DIY Home Improvement Forum banner
1 - 6 of 6 Posts

·
Registered
Joined
·
31 Posts
Discussion Starter · #1 ·
i'm looking to build a 10'x10' free standing pergola. i'm located in corona, ca so the winds can be strong a couple times a year.

option 1
buy 4"x4"x12' pressure treated wood and dig a 10" diameter hole 24" deep and use concrete to embed it.

option 2
buy 4"x4"x8' douglas fir (painted) and put it on top of an embeded simpson cb44? the concrete footing would be 18"x18"x12". i'll use knee braces on the pergola for "top support" if 6"x6"x8' doug fir is cheap then i'll use this instead.

is embedded or simpson tie stronger? which one will last longer? option 1 will be hard to replace when the time comes and option 2 will be easier.
 

·
Registered
Joined
·
737 Posts
I would expect embedding the post in concrete to give the best resistance to upward lift and it for sure provides better resistance to lateral loads. However, it has the clear disadvantage of subjecting the wood to long term contact with moisture. If you're using cedar or below-grade rated PT lumber, you'd think that's not a concern. Well, you could spend a day googling that debate and you'll probably end up where you started--it depends who you ask. I can tell you I have plenty of experience with PT wood embedded in the ground and rotting after anywhere from 6 to 15 years. So, based on my experience, I never let a post touch soil or concrete unless I absolutely need to. E.g., with fence posts, you don't have an option.

For a pergola, I would keep the posts above ground and use any of various common techniques to resist lateral loads (you mentioned one).
 

·
Registered
Joined
·
31 Posts
Discussion Starter · #3 ·
my 4x4 pressure treated posts are up. i don't really want to use pressure treated 2x6 rafters. the pergola is in southern california so would painted douglas fir be fine? i'll need to paint the pressure treated posts the same color also. what kind of paint should i use? is exterior latex fine?
 

·
Registered
Joined
·
1,169 Posts

·
Residential Designer
Joined
·
1,487 Posts
Douglas Fir is definitely NOT a good choice for your Pergola no matter how well painted it is.
It will succumb to rot and insects much too soon to give you any good life out of it.
Cedar or Red wood would be much better choices. I know that they are much more expensive than the DF but would be worth the expense in this case.
Maybe you can make the Pergola a bit smaller to off-set some of the price difference?

Andy.
 

·
Registered
Joined
·
31 Posts
Discussion Starter · #6 ·
in socal home depot and lowes, there are only redwood, pressure treated, and douglas fir in the lumber area. i just thought if i painted douglas fir, it would be ok. i might have to get redwood and paint that then. where can i find 2x6x12 cedar?
 
1 - 6 of 6 Posts
Top