Brick Patio - Gravel Bed Question

[ICT_Kevin]

Hi. I got the garage built, so now I'm indebted to my wife to finish the back yard. I have 280 square foot of brick to lay. I'm planning a 2" bed of gravel under a 2" layer of sand for a bed. My old source of 3/8 gravel has gone away. Is 1/2 inch and under gravel too big for the job, or just fine? Is it bad to the point I'd be better getting 4 inches of sand? I'll be plate compacting the gravel, then compacting again over the laid bricks.

I'm leaning toward getting the gravel unless it would be hopelessly oversize. 1/8 inch won't be enough to ruin it? I need to order tomorrow either way. I could be laying brick by Saturday.

 

[KenC]

I use screenings, the last thing left after all the other crushed limestone grades are culled of. ranges from dust to maybe 1/4". packs well and rreally locks things together.

 

[miner]

I would use way more gravel and less sand. Like 4 inches of gravel. You only need an inch or so of sand since all it really does is make a flat surface for the pavers to sit on. It is the gravel that gives structure and makes a firm foundation.

 

[Caman]

I would use way more gravel and less sand. Like 4 inches of gravel. You only need an inch or so of sand since all it really does is make a flat surface for the pavers to sit on. It is the gravel that gives structure and makes a firm foundation.

Ditto

Around here they call the gravel you would want to use "Class 5". It has a mix of coarse gravel up to 3/4" and quite a bit of fines that lock everything in place, that once compacted together are almost as hard as concrete.

 

[bigfunwmu]

At least 4" of gravel, and make sure you remove all bio-matter and black dirt from below the pad as those will never fully compact and you will have settling issues in the future. Crushed rock with fines works well, be it class 5, or 22aa or 23aa depending on where you are.

1" or less of sand is fine, the theory is you want just enough sand to float out to make sure you can lay your bricks fully seated and level. We typically used 1" pipes to run the float board across to make sure everything was level. Remove pipes before laying block, and fill in the lines with sand & and float with a hand trowel as you go.

 

[ICT_Kevin]

Good notes. Thanks everyone. I'll take a look at how many tons if I adjust depths, and get going. Off-hand it sounds like 3 tons and 1 ton. Maybe another ton if I bring the bed up to 5". I have a small amount of gravel left over from the first 500 sft of the brick work.

When I did the first bulk of my patio, it was frustrating and funny looking at recommended depths online. I saw amateurs barely using a sand base, and fine homebuilding or this old house recommending 7 inches gravel, 7 inches sand, plus the brick height, and very little in the rational mid range. 16 inch is like a hole to china when you're doing a fair number of square feet with a tiller and wheelbarrow, and not many good places to use the dirt.

 

[crab]

This is starting to sound like a lot of work.

 

[Leaflessshadetree]

When I did the first bulk of my patio, it was frustrating and funny looking at recommended depths online. I saw amateurs barely using a sand base, and fine homebuilding or this old house recommending 7 inches gravel, 7 inches sand, plus the brick height, and very little in the rational mid range. 16 inch is like a hole to china when you're doing a fair number of square feet with a tiller and wheelbarrow, and not many good places to use the dirt.

A lot of it has to do with the soil type and climate at the location along with history of the exact area (has it been dug up recently, used as a driveway for the last 75 years). Size and intended use plays a factor as well.
For a semi-temporary dog kennel I simply removed the grass put down just enough sand to screed and laid the (used) pavers. I expected it to be good enough for 2-3 years. Easy enough to pull up a few and toss a shovel full of sand down if it started collecting water.
6 years later it was still flat and being used as a patio.

 

[matt_i]

An easy way to "excavate" is to rent or use a rear tine rototiller, like a Troy Bilt, simply till the soil in stages, then its loose with a hard "bottom". The loose material will be easy to shovel and move when its dry. My Dad and I used this to great success. I think we put down 6" of crushed stone, packed in 2-3" lifts with a vibrating plate compactor.

 

[Kaizen]

When I dug my patio I had all sandy soil so wasn't concerned with drainage which is why you use the big rock. I did 4 inches of stone dust compacted by hand with a 8inch tamper. have one low spot but overall ten years later looks great. sand imo is old school. stone dust holds together better when packed and still moves when you set the paver and hit it. make sure you use polymeric sand between the joints after set all of them. the stuff is awesome. keeps weeds out and most bugs. I laid all of my pavers and before I put on the poly sand I sprayed it with sealer. mine is 2x as much as your area and I had to cut each edge paver to fit. lots of work but do it right and it will last.

 

[soob]

I'd reiterate that you don't want "gravel," especially washed gravel; you want crushed stone with the fines still in it. Otherwise it won't compact like it's supposed to.

 

[captain14]

Saving this for my paver project at the back door of the garage

 

[SARG]

And up here in the Northeast using geo-fabric is critical if you want it to last.

Without it the gravel will migrate towards China.

 

[ICT_Kevin]

An easy way to "excavate" is to rent or use a rear tine rototiller, like a Troy Bilt, simply till the soil in stages, then its loose with a hard "bottom". The loose material will be easy to shovel and move when its dry. My Dad and I used this to great success. I think we put down 6" of crushed stone, packed in 2-3" lifts with a vibrating plate compactor.

That's how I've dug this round. We would have hired a bobcat, but we had no 3-day stretches of dry for 3 months. We got started with my dad's tiller, and about the time we could have hired a bobcat, we were getting close to ready.

We're really clay for soil and up at the top of a wide hill in the neighborhood. Is the geo-fabric for loose soils?

 

[James E]

I'd reiterate that you don't want "gravel," especially washed gravel; you want crushed stone with the fines still in it. Otherwise it won't compact like it's supposed to.

Not only will it not compact but eventually the sand above it will settle into the voids and the bricks will become unstable. There is material just for this application--make sure that's what you use.