Flagstone patio - edging and joints

by Tony Vander Linden
(Austin, TX)

I have a couple questions. I'm laying my first flagstone patio. I live in Austin, TX. It will be about a 400 sq ft patio with 2 inch flagstone. We really only have a day or two below freezing, so I'm planning a 2 inch base of decomposed granite and 1 inch of sand. I'll lay the flagstone, then border with a limestone block edging. I think I'll mortar the edging, then I won't need any reinforcement on the edging right? Should I mortar the cracks of my flagstone patio or just use sand?

Thanks for any advice you can give. Love your website!

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sounds good
by: David

Dear Tony,

I'm glad our site could help you out. My dad's almost 80 and so it's great that we can use his knowledge to help people out.

It's sounds good that you want to lay your limestone block edging in concrete. That should make a strong border for the interior flagstone.

You probably don't want to fill your joints with cement since you'll have a sand/granite base. The joints will crack in a couple of years. Some people like that look, so we've seen it done. Sand or breeze is your best bet for filling in the joints.

My dad usually lays flagstone in a 4 inch base, so you might want to add another inch to your base.

Great luck with your project.

If you take some pictures of your work, people would love to see them. I'll publish them in my newsletter.

You can upload pictures half way down on this page:


Take care,


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