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Flagstone Patio Plan

Posted by Sammy1980 none (My Page) on
Tue, Apr 10, 12 at 14:22

I'd like to install a flagstone patio in the area shown in the picture below and I was hoping to run my plan by more experienced landscapers to get some feedback please.

Sorry to make another "flagstone patio" thread, I went through most of the ones we had here and I still wasn't 100% sure of what I'm doing.

The patio won't be very heavy traffic; I was going to put my BBQ grill there and a chiminea.

1. I dug that area 5 inches down. My trench dimensions are 16 foot long, 5 foot wide and 5 inches deep. I maintained a slight slope away from the house and tamped that clay soil.

2. I was planning on framing that area using landscaping timbers and then a piece of angle iron on top of the last timber so that the timbers don�t show once the flagstone and sand are down. The right side is already framed by our existing concrete patio.

3. Since the soil in that area is very hard compact red clay, I am hoping to get away from having to use crushed stone for a base. I already have some 57 stone and I was thinking of laying down a 1 inch layer to help with drainage. I will then tamp the 57 stone.

4. Following the 1 inch layer of 57 stone, I was going to add a 3 inch layer of sand; I already have a couple of yards left over from another project.

5. I will tamp the sand and level it with a slight grade away from the house.

6. Since I dug down 5 inches, I should be 1 inch below grade now. The flagstone I am buying is 1 to 1.5 inches thick so I was thinking that would get me level with grade.

7. I will start laying the stones using the more straight ones around the edges and using a level and a rubber mallet to level them with a slight grade away from the house.

8. Once all the stones are down, I was going to sweep more sand between the cracks.

9. Water thoroughly.

10. That area is almost full shade, so I will have to find an appropriate ground cover to plan between cracks.

What do you guys think? Would this work or am I making some some mistakes here?

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Follow-Up Postings:

RE: Flagstone Patio Plan

- clay's not a sufficient base. You need a min 4" compacted gravel base (21A/c6/crusher run/whatever they call 3/4" minus in your area)
- 3" of sand is way too much. The sand layer is for adjustment and levelling, typically 1". For flagstone you can use stone dust instead.
- 1" flag isn't great for dry lay, but it can work if it's all you have. 1.5"+ is better
- your edge restraint is a creative solution. Easier would have been to use a paver edge restraint, an L-shaped piece of plastic that has evenly spaced holes to accept 1/2" galvanized spikes. That way your edge doesn't start failing when the buried timbers rot.
- growing stuff in the cracks can be a challenge (not much wants to grow in sand over a compacted base in the shade. Well, except weeds.). I would use a polymeric sand in the joints and be done with it.

There are numerous ways to skin a cat. Will your way work for your purposes? More than likely. But since you asked, I figured I'd lay out the way I'd specify one.

RE: Flagstone Patio Plan

Thanks for the detailed reply marcinde.

1. I was hoping to avoid buying crusher run since I already have a bunch of sand and 57 stone. Do you think it would work better if I did 3 inches of 57 stone and then just 1-2 inches of sand to help level? What do you think can happen if I just used 57 stone and sand?

2. If I went with sand between the cracks and then found it to be a pain to keep weeds out, it shouldn't be too hard to blow sand out of the joints and come back with polymeric sand, right?

3. If you can find me a link of the "L-shaped piece" for the frame I would really appreciate it. I still have 2 sides to frame and if I can avoid a ton of work with the timbers I'd rather go with that route. Angle iron is pretty expensive too.

RE: Flagstone Patio Plan

1- 1" of sand should be plenty for leveling unless you're buying radically different thicknesses of stone. Is it coarse sand or play sand? Also, if you pour sand on top of 57s, I would imagine it'll run to the bottom like unpopped kernels in a box of popcorn

2- you could. And I could show you photos of the patio at my house, where I said the heck with it and just filled the joints with stone dust. Learn from my mistakes. I have to mow my patio.

3- I'm getting back to work but google "paver edge restraint" or look in the section of Lowes or HD where they stock pavers, they're bound to have it. Speaking of the big boxes, they sell poly sand but read the bucket. I think those aren't good for wide joints. Wider joints, you'll need to buy Gator Dust at a stone yard

RE: Flagstone Patio Plan

The sand I got was dropped off by our subdivision builder. They had some left over from building the house next door and they let me have it. Not sure what type that would be. It's light colored and seems pretty soft.

What would happen if I put down one inch of 57 stone at a time and then I kept adding enough sand until it "saturated" before I added the second inch of 57 stone? Is that a terrible idea?

A friend of mine suggested mixing sand and quickrete and then adding it to the 57 stone but that sounds pretty permanent.

RE: Flagstone Patio Plan

In full shade you may find that moss grows in the patio joints; this would be a good outcome. It's kind of unpredictable what will grow and what won't - depends on what's in the air as well as what's on the ground.

If I recall correctly, play sand has rounded particles and, like rounded gravel, can't be packed down very well. Yours is probably builder sand then.

Not knowing what 57 stone is, I can't answer the other questions.

Karin L

RE: Flagstone Patio Plan

I think 57 stone is limestone that's been broken down into inches about 1" in diameter. I don't think it packs very well on it's own.

I would have thought the sand they brought me was construction or masonry sand but it feels very fine and smooth which kinda confused me.

RE: Flagstone Patio Plan

For the groundcover, look into Sagina subulata, or Irish/Scottish moss. It is a moss lookalike that can handle foot traffic almost as well as grass, and grows in a variety of conditions from my experience.

Irish is a darker green, while Scottish has a more yellowish appearance. I used Scottish in this application and it is currently spreading out. It's listed for full-shade but this is in 90% sun and is looking great.


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