Pour pad before posts?

[Whiskeymike]

I'm about to build a metal patio using 4 6x6 posts that is 25x30. Should I pour the pad first or after the posts? The Welding company suggested putting the posts 4' in the ground with bags of concrete and then pouring the pad afterwards because it would save money on foundation. But I'm wondering if it's better for the longevity of the posts to set a plate on the concrete pad and go from there.

The patio is going to hold furniture and BBQ's, so I'm planning on a 4" pad.

 

[K'ledgeBldr]

I know some AHJ’s frown upon the post being surrounded by a slab.

I’m of the opinion that if the post was ever damaged and needed replacement- if it’s above the slab, it’s easy-peasy! I would’t do it any other way- the amount of concrete/digging is the same- it’s the “down-the-road” part that can cost a lot!

 

[msharley]

I'm about to build a metal patio using 4 6x6 posts that is 25x30. Should I pour the pad first or after the posts? The Welding company suggested putting the posts 4' in the ground with bags of concrete and then pouring the pad afterwards because it would save money on foundation. But I'm wondering if it's better for the longevity of the posts to set a plate on the concrete pad and go from there.

The patio is going to hold furniture and BBQ's, so I'm planning on a 4" pad.

The lime in the concrete will eat the post. (5yrs tops)

Your idea of putting the 6"x6" posts in mounting BASES and QWIK BOLTING them to the slab is much more durable.

Also, the GALVANIZED BASE will keep water from entering the post..

Here is a selection from Home Depot.. https://www.homedepot.com/b/Buildin...-Brackets-Post-Bases/6x6/N-5yc1vZc8hsZ1z1aqxv

Hope this helps..

 

[Git]

Around here, you would pour the slab with standoff brackets embedded into the concrete. There are a number of pdf files online from different cities for their requirements which are pretty helpful (rafter spans, etc). Here is a link to one of them for example

https://www.avcity.org/DocumentCenter/View/250/Patio-Covers-PDF

 

[mcbane]

I'm about to build a metal patio using 4 6x6 posts that is 25x30. Should I pour the pad first or after the posts? The Welding company suggested putting the posts 4' in the ground with bags of concrete and then pouring the pad afterwards because it would save money on foundation. But I'm wondering if it's better for the longevity of the posts to set a plate on the concrete pad and go from there.

The patio is going to hold furniture and BBQ's, so I'm planning on a 4" pad.

You said this was a metal patio but answers thus far seem to assume your 6x6 posts are wood. If they are in fact steel structural square tube, weld base plates on them and bolt them to the slab. You may want to thicken the slab in the areas where the posts will be located.

 

[Git]

Good point about the posts.

I assumed wood since 6x6 metal seemed like overkill... For example, we had a 20' x 20' outdoor structure built (only 4 posts) that had a heavy, concrete tile roof to match the roof of the house. The engineer called for 5" x 3/8" square posts, sunk into a 5' deep concrete footing with a rebar cage and a steel plate on the end to prevent uplift

 

[Hank11]

It matters where you live. In some parts of the country it is standard practice to put the wooden posts directly in the ground with and without concrete. Many, many thousands of pole barns have been built this way. In other places, its frowned upon. Check around locally as to the preferred method. It will be cheaper and faster to put the posts in and use them as your corner stakes with boards around the periphery to form the concrete.

 

[Pluribus]

Are there any specs on the building design? A true pole building needs those wood posts sunk into the ground to have 360 degree bearing on the soil to give the building its shear resistance. A post frame building with surface or bracket mounted posts has/needs to have some shear resistance engineered into it above ground to keep it from parallelogram-ing itself into a pancake.

 

[CraigStu]

In talking to my contractor 5-6 yrs ago he mentioned that for fences they have gotten away from concrete for the posts. Apparently no matter what has been done to avoid it, water gets in between the post and the concrete and then can't get out. So the post rots. The cure is to just put the post in the ground over some gravel and fill w/ the soil and pack it. This is different from your patio but the post in the ground caution still applies. Git's post above shows best practices.

 

[Whiskeymike]

Are there any specs on the building design? A true pole building needs those wood posts sunk into the ground to have 360 degree bearing on the soil to give the building its shear resistance. A post frame building with surface or bracket mounted posts has/needs to have some shear resistance engineered into it above ground to keep it from parallelogram-ing itself into a pancake.

This is my current design. Completely metal. It's 6x6x.25 posts, 8x2x11gauge trusses and beam, 8" C purlins.

 

[billconner]

Whomever did the engineering should determine the method of mounting the steel tube posts. With no other lateral bracing, I think I'd want the posts buried. There are a lot of steel pipes and other items buried that have been there a long time. You may want to look into coatings.