This crack appeared several weeks after gunite was placed. I’ve notified the pool builder and he said he would look at it when he returns. I’m in Utah, and we are waiting for warmer weather (March) to continue building. Is this overly concerning, and if so, what are the proper steps to resolve? The pool was poured per engineered drawings, and the rebar exceeded the detail in the drawings. Bar placement was tighter then 12” OC as called out in spec.
Thin crack about 10 feet long.
- Thread starter sullyb
- Start date
- Jul 21, 2013
- 65,110
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Welcome to TFP.
That crack does not look structural. Concrete devlelops those type of stress cracks. The plaster will seal the crack.
It is a bit late now but was the gunite watered after it was shot?
www.troublefreepool.com
That crack does not look structural. Concrete devlelops those type of stress cracks. The plaster will seal the crack.
It is a bit late now but was the gunite watered after it was shot?
Watering New Gunite and Concrete - Further Reading
www.troublefreepool.com
It was covered with concrete blankets in temps ranging from 45 to 30 degrees for two weeks.
- Jun 24, 2021
- 15,918
- Pool Size
- 29000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60 Plus
OOF!!
You have two dimensions working against your concrete strength...hydration and temperature...
Isothermal (constant shotcrete temperature) strength gain curves based on the Arrhenius function.
Watering New Gunite and Concrete - Further Reading
www.troublefreepool.com
Concrete cylinder breaks came in over 4000 psi at 28 days. The mix had hot water and 1 lb of microfiber/yard. I believe the blankets did a descent job at trapping water and keeping the slab conditions humid. I’m not an engineer, just my observation of the shell as I monitored conditions generally.
- Jun 24, 2021
- 15,918
- Pool Size
- 29000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60 Plus
You may be ok, maybe not. At 45 Degrees F, 7 Degrees C, the air is fairly dry. We will likely never know. As @ajw22 indicated, the plaster should seal the cracks. Look forward to some swimming!
Thanks. Is it beneficial to seal the crack with epoxy or something else prior to applying plaster. Also, since we’re on the topic, what is the minimum temperature requirements to ensure the structural integrity of the plaster?
- Jun 24, 2021
- 15,918
- Pool Size
- 29000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60 Plus
I'll defer to @ajw22, but I would not put any intermediary sealant between the shotcrete and the plaster.
For applying the plaster, in general not below 40F and preferably warming up to at least 60F and not above 90F.
- Jul 21, 2013
- 65,110
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Absolutely not. Plaster will not adhere to epoxy.
Let your builder handle it.
It is a common non-problem.
You want the application air temperature to be above 50F and nighttime temperature not be below 40F.
You want them to limit calcium added to accelerate curing.
Plaster Installation and Maintenance - Further Reading
www.troublefreepool.com
