Hello,

I'm redoing my front porch stairs, the old stringers were encased in
the concrete bottom step, not a good thing. I want to bolt a board to
the top of the concrete and notch the bottom of the stringers to meet
the board.

So I need to somewhat enlarge the step. It is about 66" L x 16" W x
12" D. The back side of the step is all rough concrete with large
aggregate. The top of the step is a greyish material without
aggregate; it is somewhat chipped and not particularly flat, so it
could use redoing. Here's the procedure I've come up with, I'm
looking for any comments or suggestions:

Remove any loose soil behind the step. Clean the backside of the step
with a hose and brush. Drill 4 holes 6" deep into the back side of the
step and epoxy in some 9" #4 rebar stubs projecting out 3". Form up
to extend the step 5" (providing 2" cover on the rebar ends). Mix and
pour 4-5 0.45 ft^3 bags of sacked concrete, poking it into all the
voids. Leave the new concrete about 1" below the finish surface and
allow to cure a day. Chisel the the top of the old step to roughen it
up and remove 1/2" to 1" of material. Mix some non-shrink grout (e.g.
CementAll) and pour a smooth finish surface at the desired pitch and
elevation.

Thanks, Wayne

Wayne Whitney wrote:
Hello,

I'm redoing my front porch stairs, the old stringers were encased in
the concrete bottom step, not a good thing. I want to bolt a board to
the top of the concrete and notch the bottom of the stringers to meet
the board.

So I need to somewhat enlarge the step. It is about 66" L x 16" W x
12" D. The back side of the step is all rough concrete with large
aggregate. The top of the step is a greyish material without
aggregate; it is somewhat chipped and not particularly flat, so it
could use redoing. Here's the procedure I've come up with, I'm
looking for any comments or suggestions:

Remove any loose soil behind the step. Clean the backside of the step
with a hose and brush. Drill 4 holes 6" deep into the back side of the
step and epoxy in some 9" #4 rebar stubs projecting out 3". Form up
to extend the step 5" (providing 2" cover on the rebar ends). Mix and
pour 4-5 0.45 ft^3 bags of sacked concrete, poking it into all the
voids. Leave the new concrete about 1" below the finish surface and
allow to cure a day. Chisel the the top of the old step to roughen it
up and remove 1/2" to 1" of material. Mix some non-shrink grout (e.g.
CementAll) and pour a smooth finish surface at the desired pitch and
elevation.

Thanks, Wayne


Wayne-

Sounds fine....I would add some cement to the sackrete or use the
CementAll stuff in the green bag...not cheap but hardens harder &
faster

cheers
Bob

On 2006-12-23, BobK207 wrote:

I would add some cement to the sackrete or use the CementAll stuff
in the green bag...

You know, that is what everybody says, but why? Sakrete claims their
"High Strength Concrete Mix" has a 28 day strength of 4000 psi. Is
that not adequate? I will pay attention to the amount of water, I
understand it is common to use too much.

Thanks, Wayne

Wayne Whitney wrote:
On 2006-12-23, BobK207 wrote:

I would add some cement to the sackrete or use the CementAll stuff
in the green bag...

You know, that is what everybody says, but why? Sakrete claims their
"High Strength Concrete Mix" has a 28 day strength of 4000 psi. Is
that not adequate? I will pay attention to the amount of water, I
understand it is common to use too much.

Thanks, Wayne


You know, that is what everybody says, but why?

'cuz sackrete is cheap & cement is the expensive component

and weak concrete is a problem downstream & a little extra cement is
good insurance

hand mixed concrete is questionable....I've seen it from 2000 to
5000psi

4000 pis is more than enough.....if that's what you really get...gotta
dry mix it well & not over water it...it's just easier to add some
extra cement (like a single shovel per bag) or use the grren bag stuff
(expensive but hard in no time & strong)

cheers
Bob