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SWHTM wants the back porch (concrete) extended so she can put a nice table out there for BBQ's now that we have the new grill...
I was thinking of doing a small wood deck instead of extending the concrete like she wants...
QUESTION, how do I attach the deck frame to the existing concrete... we are talking about roughly 22'x 10'
or is it necessary to do that... I intend to sink the deck uprights in concrete for max support..
Tom,
It would probably not be necessary to attach the deck to the concrete, but over time, it will move and a gap will form between the concrete and the deck. If I were building it, I would dig down and mount my ledger board to the concrete, using cement anchors. Mount your ledger board down the height of your flooring, so that the cement and the deck are level. Use joist hangers from the ledger board to hang your floor joists.
The problem that I see with this approach, is if the concrete slab will have enough strength to hold one end of the deck. How thick is the concrete?
The other end of the deck, I would build with posts and a beam.
Tom, you should bolt a header to the concrete with anchor bolts and build the deck from there. That will require drilling the concrete of course. You could rent a hammer.:rolleyes:
Tom,
Is the whole wall that you're going to be butting the deck up to concrete ?
If so, I'd go with lag shields and lag screws. Mount your ledger to the house and do one beam 9 feet from the the house. This way you'll have a little overhang and the posts will be set back from the edge a bit. You'll also avoid the problem of setting a post on backfill. At 9' you should be able to get into virgin soil when you drill your post holes. When it comes to concrete in the holes..... DON'T BOTHER ! Use pea gravel. The only wood posts I set in concrete anymore are gate posts. The rest I always set in pea gravel. It's much easier to get the post plumb and you can use them immediately. Another advantage of pea gravel is that it allows the water to drain away from the post. When you set a post in concrete, the post will eventually shrink and you'll get a gap between the concrete and the post. Water can then get in there and is trapped, thus allowing the post to rot faster. Well I could go on and on with helpful hints but I'll stop here. This is what I do, I build a lot of decks. If you'd like a hand in design/engineering drop me a line. I'd be glad to give you a hand. With just a little information I can help you with any questions you may have.
Good luck !
John
would it be posible to cover the whole exsisting conrete with the new deck? Might be time for you to post some pictures of where you are at now. If I had a back pored conrete deck that was say 8x10ish and wanted to end up with 10x20ish, i would try to make the old deck go away. You could yuse some of that new composite decking material and lay it right over the toop of the concrete and screw it to the concrete. Then just pour your footings and extend the joists right off the concrete, no header needed. But not seeing a picture makes it tough to "see".