Soil Stack Re-Routing

[Adrian86]

I recently purchased a 3bed detached house requiring modernisation. I am doing as much of the work as I can myself but will get Traders in where necessary.

The soil stack runs internally straight down from the corner of the bathroom, Straight through the kitchen to the sewage connection point beneath the floorboards which can be seen in the images below.

I want to move the stack outside

I am currently thinking the best way to go would be to connect a 92.5* bend to the ground connection point and use a core drill to go through the external wall allowing a pipe to be bedded in the wall and the soil stack to be repositioned outside.

One of the problems is the floor joist is in the way so a possible option could be to cement bricks down to the foundations to support the joist allowing the end to be cut away and the pipe to get through the wall.

I have the following questions:
1) Are there building regs regarding how close to the end of an external wall you can create an opening and if openings are permitted within the final few feet how big can they be?

2) Would it be best to chip out the old plastic joiner that’s cemented and re-cement a 92.5* bend? How tough is this stuff?
This may allow me to get the plastic pipe outside leaving the joist in place with a portion shaved off the bottom where the pipe will be.


3) Will I need to get buildings control involved?

Thanks in advance for any replies

[/img]

 

[Nige F]

Only way is to dig drain up outside and re route . Build Control "should" be involved

 

[noseall]

As per Nige F, You need to find the pipe externally and connect onto this.

 

[Adrian86]

Cheers Nige F, noseall.

This sounds like the proper way to do it.

With respect to the toilet and waste on the second floor, I read in a bit of Part H of the building regs that you need lintelling for sewage pipework that runs through an external wall. However i think that is referring to the Sewage pipe that runs underground into the underfloor cavity.

Would i need a lntel to put plastic pipe through the wall upstairs or could this just be bedded in with cement/similar?

Thanks,
Adrian

 

[noseall]

No need to lintel a 110mm pipe.

When we faff about with these scenarios i.e. fitting a WC to an external stack, we often remove the bricks whole (making a bigger hole than necessary), then fit the loo, then brick the pipe back in. It just means that you have plenty of wriggle room when setting up the loo in relation to the SVP.

The above scenario is particularly relevant if you intend lining the stack up directly with the loo. If you off-set the stack, i.e. have a 90 degree bend, then you could perhaps core drill, because there is less need for precision.

 

[Adrian86]

If I were to get someone in to do the underground foul drainage work ballpark how much should I expect to pay?

From where the stack would be on the outside wall to the manhole is between 6.2 and 6.5 meters. I have been looking into laying the foul drainage myself but I think it may be better to get it done professionally.

Would it be viable to keep the existing underground foul drainage that runs to the floor space under the kitchen and connect a small length of PVC soil pipe beneath/within a cabinet with an air admittance valve for the kitchen drainage?

Cheers,
Adrian

 

[Hugh Jaleak]

Connect onto existing drain outside, there's no need to renew back to the manhole unless that section is in poor condition. Find the drain outside, cut through and join on with plastic, then run the new stuff from there.

You could fit a junction and use the branch for the stack connection, then carry on through the wall inside and connect the kitchen sink, shouldn't need an AAV for that.

 

[Adrian86]

I have finally got round to working on this (better weather). Trenches dug and pipework mocked up, just need to underfill then reconnect the pipes, cement up the hole in the wall and backfill.

Cheers for the help

 

[noseall]

We'd have built an IC where you have fitted a 90 degree branch.

A 45 deg branch would have been better.

 

[Nige F]

Thanks for the update - just noticed my reply was on my birthday . Have to agree with Nose, is the original stack being removed or remaining as a stub stack inside to take kitchen waste?

 

[Adrian86]

The original stack will become a stub for kitchen waste with the new soil stack outside.

I originally thought about using a 45* but this option seemed a bit easier to work out the bend angles.


do you think using an LRB and 90* ish Tee could cause potentilly cause blockages ?

 

[noseall]

do you think using an LRB and 90* ish Tee could cause potentilly cause blockages ?

Any interference with the normal flow of water has the potential to block.

That junction won't be roddable. Either install a rodding eye or a small IC.

 

[Adrian86]

Cheers for the Advice guys, I diddnt join the forum not to take it.

I have replaced the LRB with a 45* tee and included a rodding point. I thought an IC would have been slightly overkill, the rodding eye is less than half a meter from the junction you could get your arm down there if you wanted to (Barf).
I am also going to include access points on the stack when i install it, the brown vertical pipe is just temoprary for the mockup.

Thanks,
Adrian

 

[noseall]

Splendid job!