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first deck build...need some help

19K views 43 replies 9 participants last post by  joetab24 
#1 · (Edited)
deck over/on top of concrete patio?




now that the pergola is gone....not sure what to do w/ the space?

maybe a low deck over ( or on?) the patio?? i'd like to close in the open spot on the right side near the garage.

could I build right on the patio?
 
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#6 ·
a friend of mine emailed me this advice....

"You don't want the deck directly on the slab, because every rainstorm will trap water there which will sit there and rot the wood, and even pressure treated wood won't last long that way. At the very least you want it up a couple inches, but personally I would "lift" it to the height of the back door anyway. That will let you get a leaf blower under it and blow the crap (leaves, twigs, hot dog bun pieces) that will inevitably fall between the boards and clean it out once in a while. I'd try to run the joists side to side so you can "blow" the stuff out, if you run them front to back you can only blow the stuff against the house, which you really don't want.

You might not have enough height to use those piers from earlier in the thread (add that height to a 2x6 or preferably 2x8 joist) and you might be too high. But using a few pavers and then the joists might give you the right height. Run the back joist into and fastened to the back wall of the house, that will give you stability from having it "drift." I'd try to run the joists side to side so you can "blow" the stuff out, if you run them front to back you can only blow the stuff against the house, which you really don't want.

My neighbor concocted an awning out of canvas (I think he told me he got it at a marine store: sailcloth, maybe?) and PVC pipes. It's about 5' x 20', with a triangular frame built from heavy duty PVC. Gorgeous blue color canvas. He put grommets in the canvas, then looped rope through the grommets and around the pipe, which attached to the house. Looks good, actually. Only covers about half the porch, but he says that's all he wanted; enough coverage for the grill and the doghouse.

Looks kind of like this without the curvature:
http://www.austinsignsfl.com/images/awning3.jpg

Attached kind of like this, with one continuous rope:
http://www.tarpcountry.com/images/lashed-tarp.jpg

Using one of these will give you a 4x4 anchor from which you can run a "stub" to lift the deck. And these will keep the end of the 4x4 off any pooled water as well.

link broken "
 
#10 · (Edited)
i probably won't do a top/cover.....in a few other threads others have commented on the problems i might have with the slope of a roof...i don't know enough about roofs to know what issues i might have with such a project...

so if i am not going to build a roof, would it be ok to go into the side of the concrete?
 
#11 · (Edited)
i've posted a few threads as i've torn down the pergola and considered various ways to improve this space





pretty sure I want to build a deck back here, no roof.

i have 8.5" from the current concrete slab to the wood at the door

not sure how exactly to proceed


found this website...

http://www.extremehowto.com/xh/article.asp?article_id=60428

they anchor the joists (perpendicular to the house) directly to the concrete using L brackets...

i know if I have to install some pier blocks into the grass to attach the joists

if i use 2 X 6s for my joists (5 1/2 " height) and 2 X4s for my decking (1.5" height), i will be very close to the bottom of the door, which is about 8.5" from the concrete.
 
#12 ·
The individual blocking for piers are rather costly.

I'd, personally, dig and cement in 4x4's (or bigger) - cantilever the deck a bit so the posts won't show - and build a classic deck bypassing the use of the current concrete and attaching the deck to the house properly.

You can get a bit creative with large wooden flower pots or decorative benches instead of a railing. . . and I'd build a privacy fence and let it grow over with a flower ivy of some type - or no flowering.
 
#13 · (Edited)
found this video from bob villa's website. a free floating deck over a concrete slab is being installed. metal fasteners are being used so that no wood has contact with concrete.


http://tinyurl.com/ygfu6sr


just curious, when i watch the villa video, i can't tell how they secured the band joist to the small posts that are nailed to the concrete via the fastener. Are they just sitting on them?
 
#14 ·
Yeah, good solution.
Any contact of concrete slabs and so forth with deck wood will lead to rot and mold - at the least.
 
#16 ·
you can definately build onto of the concrete by laying down sleepers as the substructure. Is the concrete sloped at all? if so you want to put the sleepers in that direction so water drains from underneath the deck properly. Idealy you want the sleepers (joists) running away from the house since decking looks much better if its running parallel to the house. How far is the door threshold off the concrete? what decking materlial were you thinking of using.

To do Sleepers An easy way that I dd this is I bolted 2X4s PTE flat on the concrete using Galvinized 3/8" redheads and then screwed 2x4s PTE or in your case 2x6s to the 2x4s. I also glued the sleeper to concrete and 2x4s. Before I put decking on I coverd the whole assembly with *****ethane flashing to waterproof it even more. My Patio was sloped so I had to cut my sleepers to get the deck level. this was the hardest thing to do and takes a little practice.

