putting concrete on concrete (sidewalk)

[Andrew Pitonyak]

Last year, I had a sidewalk that had sunk a bit. I do not remember the numbers, but it was similar to 1/8" on one side and say 3/4" on the other, perhaps a bit less. The city told me to fix it so I purchased Quikrete Concrete Resurfacer . It was not cheap (over $20 for 40 pounds), but I only needed 3 bags. Loved it.
https://www.quikrete.com/productline...resurfacer.asp


There is a dip in my sidewalk, it has always been there. The problem is that water accumulates there and in the winter I get an ice patch. I want to raise the sidewalk, figured I would do the same thing. The dip is not because the side walk sunk, it is because that is how it was laid (I think). Been that way for the 16 years (or more) that I have been here.

Call it 10 foot long, 48" wide, and the center is down 2.5" I figure that I need roughly 15 bags (600 pounds). OK, perhaps it is between 12 and 15...

I started looking at my local home depot and lowes (have not looked at minards). They now carry Quikrete Re-Cap concrete Resurfacer for about $27 a bag.
https://www.quikrete.com/productline...resurfacer.asp

I read in a review that this was more difficult to work with in that it is very finicky compared to the concrete resurfacer. I did not pursue that since it looked like Sakrete has a similar product (takes longer to cure) that would save me a bunch of money.


I keep seeing Sakrete Top'N Bond Concrete Patcher, which is listing at $17 for 40 pounds with about the same coverage. This would save $150 (plus tax)
https://www.sakrete.com/products/top...ncrete-patcher

Problem is that Lowes near me stopped carrying it. I might be able to drive 50 miles to get some (ouch).

I was looking at these specific products because if I break this out, then I need to figure out how to get rid of the concrete, and it will take a lot more concrete to break out the existing and then build it up so that it does not have that dip. I will have rather thin layers near each end....

Any suggestions?

Oh, while talking about concrete...

I need to cut out the main floor drain in my basement and replace it. OK, use a diamond blade and cut around it, then see how far in I need to go before I get something that I can connect to; will be no more than 3 feet unless the elbow in the cast pipe is broken then I would need to replace a section of that pipe. The main pipe is known to be at least mostly good because it looks just fine when we shoved a camera down the main line. No clean-out on the existing floor drain so no idea what that looks like from it to the main drain a few feet (less than 3) away.

Never done anything like this, but, what kind of concrete would I use to patch up that hole after I poured in my gravel around my new line?

[Steve Fish]

Have you thought about capping the sidewalk with natural stone? Regular sacks of crete should be fine for the basement slab repair. Try and expose some of the original wire mat that’s in there and tie in a repair piece before you pour in the new concrete.
Cold joints will almost always want to separate. Wash all the dust and small ruble off the old side really well and maybe look at some of the bonding agents. Don’t be surprised if you have to go back with a crack repair in a month or two.

[roger wiegand]

It might well be cheaper and will certainly have a better outcome to take out the offending piece of sidewalk, fix the base that's allowing it to sink, and replace. A couple yards of readymix should be less than half of your $600 (but I haven't priced concrete recently!) We have a concrete recycling facility close by, getting rid of the old was pretty cheap last time I needed to do it.

Regular masonry supply places are generally better stocked and often have as good/better prices than the Borgs.

[Jerome Stanek]

You would need 1/2 yard of concrete at 4 inch thick most contractors use a 2x4 for forms so you would need about 14 bags to replace that section so you would need 13.5 cubic feet of concrete. Lowes carries it in 80 pound bags for $4.80 a bag

[Andrew Pitonyak]

Have you thought about capping the sidewalk with natural stone?

This is two blocks in the front of the house so it would be really strange to just do two.... and then I would need to tie it in to the blocks before and after.

Regular sacks of crete should be fine for the basement slab repair.

Excellent

Try and expose some of the original wire mat that’s in there and tie in a repair piece before you pour in the new concrete.
Cold joints will almost always want to separate. Wash all the dust and small ruble off the old side really well and maybe look at some of the bonding agents. Don’t be surprised if you have to go back with a crack repair in a month or two.

I planned on using resurfacer so that I would need to tie in and that it would adhere. That is the only reason that I could think of to use the resurfacer. If I knew more about concrete, I might be able to user resurfacer for the bottom layer and then regular concrete on top of that, but I do not really want to experiment in that way if it is not clearly spelled out for me.

[Andrew Pitonyak]

It might well be cheaper and will certainly have a better outcome to take out the offending piece of sidewalk, fix the base that's allowing it to sink, and replace. A couple yards of readymix should be less than half of your $600 (but I haven't priced concrete recently!) We have a concrete recycling facility close by, getting rid of the old was pretty cheap last time I needed to do it.

Regular masonry supply places are generally better stocked and often have as good/better prices than the Borgs.

My biggest problem is that if I rip out the entire thing (for two blocks) then I need to have a way to break the existing blocks (rent a jack hammer) and hall away the broken out concrete (rent a truck or pay someone). In other words, the price starts going up very fast because I lack the tools to do it.

