Method to Lay Flagstone at Consistant Finished Height

[3creeks]

In installing flags (1" to 1 1/2" thick) on a 20' x 30' concrete patio slab(which already has (away-from-the-house) pitch; what is best way to maintain proper finished height of flags as they go down to keep that pitch consistant? A. String? B. Set up side boards? C. Use a scrap board ripped to the finished height depth as a guide? D. None of the above.

Thanks

[m Ransley]

Are you doing the work or hiring out. I assume you mean to set in concrete, if so set in a dry concrete, no water mix. Or what will you set them in, sand? either way work them in to be the same level hight and slope, its small enough. I would eyeball it since each piece is different thickness, you dont want one high and one low.

[nielloeb]

D. Use a level to note the current pitch of the concrete patio slab. Put down a 1 inch layer of sand. Start at the wall-sides. If the flagstone is 1 1/2 inches, work it down to a half inch. If the flagstone is 1 inch, place it on top of the sand. Use the level as you go along. Err on the side of having more of a pitch. You should end up with the stones on the grass side of the patio having

1/2 inch of sand below the 1 1/2 inch stones. Your erring on the side of having more of a pitch might make this amount 0 inches. Mortar between all the stones and at the edges.