# Deck Over Concrete Patio



## redhermes (Jun 16, 2008)

Hello to all, I just found this forum and I am excited about what looks to be a great resource. 

I live in Tempe AZ (think hot, Hot, HOT) and sunny. I have a small patio with a salt finish attached to the back of the house. To improve the appearance I am thinking of putting a deck on top of it, that is directly on the concrete not a second floor deck. 

Are there any specific issues I should be aware of with such a project? 

I am thinking of using either California Redwood or Cedar. I want to stay away composite decking (I think). Any thoughts on the best material for central Arizona? Mildew and rot are not usually an issue but the heat and sunlight of summer is very harsh. I am looking for a low maintenance solution.

I am planning to glue down 2 x 2 “sleepers” onto the concrete with an exterior glue such as Liquid Nails. Is this a good idea? Any better suggestions?

I’m not sure of the best way to attach the decking to the sleepers: nails, deck screws, adhesive, or specialized hardware. 

Any and all suggestions are appreciated.

Thanks!


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## perpetual98 (Nov 2, 2007)

I'm thinking about doing something similar, except I'm going to put a raised paver patio over mine. I would think in AZ you're not terribly concerned with frost heave, and I think they make anchors that you can attach to the concrete and then mount the lumber to those.

Then again, I don't really know what I'm talking about, so take it with a grain of salt. Lots of other smart people here though.


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## TexasEd (Jun 13, 2008)

What size deck are you building? 

Are you covering just the concrete or will the deck be larger than the existing patio?

Is there a step down from the door to the patio? How much?

I have done this in Virginia where there was a small 4'x4' pad outside the door but we built a 20x36 deck over the top.

We had a 4" drop from the door to the concrete so we took out 2" from our 2x6 joists that we ran over it. This made the decking surface almost flush with the threshold of the door (just a little low). Make sure you make the step out safe regardless of the height.

We did not attach a beam to the house so we did not have to worry too much about heave from the concrete tearing our beam off, just rising a supposedly the same rate (if at all) as the footers we put in since we did not think the pad was below the frost line like our footers were.


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## redhermes (Jun 16, 2008)

The patio concrete is 27 by 11 feet with the long side against the house.

I was thinking about adding two feet to the width, but I'm not sure it's worth the extra effort.

The step down from the door to the patio is only 4 inches so I think I have just enough room without any to spare. I was planning to use 2x2 or 2x4 on their side. How did you attach the joists to the concrete?




TexasEd said:


> What size deck are you building?
> 
> Are you covering just the concrete or will the deck be larger than the existing patio?
> 
> ...


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## Termite (Apr 13, 2008)

Typically a slab is inadequate to support a deck, but spreading the load out the way you're suggesting would probably work fine. It would be smart to check with your local building department to make sure it'll meet their local codes.

I would not glue the wood to the concrete. It just isn't a long term installation. I'd suggest mechanical fasteners such as tapcons to secure the sleepers.


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## redhermes (Jun 16, 2008)

*Checked with Building Safety...*

Good suggestion to check with the Building Safety Division. I did and he said that as long as the deck was on the concrete patio and was not attached directly to the house (except for the patio) it was not an issue at all. They consider it more of a floor covering than a structural element.

He suggested that Liquid Nails would be a good way to attach the deck, he made the suggestion on his own.

He also told me that I may have a problem with the termite inspection when I go to sell the house, because they may insist that the deck be removed for the inspection.

That got me to thinking, if the deck could be removable. That would also help with cleaning up under the deck... any thoughts?

A Google search led me to this site http://www.ezydeck.net/patio_decks.htm that offers patio deck "tiles". 

Does anyone have experience with theses?





thekctermite said:


> Typically a slab is inadequate to support a deck, but spreading the load out the way you're suggesting would probably work fine. It would be smart to check with your local building department to make sure it'll meet their local codes.
> 
> I would not glue the wood to the concrete. It just isn't a long term installation. I'd suggest mechanical fasteners such as tapcons to secure the sleepers.


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## Termite (Apr 13, 2008)

I still maintain that liquid nails is not a good idea for long-term outdoor use in this application.


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## TexasEd (Jun 13, 2008)

I agree with not using an adhesive. 

On the deck we built we had regular footers everywhere except for the Joists that ran over the existing 4x4 pad. We doubled the joists and cut out 2" and let it rest on the pad where they touched, but the footing really carried most of the load.

If the concrete is nice, stain it.

If you must have a deck over it to use masonry screws or something like a Simpson strong tie to attach your joists over it. Depending on the thickness of the decking planks you will want to adjust the spacing of the joists.


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## redhermes (Jun 16, 2008)

*Is this a crazy idea?*

First, thanks to the folks that replied to my questions.

Now my crazy idea: Instead of permanently attaching a deck to the concrete patio, create a set of interlocking “deck tiles”. I’m thinking of about 2’ by 2’ panels of decking that can be removed for cleaning out the junk that will likely build up under such a low mounted deck. This would also allow removal for termite inspection, maintenance, etc.

Via Google I have seen some commercial products such as http://www.decktiles.org/snapping_deck_tiles_about.jsp and http://www.ezydeck.net/; but they are not removable.

Any thoughts or suggestion? Has any seen this attempted before?


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## Termite (Apr 13, 2008)

I wouldn't waste the money on those systems. You're really paying for something you could create yourself if you were inclined to do so. If you use stainless screws that will last for a very long time, deck boards could easily be removed as needed.


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## Chagres (Oct 13, 2007)

I agree on not using liquid nails for an exterior project like this. For part of the deck being removable, this is actually a very good idea in many cases. For example I know that when I finally get around to building my deck, I'm going to run my decking perpendicular to the house so I'll be able to pull up planks to get to the clean-out if I need to (and possibly other things).

Kelly
www.icanfixupmyhome.com


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