Thin red concrete overlay on top of aggregate?

[peterm]

We are getting ready to repair and reconstruct the terrace at Lamberson, including the brick and terrace floor. I just got a bid to remove the exterior aggregate floor of the terrace (which was installed at some point to replace the original), and then repour a new slab with integral red color. The bid was quite steep, and much of the expense was in removing the old slab.

I am trying to find out if the thin overlays which are now available could work on top of the existing aggregate, and if so, what are the pros and cons, the dos and don'ts? These thin overlays are sometimes used to create faux stone, brick, etc., but in this case,we would need to simply replicate the original hand tooled red concrete mat.

Thoughts?

Existing aggragate, which is quite rough, and larger than pea gravel sized stone:

[SDR]

I guess the first question would be, is the existing slab sound, with no cracks or movement. The second question would be whether the surface is now flush with the interior slab, and/or how little would you be able to add before the exterior became unacceptably high.

S

[peterm]

I believe the slab is sound. There are no cracks that I can see. These overlay slabs are no more than a quarter of an inch thick. I guess my question would be will this concrete acrylic mix adhere well to the aggregate?
Generally this overlay is applied to a concrete surface.

http://images03.olx.com/ui/2/63/81/39966281_3.jpg

[dtc]

I'm sure that gravel coating top coat is covering up some problems.
Perhaps some serious cracks.
Is this gravel surface flush with the interior mat?
Have you tried removing this top gravel coating?
Most likely when your parapet walls started to fail and were altered, this coating was used to "cover up" the exterior mat problem.

Good Luck.

[Roderick Grant]

Whatever the final solution, the aggragate is worse than the timber rails; it must go!

[LikaComet]

I'm looking at a similar situation. I have a concrete floor that was flubbed by a jack leg concrete company. Originally, I was going to hand broadcast a color hardener from Brickform but it was a hot day and the concrete began to harden before the color hardener could be floated into the surface.

The Brickform rep came and looked at it and he suggested spreading a thin (1/4 inch) layer of a polymer portland cement overlay. Then Brickform gave me a cementacious coating with the red color that I originally wanted.

I have yet to try it. I have to empty the house to conduct the repair.

[peterm]

dtc-Scroll down and right to see the edge of the slab containing the aggregate. I think the original slab must have been removed. The current slab appears to be one pour:

http://www.flickr.com/photos/31185895@N ... 071341594/

The edge that sits on top of the brick is about 4 inches thick.

Roderick, you're right, both the aggregate and the wood rails are offensive...

[dtc]

peterm,

I have an idea. Invite the willing and able Wright Chatters to the Lamberson for a tear off and a new pour, after the work we can pat ourselves on the back
and have a cocktail or two. What do you think?

I'm good at standing around with hands in pocket watching it all happen.
Plus I can mix a fine drink, when backed into a corner.

Lets not forget, we have some excellent photographers who could record the event. Also a few musicians (guitarists I believe) to entertain us as we work.

dtc

[peterm]

Musique concrete?

[SDR]

Ouch !

Right -- the "gravel coating" would be integral with the slab -- so-called "exposed aggregate" -- and if it covered up a cracked slab, those cracks would have shown through by now. Slabs crack because of inadequate or irregular support from below -- no ?

In the photo, the gravel -- actually smooth river rock ? -- looks like an attractive landscape effect -- but I'm sure you want the original appearance restored. In another house it would be a desirable feature, perhaps.

I would think that a pro could inform you as to what would (or would not) adhere to the surface. Surely if it has been coated with something, that would want to be sandblasted (?) off. Perhaps an acid wash of some sort ? What adheres to what, in the world of masonry, is beyond my pay grade . . . !

SDR

[SDR]

Similarly, if the house were by any other architect, we'd perhaps applaud those low and linear wood rails as minimal and attractive, welcoming the space of the landscape into the architectural realm. But they aren't what Wright drew, so . . . out ! ( I'm not saying that you're wrong -- I'm just sayin' . . .)

S

[peterm]

Well, maybe the wood rails aren't "that bad", but it could resemble something more like this:

Courtesy of dtc and tnguy:

http://files.myopera.com/TnGuy/albums/6 ... ns_015.JPG

[SDR]

Right -- that's what Wright drew (and built ?) at Lamberson, I take it.

[modjohn]

peterm,

Can you elaborate on the break down of the bid. The slab does not look that big and I would not expect removal to be too expensive (but that is always relative).

They should be able to break it up quite quickly with the right equipment (backhoe mounted jack hammer) then scoop it up and haul it away.

Have you gotten other bids or bids simply for removal?

I think you really want to pour a new slab over properly compacted fill. And reinforced with #4 rebar on 2' grid, not with re-wire!

[therman7g]

Excuse my bad Photoshopping: