Concrete Slabs -- Ok to LAY DOWN like this?

[rosario99]

I recently purchased concrete slabs (24" x 24" x 1.75" thick). We're planning on using the 21 slabs on the small walkway from the side fence doorway to the deck stairway (area is approx. 147" x 74"). It is a very light traffic area. The slabs will be shoved against the house on the one side.

Considering the thickness of the slabs, the area size and light traffic, what is the proper way to lay these slabs down? My first thought is to simply clear and flatten the area down to 1.75" deep (perhaps a bit of a higher slope on the house side), place some dark anti-grass fabric down, then lay the slabs on top of that. Done. I'm guessing it is more involved than that.

Thanks.

[PhuFighter]

I recently purchased concrete slabs (24" x 24" x 1.75" thick). We're planning on using the 21 slabs on the small walkway from the side fence doorway to the deck stairway (area is approx. 147" x 74"). It is a very light traffic area. The slabs will be shoved against the house on the one side.

Considering the thickness of the slabs, the area size and light traffic, what is the proper way to lay these slabs down? My first thought is to simply clear and flatten the area down to 1.75" deep (perhaps a bit of a higher slope on the house side), place some dark anti-grass fabric down, then lay the slabs on top of that. Done. I'm guessing it is more involved than that.

Thanks.

Well, this is something that I have to admit that I did :) But that is out of sheer laziness than any expectation that it looks good or will last. The previous owner of my house left a number of these things around and I haven't figured out a way of disposing them, so I just laid them down as you mentioned. Just a quick question - when was the last time the soil in the area been "disturbed"? I think that it has to be untouched for some time to return to "undisturbed" state. The soil I placed my mine probably haven't been touched in 40+ years, and it's clay, so it's pretty solid. Nothing's moved in the last 2 years anyways. I have it next to my fence to check! Then there is the issue of drainage. Make sure the water doesn't collect in the area under or around them, or the frost heave may give you issues.

Of course, the best method is to clear down a few more inches, and then lay down your landscape fabric, and then some HPB, and lay down your concrete slabs. It'll keep it more level for longer. But if you don't care if the slabs go slightly out of misalignment over time, and don't really care that much about aesthetics, and have a solid undisturbed soil there now, I guess what you want is ok. But I think pretty everyone else here will recommend a more robust base of 4" or more of HPB if you want it to look better over the long term.

[Mars2012]

You need to make sure the earth is compacted well and then add a layer of aggregate like gravel or sand (at least two inches) to help with leveling the slabs.

[stt55pot]

You need to make sure the earth is compacted well and then add a layer of aggregate like gravel or sand (at least two inches) to help with leveling the slabs.

yep...I remember my neighbor did it and that is what he did...

[Poulet]

1. Dig. We dug almost 1 foot when we did a patio with interlock. You could dig less. Make sure there is no wires or pipes.

2. Put a lanscape membrane.

3. Put 0-3/4" crushed stone. 2" at a time. Use plate compactor. Compact well. Spray a bit of water to help with compaction.

4. Add 2" of 0-3/4" crushed stone. Repeat step 3 and 4. Include a little slope.

5. Then put some stonedust. Level, make sure you include a little slope, put your slabs on it. Enjoy.

6. You could fill up the cracks with polymeric sand...not sure for patio slabs

[rosario99]

I definitely want it straight so will use the crushed stone as advised.

One more thing. There is a Utility Gas meter on that side next to the house. It is elevated above the ground but a single pipe extends from it through to the ground. The pipe is about 1.5" in diameter and is about 5 inches away from the side wall of the house.

I would like the slabs pressed against the wall but then that means i need to cut a hole in the slab that rests below the gas meter. What tools do i need to properly cut out the concrete slab (perhaps a 1.75" x 5.25" area) ? Each slab is 24" x 24" x 1.75" thick.

Can this job be done with a simple hand tool (chisel and hammer) or does it require power tools even for this size?

[PhuFighter]

I definitely want it straight so will use the crushed stone as advised.

One more thing. There is a Utility Gas meter on that side next to the house. It is elevated above the ground but a single pipe extends from it through to the ground. The pipe is about 1.5" in diameter and is about 5 inches away from the side wall of the house.

I would like the slabs pressed against the wall but then that means i need to cut a hole in the slab that rests below the gas meter. What tools do i need to properly cut out the concrete slab (perhaps a 1.75" x 5.25" area) ? Each slab is 24" x 24" x 1.75" thick.

Can this job be done with a simple hand tool (chisel and hammer) or does it require power tools even for this size?

