I dont allow any forms (pegboard or MDF or plywood) of any kind in my weir walls. Your gunite boys should be able to hold a form in place on one side and shoot against it, let the gunite harden somewhat and remove the form as they work their way up from bottom to top.

12" is probably referring to a minimum thickness. So your wall would be 32' long but a minimum of 12" thick.

I always use double steel curtain on weirs. A typical pool wall will have a single mat (something like 8" x 8" steel pattern) so on a weir, you would have TWO of these mats. Much more pressure on a weir wall because there is no dirt behind it, it has to handle all the pressures on its own.
So yeah, a double steel mat on a min. 12" gunite wall is a good idea.

The only reason to set the weir 1/2" to 1" below the future water level is to leave room for tile or stone cap.
Once the pool is finished, the weir wall should finish out at the waterline (midline of the tile). So typically waterlines are 6" wide and your waterline is in the middle of this 6", so your weir needs to finish out at the midline of this 6" (or 3" below lower edge of coping level).

Obviously its critical to get the weir wall elevation just right because whereever its set is the highest level you will be able to fill your pool to. So make sure its set about 3 1/2" to 4" below the regular beam level and you will be good.

Hope that helps

Happy 4th!

I should say the weir should be GUNITED to a level thats 3 1/2" to 4" below the beam level.
It should be FINISHED at the midline.

Ditto kspoolman,
Water proofing the wall is also a must. Several products are available and they are usually painted on with at least a couple applications. It prevents water from penetrating the wall on the pool side and coming out of the wall on the weir side.

Is there a raised spa?

Additional precautions should be taken to ensure that if check valves fail, the siphon effect is stopped before the catch basin overflows.

Either two vacuum breaking elements, one from the raised spa and one from the main pool, or one from the main pool and the basin be large enough to accommodate a spa draining and a several inches from the main pool before overflowing.

A leaking check valve on the weir pump's output side could allow water to run from the pool to the catch basin, a potential overflow of rather large proportion. A vacuum breaker would sense when the basin is getting full and open the pipe from the pool returns for the weir pump to the atmosphere, breaking the siphoning effect of a failing check valve.

If the spa is even with the pool, it's spillway will need to be a little bit higher than the pool level and the catch basin size should still permit draining the spa in addition to it's other job of holding a couple inches of pool water and then some extra for a margin of error allowance.

Scott

Thanks guys for the great info.

No spa, thank goodness!! Will check w/PB on the vac. breakers.

What is the product that you recommend to water proof the weir wall?

Can it be installed by us, or does it need professional installation? PB did not know of this step in the process.

Thank you,
s

shellip,
There are several products. I like Thoroseal. It's a cement based product that is easy to install. It comes in white and grey so you can see your coverage of multiple coats.

If he didn't know that step, I'll bet he has no idea about the vacuum break either. I wonder how many negative edges he's done.

Scott