Another thing you can do is use slate tile or something to cover the patio. Slate is not that expensive and probably won't cost or take you any more time than a deck.
 

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#17 ·
Oh another solution instead of bolting 2x4s down is to fasten them with concrete nails. You can see from the picture above I had some issues synch the nails all the way in even on highest charges so I stuck with redheads. I have done on a previous deck with no problems and its a lot faster.
 
#18 · (Edited)
At count 1:25 he says:
"with the joist hangars in place we're ready to assemble all the pieces and nail them after . . . " then they pick up their piece and just rest it on top of the supports without attaching it at this point.
It looks like they're trying to fit a bracket onto the support, but they're just balancing it on the edge. (at least that's what it looks like)

It doesn't look like there is a bracket on top of the support and under the deck rail - but there should be (maybe a true floating deck doesn't have them, but that makes no sense in a place like florida with hurricane force winds) - So the best bet is that there is a cap-bracket on top of the support which attaches to the underside of the top joist. . . it would look just like the bracket that attaches the support to the slab itself.
 
#21 ·
http://www.strongtie.com/deckcenter/index.html?source=category

Under the category listed as "Beam to Post" there are a variety of brackets that are called "caps" - these are for the top of vertical supports. Choose it based on the support size and the beam size, as well as the location of the bracket (inside/outside - where exactly does it need to support the beam overtop, center or off-center, etc).

I built our deck without base or cap brackets - the only brackets I used were joist hangars. I used 5x5's for the posts and the beams hang on the side of the posts with lag bolts. My design, however, exceeded code (which isn't strict around here) - but I know that if I lived elsewhere I'd be required to use the brackets, which would have been no big deal to purchase anywhere and install (and can be installed in the future if things change)

You don't have to be classic with your deck, either, if you're designing your own you can be as creative as you want and personalize it for your needs.
I refused to just build a box deck. Several reasons - for one, our yard is huge and a box deck looked good on paper but really was tiny in comparison. I needed to bring it into the yard but was limited by my budget. I, also, didn't want much of the deck to be near the house - I've yet to install gutters and always thought it dumb to have a deck next to a wall which would detour that area from being used - such as when it rains or when hornets decide to invade the soffets, etc. I, also, didn't want kids all up in "my space" when I'm outside tanning and so on.
To solve these things I designed it with a bridge from the doorway that extends out and away from the house - with a step down to a larger deck for chair-lounging and at the other side is a step-up medium sized deck for adults-only.
There is an alcove dirt area next to the house and I've turned that into a smoke-corner for our grill and so forth, complete with a wind shield and overhang.

Now - back to your deck picture.
There are several things I see that you need to keep in mind and consider. #1 - in the photo the deck boards (which are called 5-quarter or 5/4 board) are on an angle and the angle turns the other direction in the middle.

This means that their joists probably run in direction of the door to the step. There is also a beam running left-right in center (which is likely supported in the center with a support post) so the diagonal beams can be supported at the inside where direction changes.

They likely used traditional step-forms that are pre-cut and then just nicely boxed off the steps to conceal it.

The upper deck overhangs on the front (this is called cantilever) - however, it's not a true cantilever because they have installed supports from the lower portion of the deck/step to the upper deck. You don't need this. If you double your beam that extends out past your post you can properly cantilever your deck (how much depends on the size post/beam used)

Hope that helps some - I'm out of time :) Good luck, read up on decking and crunch some numbers. Sketch out some ideas on paper.
 
#22 · (Edited)
trying to get the space and my ideas on paper

noticed a typo i meant 16'9" (not 16 X 9)





after watching the bob villa video above, i put together this drawing, showing the connection to the concrete.

in the video, it looks like he built a frame using 2 X 6s, attached joist hangers to the rim joists and ran them across. there was a beam in the center (a girder?) to prevent the joists from sagging. can i run 2 X 6 joists 16' 9". I've never worked with wood of this size.

I have about 10" from the slab to my door. The drawing above takes me to 9 3/8 (3 1/8 + 5 1/ 2 + 3/4 for decking)

 
#24 ·
please butt in :)

I am in SE PA

not sure of frost depth...

the slab measures 16" from the ground

i am not certain the slab has a foundation...when i examine it, the larger portion seems to be "sitting on" a slightly smaller section. is there anything else i can look for?

the part of the addition where the windows are is original...from the door to the left (you can see a different roof) is newer.
 
#25 ·
My concern is that both parts are just on slabs and will move independently with frost. This could ruin your new wooden deck or house. Can you check if there is a record of previous permits or inspections?

I'd seriously consider demo the slab and start from scratch.
 
#26 ·
Hey Joetab,

Have you checked with your city (or county) to see if there are permits required and/or codes. I know a free standing deck (ie not attached to the house) in my area as long as it is less than 1 feet off the ground require no permits.
 
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