I wouldn't do this with a hand tool. What you could do is mark on the slab the section that you want cut, and then call around to see if any places that sell patio stones would do the cut for you. Anywhere that sells things like driveway curbs, etc., should be equipped to cut. Milliken Farms, at the corner of Kennedy and Steeles ave E in Markham advertises that they do it. For a few dollars a cut, it's far cheaper to go that route for a couple of cuts than to rent a tool or spend time chiselling it out yourself.

EDIT: Milliken charges $4/cut, so it looks like you'd need 2 cuts, and then knock out the middle yourself: http://www.millikenfarms.com/otherservices.html

[Zamboni]

2" hole saw (masonary type)....since you're going about 6" deep I would cut 2 holes that don't quite touch; then chisel out the rest. With a hole saw, especially in cement or brick always install the drills side handle....otherwise if the hole saw binds while cutting the torque could break your wrist.

[PhuFighter]

2" hole saw (masonary type)....since you're going about 6" deep I would cut 2 holes that don't quite touch; then chisel out the rest. With a hole saw, especially in cement or brick always install the drills side handle....otherwise if the hole saw binds while cutting the torque could break your wrist.

I guess if you're going to go that route, you could just get a hammer drill and drill all along the cut line and then smash it out with a hammer and a cold chisel.

Although, I think, hiring someone to make the cuts would make it look the cleanest. Especially if aesthetics are important.

[dirkpitt]

I definitely want it straight so will use the crushed stone as advised.

One more thing. There is a Utility Gas meter on that side next to the house. It is elevated above the ground but a single pipe extends from it through to the ground. The pipe is about 1.5" in diameter and is about 5 inches away from the side wall of the house.

I would like the slabs pressed against the wall but then that means i need to cut a hole in the slab that rests below the gas meter. What tools do i need to properly cut out the concrete slab (perhaps a 1.75" x 5.25" area) ? Each slab is 24" x 24" x 1.75" thick.

Can this job be done with a simple hand tool (chisel and hammer) or does it require power tools even for this size?Personally, I would use a masonry blade in a circular saw. They're not cheap... ~$35, but you can cut a slot down each side, and knock out the resulting slot. Once the slab is in place, trim the cut-out to fit, and place it behind the gasline. Be sure to leave some room around the gasline--1/4" or more--which you can caulk for aesthetics.

An alternative would be to use a angle grinder and a masonry blade to suit.

[rosario99]

Is aluminum edging restraint around the 4 sides of the patio slabs area important? I notice no one makes mention of such a thing.



1. Dig. We dug almost 1 foot when we did a patio with interlock. You could dig less. Make sure there is no wires or pipes.

2. Put a lanscape membrane.

3. Put 0-3/4" crushed stone. 2" at a time. Use plate compactor. Compact well. Spray a bit of water to help with compaction.

4. Add 2" of 0-3/4" crushed stone. Repeat step 3 and 4. Include a little slope.

5. Then put some stonedust. Level, make sure you include a little slope, put your slabs on it. Enjoy.

6. You could fill up the cracks with polymeric sand...not sure for patio slabs

[dirkpitt]

Is aluminum edging restraint around the 4 sides of the patio slabs area important? I notice no one makes mention of such a thing.Edging restraint is a "nice to have", especially with large patio slabs. Smaller blocks are more prone to shifting, and will be more likely to require restraint.

It's definitely not needed along the side that will be against the foundation of your house. If you're excavating (removing grass, topsoil, etc.) and you leave a clean, straight edge close to the edge of the slabs, lateral shifting shouldn't be a big issue with 2' x 2' slabs.

[PhuFighter]

Edging restraint is a "nice to have", especially with large patio slabs. Smaller blocks are more prone to shifting, and will be more likely to require restraint.

It's definitely not needed along the side that will be against the foundation of your house. If you're excavating (removing grass, topsoil, etc.) and you leave a clean, straight edge close to the edge of the slabs, lateral shifting shouldn't be a big issue with 2' x 2' slabs.

I think that even 2x2 slabs will move with time. Especially if there's a slope away from the patio of some sort. I personally don't like the look of exposed edging. What about using cement to hold them in place?

[dirkpitt]

I think that even 2x2 slabs will move with time. Especially if there's a slope away from the patio of some sort.Mountains move with time. If the surface is relatively flat (like a sidewalk) and prepared properly (as detailed above), they shouldn't move.
I personally don't like the look of exposed edging.Aesthetics is a "nice to have".
What about using cement to hold them in place?Why not just crib the entire sidewalk, tamp mixed compactable gravel, tie in rebar, pour with dyed concrete and finish it with a nice stamped finish?:razz: I believe the intent is a simple DIY.;)