Grading the patio base

[crokett]

I got the patio base delivered last week and am in the process of spreading it. I know the pitch I need but need suggestions on how to grade to get a flat surface. There are two existing brick walls 13' apart that run the length of the patio (about 17'). Advantage there is I can use the brick courses as guide for the pitch. However unless I come back in to fill the edges I can't lay 2x4s for a screed guide.

Any ideas?

[dkhoward]

how ddep is your base . . . when I laid the sand for a brick patio, I used 1 inch PVC pipe, laid across the area . . I then in filled with sand and used the pipes to guage depth . . then pulled them out and carefully back filled where they had beenlaying

[crokett]

Dennis -

Thanks. The reply I got on another forum was to use black pipe, but the same idea. He said some folks use pvc but he likes black pipe - it doesn't flex.

[Hellrazor]

How deep a base are you doing? I marked the pitch I need wth string, spread the modified stone out and compact it. Then I used th string and a piece of strut to screed the stone back.

If you are using modified stone, keep wetting it down as you layer it in, it will compact better.

[crokett]

Base will be about 3" thick. Watering it down is a good tip. I will have to remember that.

[Hotlanta]

I have a landscaping company and this is right up our alley.... I would recommend laying a geotextile fabric below the base and above the copacted dirt material first. This will insure that no sinking for settling ever takes place. Then spread out your volume of Crushed aggreagate base...a.k.a. Crush-n-Run. To find out how much you need, you will need total square footage x dephth of cruster run (typically 4" for a patio) Then divide that number by 12 to conver the 4 inches to feet. Now you have cubic feet. Well, Crusher Run gets delived and ordered by the ton so let's get you there next. Take your total cubic feet and divide by 27 to get cubic yards (you can stop here if you ever need to order just dirt or mulch) then take the total cubic feet and multiply by 1.6 to convert the number into tons. Now you are ready to place and order and definitely ready to hire some friends for the weekend...movin that stuff ain't too kind on the back, neck and knees.

Anyway, let's say your brick is 2-1/2 thick. Then you will need to excavate an area that is about 7" to 7-1/2" deep to make room for the Crusher Run and the sand. Spread the geotextile fabric (available at Home Depot) AFTER compacting the dirt sub-base with a vibratory plate compactor. Then spread the fabric. Then dump in the crusher run material. You ideally want to to this in 2" lifts so having 1-1/2" PVC pipe availlabe to accurately do this is great. Lay pipe down, spread crusher run and screen off excess. Remove pipe, fill in voids left behind and begin compaction of the area. Do this until you reach your final height of 4".

Next, lay down 1" PVC pipe and spread the M-10 granite sand (be sure to ask for M-10. Compact the area well and then start laying the brick pavers.

To keep lines and pitch accurate, You will need to snap string lines from high points and using the 1/4" per foot rule of pitch, set your low point using the string. If your low point is still higher or lower than where the actrual grade is set, you may need a small wall to serve as the edging.

Finish the joints with a polymeric joint sand. Don't use play sand or granite sand as it will wash out of joints, be messy and grow weeds.

Hope that helps and good luck with the project.

Phil in Hotlanta