"Break spa shell" for demolition of rooftop spa?

[Yikes]

I have a project where we are demolishing the existing (public) spa that was previously built into the roof of a parking structure below. The plan is to remove the coping and infill the spa with load-bearing styrofoam, waterproof membrane with miradrain, and pour deck topping slab to match the adjacent existing deck topping slab.

There are cars parked directly underneath this spa.

The original permit set shows that the spa is built into a vault / well in the structural concrete roof deck (see image below):



So, here's what's weird: This city's environmental health department (like many others in the area) has a standard correction for pool/spa removal that says to "crack the shell" of the spa. To me, this presumes that it's a conventional in-ground spa/pool built into the dirt, and they want to make sure that stormwater drains away after it's abandoned.

However, in our case where it's a rooftop spa built into a structural vault/well above the parking garage, then cracking the shell makes no sense, because (a) stormwater should never get in the old spa area due to the new waterproof decking above, and (b) if it did get in there it would have no place to go, because it's built into a well. I'd rather not crack the shell, because I don't want some careless construction worker to accidentally go too far and start demoing the structural slab below it.

QUESTION before I respond to the health department: Is there any other reason or code that I'm missing that should compel cracking the spa shell to expose the structural well underneath?

 

[Joe.B]

Way out of my level of experience, but a thought popped up in my head in case they push for this. Ask if you can drill a hole (or holes) instead of "cracking" the shell. Seems like it would serve the same intention and would be less at risk to a "careless construction worker." Hopefully common sense will prevail.

 

[BN4537]

The spa has a drain in the bottom, correct? If the drain stays, it could serve the same purpose as "cracking the shell", IMO.

 

[ICE]

So, here's what's weird: This city's environmental health department (like many others in the area) has a standard correction for pool/spa removal that says to "crack the shell" of the spa. To me, this presumes that it's a conventional in-ground spa/pool built into the dirt, and they want to make sure that stormwater drains away after it's abandoned.

"Crack the shell" seems wholly inadequate.

 

[north star]

@ ~ @ ~ @

If I understand ** Yikes ** question, he wants to remove the Coping ONLY,
infill with approved type sealing materials & a waterproof liner, and leave
the whole Vault undisturbed & intact.

IMO, ...cracking or drilling the shell will not accomplish anything.

I recommend a respectful & courteous challenge to the Health Dept.

@ ~ @ ~ @

 

[bill1952]

The spa has a drain in the bottom, correct? If the drain stays, it could serve the same purpose as "cracking the shell", IMO.

Have to add a trap primer.

 

[Joe.B]

@Yikes point was that the intention was to make sure any water that gets in has a way to get out, that makes sense to me. In this application we would assume that the new waterproofing will do it's job, but in the event that there is a failure of the water proofing I would think that leaving a place for the water to escape would be a good thing. Opening up an existing drain seems logical. I'm curious about this "load-bearing styrofoam", is that mixed as a styrofoam aggregate and a resin? Or is it like a concrete mix but replacing the stone with the foam? I've heard of foundations that were basically concrete with perlite mixed in for insulation, kind of like that? If the waterproofing failed would the water work its way through it, around it, or would it be absorbed? Thanks for sharing.

 

[Jay Smith]

@Joe.B - Polystyrene foam as fill:

Geofoam

Geofoam is a lightweight fill material. Find your local supplier of Geofoam meeting ASTM D6817.

www.geofoam.com

 

[ICE]

Water will get past whatever is done. Condensation is a possibility.

 

[Msradell]

It definitely seems like he going to have to have some way for water to drain out of the shell if and when it gets into it! Leave the drain wide open or drilling a hole through the bottom seem like good choices.

 

[Yikes]

@ ~ @ ~ @

If I understand ** Yikes ** question, he wants to remove the Coping ONLY,
infill with approved type sealing materials & a waterproof liner, and leave
the whole Vault undisturbed & intact.

IMO, ...cracking or drilling the shell will not accomplish anything.

I recommend a respectful & courteous challenge to the Health Dept.

@ ~ @ ~ @

Yes, that's exactly what I meant.

The spa sits in a post-tentioned parking garage deck that had a special depressed well cast into it that was later gunited to form a spa. Poking holes in the gunite accomplishes nothing, and some idiot could jackhammer through the structural deck below. god help us if they hit a tension cable. It's like poking holes in the trash bag lining your trash can. That won't make water drain away. It will just fill up the trash can.

Instead, underneath the deck topping slab, we have a miradrain drainage board system and waterproof membrane. This will sit on top of the structural foam and drain the water away.

 

[north star]

@ ~ @

There is an unspoken assumption here that the
current Spa does not currently leak to underneath.

The Health Dept.; by policy \ correction, requires
a spa \ pool shell be cracked to allow for drainage
of water to prevent a "growth medium \ haven"
for insects \ vermin \ other kritters.

The policy should be challenged all the way up
the city's chain-of-command.

Creating a penetration where there is currently
not one, only to comply with a policy, would not
be a feasible \ long term solution, but Hey, ...what
the heck do I know ?.......The prima donnas &
pampered princesses seem to be ruling government
these days.

I guess that the whole Vault could be removed and
create a much larger opening in the concrete slab.
Then it could be described as a "water gathering feature".
Put up some safety railing \ bollards.........Why heck
...there could be some LEED points awarded here,
just by complying with the Health Dept.

Yah, that makes perfect sense !

@ ~ @