. That will tell you how far to dig down. Then make sure each layer ends up being the thickness you need. It helps to make your measurements from the slab you have to match and go down from there. So if your pavers are 3 inches thick and you have an inch of sand and 6 inches of base, your overdig needs to be about 10 inches below your existing concrete. Then when you put the base in and have it all compacted, measure again and you should be 4 inches below the slab... If you are off, correct it before going on to your next layer.

Find out what to do if you uncover hidden electrical while excavating at: //