Gunite: Weep --> Trickle?

[dakine259]

Hi All! Under construction, first time poster here. Seems like a really great community.

30k gallon pool. IG Gunite.

After excavation, we had a moderate amount of groundwater collecting in deep-end. Mostly through a vertical wall at the shallow end, then flowing to deep end, oddly enough.

We finished gunite ~36 hours ago. The PB left three larger weep holes near/in the deep end, and those are getting a little activity. Expected.

However - before watering the gunite this afternoon, I noticed that there were several damp locations already on the gunite floor - and read about how some level of weeping through the gunite is ok/normal. However, we have one weep spot where the water is visibly trickling through. Downhill of this particular weep spot, there's a pretty significant amount of white residue and what looks like dirt/sand.

Question 1: Should I be concerned about shell structural integrity with weeping that is essentially a small trickle? I poked around on the gunite a bit, and it seems....softer/sandier? in this one spot.

Question 2: How are the intentional weep holes closed? Always plaster? (we will be doing pebblesheen).

Question 3: Is there a threshold of weeping at which plaster doesn't create an impermeable barrier? I'm trying to avoid both structural and leak/stain issues down the road.

I attached a picture of the weep spots. The spot closest to my shadow is the "trickle," and the deep end of the pool is to the right in the picture.

Thanks all!

 

[ajw22]

Welcome to TFP.

Intentional or unintentional holes in the gunite can be filled with hydraulic cement.

Gunite is not waterproof and weeping can be expected if you have underground water.

See if the weeping dries up. Otherwise you may need some well points around your pool to control ground water before you can plaster.

 

[AQUA~HOLICS]

#1: I would not be concerned about the structural integrity from the weeping, softer/sandier area due to cement powder being washed away and aggregate being left behind. Minimum of 6” of Shotcrete/Gunite for thickness of the shell.
#2: from the details of the picture you provided, plaster will more than likely be used to seal the weep holes.
#3: if their is too much water weeping into the shell a hydro valve would be installed and water will take the path of least resistance. This is very common when constructing pools near the beach that have very low water tables.
I understand your concerns but looking at the picture this a very common situatio.

 

[dakine259]

thanks all. PB told me that hydraulic cement and/or a waterproofing spray was an option down the road if needed. I'll report back!

 

[dakine259]

just to follow up with conclusion here -

1) I pumped out of two drywells on either side of the pool for about a month, and then they dried up - likely because we exited the rain season. In our case, I don't think these drywells did much

2) We did an aquron CPSP application. This didn't seem to do a ton - but also hard to tell as we entered summer and things in generally started drying up.

3) The weeping in the shallow end slowly stopped, and the one weep spot that was "trickling" also dried up.

4) Pre-plaster, pebbletec folks weren't worried about the remaining weeping out of the three designated (e.g. holes thru to gravel) weep holes. They applied several "dustings" of hydraulic cement, which slowed weeping (but did not eliminate).

5) A day prior to plaster, pebbletec folks opened the HRV at the deep end, and hooked up a pool pump with a 1.5" line coming out to continually pull water from under the shell. That pump was pulling a pretty significant amount of water out all the time.

6) Weeping never fully stopped. Pebbletec/plaster applied, and then right before fill, we got some weeping moisture thru on a couple of spots. Had pebbletec folks out again, and they said "no problem, fill the pool."

7) We filled pool and there's no visible staining or any other indication in these areas. So - so far so good.

I was somewhat concerned about the pool shell leaking. I brought this up to pebbletec folks, and they said that the plaster curing will take some time, and will slowly become more and more waterproof as this happens. I don't know if I buy this, but thinking about it afterwards, weeping thru gunite + plaster from the backside of the pool is no different than weeping thru plaster + gunite from the inside of the pool. So, these "weep" spots are really no more likely to leak than the rest of the pool (e.g. the areas that were always dry).