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Attaching deck to house

AK_F250

Red Rocket
Joined
May 19, 2020
Member Number
178
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743
Loc
Alaska
I'll start off by saying that I know fuck all about framing, carpentry, general terms and all that. I do metal, not wood.

My house is a split level, and originally had a little porch thing out of the back door upstairs, I assume built off of extended floor joists. Someone added another 3' and some stairs at some point. I need to replace my septic tank which is right under it, so it needs to come down. Plus it's rotten as shit in places, as in the paint is all that's holding the untreated wood together.

I'm going to build a new deck that extends over to the meter base area and out 20' or so. The structure itself is going to be made out of formed steel channels in sections that bolt together so that I can build them at the shop and set with an excavator since my yards gonna be torn up anyway. I'll drive piling with the excavator to support it all. Dad and I build docks for friends in the winter using this method which is why I'm going this route versus normal wood construction. Did I mention I don't like wood?

How do I tie it into the house? I can get fairly close to the house with the piling but the hammer takes up some space, plus I have water, septic, and gas right there so I can't put them just anywhere. The house is going to have to bear some of the load. The neighbors had a similar size deck built and it looks like they just screwed a whatever x whatever to the house with a beam over 3 piling supporting the other end and joists on top of those.

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I'd build it freestanding
attaching it to the house only invites bugs, water, rot and mold into your house
 
Nevermind, just saw the steel framing bit. Build it free standing.

The issue I have with 100% free standing is I'm limited to the diameter pipe I can drive with my mini and demo hammer turned pile driver. Typically we use ~4" drill stem which has some flex sticking out of the ground 6'. I guess I could cross brace everything, but I'd like to use the area under it for storage and it seems like that might get in the way.

Is there any connection to the house free standing at all, or are they completely isolated from each other?
 
should be able to get it pretty damn stiff with just some little 2' long gussets, still plenty of access to the underside that way
 
remember that you're tying like 6 of them together, it isn't one post freestanding unsupported at the top
 
Is the basement finished? You could bolt a metal rim thru the rim joist if not. My biggest concern with that would be creating a place for moisture to be trapped. And the metal rusting. How are you gonna keep it from rusting even if it is free standing? I’m guessing you are gonna screw some kind of poly decking planks to the metal joist?
 
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I’m basing the flex/motion experience off of stuff like this dock at my cabin. 12 piling in each, and I can easily rock it a couple inches just planting my feet. But I guess I could do some smaller gussets and eliminate a lot of that while still keeping it clear for storing my crap. It seems like it would still need to be tied into the house though?
 
Is the basement finished? You could bolt a metal rim thru the rim joist if not. My biggest concern with that would be creating a place for moisture to be trapped. And the metal rusting. How are you gonna keep it from rusting even if it is free standing? I’m guessing you are gonna screw some kind of poly decking planks to the metal joist?

Yes it’s finished. I’m going with some poly decking that used clips between the planks to hold it down. I’m planning on using treated lumber on the actual attachment points, the steel is going to be the “frame” of the deck with pockets for the wood, I probably should have made that clear sooner.
 
I’m basing the flex/motion experience off of stuff like this dock at my cabin. 12 piling in each, and I can easily rock it a couple inches just planting my feet. But I guess I could do some smaller gussets and eliminate a lot of that while still keeping it clear for storing my crap. It seems like it would still need to be tied into the house though?
I doubt the dock is very securely attached to the pilings, what with winter and all meaning that you can't weld them together
 
Drill some holes in the steel frame that is tied to the house, use some non rotting spacers (hockey pucks) and lag bolt it through into your rim joist. Do you have building codes there or enforcement of codes?
Maybe this will help you https://www.awc.org/pdf/codes-standa...Guide-1405.pdf

ETA: would love to have a cabin set up like that :)
 
If I’m understanding you right. You are gonna attach the deck to the house using treated lumber? You could use lags to run a rim joist along the house . There will be a 2x8 or 10 rim joist running the length of the house. I’ve done a few decks this way on bi levels like yours. It isn’t the ideal solution, but with the basement finished you can’t access the inside to put bolts in. If you went this route I wouldn’t trust this to carry the whole weight on the house side. But it would tie the deck to the house.
 
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I doubt the dock is very securely attached to the pilings, what with winter and all meaning that you can't weld them together

The piling land in the 90* corners, they’re solid. We lay the sections out, mark, pull them, auger, replace, and drive. Flat bar spans the gap after the pipe is burned in place.
 
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The issue I have with 100% free standing is I'm limited to the diameter pipe I can drive with my mini and demo hammer turned pile driver. Typically we use ~4" drill stem which has some flex sticking out of the ground 6'. I guess I could cross brace everything, but I'd like to use the area under it for storage and it seems like that might get in the way.

Is there any connection to the house free standing at all, or are they completely isolated from each other?

Fill pipe with concrete
 
Drill some holes in the steel frame that is tied to the house, use some non rotting spacers (hockey pucks) and lag bolt it through into your rim joist. Do you have building codes there or enforcement of codes?
Maybe this will help you https://www.awc.org/pdf/codes-standa...Guide-1405.pdf

ETA: would love to have a cabin set up like that :)

This is what I would do, but I would use Ledger Loks instead of lag bolts. Do them two at a time in vertical fashion to add strength.
 
I'm not going to lie, this sure sounds a lot harder than just building it out of treated lumber. If you can measure and cut with a tape and miter saw, you can build a deck.
 
I like doing things the difficult way. The stairs are gonna be much easier out of steel too. Honestly how is steel making it much more difficult?
 
I would do it free standing as well. Want to cross brace everything both ways horizontally and vertically, its amazing what a few 2x4 can do to a deck when placed in the right place.

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Could you not build it like that to take up some of the gap? Most posts I've seen are 12-18 inches off the house.
 
I like doing things the difficult way. The stairs are gonna be much easier out of steel too. Honestly how is steel making it much more difficult?

Its not necessarily more difficult. It’s just that conventional wood framing is so mainstream that you can buy everything you need at the hardware store and then boob tube any questions.

if you like working with steel then hell yea do it. Small triangulation on your post to beam connections with help a ton and you can also weld some triangulation on to the joists to really gelp lock it all together. I am currently building decks again and mainly do wood with some composite here and there. Build that fucker with steel and post up the pimp pics. :smokin:
 
I just installed a metal cable railing ( :smokin: ) around a metal deck. They used 6x6 wooden posts topped with I beams. It was built conventionally, but with big I beams instead of timber framing. I recommend joist spacing of 12" if you're using composite decking. That stuff is flimsy.
 
I built a 2nd story freestanding wood framed deck years ago. With the diagonal bracing it was solid enough but, relative to the house, it swayed enough to be noticeable. I added stainless pipe standoffs and lagged it to the rim joist to tie the two together.
I'm sure you could come up with something.
 
I just installed a metal cable railing ( :smokin: ) around a metal deck. They used 6x6 wooden posts topped with I beams. It was built conventionally, but with big I beams instead of timber framing. I recommend joist spacing of 12" if you're using composite decking. That stuff is flimsy.

Definitely 12" OC for composite. That stuff cost a fortune and is terrible.

When we moved into our house the previous owner built an absolute nightmarish deck. I lagged it to the house properly, double banded the outer framing, put in real hand rails, and then built an 8'x8' landing for the stairs off of it. Everything is solid as a rock. Even the 8x8 was solid before I attached stairs to the deck above and the ground. I wrapped it in 2x12's, 6x6 on each corner, and used 2x10's 16" OC for the decking.
 
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