Rendering a pond ready for fibreglass coating help

[Jjj]

Hi everyone,
I’m helping a builder mate out on a little job.
Customer keeps koi carp and wants a nursery pond.
It’s a 3m x 1.5m x 1.2m trench, base is concrete and walls are concrete blocks, the heavy white ones.

After it’s rendered it is getting a fibre glass coating on top.
The bloke doing the fibreglass has told the builder to use fine building sand.
3:1 scratch
4:1 top coat floated finish

I think 3:1 sounds a bit strong what do you lot think?

 

[Stevieo]

Hi everyone,
I’m helping a builder mate out on a little job.
Customer keeps koi carp and wants a nursery pond.
It’s a 3m x 1.5m x 1.2m trench, base is concrete and walls are concrete blocks, the heavy white ones.

After it’s rendered it is getting a fibre glass coating on top.
The bloke doing the fibreglass has told the builder to use fine building sand.
3:1 scratch
4:1 top coat floated finish

I think 3:1 sounds a bit strong what do you lot think?

Won't matter a fcuk once it's under the glass, I wouldn't have thought. Fibreglass is fcuking bullet proof.