Plastic Inspection Chamber Base Support

[BathDIY]

Am replacing an existing chamber with new plastic one.

Is it OK, even desirable to retain some of the existing chamber structure (if possible) to support the plastic base, or should I beak up all of the old and remove? Was thinking of using concrete to get the base sitting level and the water flowing properly.

Assuming I have to remove the old structure entirely can the new base just sit on the earth? Previously when I have fitted gully's I have put down a paving slab onto the earth to support them and backfilled with pea gravel up to the crown. Is it the same for plastic inspection chambers, if not what method should I use?

Cheers

Justin

 

[Buck_68]

I would have thought you’d be best installing on a bed of pea shingle.

 

[noseall]

Ordinarily you would pack dryish concrete around the base of a new plastic chamber.

Because of their awkward shaped (placcy IC chambers) bottoms, I would say it was more economical to remove all hard material and start again.

 

[^woody^]

Yeah leave the base in if it's not to high.

 

[noseall]

Yeah leave the base in if it's not to high.

It would need to be very low, if he is lucky. The through channel on a placcy fella sits quite high relative to the actual base.

 

[BathDIY]

Thanks guys,

I will see what I can do with the existing base, assuming it needs to be removed, how deep should I pack in the dry concrete? Is it as little as I can get away with and just enough to support the base or is there a depth requirement?

Justin

 

[noseall]

We normally have enough for a smattering of a base (50mm or so) then fill the cavities of the base as full as you can.
Be careful that you don't block or restrict any of the outlets though.