Drainage Questions - Advice Needed Please.

[cr0ft]

Hi all,

After some advice on a drainage job I am starting tomorrow. Done an inspection of the existing drains today and at the mini inspection chamber (300mm) at the head of the drain the top of the underground PVC pipe is 0.2m or so below the surface. We are replacing the old mini inspection chamber and running a 3rd connection into it which will be our new soil stack.

Problem 1 - Due to the low depth of the drain at the head of it's run we can't put a normal 600mm radius swept bend on the bottom of the soil stack. Part H of the Building Regulations says the minimum bend radius will need to be 200mm measured at the centreline of the pipe. Does a normal 87.5 degree soil pipe elbow comply? I don't have one handy to measure at the moment or I would check myself.

Problem 2 - At the bottom of the garden (just before the public road) the top of the existing clay drain pipes is 0.4m or so. None of these depths comply with current regulations of course as there is no concrete slab protecting these drains. I intend to pour concrete slabs over them all once I am done. The question is, Diagram 11 of the Part H of the Building Regulations refers to a compressible material to be laid between the granular fill and the concrete slab. What should I be buying to fit there? No suggestions as always in the Building Regulations so advice appreciated!

Thanks to all in advance for advice.

 

[Centralheatking]

Its a bit late mate if ur startin tomorrow - but my approach would be

1. is it going to inspected - if not
2. open it all up - bang the components together - pressure test
3. give it a whirl - bird feed golf balls are quite represenative of poo

Usually if you have a really slight fall or even level for a short length 4inch
will carry loads away CHK

 

[cr0ft]

Hi. No worries about tomorrow, I have plenty of fittings of various types to hit the job. Nothing hugely worries me to be honest, just want to make sure that soil pipe elbow at the bottom of the stack is going to be ok. Will measure it tomorrow.

 

[Ray Stafford]

You need a Polypipe UG483 or equivalent. Made specifically for the job. Tight, but not too tight. Sort of like Goldilocks fanny.

 

[cr0ft]

Hi Ray. I don't suppose you know *roughly* what the drop is on that, from the bottom of the collar to the invert?

I only have around 0.2m between the crown of the drain pipe and the ground level so I'm not sure it would fit to be honest. I have a couple of rest bends in the van but they appear to tall for the installation.

 

[cr0ft]

Hmm I think I am worrying about nothing to be honest. Just measured the long radius bend and I think I may have to have the collar of it sticking out of the ground, not a big deal really as it's on the back of the house. Better that than putting in a bend that's too tight I say.

 

[SimonG]

Not an orange fitting is it? I was always told that they are not uv stabilised.

 

[cr0ft]

I will pour earth over the 50mm or so that sticks out above ground level Much better than putting in a normal soil pipe elbow fitting I think.

 

[Centralheatking]

You have the right approach - it is what we do - DO IT - all we do is look for solutions
and not problems ---------- After all all our work on UKPF is guaranteed is it not


UNTIL THE CHEQUES CLEARED happy days CHK

 

[Centralheatking]

Oh and dont forget the really special silicone grease join the bits together - we used to use
very expensive 'fairy liquid' to do this - but our local council building control officer -(i wont name him) reckons Aldi 'purple' washing up stuff is better !!!!!!!!! least ways he has not moaned CHK

Not an orange fitting is it? I was always told that they are not uv stabilised.

 

[Leo21]

You need a Polypipe UG483 or equivalent. Made specifically for the job. Tight, but not too tight. Sort of like Goldilocks fanny.



View attachment 16307

Having a Jimmy Saville moment then Ray?