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Building a wooden deck over a concrete one

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So we've had this very sturdy but extremely plain looking concrete porch in the back of the house, and we've always wanted to make it warmer and more inviting. The obvious solution, to us, was to replace it with a wooden one. Wood is by far warmer and better looking than concrete, and if you maintain it properly it can easily last a couple of decades before you need to start replacing a piece here or there. On the downside, obviously, is the commitment to maintain it regularly. And by regularly, I mean a thorough cleaning and restaining (or repainting) once every two or three years.

Replacing the concrete deck with wood could have been done in one of two ways: completely demolish the concrete porch and build a 100% wooden one in its place, or use the concrete as a base and just add wood on top of it. Since our concrete was in good condition and would offer a solid base we decided to keep it and just cover it all with wood. 

Building a wooden deck this way does offer the advantage of not needing to worry about digging foundations, putting in joists, etc, but you do have to worry about the proper slope of the concrete porch, allowing for good water drainage, ensuring any parts that would be subjected to possible water pooling are treated against it, and such. I've done my best to protect against those things and take notes/photos of them, but I'm sure there's always room for improvement. If you're going to build something like this, remember this really important rule: an extra ten minutes spent putting in better water protection at this point will save you from headaches, hours of hours and $$$ in replacement materials down the road.
 
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Beautiful! Well thought out. I especially appreciate the detail you provided on the railing construction. Well done.
David Catriel (author)  captain Jack1 year ago
Glad you liked it, and thx for the compliment.
Vince_332 years ago
I really enjoyed reading this - it's given me lots of ideas. Thank you very much for taking the trouble to post such a detailed description - much appreciated!
David Catriel (author)  Vince_332 years ago
Glad you enjoyed it, and thx for taking the time to say so. The comments are appreciated by the authors as much as the articles are appreciated by the readers :)
ambiguator2 days ago

After 2 years, how is it holding up?

Have you had trouble with rot?

Any other ideas to reduce maintenance overhead?

David Catriel (author)  ambiguator2 days ago

Hi

I can unambiguously (and happily) say that there have been zero issues after two years. Some of the boards on the more highly trafficked areas are losing the stain a bit more than others, but structurally everything is peachy. I can't really see underneath the boards very well because the gaps are small, but from what I see the silicone is still there and holding on well.

Are you building something similar ?

I have a concrete patio, and other places I'm reading say that wood in contact with concrete is a recipe for rot. Without airflow below the wood - 10 inches, preferably a foot - the lifespan is degraded, so they say.

Glad to hear you're not having any issues.
David Catriel (author)  ambiguator2 days ago

There's about 4" of good airflow underneath the floor, and only the runners are sitting right on top of the concrete. There's zero clearance between the runners and the concrete, and the points where they come in contact with it are all sealed with silicone, so that should provide good protection.

I suppose the only way to know for sure would be to check in a few years. I'll check it again in the summer of 2017 (for a five year span) and get back to you :)

David Catriel (author)  David Catriel2 days ago

As for reducing maintenance - I would just go with the two main recommendations in the article: put silicone everywhere there is a chance water can get in (e.g. between the concrete and the runners), and use plenty of wood sealer on all the cut ends.

sneal920 days ago

Having trouble with the hinges... Any help appreciated. I have no experience with hinges. Tried and the door wouldnt shut.

David Catriel (author)  sneal920 days ago
Would be glad to help, but kind of hard to do without knowing what your troubles are. Are you having issues putting them on? Do they not close properly? If you add some images it would be easier to lend a hand.

It did not close correctly. Its dark but will try to send pics tomo. My first hinges so I wasnt sure how high or where to put them and stuff.

sneal920 days ago

We have built this but are having trouble with hinges. Could you help. I am not very good with hinges.

colelemi1 year ago
I've seen decks in Cambridge like this, but didn't know how to go about building it. Thanks for posting!
David Catriel (author)  colelemi1 year ago
thx. hope it helps you make your own :)
drawe212 years ago
I like it, I would make the box's around the edge taller to top of fence for planters with storage access under planters on the front. (6 to 12 inchs of dirt at top) I love storage.
David Catriel (author)  drawe212 years ago
Not a bad idea. The boxes are already used for storage, but were left at half the height of the railings so people have a place to sit.
tim_n2 years ago
I've got a large flat slab outside my house, but it has cracks and doesn't drain water away very efficiently, so I'm currently considering my options - one is to cover in decking, the other is to lay a concrete patio over it.

I was interested to see how you deal with the wood sitting on concrete - and I see what you've done - just laid it on top - as the concrete is porous, surely the water will seep under the silcone and work its way into the wood? I've been recommended when I put a shed on concrete pavers to put off cuts of pond liner or similar to stop the water soaking up into the wood.

Similarly depending on the variation in temps, won't the sealant eventually split off?

It's a neat job btw... just curious to what you think!
drawe21 tim_n2 years ago
Clean out the cracks as deep as you can and Epoxy them closed, then you can hide the ugly fix with this wood project.
David Catriel (author)  tim_n2 years ago
Several considerations here. First off - yeah, concrete is a bit porous, but the kind used for exeterior construction is usually a bit better at repelling water since it's exposed to it all the time. No telling if any additives were added to the mixture when it was made, but I have to trust that it was done properly.

