Want to wood deck over concrete floor in screened porch


  #1  
Old 02-17-14, 05:23 AM
Z
Member
Thread Starter
Join Date: Feb 2014
Location: USA
Posts: 5
Upvotes: 0
Received 0 Upvotes on 0 Posts
Want to wood deck over concrete floor in screened porch

We have a 300+ sq ft screened porch with a concrete floor. The porch steps down 2 steps from the sliding door of the house, so raising the floor will be helpful. Currently there is outdoor carpeting covering the floor. We want to rip it up, put down 2x4 or 2x6 joists and pressure treated decking. The concrete is uneven- about 3' back from the far wall there is a 3/4" lip in the concrete- I'm not sure if the slab was poured at different times or what is going on under the carpet.

1) What's the best way to space the joists off the concrete so we can level it all out?

2) What spacing, and what kind of decking should I use?

3) The door frame has about a foot of open area above it that we can utilize to raise the door.







Uneven floor:


 
  #2  
Old 02-17-14, 05:54 AM
M
Forum Topic Moderator
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 45,643
Received 832 Upvotes on 729 Posts
Welcome to the forums!

I'd be inclined to use 4x4s to raise the new floor structure. What do you intend to do with the screen that will now be below the floor level? Does much rain enter the screen room? you'd need to allow for any water that gets under the wood floor a way out.

While I've stained 100s of decks, I've only built a handful - the carpenters should be along later
 
  #3  
Old 02-17-14, 06:04 AM
Z
Member
Thread Starter
Join Date: Feb 2014
Location: USA
Posts: 5
Upvotes: 0
Received 0 Upvotes on 0 Posts
I don't plan to do anything with the screens, it's a junky porch and we can't afford to knock it down and start from scratch. This is why we just want to DIY a wood deck to make it "nicer". If there's screen below the deck height, that would allow some airflow.

My dad's idea is to rip every joist to follow the contour of the floor and be level. I think that will be a nightmare. I'm thinking along the lines of spacers/shims/or some kind of adjustable posts to put the joists on.

The porch does get wet from rain mist blowing in, but it dries out pretty quick. The carpet is pretty much dry a couple days after a rain.
 
  #4  
Old 02-17-14, 06:10 AM
M
Forum Topic Moderator
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 45,643
Received 832 Upvotes on 729 Posts
You don't want standing water under the wood deck. That will promote mold and decay. Water under the deck won't dry as quick as the water that gets on top of your open slab. The more air flow you have under the deck the better. Scribing the joists to the floor's contour severely limits the air flow under the deck. Using posts to raise the deck or even thick shims would be better.
 
  #5  
Old 02-17-14, 06:14 AM
Z
Member
Thread Starter
Join Date: Feb 2014
Location: USA
Posts: 5
Upvotes: 0
Received 0 Upvotes on 0 Posts
What about using little 2x4" "legs", say at 4 points along the sides of each joist. Level the joist, then nail the joist to the side of the legs. The would keep the overall hight lower than laying on top of 4x4's, but all the weight of the deck is now riding on the nails, not wood on top of wood.
 
  #6  
Old 02-17-14, 06:19 AM
M
Forum Topic Moderator
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 45,643
Received 832 Upvotes on 729 Posts
That might be ok if the 2x4 is under the joists. When you attach it to the sides you are relying on the nails/screws to carry the load.
 
  #7  
Old 02-17-14, 06:15 PM
Join Date: Feb 2014
Location: usa
Posts: 1
Upvotes: 0
Received 0 Upvotes on 0 Posts
new deck

too many unknowns for an accurate advice.
ie length and width of slab.
can you be a little more specific. the pictures help but pictures are worth a thousand words and guessing is not a construction technique.
 

Last edited by chopper spotter; 02-17-14 at 07:19 PM.
  #8  
Old 02-17-14, 06:59 PM
BridgeMan45's Avatar
Member
Join Date: Oct 2011
Location: USA
Posts: 2,838
Upvotes: 0
Received 2 Upvotes on 2 Posts
I'd support all joists on two new beams, one near the house and one at the outboard end. If you're going to make this compliant with DCA-6, the beams should be supported by 6 x 6 stub columns, resting on concrete footings deep enough to reach below the frost line.

I'd also completely remove that stair assembly leading into the house, and replace it with one that better serves the new deck grade --the existing narrow top tread can be a "killer" for someone not expecting it, especially without a handrail of any kind.
 
  #9  
Old 02-18-14, 08:26 AM
D
Member
Join Date: Feb 2014
Posts: 37
Upvotes: 0
Received 1 Upvote on 1 Post
I would not put a deck there. You may hate your aluminum patio, but it looks perfectly fine in those pictures. How about some thin pavers? Rubber ones would work here too. When I priced out a deck vs pavers in my 10x10 project, it was about the same. I only chose the deck, because it would be easier to get just wood vs 100 pavers + sand + gravel. Here you don't need gravel, sand, and no compacting. Just cement down the pavers, no mortar, just sand in between. It's a night and day difference and it looks normal along the edges of the screen.

Those steps are horrible - and I think that's your main concern anyway. If concrete, just build some nicer ones on top of it out of wood, maybe make it a half oval shape, or angle it out like a trapezoid.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description: