Pier foundation for a carport

[handirifle]

KYErik
I agree, the more the better., The last thing I want to see in a windstorm is my carport headed to the land of oz. I am thinking that I might go one of two ways with this now. I could put the round concrete forms in the ground, and fill them with concrete, instead of the posts, using a similar system to flushers. Or, if I put the posts in the ground, I could use a 2x8 to connect them but anchor the bottom sill of the carport to the posts with an upside down "U" going over the carport sill and down the sides of the posts 10" or so, and lag bolted in with about 4" lag bolts, 2 per side?

I dunno, maybe I ought to just pour a footer, and lay concrete blocks all around to get the 2 foot wall. That was one of my original thoughts. It's just that the costs on these ideas keep going ever upwards and makes me wonder if I can do them at all.

 

[handirifle]

Let me ask this. If I were to use concrete blocks for the wall, if they were set, say, 18" underground, on a gravel base, would that suffice, or does it NEED to be on a concrete footer, underground?

I am thinking that if I built it like that, it would be 3-4" of gravel, with the blocks locked together with rebar, horizontally and vertically, and the vertical rebar sections back filled with concrete. I would then anchor it like flusher did. I could do the blocks in stages that way and not have to pay the horrendous delivery fees the concrete trucks charge. I live about 30 min from any concrete source, on country roads.

I did a project similar to this for a small retaining wall in my back yard, except I made a footer for it, but I am thinking that if the blocks are buried 18" underground and extend 2 ft above ground, that might just do it.

Thoughts?

 

[tmc_31]

I built a carport a few years ago for my dad. It was similar sized, 20'X24' I think. On his I had 4-4"X4" steel posts with 3/16" wall on each side of the carport. Each post was set in a 18"X36" deep pier and backfilled with concrete. 8 piers total. The roof frame was built of 6" purlin that was screwed to the top of the posts. A R-panel roof was laid on top of that.

If I was in your shoes, I think I would drill 3' deep 18" diameter holes at each post location. Set a 4"X4"X3/16 steel post in each hole and concrete them in place. The posts can be cut off so that the tops are level all around and so that they will raise the carport to the height that you want it. You said that the bottom rails of your carport were 2" square tubing. I would weld a steel cap on top of each post to seal out the rain and then weld a 2"X2"X4"X3/16" angle iron on top of that so that you can screw your existing rail to the top of the posts. Then I would grade between the piers and lay a concrete block wall to meet up with the bottom of your rail.

If this concept interests you, feel free to ask any questions you may have.

Tim

 

[tmc_31]

Let me ask this. If I were to use concrete blocks for the wall, if they were set, say, 18" underground, on a gravel base, would that suffice, or does it NEED to be on a concrete footer, underground?

I am thinking that if I built it like that, it would be 3-4" of gravel, with the blocks locked together with rebar, horizontally and vertically, and the vertical rebar sections back filled with concrete. I would then anchor it like flusher did. I could do the blocks in stages that way and not have to pay the horrendous delivery fees the concrete trucks charge. I live about 30 min from any concrete source, on country roads.

I did a project similar to this for a small retaining wall in my back yard, except I made a footer for it, but I am thinking that if the blocks are buried 18" underground and extend 2 ft above ground, that might just do it.

Thoughts?

It depends on how much the ground moves where you live, and if it heaves much when it gets cold. Where I live the ground is pretty stable but I still would want a 18" deep steel reinforced concrete footer under that block wall. That said, if you set the carport on very stable piers, the worst that could happen is that your block walls might crack. I think the carport would stay put.

Tim

 

[handirifle]

Well the ground around here doesn't heave really at all. I mean a water line 6" deep would never freeze. We just don't get sustained cold.

If I did do a footer, not sure how deep it would have to go.

 

[KYErik]

KYErik
I agree, the more the better., The last thing I want to see in a windstorm is my carport headed to the land of oz. I am thinking that I might go one of two ways with this now. I could put the round concrete forms in the ground, and fill them with concrete, instead of the posts, using a similar system to flushers. Or, if I put the posts in the ground, I could use a 2x8 to connect them but anchor the bottom sill of the carport to the posts with an upside down "U" going over the carport sill and down the sides of the posts 10" or so, and lag bolted in with about 4" lag bolts, 2 per side?

