Floor loading and joist sizing

[Egon]

Many years ago on the farm the only time a horse got to see the inside of a barn was when they were working. Most of the year was spent outside including the winter which could see -40F with no problem.

The plywood floor will eventually [ actually not that long ] become wet and lose its stength. If a horse puts its hoof through at the deep end there are really good chances of loosing a horse due to broken leg!

 

[MikePA]

Bruce, is there any way to get the horses on the ground floor? As others have mentioned, while going to 2x12 on 12" centers with the right flooring is an improvement on the existing situation, it's going to be an on-going maintenance issue that if it's forgotten, the horses could (would?) be hurt.

I've seen bank barns before, in fact the person I buy hay from has one. He keeps all his hay, tractors (2 ag tractors), hay wagons, etc. on the 'upper floor', but I've never seen a situation where animals are kept on the 'upper floor'. Of course, this doesn't mean it doesn't happen, perhaps others can chime in if they've seen this before.

 

[rozett]

Bruce, is there any way to get the horses on the ground floor?

No, there is really no ground floor. The barn is built into the hillside, with the north wall at ground level and the south wall about 5' above. I agree that it's not the best situation, but that's what I got. The stall mats have really been pivotal here. First, they hid the damage to the plywood until it because critical. But they have really prevented any injury by keeping the horse from stepping through the damage. I'm going to do a cost tradeoff between the PT plywood and 2x10 floor boards. In either case, the stall mats will be reintalled. The 2x10 floor boards may be prefereable because they'll allow better air circulation to dry the urine that seeps through the joints between mats.

Egon is right (again ) that in yesteryear, the horses would have been outside all the time. Our two definitely prefer to be outside all day long, but they have always spent the nights indoors. My wife's appy could easily deal with being outside with all those strange creatures at night. But my registered Quarter is a primadona. He gets very vocal about being brought in at night. His grandfather was 3 time world cutting champion. Obvioulsy, Peppe didn't inherite the right genes otherwise he'd still be in Texas.

 

[Egon]

With 2x10" wooden floor boards [ rough cut ] you would not need the mats.

 

[dmccarty]

Bruce,

How about composite decking. Yes I know its expensive.

But it sure beats have to rebuild over and over.

How about PT 2x12 with composite decking on top. I'm guessing that the composite would be better able to handle the pee and poo better than PT. And the composite would protect the PT 2x12s.

Later,
Dan

 

[MikePA]

Dan's post triggered a thought...What about engineered lumber (gluelam beams, wooden I beams, etc.) instead of the dimensional lumber for the underlying support structure?

 

[rozett]

What about engineered lumber (gluelam beams, wooden I beams, etc.) instead of the dimensional lumber for the underlying support structure?

I thought about that, but after crawling around under the barn, I am convinced that the joist failures were just a secondary failure. The primary failure was the plywood, which caused a lateral failure of one joist. With one joist out, the others have failed sequentially. The ply failure was caused by the horse urine, but aggrevated by the fact that the previous owner used 3/4 sheathing instead of 3/4 T&G subfloor and by the lack of any bridging. The lack of bridging meant that there was no lateral load support for the joists. So I will replace the joists with 2x12's 12" OC and bridging every 4 feet. I am still evaluating decking options..... PT subfloor, composite decking, and 2x10's. Unfortunately cost is an issue because I am covering almost 300 sq. ft. of floor.

These same two horses have been in these stalls for five years. If the primary failure was overloading the joists, I would expect that to have happened several years ago.

 

[dieselsmoke1]

Sure seems like some support near the center of the spans would help the situation. Would something as simple as some 4" solid blocks turned lengthways with the joists, laid flat on the ground and baited up to the bottom transfer most of the load and shock directly to the ground?

 

[rlk]

Bruce, interesting question you asked.

My response will be different from everyone else:

I would talk to a specialist in designing floor joists. Here is one web site where you can ask them questions about design loads, etc: http://www.trimjoist.com/spans.html A google search on engineered floor joists will give you more options.

The last time I put an addition onto my house, I had a similar question, as the addition was a sun room and I wanted ceramic tile. I called a similar floor joist company, and told them what I was doing, and asked for their recommendation.

They told me the size of engineered floor joists I needed. I upsized one increment, and doubled a couple of the floor joists to ensure there would be no bounce which could cause the tile and/or grout to crack.

My second recommendation is to talk to someone about the floor material. Some have said you should use 3/4 tongue and groove plywood or osb. If you go this route, be sure to seal the material with a good water sealer, I'm not talking about Thompsons, but a good sealer that you know will last.

To be sure you do not have a failure that could cause a horse to break a leg, I would use 2 layers of 3/4 tongue and groove material where each layer runs a different way. The material should be glued to the floor joists.

I know this will be more expensive, but if you do it this way, and thoroughly coat each layer with a good sealer, plus put a moisture barrier between the two layers, plus use 2 inches of wood shavings on top, you should not have to worry about the horses falling through the floor.

You only want to make this repair one time, and you want to be confident that your repair will be safe for the horses.

 

[MrJimi]

Here is a picture of my wooden I beams for my second floor, they are 16 inches tall and 3 and a half inches wide and 24 feet long and are designed to be spaced at 24 inches and I am putting them 16 inches on center, I am not sure what they will support but it is a huge amount

This is 2 on the end of my hoist, 108 pounds each

Jim