I need to ask about a project I came across last week to see if I should make sure my kid doesn’t ride inside this barn in the future. A friend of ours is looking to make the use of their hay conveyor easier by adding a trapdoor to the hay loft in their horse barn. I suggested he have the truss company design a recommendation, but he isn’t going to do that, says they went out of business.
The idea as it currently stands is to make the opening by cutting into one of the trusses at the center of the barn and header it off to the truss on either side. The bottom plate of the truss on either side will be strengthened by adding a 1/2†plywood plate between a 2×8 sistered to the existing 2×8 across the entire span. This will be thru bolted, bottom and top, about every 18â€. The headers carrying either side of the cut truss will be a double 2×8 (about 46†between the strengthened trusses) fastened with a simpson hanger. The trap door will be about 30†wide by the 46†length. The cut truss will be fastened to the header with a simpson hanger.
This 24’ wide barn has trusses on 2’ centers. The trusses are a 2×8 bottom chord with (3) 2×4 web supports and a 2×6 rafter. There is a 12’ wide clear section in the middle where the hay is stored, 2 layers of 1/2†sheathing are there for the flooring. The owner says the truss spec for the barn had 8,000 lb load rating for storage. They don’t come close to that with their hay storage, maybe 4,000 lbs at a time.
I thought I would ask the brain trust here their thoughts on this plan. Any info I forgot to include that would help? – thanks.
I almost forgot….should he use nails or screws?!?!?!?!?!!?!? 😉
Replies
Any truss co would help. I wouldn't toudh without proper engeneering!
I wouldn't touch it without an engineer either, even if it was my own house. Having said that, most trusses are engineered for the worst case scenario, and I'd be willing to bet that you could remove every other truss in a lot of cases and the building would stand, at least until you got that once in a lifetime snowfall or hurricane or whatever. HOWEVER, the wildcard here is that they are storing hay in their attic. That would make me a little uncomfortable.
A long time ago I did a thread about cutting trusses for situations similar to this:
http://forums.taunton.com/n/mb/message.asp?webtag=tp-breaktime&ctx=1&cacheTag=1-40&msg=26387.1
The situation you mentioned is a bit different in that it apparently involves attic trusses. I'm sure what they want to do can be done correctly, but it would require input from an engineer. And it doesn't sound like they have any intention of doing that.
There's nothing I can tell you that would help any. At least it's a barn, and not a house.
Like I thought initially, I'll keep my kid home on rainy days where they would be riding in the barn.Thanks for the info.