concrete post advice

[ddoss]

I'm making a coop+run similar to the simple suburban coop at sslfamilyfarm.com. The overall dimensions are 6' wide x 12' long. The coop portion is 4'x6' on one end and is raised up about 30". Both coop and run will have a metal roof. The base of the coop+run will be 2x6 pressure treated.

I live in an area with lots of straight-line winds and am probably over-concerned with building it strong. I want to cement in the 4x4 posts and have a question about my method. This last weekend I had to fix a leaning fence, so I dug three new post holes and learned how to concrete in the posts. The coop has (4) 4x4 posts and I was planning on adding a set of 4x4 posts at the other end of the 12'. So each corner will have a 4x4 and one set in the inside where the coop ends. I see all kinds of videos showing digging and setting posts and then building from there. What I want to do is this.

1. build a 6'x12' frame out of (4) 2x6 pressure treated lumber. I'll build it on garage floor and make sure it's level as possible.
2. position the 6'x12' frame where I want the coop to be on the ground and mark the places I intend to have the posts.
3. sit the 6'x12' frame to the side while I dig holes for the 4x4 posts.
4. put the 6'x12' frame back in place and then put the 4x4's in the hole (they all sit inside the board frame)
5. use levels to both level the frame and make sure the 4x4s are plum and then screw the frame to the 4x4's
6. Once I have the frame secured to the 4x4's and it's all level and plum, fill the holes with concrete- temp bracing at the top of the posts to the ground.

You usually have to brace the 4x4's and make sure it's all plumb before you add the concrete to the hole, so why not make my frame that I want to be attached to the 4x4's be part of this support? Is the idea bad because I won't be able to get it all level and plumb at the same time?

I feel like I'll have better luck doing this than if I try to line up the posts separately, without the framing.

attaching examples of what i'm thinking. the gray circles are the holes I would dig.

I appreciate any advice.

 

[BaaKaaawk]

If you build this coop with treated lumber it is going to weigh a good 300 pounds or more. I don't see any reason you need to concrete the posts (and I have built a lot of coops). If you are really worried, just up your wood posts to a 6x6 and that will add even more stability and more weight. If you really want to concrete them in, once you have levelled everything and your posts are in the holes, just toss a bag of concrete in each hole. As mentioned, this coop is going to be really heavy and highly unlikely to wiggle on you much.

That said, here's one I dig and absolutely I built the entire frame and leveled everything before I set it in.

https://www.backyardchickens.com/threads/baakaaawks-spring-2020-coop-build-thread.1357348/

 

[ddoss]

I was worried about winds catching under the roof and blowing it over. that's why I thought about doing concrete. believe me after digging three posts for a fence this weekend I don't want to use a post hole digger any more than is required! I do feel like almost everyone I see overbuilds the coops to death. If I don't concrete them in, do you find value in sitting the posts on a level concrete paver, or just on the dirt?

 

[BaaKaaawk]

I was worried about winds catching under the roof and blowing it over. that's why I thought about doing concrete. believe me after digging three posts for a fence this weekend I don't want to use a post hole digger any more than is required! I do feel like almost everyone I see overbuilds the coops to death. If I don't concrete them in, do you find value in sitting the posts on a level concrete paver, or just on the dirt?

It's up to you. I think you are overestimating the strength of the wind and underestimating the weight of your finished product.

Putting the posts on a paver just helps increase the surface area of the foot, which is always a good thing. I'd really just up to the 6x6 unless you already bought the material if you are concerned. A 6x6 has more than twice the square-foot ground contact / coverage as a 4x4.

6x6 = 36 square inches of post connection with the ground vs a 4x4 = 16 square inches.

 

[DobieLover]

I'm making a coop+run similar to the simple suburban coop at sslfamilyfarm.com. The overall dimensions are 6' wide x 12' long. The coop portion is 4'x6' on one end and is raised up about 30". Both coop and run will have a metal roof. The base of the coop+run will be 2x6 pressure treated.

I live in an area with lots of straight-line winds and am probably over-concerned with building it strong. I want to cement in the 4x4 posts and have a question about my method. This last weekend I had to fix a leaning fence, so I dug three new post holes and learned how to concrete in the posts. The coop has (4) 4x4 posts and I was planning on adding a set of 4x4 posts at the other end of the 12'. So each corner will have a 4x4 and one set in the inside where the coop ends. I see all kinds of videos showing digging and setting posts and then building from there. What I want to do is this.

1. build a 6'x12' frame out of (4) 2x6 pressure treated lumber. I'll build it on garage floor and make sure it's level as possible.
2. position the 6'x12' frame where I want the coop to be on the ground and mark the places I intend to have the posts.
3. sit the 6'x12' frame to the side while I dig holes for the 4x4 posts.
4. put the 6'x12' frame back in place and then put the 4x4's in the hole (they all sit inside the board frame)
5. use levels to both level the frame and make sure the 4x4s are plum and then screw the frame to the 4x4's
6. Once I have the frame secured to the 4x4's and it's all level and plum, fill the holes with concrete- temp bracing at the top of the posts to the ground.

You usually have to brace the 4x4's and make sure it's all plumb before you add the concrete to the hole, so why not make my frame that I want to be attached to the 4x4's be part of this support? Is the idea bad because I won't be able to get it all level and plumb at the same time?

I feel like I'll have better luck doing this than if I try to line up the posts separately, without the framing.

attaching examples of what i'm thinking. the gray circles are the holes I would dig.

I appreciate any advice.