Off hand, there is nothing wrong with the existing concrete, it is just that there was a dip in the grade and they followed it. Unfortunately, there is a slope down to the sidewalk (small one, but still a slope) and all the water accumulates on / between these two blocks. The fact that they would pour it that way defies me a little bit.

I was not aware that a "regular masonry supply" might exist. I will see if I can figure out how to find one.

[Stan Calow]

My experience in patching concrete is that it is difficult to get more than a temporary bond between new and old concrete. There's a liquid concrete bonding additive I've used to prime the old surface and mix into the new concrete that helps, but only in patching small areas. In a wet area, the freeze/thaw will win.

[Andrew Pitonyak]

My experience in patching concrete is that it is difficult to get more than a temporary bond between new and old concrete. There's a liquid concrete bonding additive I've used to prime the old surface and mix into the new concrete that helps, but only in patching small areas. In a wet area, the freeze/thaw will win.

Did you use a resurfacing concrete, or just the bond agent? I have a bond agent, but I did not use it since I was told at the time that the product I was using already had it in there.

Bad news for me if I cannot. My test application on my driveway has held well in a high traffic area, as has the other sidewalk block that I did, but it has only been a year and we had a mild winter.

[Stan Calow]

Did you use a resurfacing concrete, or just the bond agent? I have a bond agent, but I did not use it since I was told at the time that the product I was using already had it in there.

I patched with both kinds - a topping mix, and some regular concrete when I ran out of the topping mix. But as i said, this was patching small areas (less than 1SF) not a whole slab section.

[Kev Williams]

repair area per OP: 10' long x 4' wide x .25' (3") deep = 10 cubic feet

An 80# bag of Quikcrete nets .6 cubic feet of cured concrete,
a 60# bag nets .45 cubic feet,
a 50# bag nets .375 cubic feet...

10cf needed/ 80# bag = 16.66 bags, 60# bag = 22.22 bags, 50# bag = 26.66 bags

Not sure the best product to use, but for ref, an 80# bag of Quikcrete Concrete mix at my Lowes, $4.25 each--

As to getting new to adhere to old, you might consider coal tar epoxy. While I've never done this myself, I've found while researching the stuff to use on my steel-hulled houseboat, that many people use it to fill and repair spalling concrete; before fully cured, you brush portland cement over it, and once more when dried, ends up close to the color of concrete. (works on asphalt drives too)

As a 'primer' for additional concrete, applying a gallon of coal tar epoxy to the original sidewalk and embedding some rebar into it will give the new concrete something grab..

[Andrew Pitonyak]

repair area per OP: 10' long x 4' wide x .25' (3") deep = 10 cubic feet

An 80# bag of Quikcrete nets .6 cubic feet of cured concrete,
a 60# bag nets .45 cubic feet,
a 50# bag nets .375 cubic feet...

10cf needed/ 80# bag = 16.66 bags, 60# bag = 22.22 bags, 50# bag = 26.66 bags

Not sure the best product to use, but for ref, an 80# bag of Quikcrete Concrete mix at my Lowes, $4.25 each--

On each end the depth is zero (since everything lines up) and in the middle it is about 2.5"

So the math is more like (for inches) 110 * 2.5 * 48 / 2 because the area of a triangle is 1/2 base times height. So this works out to about 3.8 cubit feet if I only top coat. For a 40lb bag, I assumed about 1/3 cubic feet so about 12.73 bags (call it 13). I was going to buy 15 since I am paranoid.

If I rip it out and start fresh, then it is more like 4 or 5 inches so over 15 cubit feet or 26 80lb bags. That is still only about $130, but I anticipated that the cost of renting the extra equipment would take me over. Also not sure what the minimal amount of concrete I can have a truck deliver since it would be a lot faster to just have the truck pull up and then fill the forms. It is right next to the road so they could probably just pull up and be done with it. Last time I had a pour, they cleaned the truck out onto my lawn and I ended up removing concrete from my lawn, that was a lot of work. I was not there when it was done since I did not do the work, but I was surprised by it.

[Kev Williams]

The dimensions of course are up to you to figure out, I wasn't taking the 'triangle' into consideration

-There are places that mix up a cubic yard of concrete which is put into a towable hopper that you tow home, then pour into a wheelbarrow to use as needed. I'm not sure if they can make up 'special' small batches or not-?

Another option is to buy the cheap cement mixer from HF- they work, and a good deal for $170, especially if you have other cement projects- or rent one for a day. I can't imagine hoeing 26 bags of concrete by hand...

[Darcy Warner]

Have it mudd jacked.

[Andrew Pitonyak]

Have it mudd jacked.

Makes too much sense.... I will look into it. At the expected price point, no reason to not check it out. sounds like an ideal way to fix it. I am embarrassed I did not think about it.

[Ron Selzer]

Columbus Coal and Lime is fantastic to work with for supplies, looks like they have been bought out
http://www.columbuscoal.com/
have heard good things about Hamilton Parker, have not dealt with them
https://www.hamiltonparker.com/
Columbus Builders Supply is a good choice also
http://www.columbusbuilders.net/
good luck
ron