That being said, it's always possible that some water will get through to the wood, but sealing the edges between the wood and the concrete should minimize that.

And as for climate changes affecting the sealant - also, a possiblity, which is why I used high grade exterior use sealant. Should buy me a few more years. We've got a lot of heat, water, snow and ice over here, so it will definitely be subjected to the elements.

Finally, you have the fact that the wood is treated lumber, and has been attached at several points to the concrete. Even if some part of it starts weakening, I have faith that the wood (as a whole) will stay solid and well attached for years to come.
daveand52 years ago
Nice looking deck, and an improvement, but....
ACQ is protected against insects and fungi, not moisture, proper drainage does that. Just do a search for ACQ and read the facts.
Standard building code calls for 16" centers not 18"
Proper drainage starts with the side of the house, proper flashing to redirect the water away from it and the deck. Proper flashing and rubber seals make a deck outlast the home.
"skirting" should be applied to cover the ends of the decking for esthetic reasons and with proper drainage with flashing to protect the wood joists.
A spot of glue on each runner where the decking touches extends life of the wood and 'firms' up the deck tremendously. also eliminates screws from backing out from vibration.
I use the 20yr siding stain on the decks I build, since most 'deck stains' say right on the can, to reapply yearly, clearly a rip off.
Always check with local authorities on building codes and accepted practices to avoid fines and rebuilding.
Again nice deck, and enjoy a bbq and beer on a warm evening for me.
David Catriel (author)  daveand52 years ago
Thx for the info. Drainage won't be a prob since the concrete is already slanted away from the house, and we'll be treating/staining the wood next year for extra protection and looks.
JakeBlanton2 years ago
Since your concrete was in good shape, I would have just covered the concrete with slate or some other stone instead of wood. With a concrete deck, you had something that was basically maintenance free -- basically you just pressure wash it when it gets too green for your tastes. With wood, you're going to be pressure washing, resealing, replacing rotten boards, fixing loose boards, etc from now on. I've owned houses with wooden and concrete decks / patios before and in my opinion, the concrete is a better choice.
David Catriel (author)  JakeBlanton2 years ago
A wood deck will defintiely take more work in maintenance that concrete, and I think I mentioned that somewhere in the article. It all comes down to what your tastes are, and in my opinion nothing beats the warmth and aesthetic value that wood has. It's well worth the maintenance costs.
Azayles2 years ago
Norm Abram himself would be proud!
This is a fantastic instructable, very detailed and well put together.
sfurst Azayles2 years ago
AHH . . . Norm Abrams. I was already getting all sentimental thinking about my dad today (he's been deceased 12 1/2 years) and then I see this AND the Norm comment. My dad LOVED Norm Abrams, the New Yankee Workshop, This Old House, etc. He always joked that "Normby" was on . . . "Time to watch Norm-by!" I actually got to meet him in 2001. The man has a router for every bit he owns so he never has to change a bit. THAT is woodworking luxury!

That being said, my dad (an accomplished woodworker) would be impressed by your work. Wanna swing over to Wisconsin and build one for me? ;) Great stuff.
Azayles sfurst2 years ago
Wow, I didn't know he had a router for every bit! Mind you, the size of his workshop and the stuff he used to turn out :P Not really surprising!
Also the safety glasses. very important that.
"There is no more important safety rule than to wear these safety glasses"
Wise words indeed.
David Catriel (author)  Azayles2 years ago
I would add the ear plugs to that ...
I heard an interview with Norm,, I also remember the very first "This Old House" show, Norm actually was just a hired carpenter for the job along with several others. The Construction lead never showed up and the camera's were rolling. Bob Villa saw Norm walking by with a ladder and stopped him and started asking him questions about the job..

Norm was one lucky SOB,, that made his future.
David Catriel (author)  sfurst2 years ago
That's got to be one of the most flattering comments I've received to date. But in spite of that, I've got to turn Wisconsin down. Trust me - the paperwork my wife would have you do in order to borrow me for this project just wouldn't be worth it!
David Catriel (author)  Azayles2 years ago
Never knew who Norm Abram until this comment (and Wikipedia) came along. Thx for the learning experience :)
I used to watch his New Yankee Workshop show all the time when it aired in the UK. Well worth looking out for his work if you're into the carpentry :-)
jzelensk2 years ago
Really well-done project and photos. Congratulations!
David Catriel (author)  jzelensk2 years ago
Glad you enjoyed it.
Ortzinator2 years ago
That concrete looked terrible, good job! The roof is next perhaps? :o)
David Catriel (author)  Ortzinator2 years ago
Thx. Would love to redo the roof, but I think I know a non-one-man job when I see one. The shingles need some TLC all over the place. Time to call in the experts and have the whole thing redone ...

Then again, maybe I can cover it in treated wood to match the deck? I wonder what the wife would to that.
derte842 years ago
nice and simple!
David Catriel (author)  derte842 years ago
Hi
Thx for the comment. I wouldn't exactly say the project was simple to make (although you're probably referring to the design), but I agree that it was nice :)
buckmcf2 years ago
Exactly what I was thinking of doing to my back patio.
David Catriel (author)  buckmcf2 years ago
Then go for it. It's a bit of work, but so worth it in the end.
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