Helppp need to reinforce coop foundation!

[kmpcfp]

I started building a coop without plans and when I built the posts and flush beams/joints I wasn't thinking clearly as to where the weight of the walls/roof would be. Nor was I initially planning on putting in the weight of osb/shingles (initially was going to do purlins/tin).

Anyway, the outer 2x6 joists are sagging as that is where the majority of the weight of the walls/roof is. I ordered adjustable crawlspace jacks, I just need to figure out what I need to do to fix the sag.

One side the posts (4x4) are on the corners, the other side they are cantilevered out 2 feet as I initially thought I would make a 6x10. I changed it to an 8x10.
The cantilevered side I am most worried about.

I am thinking of sistering 2 2x6 for a central skid and digging two concrete block footings in the center of each of the outer joists, then using the crawlspace jacks to hopefully fix the sag, or atleast prevent any future sag.

Suggestions? Thanks.

 

[archeryrob]

Sistering will help but nothing like the center support on what you already have. Bracing the span in the center will make it over 4 times stronger by having the span distance. I don;t think you need sistering, or it will help much.

By concrete block, do you mean Cinderblock or a solid concrete block? Cinderblocks need a hard footer to sit on.

 

[kmpcfp]

Sistering will help but nothing like the center support on what you already have. Bracing the span in the center will make it over 4 times stronger by having the span distance. I don;t think you need sistering, or it will help much.

By concrete block, do you mean Cinderblock or a solid concrete block? Cinderblocks need a hard footer to sit on.

I think sistering was the wrong term to use. I meant like a double 2x6 beam, nailed/glued together, then run that beam perpendicular underneath the joists in the center (where the lowest point of the sag is).

As to the concrete, if I could dig enough, I was going to try to do a concrete pier. However, I might start hitting some large roots. That was a struggle when trying to get the initial posts in. I could try to dig enough to put down some crushed gravel and some solid concrete blocks, or a cinder block sandwiched between two concrete blocks, depending on what height I would need.

 

[archeryrob]

Sistering is 2 2x6's side by side. Normally done to sure up a broken or violated beam. it is not going to strengthen it over a long span, a lot. It will some, just not enough.

Get a car jack and place on the beam or wood across the 2x4's for the floor and jack it up to relieve weight on the 2x6. Or jack up the 2x6 close to the center. Get a pressure treated 4x4 and cut a 1.5" x 5.5" slot out for the 2x6. Dig as much hole as you can and put the 4x4 in the center of the beam while its jacked up. Pour a bag of concrete in the hole and let it set over night. Pull the jack out the next day.

Then the sag should come out of the 2x6 and it should be 4x stronger by reducing its span in half.

 

[blackdog043]

For your location, I think putting a crushed gravel base and using cap blocks will work. You could jack the 2 x 6 a little more than straight, put your block under and use shingles to shim the last inch or less. If it's a bigger gap use a piece of pressure treated wood.

I used cap blocks to set my 4 x 4 skids on when I built my coop. That's a 12 ft span with three piers on each one. My shed has the same set up and is fine 14 years later.

 

[Ted Brown]

I am a little confused about your construction techniques for the floor. You have stated that the rim joists are 2" by 6" but say nothing about the floor joists. @archeryrob suggest that these are 2" by 4", not sure where he got this from. What size are the floor joists?

I agree with archeryrob that placing a support mid way along the 10' rim joists is needed. His suggestion to use vertical 4" by 4" PT posts is one way to go, my only modification would be to use a Simpson Strong Tie product to avoid notching the post; will make your life easier and they are not expensive. These are available at most big box places like HomeDepot on online at Amazon.

I would prefer a 8' 4" by 4" beam running horizontally from one side to the other and supported with vertical posts per archeryrob's suggestion. I think this will provide a more stable support than just vertical beams on either side AND may also support the floor across the middle (ie. are the floor joists 8' across or 10' end to end?).

Your biggest problem will be how you support the vertical post in either solution. Again archeryrob's suggestion of pouring concrete can work but make sure you get concrete under the posts so that they are not sitting on earth with concrete surrounding the lower portion, if this is the case the concrete will not do much. As an alternative go buy 2 concrete patio blocks.

Again big box store. Note that these are formed to accept a 4" by 4" vertical post OR 2" by x" lumber. About $10" each. Obviously you will need to excavate a flat surface on the ground to place them but easier than digging a hole, just make sure the ground is firm where you place it. Depending on the distance between the ground and the rim joists you may be able to use these without vertical posts. Obviously a jack will be needed to remove the bow and place whatever supports you use.

Good luck.

 

[BReeder!]

Sistering is 2 2x6's side by side. Normally done to sure up a broken or violated beam. it is not going to strengthen it over a long span, a lot. It will some, just not enough.

Get a car jack and place on the beam or wood across the 2x4's for the floor and jack it up to relieve weight on the 2x6. Or jack up the 2x6 close to the center. Get a pressure treated 4x4 and cut a 1.5" x 5.5" slot out for the 2x6. Dig as much hole as you can and put the 4x4 in the center of the beam while its jacked up. Pour a bag of concrete in the hole and let it set over night. Pull the jack out the next day.

Then the sag should come out of the 2x6 and it should be 4x stronger by reducing its span in half.

I second this

 

[kmpcfp]

The joists are 2x6 at 24 inches. I added 2x4 joists in between the 2x6's to stiffen up the floor a bit. The floor joists also run 10 feet.

So basically I need to add a center post at each rim joist. Perhaps also a center beam. I will need to jack up the center of one side about an inch and the other side about 1/2"... Would I be able to do this in one go or will I have to do it gradually you think?

I guess when we get a few rain free days I will start digging and see if I can avoid any large roots.

 

[Ted Brown]

If it were me I would add the cross beam from the get go, much easier now and will really stiffen up the floor.

As to jacking you can probably do it in one go but take it easy, have a look both sides and keep your ear open - the building will tell you. Hopefully you have two jacks and you can go side to side.

 

[kmpcfp]

I just realized this rim joist always had a decent sag in it and of course I put it in crown side down. Whoops. I guess I never realized how pronounced it was, or maybe it has got worse. This picture was before I put in the diagonal supports and the 2x4 bracing. The small 2x4s were in place to support the floor boards (I used fence pickets - they were inexpensive).