Thoughts about the foundation of my hen house?

[rod5591]

The hen house will be 10x10 in size. The 2x4s in the photo is the sill plate, held in place by anchor bolts. The cinder block foundation is not quite level—there is a one inch gap for about 3 feet.

I am trying to figure out where to go from here regarding the floor. Originally I was going to screw 2 x 4s to the sill plate with the 4 inch side down but I read where the floor joists are supposed to be with the 2 inch side down? Not sure where to go here.

I am a retired accountant not a carpenter. Any suggestions on how to build a floor to the sill plate I built?

 

[cholland]

Fill the 1 inch gap with something to keep small things from crawling under there.
Would be best to use pressure treated sill plates.
Otherwise yes, use 2x4 or even better use 2x6. Narrow sides down, spaced at 16 or 24 inches apart, measured from the center of the joists, the use 1/2 or 3/4 plywood to cover.

 

[blackdog043]

Here is a good YouTube channel (icreatables) on building a shed, from the ground up. Your foundation and base need to be level and square or your gonna run into problems as you build. 2 x 4's (with 2" side down)would be ok for the base, but your floor may end up dipping in the middle and feel spongy. I would and did use 2 x 6 pressure treated wood for the base and used 3/4 inch plywood for the floor. You should be able to use your block foundation, to put your base on. You can use roof shingles for shims to make it level. They won't rot or deteriorate under the base. You should put 1/2" hardware cloth around the base to the ground, to keep rodents from getting underneath the shed.

I used cap blocks and 4 x 4 runners to put my base on. I don't have a coop build page yet, but here is a couple pics of my base.

 

[rod5591]

The sill plates are pressure treated pine.

If I place the floor joists narrow side down, then I need to attach them to the sills via brackets, right?

Also, since the space is 10 x 10, won’t I need a 10 x 6 running down the middle, attached with brackets, and the rest of the 2x4 reduced to 5 ft, and attached by brackets to both sides?

 

[aart]

Your foundation and base need to be level and square or your gonna run into problems as you build.

Yes!! ....and it can get worse the farther up you go.

If I place the floor joists narrow side down, then I need to attach them to the sills via brackets, right?

Also, since the space is 10 x 10, won’t I need a 10 x 6 running down the middle, attached with brackets, and the rest of the 2x4 reduced to 5 ft, and attached by brackets to both sides?

You need a rim/band joist(set on edge) on top of your sill plate, then attach the floor joists to the rim joists.(see below-ignore the insulation)

What size floor joists you need dependents on span.
2x8's at 16" spacing across your 10' span should be fine.
There's lots of ways to support a floor to change the lumber size of joists.

 

[Hoytman]

Under any block footings for a building, shed, or coop I would highly recommend you dig down in the dirt enough to either pour a concrete footer for the block to sit on, or put a foot or more of gravel underneath those block. I would suggest finding out how deep your frost line is in the area you live and make your footings at least that deep. In my area the frost line is 36 inches. It adds a lot of work, but pays dividends in the long run with a structure that will last and last...and last.

For those reading this into the future that don't have much building experience, below is an explanation as to why a good footing is so important.

What happens is over time if the block are just sitting on dirt or only on a few inches of gravel, with the freezing and thawing of the earth the footings begin to move and tilt and sink. Over time, say 15-30 years...or even far less time, your structure will begin to move and get all out of square/plumb...and could begin to pull apart. A good footing is the most important part of the project and will help the structure last for decades or quite possibly a century or more.

I have a shed that my dad built where he just put blocks on the dirt, then placed 4x4 runners on that to hold the floor frame work. That shed is now 35 years old, but it's been sinking for more than 2/3 of that time...the blocks look like a bow-legged old man and one corner of the shed is in the dirt. If I hadn't just sold that home I would be looking at having to jack the shed up, move it, dig new footing holes, and then place the shed back where it was with new and proper footings.

If it's worth doing, then it's worth doing right the first time! How you build the rest of the structure is up to you, but heavy consideration should be putting in a good, durable foundation.

Hope that was helpful.

 

[Hoytman]

Example:
Where the block are supporting the framework in the photo above that blackdog posted, I would highly recommend, at a minimum, digging holes below the frostline and then filling those holes with concrete, gravel, or even pea gravel, then putting the blocks in place to hold the 4x4 runners and then the framework over that. Just by putting gravel filled post holes under those block in the photo above you increase the likelihood of the structure staying solidly by more than 10 fold.

Again, I hope this helps those reading this into the future who have less experience.

 

[rod5591]

Yes!! ....and it can get worse the farther up you go.

You need a rim/band joist(set on edge) on top of your sill plate, then attach the floor joists to the rim joists.(see below-ignore the insulation)

What size floor joists you need dependents on span.
2x8's at 16" spacing across your 10' span should be fine.
There's lots of ways to support a floor to change the lumber size of joists.

View attachment 1551075

man o man, this is the first I have heard of a rim joist. How is the Rim Joist attached to the sill plate?

 

[rod5591]

The frost line in central Tennessee where I live is 10 to 20 inches, per the website I looked at.

I am afraid my foundation doesn't meet the standards I am reading in the replying posts. What I did was laid out a 10x10 foundation with string, then dug a trench around the peremeter and laid in the cinder blocks. On each corner I dug down another 6 inches for a depth of 1 foot and then drove in a 3 foot steel spike (you can see the head of the spike in the corner cinder block of the attached photo). Then I poured concrete into each corner, and attached 2 anchor bolts on each corner (see other photo) to bolt the 2/4 sill plate to.

I used a level on each cinder block as I laid them in but I am sure the foundation is not perfectly level.

I am not certain what to do now. Can I use the foundation as it is, or do I need to tear it all out and start over? Truth be know, its taken me nearly 2 months just to get where I am now--I wanted to get a nice dry place for my birds before winter. Currently I use 2 small Chinese made prefabs that my 17 birds cram into each night.

 

[aart]

man o man, this is the first I have heard of a rim joist. How is the Rim Joist attached to the sill plate?

I suggest you look over some shed plans before proceeding further, you'll learn a lot and save some time in the long run.