Replies

1. 
   Guest_ | Mar 06, 2000 03:25am | #1

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   Steve,

   I'm by no stretch of the imagination an expert on this but, I do recall seeing it done once of twice. The first way was to pour concrete and then pour on the stone and tamp it into the still wet concrete. Once the concrete set, they used a hose to wash off the top layer of concrete to expose the stone. The other way was to just use more stone in the mix and than do the same.

   Hope this give you a place to start.

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1. 
   Guest_ | Mar 06, 2000 06:07am | #2

   *I did a job with a partner in which the customers requested an exposed aggregate slab about 600 square feet. We did the site prep and subbed out the slab to an ace flatworker with a big crew. The slab was about 6" thick with 1/2" rebar at 2' o.c. both ways. The joints formed panels about 13' square, which haven't cracked at all 18 months later, so you shouldn't need any joints in yours. The way the sub did the surface was to simply float it like a normal slab, followed by spraying onto the surface a retarder chemical. The next day the head honcho, working alone, showed up with a power washer and very carefully washed away the surface fines to reveal the aggregate. The thing is beautiful. I gather that in the old days it was done by careful brooming.The retardant really helps as it allows the body of the slab to cure to where you can carefully walk on it as you are exposing the aggregate. This was critical on our job, as it was 13' wide, adjacent to a wall. You could work yours from the edges if all sides are open. Good luck on your project, hope this helps.Bill

2. 
   Bearmon_ | Mar 06, 2000 04:13pm | #3

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   Steve, although I can't help with the concrete technique (I'm a paving stone contractor), I can offer some advice on design.

   Most umbrella type tables are 42" or 48" in diameter. You will want at least a 12' d. circle for this type of table, so that you can get around a seated person to an empty chair without stepping off into the garden or lawn.

3. 
   steve_tinder | Mar 06, 2000 04:13pm | #4

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   great forum i stumbled into.
   i play in se pa.
   i'm contemplating a 6 to 8 ft dia pad, or maybe square, for umbrella table & chairs in the yard. i must have a margarita respit this summer. i want some character, so im trying to find the proper technique to produce a slightly exposed 'cobble' surface such as ive seen commercially on walkways, etc. not the smooth surfaced - terzano or something. ill probably employ a 1/2 - 1 in dia yellow / brown river stone type aggregate. been casually 'advised' a few techniques so far. iso professionally proper.
   and what's a guess on min slab thickness for advised technique ? (rounded quartz aggregate (if part of entire mix pour) must bump up min slab thickness req.) but can i get away with no expansion joints ?
   thanx
   old house; always looking for options.
   esteph