Seems to me you want to get some support under the cement to begin with. IS
that practical?
There are a few possibilities, fill under the steps with some sort of sand.
Maybe something like polymerized sand, a little expensive but as it becomes
moist it stabilizes as the sand sticks together.
Just trying to patch will result in the cement falling through the holes unless
you can get something under or behind it. Having said that I suggest you go for
some form of hydraulic cement, the sort which expands as it cures. If the holes
are too bit this might cause more expansion and stress on the existing concrete
and I suppose could split it however expanding cement will hold the patch there
much better assuming the shape of the holes don't cause the expansion to just
pop the patch out. When filling cracks you get around that by under cutting the
crack before forcing the expanding concrete into the crack, if the holes though
are wider top and bottom the effect will be the same and the plug should fit
well.
They also use acrylic in some of those patch cements. that allows you to
feather out and if the surface is pretty clean it sticks to the surface better
by adhesion but does not make the mechanical bond that an expanding cement will
make.
Hope this gives you a few ideas.
Dale Leavens.
----- Original Message -----
From: Dan Rossi
To: Blind Handyman List
Sent: Wednesday, June 16, 2010 8:12 AM
Subject: [BlindHandyMan] Patching cement.
Every time I go to a big box store and look at the small buckets of cement
mixes, I come away quite confused. There are no less than 20 different
buckets claiming to be exactly what you need to patch a hole in cement, a
crack, this one you can feather out to an eighth of an inch, that one can
be used to anchor a railing. Blah blah blah.
Here is what I need to do. What do I need to do it?
The main stairs to the courtyard are deteriorating. It will be big bucks
to replace them. We are looking into that, but I would like to make some
temporary repairs. The soil under the steps has subsided over the last 90
years, so the cement is actually suspended in the air. At the landings
there are I beams supporting the slab, but that's not important at the
moment.
A couple of holes have opened in the cement slab. I can actually stick my
cane right through the cement and down another six or eight inches to the
dirt below. The holes are several square inches in size. I want to patch
the holes. I figure I can jam some largish rocks into the opening then
pack in cement around those rocks.
So, is there another way that I should consider? What kind of cement
patch material should I be looking for?
Thanks.
--
Blue skies.
Dan Rossi
Carnegie Mellon University.
E-Mail: [email protected]
Tel: (412) 268-9081
[Non-text portions of this message have been removed]
