How to cut control joints

I need to cut 2 control joints in my 4' concrete patio slab, each 11 feet long.
Can I do that with my old circular hand saw? Would I use a masonry blade (the clack stuff) or a do I need a diamond blade (expensive)?
How deep should the control joint be?
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Walter
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You need to rent a concrete sway. Typically there is a hourly fee plus whatever portion of the diamond blade you use (like a tile saw). I have used a masonry blade and skil saw before, but the rental will likely prove cheaper than burning up your saw.
I think theyr'e supposed to be 1-2" deep, but I could be wrong on that.
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That should say concrete SAW.
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I really don't think it's 1-2" deep. Do some research to find the exact value.
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Walter R. wrote:

On small jobs like yours we use a skill saw with a diamond blade. Typically we go 25% of the thickness of the slab.
What are the dimensions of your patio?
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The patio is 11x40'. It has some small cracks in them that have served as "control joints". To avoid further cracks, I thought it might be wise to cut a few more control joints where it can break with ease. The whole patio will be covered with a layer of split paver bricks, laid over heave roofing felt.
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Walter
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Walter R. wrote:

Yes, the patio should have had joints so the patio is sectioned in 5.5' x 10' sections. For this many joints, rent a walk behind saw at your local tool rental place. It will be much easier. Or, if savings are a priority, get a diamond blade and skill saw. It will take a while. This is why I prefer to install tooled joints while the concrete is wet, much easier.
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Out typical spec is:
1. SAWCUT CONTROL JOINTS , 2" DEPTH, EVERY 100 SF OF PAVING MAX 2. SQUARE PATTERN SAWCUT JOINTS, 1" DEPTH, APPROX. EVERY 5'x5' GRID
So for your patio you'd have two control joints at 5.5' and 20'.
Greg M
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Walter, Why cut it if you're covering it? Control joints are basically cosmetic. The concrete's going to crack anyway. The saw cut just controls where. If you do cut it, don't go over 150 sf per section and also don't have a section more than 1 1/2 times longer than it's width. Real good chance of cracking between cuts if too long.
Tim
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