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Discussion Starter · #1 ·
Hello,

First time poster here after constantly pulling up this forum in search results.

I have done a wide array of home improvement projects, but a patio paver is not one of them. I wouldn't have considered it if I don't work with a guy that used to sell the stuff so he can give me a lot of advice on it and he convinced me to take it on.

However, I keep running into items that I am not positive how to handle. I want to make sure I do this right. I'm the type of DIY'er that often does jobs more thorough than a hired professional (which is why it takes me months to complete a job that would be done by them in a weekend :wink2:)

I tore out a deck, planning to put in a 16x24 paver patio with holland stone. Soil is Michigan clay- not solid clay but not sandy by any means. Drainage on the property overall is very good considering my backyard is at my neighbor's roof level. I plan to compact the sub soil with a jumping jack, then lay geotextile fabric, followed approx. 7"+ of 21AA base compacted in about 3-4 lifts, and 1" of bedding sand.

As I started excavating the area I found that there was what seems to be an old concrete footing. I don't know how deep it goes down, but it's at least 16" which is the most I've been able to probe to check. I would think it goes down to the recommended 42". After putting the pieces together, I'm pretty sure this used to be an attached porch with brick walls.

Since there is no way I can get out this whole footing, the consensus I have with my advisor is to just leave it be. So I am starting to chip away at it with a jackhammer to get it around the same level as the subsoil, so that I can have at least 3" of 21AA going over the footing for peace of mind. In my mind, that would help keep the gravel base as a single "unit" as opposed to leaving the footing at the height it's at which would only allow for the 1" of sand to go over it. (I have verified all of this with laser levels). So that is my first question- do you think this will be OK? (of course assuming that the footing is at proper depth and won't heave).

My next concern is that I am finding that much of the soil closer to the house is VERY loose. In fact, I'm finding much of it is pea gravel. I don't know if they may have backfilled a big area against the house and/or footing with pea gravel. I'm digging down close to 2' as you can see in the pictures and I am not getting to solid subsoil- I don't know how much farther I can go.

I know pea gravel doesn't compact....but given that it is pretty far below the grade, and that I'm going to use the geotextile fabric, I'm hoping it might be ok. Thoughts? I don't want to convince myself it's going to be ok if it's not. I'm getting to the point where I've done so much work on it so far, and I wonder if I should just throw in the towel and hire someone if I can even afford it. But then again, I don't know if they would do anything different.

Am I overthinking this? Will it be fine considering all the other steps I am taking?
 

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The only purpose of a compacted rock base is to create a firm foundation.


Since there is no way I can get out this whole footing, the consensus I have with my advisor is to just leave it be. So I am starting to chip away at it with a jackhammer to get it around the same level as the subsoil, so that I can have at least 3" of 21AA going over the footing for peace of mind. In my mind, that would help keep the gravel base as a single "unit" as opposed to leaving the footing at the height it's at which would only allow for the 1" of sand to go over it.
Depending on soil conditions I might chip away or I might just cover it with the sand. Once you have a firm base you are good to go. This only has to support foot traffic, a driveway would be a whole 'nother discussion. The concrete is more solid than the compacted rock so IMO you 'over-thinking' this.


I've done 5-6 of these in my lifetime and not had a failure yet.
 

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Discussion Starter · #3 ·
The concrete is more solid than the compacted rock so IMO you 'over-thinking' this.
I hope you are right! But I failed to mention this is exactly part of my concern. With the subsoil not being as compacted as even the rest of the yard (I can easily dig a big hole), I'm wondering if the whole patio may settle a little bit over the years, leaving a raised outline of my concrete footing....

If it were all the same material, I would expect any settling to be somewhat consistent.
 

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I hope you are right! But I failed to mention this is exactly part of my concern. With the subsoil not being as compacted as even the rest of the yard (I can easily dig a big hole), I'm wondering if the whole patio may settle a little bit over the years, leaving a raised outline of my concrete footing....

If it were all the same material, I would expect any settling to be somewhat consistent.
I would also be concerned, and would suggest getting the foundation down as far as realistically possible. I wouldn't be comfortable with 3" of gravel over the old foundation, but maybe 8"?

The pea stone makes for a great sub base, and allows great drainage for the basement walls. No concern there other than keeping the fines of the gravel from infiltrating it, but your geo fabric should handle that.
 

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Discussion Starter · #7 ·
nothing yet! But the next step is to get a jackhammer to knock down the old footing to the soil level. Based on these responses I should be OK with the fabric before putting down gravel. I hope to do that this weekend, then rent the jumping jack next weekend, then possibly do everything else by the end of July
 
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