I ve got a barn that has a really deep crawlspace that I would like to be able to park my truck above. Existing wood floor is shot.
I would like to keep the crawlspace(bringing in fill and pouring a slab is not really doable) and set some steel and then the corrugated metal decking, then rebar it and pour a slab. Originally I was going to do a joisted floor until I realized that this would be better if its possible.
Before I call my engineer, anybody ever do this? Does the metal decking get welded to the beams, or bolted, or what.
The bay I would like to do this in is 14w by 20d.
Tanks a rot.
Replies
yes it get welded to the beams, usually spot welded every six inches.
The latest issue of JLC has an article on doing exactly what you are considering, but with styrofoam panels (believe it or not) instead of steel decking. It was for a garage floor so it was built to support vehicle weight.
Billy
Good article in JLC as Billy sugested, but what are the load bearing stem walls and footings designed for? No point in pouring tons of concrete for a floor if you don't have the footings to support it. Same for setting steel post and beams with pan decking. Both are possible, but you need an engineer for your design loads and footing/pier requirements.
Dave
That wasa an interesting article in JLC this mionth. Did you notice that there is some type of structural steel embedded in the foam? Looks like lightweight I beams.
Whenever you are asked if you can do a job, tell'em "Certainly, I can!" Then get busy and find out how to do it. T. Roosevelt
I remember that there were Z-bars embedded in the foam, but I don't remember the I-beams. Maybe that's waht you remember?
It looks like you have have everything supported well before the pour. Don't want to have a problem during the pour... Of course, the concrete and rebar are self-supporting after the pour. The foam forms create structural concrete girders for strength.
Billy
I gatthered that they where there to make it stiff enough to work on during handling and assembly and also for blocking for whatever get mounted on the bottom.
But not structure for the resultant slab. That is what the rebar is far.
Bill & Billy ... I didn't look cl;osely, and I'm not within reach of the issue ... but you're right, the steel is there to support the foam during constructiuon and concrete placement. After that the foam becomes insulation. The article also showed scaffolding used to support the foam with temp headers every 7 ft.
Whenever you are asked if you can do a job, tell'em "Certainly, I can!" Then get busy and find out how to do it. T. Roosevelt
BTW my house has a suspended slab floor in the garage.
Poured over plywood supported by bar joist and temporary supports. Then all stripped so that I have lovely wood grained concrete ceiling.
That was done 25 years ago. I did not check closely, but that I have seen a couple done in the area a few years ago and that still seems to be the way that it is done here for residentail vs either the precast slabs or the metal decking.
The steel decking can be quite thin and the welds burn right through. We have used steel washers on top of the decking to weld through for a better hold. We also used fiber reinforced concrete instead of steel rebar or mesh for floors.
The steel decking can be quite thin and the welds burn right through. We have used steel washers on top of the decking to weld through for a better hold.
Washers work well, ignore the decking and weld the washer to the joist. But I did a whole lot better when I switched to nailing the decking to the joists. Powder actuated, with the correct nails, is really fast. PAHS Designer/Builder- Bury it!
Thanks for the info..are the pans real expensive?
The 3 beams I need would be south of a grand..they get pocketed into existing stone walls, that leaves me with cost of concrete/rebar/pans for 14x 20 bay.
My problem is there's around 4-5ft of crawl to fill. Not to mention this used to be a bank barn with a 8' basement/cattle area, so theres at least 4 ft of uncompactable fill in there that someone brought in for God knows why. Neighbor who is 80 was telling me about a truck that was parked in the basement...hmmm.
we ran some quick numbers on doing one of these recently and filling in the space with modified and pouring on top worked out to be cheaper.
carpenter in transition
It can be done just as you described. The metal decking has to be welded to keep from shifting while placing concrete. Usualy a weld at each edge and one in the middle of the decking. You must support the decking with scaffold below or post and stringers. Can you easily get the scaffold out of the crawlspace when done? Another way is to form the slab with scaffold, lumber and plywood.
You can use 4x4's for joists and plywood nailed on 6d nail at each corner several on the peremiter , enough to hold the sheet down, no more. When concrete is cured the scaffold, plywood and 4x4's are removed.Have you given any thought to installing a grate in the slab to faccilatate working on a vehicle from below the chassis.Makes it easier to change oil and other work normally done on a lift.
mike