What Type Of Reinforcement Neccessary?

ruskent

I am pricing out a raised patio. The patio will be masonry. The patio will be 12" above grade and have 20-24" tall seating walls around the patio.

If it was a ground level patio with seating walls I would just do a normal footing and build the wall out of 12" block with no reinforcement. But since it is retaining some, what exactly is neccessary?


The more I think of it it really is not retaining anything. But how should I build it?

artisanstone

That's a hard question to answer as everyone builds to their local soil (and frost) conditions. In my area, the answer would be, pour footer 8" deep, build seat wall, install asphalt expansion material against house and seat wall, pour patio slab, no steel required. Make sure the patio is not built on uncompacted fill (I would fill with crushed stone). I have no idea if this works for your area. I've never used 12" block for a seat wall, but this is probably because of the additional thickness for natural stone. I would probably do 2 wythes of stone, filled with mortar and chips, and tied together by the cap.

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ruskent

I should of gave more info. We do a 42" footing in Jersey. Most likely doing cultured stone or thin natural for the walls.

rbsremodeling

Do you pour footings and slabs seperate??

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artisanstone

Like I said, most folks base their solutions on other (possibly engineered) projects they've worked on. You would receive the best advice from other local masons. The only thing I'd add is that normal seat height is from 16"-18" which for me would be 2 courses plus cap.

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Bill Baddorf
Bill@artisanstoneworks.net
www.artisanstoneworks.net
www.stonefoundation.org

ruskent

I never did a wet laid patio with walls. Would it be better to do a mono pour and then block up off of that for my walls?

rbsremodeling

I guess depending on your skill level. I do mono pours with rebar/dowels up and lay my blocks over the steel then fill the block holes and cap. It just seems easier that way and everything is sturdier and locked in. But I use to live in a hurricane area so that just how I first learned to do everything like you are build a bomb shelter.

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ruskent

With a mono pour, which would be easy with this design, would I advoid the need for expansion joints?

rbsremodeling

What is the dimensions of the patio?? I would doubt it would not need expansion joints unless it is really small

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ruskent

RBS For some reason I was thinking expansion joints had to do with frost heave causing cracks and that a premiter footing would eliminate the need.

rbsremodeling

Concrete will expand and contract with moisture and change in temperature regardless of footing size, slab thickness or anything else. Control joist function to limit the cracking and help alleviate stress forces

As stated in another post it will be heavy and it will always crack

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tkle

Concrete 101. Expansion joints are for expansion.
I'm doing a bridge. Can somebody tell me how to do it?

6stringmason

Start on one side, and work your way to the next.

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tkle

Thanks. I was almost finished and then splash...

RAY MERCHANT

JUST POUR A MONO , MAKE SURE YOUR STEEL ( VERTICAL BARS ) (UP RODS) IS EVER 32" APART OR WHATEVER YOUR CODE IS THEN LAY WITH A 8" BLOCK IF IT IS NOT RETAINING ANYTHING,
IF YOU WANT ( I WOULD) PUT A OPEN BOTTOM BOND BEAM BLOCK ON THE TOP WITH YOUR REBAR RUNNING
HORIZONTAL ALSO . THEN YOUR SLAB BLOCK ON TOP OR WHAT EVER YOUR USING FOR A CAP , AND WOW YOU HAVE YOUR SELF A KNEE WALL.

Tommy C

Ruskent,

Being from NJ as well, here is what I'd do. I'd pour my footings separately. I'd have vertical reinforcement coming out of the footings every 3 feet, and I'd probably use Durwall as well for horizontal reinforcement. This is probably overkill, but it is cheap. I'd pour the slab after the block wall was built, with expansion joints against the wall, and grid wire inside the pour. Are you wet laying natural stone on this slab?

Also, be sure to backfill the knee wall with clean crushed stone, as the bottom 12" or so of that wall will act as a retaining wall. And do not forget weep holes as well.