We are building a new house and are considering building a 1000 SQ FT plus deck out of concrete. Several people have now made us worried when they tell us horror stories about cracking/ maintenance, etc. I just want some opinions.... If you have a concrete deck, do you like it? How maintainable is it? etc.
Much Thanks!
Jennifer
If poured and cured properly on properly prepared ground a concrete deck will last 5000 years with very little maintenance. Just ask the Romans.
It would be my opinion that there would be expansion and contraction which would have to be taken into account. otherwise am sure you could expect cracks to develope. Especially in that square footage.
If you pour a slab that big, you need to install expansion joints. I don't know the proper spacing of them, but they will help keep the slab from cracking. You will get some cracking, but nothing major. If you want to add to the looks of the deck, check out stamped concrete. It comes in many colors and patterns. The patterns will also help hide any cracking. It also is sealed which helps keep dirt from staining. I have a stamped patio (20' x 10') and it looks great. Ed
Take a walk in any big city. Take a look at some of the wide expanses of concrete. Are they in a condition you can live with? Yes, it is possible to crack, but properly poured, it can last a hundred maintenance free years. You need a proper base and expansion allowances. Just my opinion, but a large expanse of concrete can be rather blah. But stamped concrete, or flagstone, or some decorative touches can be very nice, very durable.
My deck is 8' off the ground and made of wood. Under the deck though, is a concrete patio that we use often and like a lot. In the 10 years or so that I've had it, no cracks and the only maintenance is to sweep it with a broom or blow away some snow.
Done right with the correct foundation (yes a slab has a foundation) the right design and materials for your area (it would be different in different areas) it will be very long lasting and trouble free. Make sure the contractor knows what you want and that you are willing to pay extra for the job done right. In this case it will mean better than the local codes require.
Better concrete mix. Better reinforcement Better foundation Quality finishing.
That much concrete will push against your house, even with expansion joints.
If a basement leak develops - you'll need to cut through the concrete to get at the outside of the underground wall to fix it properly.
I like patio stones.
Expansion joints are there to relieve stress from the concrete shrinking as it cures, not to stop pushing against the house, which makes no sense. Just look around, there are cement patios in back of lots of houses. How big they are has nothing to do with pushing against the house. Whether a patio extends 6ft fromt the house and runs 20 ft along the foundation or extends 20 feet and runs 50 feet along the foundation makes no difference to the house.
If the OP wants cement, I would definitely go with stamped concrete. A regular concrete deck, especially one that large, doesn't look attractive. Stamped concrete can be made to look like cobble stone, slate, brick, etc. and for the total job, is well worth the extra money. Make sure you check out the contractor. As for cracking, make sure the base is established correctly, compacted, and there are expansion cuts at least every 10 ft or less. Stamped concrete does need to be sealed about every 2 years to keep the finish looking nice.
Another alternative is pavers. They do have the advantage of not cracking, but have their own issues. Over the years, they can go out of level. And you do need to apply weed killer to keep weeds out. The advantages are no sealing, and you can redo the design, giving you some flexibility, and they are somewhat less expensive than stamped concrete.
I'm pretty sure something made of concrete would be a patio, not a deck.
Concrete will last a long time but it can crack or move. In most cases it can be fixed but it might be a big job.
Something made out of pavers will last almost forever. Any settling or cracked paver is easily fixed.
I had concrete, I replaced it with pavers. No regrets.
Thank you, I was wondering if the OP was planning on some sort of prestressed support system to raise it up (a deck is raised, and Patio is in contact with the ground)
Better to do it right the first time.
No, it'll last less than concrete in general, but...
Yes, far more easilly than a patio.
The home I grew up in has a patio of about the size the OPs planning with no cracks at all after 40 years.
I'd go with a patio of concrete done well. Doing it myself, I'd go consider the pavers for the ease of maintenance, over the chance that I might not get the concrete good enough.
John
I would be concerned, especially for a new home, with the ground settling and the concrete either cracking or settling so it slopes towrd the house. If I opted for concrete patio, I would opt for small slabs with expansion joints - if problems occur, you don't have to chop up the whole thing.
In Florida, with no freezing to worry about, we have two patios (old) and enlarged the space next to one using large concrete pavers, river rock and landscape cloth. Not too weedy, drains quickly, firm surface for grill, chairs, etc. Cheap. Easy to change.
Pavers are made of concrete. In what way would they fail?
I don't see movement in pavers as failure, but if concrete moves, I do consider that failure. Same with cracks.
The way I look at it, pavers last as long as you can get replacements. If you have a few extra pavers in storage, you could get hundreds of years out of pavers.
you people have no clue about construction.
"That much concrete will push against your house, even with expansion joints" "It would be my opinion that there would be expansion and contraction which would have to be taken into account. otherwise am sure you could expect cracks to develope. Especially in that square footage. "
"I would be concerned, especially for a new home, with the ground settling and the concrete either cracking or settling so it slopes towrd the house. If I opted for concrete patio, I would opt for small slabs with expansion joints - if problems occur, you don't have to chop up the whole thing. "
What do you people think the foundation is made out of...? This post really made me laugh. Thanks
Yes, I thought the same thing. Reminds me of the old saying that it's better to remain silent and thought a fool, than to open your mouth and remove all doubt!
Shift relative to each other.
I do. If it needs reapir, that's becuase it's failed.
Sure. I don't expect the pavers _themselves_ to fail, but the system is what's important.
I like stuff that you install once and then it last for generations without maintenance.
John
They're called expansion joints because of what happens when the concrete expands without them.
I guarantee without enough room for expansion between the house and the slab - a poured wall will give in before a 30 ft slab will.
If you doubt things expand - have a look at this link.
When concrete cures, the first thing it does, is it shrinks. Without expansion joints, the concrete will crack from that before anything else. That was where I was coming from. You are of course correct that it will expand and contract from temperature too and expansion joints are there to relieve that potential to crack too.
Now what does any of that have to do with your warning that"
"That much concrete will push against your house, even with expansion joints. "
All you have to do is have normal expansion joints, placed about 10 ft apart, like in any concrete pour. It has nothing to do with the fact that the OP wants a large patio and that somehow this means that it can't be done as normal, expansion joints.
Ok now I see, thanks.
This stuff:
In case you were wondering, that link looked like a high school text book.
If the poured concrete somehow gets below the expansion joint (as I have seen it do) it will come to rest against the house foundation.
When both the slab and the house expand in summer they will push together. They dont expand together. They are separate and expand separately. (just like the pictures in the link)
Unless the foundation wall has been designed strong enough to push the slab back the foundation wall will crack.
I am no concrete worker - but I do understand physics and have limited personal experience with both concrete patios and leaky basements. I'd rather not get into that.
As I said earlier, I agree a properly installed expansion joint should prevent the problem.
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