I'm putting in a patio. I guess I'm afraid I've dug too deep. It's about 17" deep at the end by the steps. I only meant to go down about 10". I'm not done digging so should i use some of the dirt that i haven't removed yet to fill in the low area or just get more gravel?
Next question, the ground here has lots of clay. My understanding of "weed barrier" is that its actually more apt to call it "keep gravel from sinking" barrier. Should i put that fabric stuff down for that reason?
Third, what sort of gravel should i get? Pea gravel? Multi purpose gravel? Paver base? Something else entirely?
I really really REALLY don't want the patio to sink at all. Knowledge and recommendations greatly appreciated, TIA.
by Foehammercdxix
26 Comments
1. Yes bring the low spot up some, it’ll save you some money on gravel
2. Geotextile fabric is what you want and isn’t really a weed barrier, it’s an underlayment to keep the materials stratified. There is woven (not water permeable) and nonwoven (is water permeable). For pavers you want nonwoven.
3. You need paver base, it is cracked/chipped which gives it jagged edges that will interlock and won’t shift. You’ll need to compact the dirt, then compact the gravel in layers too. The exact material will depend on your region, some areas use decomposed granite and some use limestone chips
if it was me I would not fill it back in with dirt because you will never get it back to natural compaction and it will settle. filling it up to the right height with stone should get a rid of the settling problem.
If what you said is correct and it’s 17”, then yes you dug way too deep. You don’t want to go more than about 13” and that’s being generous. You’ll have to account for the dirt, sand, and pavers and that should take you to about 8-10”.
Be careful around that foundation too. You’re pretty close to it and you don’t want water to just flow under it.
If you back fill with mud, water it down for a good day. It will help compact it. I’d go with crushed rock on top of a geo fabric. Since you already so deep might want to take the opportunity to put in some drainage.
Roughly need 8” of compacted “A base” (clay sand stone mix) using a tamper. Level or slope using sand, about another inch or two, then place 2” pavers. Finish height roughly 11-12” … if it’s excavated 17” you can put soil back or just use more “A Base”.
You’re probably a little deep, but not too much honestly. And as someone here already mentioned, unless you’re going to do a really nice job compacting any new dirt you put back in, you’d probably just as well off filling with gravel, it’s not that expensive that a couple of extra inches will break the bank.
I live in Wisconsin and I typically go with at least 6 inches of compacted road base, and 1 inch of screeded concrete sand under the pavers which are typically 2.75 inches thick, so that means I’ll typically excavate 9.75 inches down from the top of where I want the surface of the patio to end up. Extra road base won’t hurt, it’ll just make it less likely to sink or heave in winter.
Important! Make sure to compact the road base using a plate compactor and not in more than 3 inch thick layers. A plate compactor that you can push around typically can’t compact more than that and you’ll end up with settling over time.
As others mentioned, use the water permeable geotextile fabric if you’ve got clay soil to keep the road base from sinking in.
Rent a compactor and use it properly.
I’ve had to raise my patio blocks a few times over the last 30 years. My neighbor was putting in a sidewalk and I told her to put it directly on top of the yard. She instead dug out a trench and put the blocks in. Now, every time it rains, she has a walkway that is a river.
I’d consider an open graded paver base (google it) for this since it’s so close to the house. Fabric then 3/4 crush then 1/4 crush on top for your pavers. I did something similar next to my house a few years ago and it still looks good. Go to your local landscape store to get the crushed stone instead of the big box. You can put soil back in but it has to be tamped. The geo fabric was cheaper on Amazon for me so check that out.
I would fill it with a crushed rock base up making sure to tamp it every few inches. We use crushed recycled concrete. We wet it every 2-3” and run the mechanical tamper over it. We dig them too deep too sometimes. It’s never a good idea to fill it back in with soil. You’ll never get it packed correctly. Worth the little extra
on the rock and do it right. That walkway will be there for decades
I use 21AA crushed concrete as my base layer for pavers. I usually go 6” but you’ve got that beat by a long shot. If you have access to a pickup truck go to a landscape supply yard and get base material from them. It’ll be loads cheaper than the big box stores. I would bite the bullet and only backfill with base material. Dirt is going to sink.
The finished elevation should make the rise of the first step match the others.
Fabric, gravel (paver base) to height.
I personally don’t understand saving money on gravel, because, deeper gravel will give you more long term stability. More robust is better, and gravel is … dirt cheap.
A thick compacted stone base is what you want.
I’m no expert, but if it were me and this was my situation I think I’d add back all the dirt you easily can and compact that. Then I’d fill it in with extra QP to level it out, but I’d tamp it in layers.
Just go back with clean 57 stone to your correct height. Do not go back with soil or it will settle.
Not in my opinion. For our pavers, I wanted a 6″ to 8″ underlay (we are on clay soil), so we dug down about 12″. That was about 5 years ago and my pavers still look great. Having a thick/good underlay is the key to having your pavers remain flat over time.
Fak it… Just pour concrete at this point
Just did this same thing myself in red clay. I dug out pretty deep. Just fill it all in with crushed gravel / paver base, compacting it with a plate compactor until you get to a couple inches of your desired height. Then put 1inch of sand on top and screed it flat, lay pavers
Yes use non woven fabric barrier to prevent the clay from mixing with the base
Geo grid. This holds the gravel in place
Yes.
May as well go concrete since you’ve done all that digging. Easy now. Stamp it if you want it to look like pavers
It depends on what kind of base you intend to lay it on. If you’re doing open grade then you’ll want to you a 3/4 clean crushed stone subbase up to the leveling layer which will be 1/2 or 1/4 inch clean crushed stone.
If you’re doing dense grade which would be a sand or screenings leveling base, then you want to put that on a dense subbase like modified, or 3/4 minus.
You can use a dense subbase with the clean crushed leveling base, but you have to pitch the subbase to evacuate water and ideally have a drain field for it. I only add this tidbit of info, because it’s reddit and some armchair hardscaper will come in and turn that into a whole unnecessary conversation.
Geofabric is unnecessary and can be a detriment to patios. There are ways to apply it to driveways that help with stability, but that’s another subject. It will inhibit the subbase stone from binding with the soft earth below it. If there ends up being a soft spot, it’s impossible to repair without digging down and cutting the fabric out of that area, where sometimes those issues can be fixed with a jumping jack and more stone. Using fabric won’t necessarily cause issues, but it doesn’t fix anything, so it’s a gamble with no payoff. It’s the opposite of “cheap insurance” as some people like to call it.
Lol OP trying to build a Roman road here.
No such thing as too deep. Just need to compact it every couple of inches rather than wait until it’s filled.
Please make sure your final patio slopes away from the house.