Home Repair forum - How to cut control joints

Author

How to cut control joints

Walter R.

2006-06-29, 9:28 am

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?

--
Walter
www.rationality.net
-

scott21230@gmail.com

2006-06-30, 9:25 am

I really don't think it's 1-2" deep. Do some research to find the
exact value.

ephedralover@hotmail.com

2006-06-30, 9:25 am

Walter R. wrote:
> 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?
>
> --
> Walter
> www.rationality.net
> -

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?

Walter R.

2006-06-30, 9:25 am

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.

--
Walter
www.rationality.net
-
<ephedralover@hotmail.com> wrote in message
news:1151594663.573341.196970@b68g2000cwa.googlegroups.com...
>
> 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?
>

ephedralover@hotmail.com

2006-06-30, 9:25 am

Walter R. wrote:[color=darkred]
> 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.
>
> --
> Walter
> www.rationality.net
> -
> <ephedralover@hotmail.com> wrote in message
> news:1151594663.573341.196970@b68g2000cwa.googlegroups.com...

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.

Greg M

2006-06-30, 9:25 am

"Walter R." <wer25@example.com> wrote in message
news:wESog.21689$uy3.6567@tornado.socal.rr.com...
> 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.

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

Tim Mulvey

2006-06-30, 9:25 am

"Walter R." <wer25@example.com> wrote in message
news:wESog.21689$uy3.6567@tornado.socal.rr.com...
> 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.
>
> --
> Walter

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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