Ask Experts Questions for FREE Help !
Ask
    jsjs97's Avatar
    jsjs97 Posts: 1, Reputation: 1
    New Member
     
    #1

    Jan 5, 2012, 11:49 PM
    Adding control joints in 6 month old concrete?
    My concete floor in my shed is about 6 months old. It was made in two pours of 28'x30', 6 inches deep with wire panels. No control joints were sawn in at the time. Can I still saw them now and will they still work to guide any cracks that may occur. So far no visible cracks but I am in Illinois and have not went through the winter yet.
    ballengerb1's Avatar
    ballengerb1 Posts: 27,378, Reputation: 2280
    Home Repair & Remodeling Expert
     
    #2

    Jan 6, 2012, 09:06 AM
    That is some shed. You can cut the control joints but it will not guarantee no cracks will happen between the joints. Concrete always cracks not matter what you do but control joints will partially hide the issue. I have a 28x30 garage in Illinois with 4 control joints dividing the space into quarters. I now have a small crack running diagonally through on of the quarters.
    smearcase's Avatar
    smearcase Posts: 2,392, Reputation: 316
    Ultra Member
     
    #3

    Jan 6, 2012, 02:18 PM
    This is one opinion about cracking from the Portland Cement Association.

    "Why does concrete crack?

    Concrete, like all other materials, will slightly change in volume when it dries out. In typical concrete this change amounts to about 500 millionths. Translated into dimensions-this is about 1/16 of an inch in 10 feet (.4 cm in 3 meters). The reason that contractors put joints in concrete pavements and floors is to allow the concrete to crack in a neat, straight line at the joint when the volume of the concrete changes due to shrinkage. "

    In highway construction, control joints in concrete pavement must be sawn within a few hours of placement (often in the middle of the night) because most cracking occurs due to shrinkage as the mix water evaporates. Water will continue to evaporate for days (some say years) but the rate of evaporation is much greater in the first few hours after placement.

    Contraction will occur as temperatures fall and if there are areas where the slab cannot move toward the center of the slab, cracks could occur.

    The other causes of cracking such as unstable grade, water penetration (then affected by freeze/thaw), etc will probably not be lessened by sawing joints now.

    I don't think that sawing joints now will help much but probably won't cause any damage either.

Not your question? Ask your question View similar questions

 

Question Tools Search this Question
Search this Question:

Advanced Search

Add your answer here.


Check out some similar questions!

Cast iron pipe joints set in concrete [ 9 Answers ]

What is the approriate way to set pipe joints for sanitary cast iron pipe in concrete? Is it best to go with hub-less or Hub and Spigot for cast iron joints that must be set in concrete?

Concrete patios laid, incorrectly, without expansion joints. [ 1 Answers ]

I have recently employed a 'Concrete Specialist Firm' to lay my patios around three sides of my lounge. I gave them a drawing of how I visualised the finished result and they quoted and have now done the job. In the month since that has been laid everyone who comes here comments on the fact that...

Concrete cold joints [ 1 Answers ]

The method of rectify concrete cold joints

Need answer for concrete patio slope/expansion joints [ 3 Answers ]

Hello. I am pouring a 18" stamped border around a patio. Most of it is covered and protected from the rain. The width of it is mostly 10' with a section that extends approximately 10X15', My question is the border completely forms around the middle patio section; therefore, sort "enclosing" this...

Adding new bath to concrete slab [ 3 Answers ]

Hi, We just purchased a home in L.A. built in the 60s that has a concrete slab construction. We want to add on a master bath to the house but I don't know how we would tie into the plumbing lines in this kind of a foundation. Do they actually pour concrete onto the pipes when the foundation is...


View more questions Search