I dunno, maybe I ought to just pour a footer, and lay concrete blocks all around to get the 2 foot wall. That was one of my original thoughts. It's just that the costs on these ideas keep going ever upwards and makes me wonder if I can do them at all.

"More expensive" is typically better/stronger, but we all have to work within a budget. I think any of these ideas would work fairly well. If you have many trees near this structure, you might try to save some money on the base since an extreme wind storm would likely result in it being damaged by a falling limb.

I would guess that 6-8 steel posts, set deep in concrete and firmly bolted to the base would be the strongest AND most economical method to keep it from blowing away and sunken wood posts would be the cheapest retaining wall.

 

[handirifle]

I built a carport a few years ago for my dad. It was similar sized, 20'X24' I think. On his I had 4-4"X4" steel posts with 3/16" wall on each side of the carport. Each post was set in a 18"X36" deep pier and backfilled with concrete. 8 piers total. The roof frame was built of 6" purlin that was screwed to the top of the posts. A R-panel roof was laid on top of that.

If I was in your shoes, I think I would drill 3' deep 18" diameter holes at each post location. Set a 4"X4"X3/16 steel post in each hole and concrete them in place. The posts can be cut off so that the tops are level all around and so that they will raise the carport to the height that you want it. You said that the bottom rails of your carport were 2" square tubing. I would weld a steel cap on top of each post to seal out the rain and then weld a 2"X2"X4"X3/16" angle iron on top of that so that you can screw your existing rail to the top of the posts. Then I would grade between the piers and lay a concrete block wall to meet up with the bottom of your rail.

If this concept interests you, feel free to ask any questions you may have.

Tim

TMC
I am interested in this idea. I think I will give up on the wood posts, for a number of reasons, possible rotting of the wood being one of them. I hate to redo stuff I have put a lot of time into.

You gave the dimensions of the angle as 2x2x4 x 3/16" is the 4" the suggested length of each piece? As for grading, I would most likely grade the entire area before I did anything else, mainly because the whole area needs to be graded. There is too much slope. I would leave some slope for drainage.

n my mind, I would dig out holes and put concrete forms down, so that they would top out just slightly above grade, for drainage, with the posts set in them. I think I might invest in a steel top that connects all the posts together, to control any shifting. If I did that, I could get away with 4 piers per side, and clamp them to the post caps similar to how flusher did.

I will have to do a cost comparison, for that method compared to block walls. Steel prices have gone astronomical around here, so that can change things up a lot.

 

[Ted Summey]

I built a 24x30 shop building with two 12x30 sheds on either side. It is a metal building built with the 2"x2" galvanized tubing like you describe for your carport. My shop had to be engineered for 140 mph wind loads and for some astronomical snow load. The sheds are on 8" of crush and run gravel pads ( the main shop is on concrete). The plans required and engineer's certification/ stamp.

I tell all of this to say that the sheds are anchored with 36" long by 4" auger type mobile home anchors. The bottom tube is drilled and the top of the anchor is bolted to that tube. The building is 9 years old and has withstood both high wind of 60 mph and snow loads of 10 to 12 inches.

 

[tmc_31]

handirifle, yes I was recommending a 4" long piece of angle iron. Four piers on each side should be enough to support a 18'X18' carport. If you have more posts than that and you want to run a full length steel cap over the top of the square steel in the piers, I suggest that you use something like 4X4 angle or Jr. I beam so that your intermediate posts are supported.

Tim

 

[handirifle]

Ted
That is kinda how it's built now, but I want to raise that bottom section by 2', for added wall height.

I have asked the various car port companies about just getting longer wall pieces, but they say the new pieces need to be 2x3" and the roof needs to be trussed differently, so that is why I came up with sitting the existing design on top of my own 2ft wall.