Tying concrete sidewalk into foundation

[Lakee911]

I am going to be replacing a sidewalk that adjoins my house in the next week or so. The sidewalk is in a narrow, and low laying passage between my house and the neighbors. This is at least the third time that it will be replaced in 83 years. Cracking and settling from too thin of a slab, roots and sink holes (fill dirt probably not being compacted near the house) and have allowed a little water to enter the basement where the old sidewalk had settled.

I will be installing a catch basin and sloping the walk away from the house and I plan on it being least 3.5in deep w/ rebar (is this overkill?). My question is, since this adjoins the house should I drill holes in my concrete (not cinder) block foundation, and epoxy rebar in place? This will help tie everything together so it doesn't pull away allowing water to infiltrate and it will support the house egde of the sidewalk should the earth settle more below. I don't have the time or the money to dig and compact all the soil underneith.

What do you think?
Thx
Jason

 

[hj]

sidewalk

If you are in a cold area of the country, no matter what you do, the concrete is going to "heave" and settle when the ground freezes and thaws, so if the walk is tied to the foundation at several places, it will probably crack between those points.

 

[Sponsor]

 

[Lakee911]

Yup .. Columbus is cold. Good point--Thanks! Would hate to have new cracked sidewalk and/or foundation next spring.

Jason

 

[Jimbo]

I think rebar is overkill for a sidewalk. 6X6 mesh should be fine.

I would not tie this to the foundation. But I would seal the joint where they meet to exclude water.

Seems like most of your trouble is related to frost and roots. Can't solve either of these, except to provide drainage will help, as will providing a deep base of compacted gravel.

You could also have a landscaper install some root barrier fabric.

3 repairs in 85 years: not bad. At my condo complex, 20 yrs old, sidewalk repair is an ongoing issue. No frost, just roots.

 

[Bob NH]

Heaving from freezing is a result of freezing water in the soil. The solution is to use a porous gravel base that is as deep as the winter frost, and make sure it is well drained to below the frost line.

Most residential sidewalks are put on top of the natural soil, with maybe a little gravel under, and allowed to "float" with the surrounding yard.

Your new sidewalk should have "crack control grooves" spaced about 1.0 (preferred) to 1.5 times the width of the sidewalk. Even with reinforcing, the sidewalk will crack. Cracks in the grooves, with the whole tied together with reinforcing mesh, will not be so ugly and will not have differences in elevation that you can trip over.

If you have any inside corners in the sidewalk, such as at a 90 degree turn, you should have "crack control grooves" going from the inside corner across each of the sections approaching the corner.

Crack control grooves are put in with a special tool run along a straight-edge after the concrete is floated and broomed but before it sets up. If you look at a professionally poured sidewalk you will often see a smooth section 2 or 3 inches wide at the location of the grooves. That is where the tool smoothed the surface. You can probably make a wooden tool for your small job.

Beware of water! Too much mixing water makes weak concrete. And when you finish it, you get a lot of water in little globs on top that later evaporates and leaves you with ugly little holes. Concrete coming out of the truck should stand in rounded piles. If it flows like thick soup, it has too much water. The best (strongest) concrete is only as wet as it takes to fill the forms and permit finishing.

But after it is poured and sets up, it should be kept damp for a week. After it's in place the cement in the concrete needs the water to form the chemical bonds.

 

[Lakee911]

Thanks for the info. I'll probably tamp what I can and add some gravel, but I'm not sure I can easily prepare the area properly. There is approx. 6feet between the two houses so no room for equip. It's just got to last a few years until I move out.

Like I mentioned, roots are a problem. It's predominately one root about 3in in diameter that I traced from the tree around the house about 50feet away. Might be same root that goes to my sewer lateral.

I'll look into the 6in x 6in mesh too. Poor next-homeowner, gonna have trouble busting up this one.

Thanks!

 

[hj]

roots

Grind up the copper sulfate root destroyer crystals and spread them under the concrete where they will dissolve and treat the soil, hopefully discouraging roots in the process.