Concrete references?

[Bruce Ramsey]

Concrete gets hard and it cracks. Expected and normal.

Buyers want every crack in every driveway, patio, walkway, etc. fixed. Builders want to discount every crack to normal expansion.

I am looking for an industry standard that says in effect, these size, type, location, etc. of cracks are normal and accepted. If cracks are outside of this criteria, then the concrete was not installed correctly and should be repaired or replaced.

Something I can send buyers and builders to and say this is what the concrete industry says.

I rummaged around a few concrete websites and placed calls with half a dozen phone numbers. Left some msgs, talked to assistants, actually talked to one fella. Some may pan out, some may be dead ends. Anybody got anything definative?

[Matt Fellman]

This is far from scientific and pretty much just my own opinion but in the absence of much other input here goes.... I say if there's no differential settlement and you can't fit a dime in the crack it's normal. And, honestly, many that you can fit a dime in are normal but I guess you have to keep builders honest.

I'm often tempted to tell anal SOBs like these buyers that they should go live for a week in a 3rd world country where they're lucky to have a meal without getting shot at. When they come back I bet those hairline cracks in the driveway will seem a bit less important.

[Dan Harris]

AZ standards require cracks in excess of 3/32" width, and cracks in control joints exceeding 3/8" be repaired.
I don't know if this is just a State requirement or something common in the concrete business.

[Daniel Leung]

"3M" recommended to repair the 1/8" cracks. see video 3M Canada: Manufacturing and Industry: Concrete Repair (http://solutions.3mcanada.ca/wps/portal/3M/en_CA/concrete/home/).

[A.D. Miller]

Concrete gets hard and it cracks. Expected and normal.

Buyers want every crack in every driveway, patio, walkway, etc. fixed. Builders want to discount every crack to normal expansion.

I am looking for an industry standard that says in effect, these size, type, location, etc. of cracks are normal and accepted. If cracks are outside of this criteria, then the concrete was not installed correctly and should be repaired or replaced.

Something I can send buyers and builders to and say this is what the concrete industry says.

I rummaged around a few concrete websites and placed calls with half a dozen phone numbers. Left some msgs, talked to assistants, actually talked to one fella. Some may pan out, some may be dead ends. Anybody got anything definative?

BR: To my knowledge there are no specified tolerances for shrinkage cracks in slab-on-ground foundations or flatwork. The closest reference I am aware of is a voluntary standard from the Residential Construction Performance Guidelines for Professional Builders & Remodelers, published by the NAHB:

2-2-4 Observation: The concrete floor slab is cracked.

Performance Guideline: Minor cracks in concrete floor slabs are normal. Cracks exceeding 3/16-inch in width or 3/16-inch in vertical displacement shall be repaired if the slab is in conditioned space or the crack interferes with the installation of finish flooring.

This equates to 0.1875-inch, which is twice what the previous poster claims as a personal standard. Another poster lists the thickness of a dime (0.045-inch) which is, like the 3/32-inch (0.09375-inch) claim, not elsewhere documented or likely enforceable.

In Texas, the soon to be defunct Texas Residential Construction Commission had the following mandatory performance standard:

(b) Performance Standards for Concrete Slab Foundations, excluding Finished Concrete Floors.

(1) Concrete floor slabs in living spaces that are not otherwise designed with a slope for drainage, such as a laundry room, shall not have excessive pits, depressions or unevenness equal to or exceeding 3/8 of an inch in any 32 inches and shall not have separations or cracks that equal or exceed 1/8 of an inch in width or 1/16 of an inch in vertical displacement. If a concrete floor slab in a living space fails to meet the standard stated in this paragraph, the builder shall take such action as is necessary to bring the variance within that standard.

[EmmanuelScanlan]

I am looking for an industry standard that says in effect, these size, type, location, etc. of cracks are normal and accepted. If cracks are outside of this criteria, then the concrete was not installed correctly and should be repaired or replaced.

Something I can send buyers and builders to and say this is what the concrete industry says.

