Pre-gunite: How much clearance between rebar and face of dirt?

[joelq]

We're one week into our construction process and are currently awaiting our Pre-Gunite Inspection. I've noticed over the last couple of days that a fair amount of the dirt behind the rebar on the backside of the pool has started to crumble, and more recently, a big chunk of it has actually collapsed about a foot. In the first photo below, you can see the horizontal piece of PVC. Well, a few days ago, that was completely buried in dirt. Now you can see that the dirt in front of it has dropped several inches.

I'm pretty sure this is being caused by water run-off from the yard behind us - our yard is lower than the yard of the house behind us, and when they run their sprinklers (or when it rains), some water runs down to our yard. In designing the pool, our pool builder already made provisions to install drains back there in order to divert any runoff away from the pool, so I'm not too concerned about this after the construction is finished.

What I'm concerned about is making sure there is enough clearance between the rebar and the dirt so that the gunite shell is as strong as it should be. It probably depends on City code, but how much clearance should there be? I've just talked to our Superintendent and he assured me that they will clear the dirt prior to shooting gunite, and that the City will likely fail inspection on it for lack of clearance anyway. I just wanted to make sure that whenever they did clear the dirt, that I could verify that there is enough clearance there.

Is there anything else I should be concerned about at this stage? Specifically, when the drains are installed, what if they're too high to actually catch the water? It would seem to me that the water would make its way down the side of the gunite shell and eventually under the bottom of the pool. Would this be a problem? Or is it ok to expect that there will always be some water underneath the gunite shell?

Photos below. Sorry for the long post! Thanks everyone!

[ehorn]

From what I've read that could be a problem. Here is an image from the website howibuiltmyownpool.com. It suggests spacers of 3" deep to keep the rebar away from the dirt. I would assume the pictures of your dirt that has fallen will need to be taken care of on the day they shoot the gunite.

On another note I'm very jelous you are that far along after a week. I just passed the 3 month mark from the day they dug the hole for the pool and all I have is plumbing.

Eric

[rbonin]

Our builder was very concerned about wall collapse because our soil is so poor. In fact, a moulded bench did collapse after rebar was in place and we had to pay an additional $800 for workers to manually clear all the dirt. There was only about 3 days between the rebar completion and the shoot.

You need to be sure all that loose dirt is removed which will mean more concrete usage (more $) and thicker walls. Our walls ended up being about 12-14" thick so I would say there was 3-4" of spacing between the rebar and the dirt.

~Rick~

[bradjo]

.....snip...... are currently awaiting our Pre-Gunite Inspection.

Hi joelq;
We just finished an owner/builder pool (it finished filling about 2 hours ago). Anyway you're right to be concerned about that crack in the side and the dirt won't allow you to shoot gunite. Your steel skeleton should float on these 3" bricks they place under the steel to give clearance from the dirt. Worse than the dirt that fell is that crack. It concerns me that the dirt there isn't compact enough to support the pool. I'd ask him how they will cope with this to ensure the long term structural integrity of my pool.

If you aren't an owner/builder I'd phone up my general contractor and have him come look at what happened. I hate failing inspections it's a major waste of time. I'd want him to deal with it prior to inspection.

Depending on ground water levels in your area they can install a special main drain that has a ball valve in it so that the water under the pool when it reaches enough pressure to overcome the pools own hydrostatic pressure can seep into the pool. So ask about it but the builder should be aware of this if it's necessary in your area.
hth,
Jo