You can try it that way.
I'm not a fan of embedding wood in concrete. They will eventually rot. I have to tear out the front porch supports at my dad's house because they were embedded in the concrete pad and they've rotted completely through.
I run string lines to make sure everything is square, mark the holes and dig a much wider diameter than I need, place sonatubes and make the plumb, run out the strings again to make sure everything is where I want it and start mixing and pouring concrete. I'll set a full line then run the strings and make sure everything is still plumb and relatively centered and carefully set a 9" J-bolt in the concrete centered where I want my 4x4 post (I even use a torpedo level on the bolt to make it plumb).
I use adjustable post bases to get the 4x4 centered and use a string to ensure they are in a straight line.
I then temporarily set the posts into the bases and plumb them with bracing and snap a chalk line at the height I want to cut them at for the beam, take them down one at a time, cut them then put them back in and put post to beam caps on. Build and set the beam and off I go.
Make sure when you are selecting your PT lumber that is is clearly labeled as rated for ground contact but still keep it about 1 to 2" above the ground to extend it's life.

 

[BaaKaaawk]

You can try it that way.
I'm not a fan of embedding wood in concrete. They will eventually rot. I have to tear out the front porch supports at my dad's house because they were embedded in the concrete pad and they've rotted completely through.

I think a lot of it depends on climate and location. Here in NC I can set posts in concrete and they last pretty much forever. as best I can see from projects that are 20+ years old with no issues. But my friend up North said they rot out in 5 years where he is in MD!!! That's crazy. Maybe has to do with the soil as well- we have nothing but red clay down here.

 

[ddoss]

If you build this coop with treated lumber it is going to weigh a good 300 pounds or more. I don't see any reason you need to concrete the posts (and I have built a lot of coops). If you are really worried, just up your wood posts to a 6x6 and that will add even more stability and more weight. If you really want to concrete them in, once you have levelled everything and your posts are in the holes, just toss a bag of concrete in each hole. As mentioned, this coop is going to be really heavy and highly unlikely to wiggle on you much.

That said, here's one I dig and absolutely I built the entire frame and leveled everything before I set it in.

https://www.backyardchickens.com/threads/baakaaawks-spring-2020-coop-build-thread.1357348/

Holy Moses! your coop is beautiful. your base framing is pretty much what I was thinking. thanks!

 

[ddoss]

It's up to you. I think you are overestimating the strength of the wind and underestimating the weight of your finished product.

Putting the posts on a paver just helps increase the surface area of the foot, which is always a good thing. I'd really just up to the 6x6 unless you already bought the material if you are concerned. A 6x6 has more than twice the square-foot ground contact / coverage as a 4x4.

6x6 = 36 square inches of post connection with the ground vs a 4x4 = 16 square inches.

Yeah, I already bought the 4x4's. I see people setting the entire coop/run on paver squares. what are your thoughts on me doing that? that way it's all sitting off the ground and the paver stone will increase the surface area of the foot like you mentioned.

 

[ddoss]

You can try it that way.
I'm not a fan of embedding wood in concrete. They will eventually rot. I have to tear out the front porch supports at my dad's house because they were embedded in the concrete pad and they've rotted completely through.
I run string lines to make sure everything is square, mark the holes and dig a much wider diameter than I need, place sonatubes and make the plumb, run out the strings again to make sure everything is where I want it and start mixing and pouring concrete. I'll set a full line then run the strings and make sure everything is still plumb and relatively centered and carefully set a 9" J-bolt in the concrete centered where I want my 4x4 post (I even use a torpedo level on the bolt to make it plumb).
I use adjustable post bases to get the 4x4 centered and use a string to ensure they are in a straight line.
I then temporarily set the posts into the bases and plumb them with bracing and snap a chalk line at the height I want to cut them at for the beam, take them down one at a time, cut them then put them back in and put post to beam caps on. Build and set the beam and off I go.
Make sure when you are selecting your PT lumber that is is clearly labeled as rated for ground contact but still keep it about 1 to 2" above the ground to extend it's life.
View attachment 2115300View attachment 2115302View attachment 2115303View attachment 2115307View attachment 2115308View attachment 2115311

You can try it that way.
I'm not a fan of embedding wood in concrete. They will eventually rot. I have to tear out the front porch supports at my dad's house because they were embedded in the concrete pad and they've rotted completely through.
I run string lines to make sure everything is square, mark the holes and dig a much wider diameter than I need, place sonatubes and make the plumb, run out the strings again to make sure everything is where I want it and start mixing and pouring concrete. I'll set a full line then run the strings and make sure everything is still plumb and relatively centered and carefully set a 9" J-bolt in the concrete centered where I want my 4x4 post (I even use a torpedo level on the bolt to make it plumb).
I use adjustable post bases to get the 4x4 centered and use a string to ensure they are in a straight line.
I then temporarily set the posts into the bases and plumb them with bracing and snap a chalk line at the height I want to cut them at for the beam, take them down one at a time, cut them then put them back in and put post to beam caps on. Build and set the beam and off I go.
Make sure when you are selecting your PT lumber that is is clearly labeled as rated for ground contact but still keep it about 1 to 2" above the ground to extend it's life.
View attachment 2115300View attachment 2115302View attachment 2115303View attachment 2115307View attachment 2115308View attachment 2115311

this photo showing the sonotube closeup - is that area covered over by dirt? I see the benefit of not putting the frame on the ground - up what looks like a inch. does dirt cover that up? is that ok because of how it would drain?

 

[DobieLover]

this photo showing the sonotube closeup - is that area covered over by dirt? I see the benefit of not putting the frame on the ground - up what looks like a inch. does dirt cover that up? is that ok because of how it would drain?

I'm not sure which photo you are referring to.
The tubes were buried. The footers go down to the required code depth for deck footer construction in my area. The post base that is bolted to the concrete pier has an internal 1" offset so the 4x4 never touches the ground.

I would expect a large ark to float by if water ever got that high here. My coop/run setup is on higher ground than everything around it.