This is a handy little publication you can use from the ACI:

http://cobweb.ecn.purdue.edu/~ce676/CRACK/Causes_Eval_Control.pdf

[EmmanuelScanlan]

Here are some more good references:

Concrete Cracking Prevention- - The Concrete Network (http://www.concretenetwork.com/concrete_cracks/)

http://www.azobuild.com/downloads/mga_training_notes.pdf

[A.D. Miller]

Here are some more good references:

Concrete Cracking Prevention- - The Concrete Network (http://www.concretenetwork.com/concrete_cracks/)

http://www.azobuild.com/downloads/mga_training_notes.pdf

ES: Good info. Thanks.

[Bruce Ramsey]

It looks like most of the information is about how to install concrete to reduce unwanted cracks. There seems to be more information about identifing the cracks and the source of the cracks. Apparently based on the cause and type of crack, then you make a judgement call.

Thanks for all the links.

[EmmanuelScanlan]

Bruce,

I feel your pain! You would like an authoratative source defining these parameters. The problem is that most of these type standards are created by organizations like the ACSE or ACI and these people want to sell you everything, including general access to their site :rolleyes:.

I also look for these types of information for the same reason. What we wind up doing is finding another well known source that might quote the ASCE or ACI standards. Sometimes we need to get it in bits and pieces from here and there which is a pain. Try these:

Chapter 9 not only speaks of sizes but also the acceptable repair methods.
http://www.toolbase.org/PDF/DesignGuides/rehab1_foundations.pdf

This one will not give you specific sizes but will specify that cracking is unavoidable to some degree:
http://www.toolbase.org/PDF/DesignGuides/ResidentialStructuralDesignGuide.pdf

Kim Basham teaches seminars for ACI and has a couple of good articles relating to preventing cracking and repairing cracking. He can be considered an authoratative source. These can provide part of your information needs.
Articles (http://kbengllc.com/Articles/tabid/297/Default.aspx)

If you feel up to it here is a list from the PCA on all of the searchable journals out there dealing with cement and concrete. I'm sure you can find an article or two from another authoratative source for the information you seek.
PCA Library | Web Resources| Portland Cement Association (http://www.cement.org/library/lb_web.asp)

It is sad an unfortunate that with all of the information available today on the WEB that you can't find it when you want it but stumble across it when you're not looking for it!

[A.D. Miller]

Bruce,

I feel your pain! You would like an authoratative source defining these parameters. The problem is that most of these type standards are created by organizations like the ACSE or ACI and these people want to sell you everything, including general access to their site :rolleyes:.

I also look for these types of information for the same reason. What we wind up doing is finding another well known source that might quote the ASCE or ACI standards. Sometimes we need to get it in bits and pieces from here and there which is a pain. Try these:

Chapter 9 not only speaks of sizes but also the acceptable repair methods.
http://www.toolbase.org/PDF/DesignGuides/rehab1_foundations.pdf

This one will not give you specific sizes but will specify that cracking is unavoidable to some degree:
http://www.toolbase.org/PDF/DesignGuides/ResidentialStructuralDesignGuide.pdf

Kim Basham teaches seminars for ACI and has a couple of good articles relating to preventing cracking and repairing cracking. He can be considered an authoratative source. These can provide part of your information needs.
Articles (http://kbengllc.com/Articles/tabid/297/Default.aspx)

If you feel up to it here is a list from the PCA on all of the searchable journals out there dealing with cement and concrete. I'm sure you can find an article or two from another authoratative source for the information you seek.
PCA Library | Web Resources| Portland Cement Association (http://www.cement.org/library/lb_web.asp)

It is sad an unfortunate that with all of the information available today on the WEB that you can't find it when you want it but stumble across it when you're not looking for it!

ES: More very good info. Perhaps you are in the wrong business. Google could use some help with their search algorithm.:D

[EmmanuelScanlan]

ES: More very good info. Perhaps you are in the wrong business. Google could use some help with their search algorithm.:D

Aaron,

Thank you sir. Sometimes I even wonder if I'm in the wrong business. As for Google they have really slipped over the years!