3 month old pool should I have cracks in deck

[pinstripepat]

All,

My pool specs are below...however, in one square if-you-will of the decking I have noticed hairline cracks in the washed aggregate. Is this normal for a new pool? It is in the square or section of concrete that has a drain in the middle. There are four drains in all in my decking and this one and one other section with a drain, have the cracks. You notice them when it rains and the water follows the crack line.

Thanks, new to this and don't know if this is normal settling etc...

 

[y_not]

Can you post a picture?
We like pictures here as they are often very helpful.

 

[JeffJeff]

My aggregate deck started showing hairline cracks a few months after it was poured. Pool builder said it was "normal" (imagine that) and that all concrete will crack. Said he would do something about it if it turned into a tripping hazard. Also said he was surprised there were not more cracks.

Three years later the cracks have become slightly worse and more visible mostly because the rocks in the hand seeded aggregate have popped out, but I don't have any new cracks show up which were not visible within the first 6 months of them pouring the deck.

 

[Just-a-PB]

My concrete guy guarantees his work.




He Guarantees, it will be hard, no one will steal it, and it will crack.

This is why I only install stone around my pools now, no more of these calls.

Hairline cracks are not even considered "cracks".
Not easy to get a perfect deck, especially exposed agg. The temp outside, wind, moisture content. Just exposing the agg, can cause issues if not done exactly right.

Would love to see pics.

 

[tcat]

My coping has hairline cracks about every 6-12". 4 year old pool, I just moved in. Is there a "paint" or urethane elastomer that will coat/hide them? The coping is poured concrete about 2" x 13", kind of a "pitted" look.

 

[ps0303]

Cracks are a byproduct of improper compaction of the soil where the deck it. Do you see or do you know if the ran a compactor over it before they poured it? Did they tell you to water the area several times a week or more after they framed the area? More then likely they didn't do either and that is why you are seeing the settling and cracks. I would say about 99% of the pools I see have cracks in the decking.

 

[Just-a-PB]

Cracks are a byproduct of improper compaction of the soil where the deck it

So if the soil is prepared properly nothing else will cause the concrete to crack, Interesting.........

Here are a couple of nice articles with a few other reasons as well.
http://www.cfawalls.org/foundations/cracking.htm
http://www.concretenetwork.com/concrete/preventing_concrete_cracks.htm
http://www.cement.org/tech/faq_cracking.asp
http://www.nrmca.org/aboutconcrete/cips/04p.pdf

 

[ouachita]

If concrete wasn't supposed to crack at all you would not need expansion joints. Concrete can crack for a number of reasons other than lack of compaction.

 

[duraleigh]

While I do not disagree with the last two posts, I think ps0303 makes a very rational point.....MOSTobjectionable cracks in pool deck concrete occur when the substrate is poorly compacted and has settled, removing underlying support from the slab and allowing the slab to crack.

I would also say that that MOSTpercentage is over 90. I base that from seeing pictures of cracked decking on this forum over the last 6 years and I cannot remember one where the cause did appear to be anything other than poor compaction. Anybody got pics showing cracked pool decking where it was a different problem?

 

[ouachita]

My guess is the soil settled more in the other areas of you deck than where the pipe runs underneath your decking.

It's hard to explain. Imagine putting a cracker on top of a pencil laying on it's side. Like a see saw kind of. Now apply pressure to opposite ends of the cracker and it will break where the pencil runs underneath it. The same thing can happen with concrete decking with pipes running underneath it and close to the bottom of the concrete.

Do the cracks run in the same direction as the pipes? If so then that's probably what happened. Mine did that where I ran a conduit for wires. A friends did that where he ran sprinkler system conduit. Both of these were on solid ground which didn't need compacted.

Duraleigh, most cracks are from settlement, but to say that is the only cause of cracking is incorrect. That is what I was trying to point out in my previous post. And properly compacted fill can still support concrete that cracks.

You are correct that most of the major cracks are from inadequate compaction.

 

[ouachita]

Also, "objectionable cracks" are relative. Some people will find a hairline crack to be objectionable. Reasonable people do not.

http://www.fhwa.dot.gov/publications/re ... 122/03.cfm

See the link above for some examples of weather related cracking. I have had a couple of driveways look like the second picture. We finally stopped pouring on hot windy days.

 

[y_not]

I would be annoyed by a hairline crack, but I would ultimately be OK with it under the following 2 criteria.

1. So long as I could verify that there wasn't anything further underneath that could be structural or end up being so down the road.

2. If I could somehow fill the hairline crack, as I have seen such things grow larger over time due to heat, cold, water, salt, etc..

So I supposed the real answer for the OP and myself having causally watched this thread, is there a way to fill it so it looks good and matches the surrounding surface?

I have seen crack fills in concrete before, never been overly impressed with most, many just crack further and shove the fill up, even breaking it up into pieces. Is there some sort of more flexible, yet still solid, not tar like, elastomer/polymer based fill or something along those lines that can have a little give and take to it.

PS. If my driveway or other concrete slab type project ended up the way those pictures show in the last post above, I'd really flip out over that!!

 

[ouachita]

There is a caulk, polyurethane I believe, that is flexable. The problem with a hairline crack is that it is too small to get the caulk in. Therefore you would have to grind it out to about an 1/8" to be able to get caulk into the crack. Not attractive.

There are some coatings you could get to coat the concrete with that are cement based. But they don't flex and will crack as well if there is still movement.