Soil pipe routing idea

[bmb4cjt]

Hey everyone,

We're currently having an extension built, doing a fair bit ourselves and would like to move the svp outside the extension

As it currently sits it'd end up going through a new roof along with the waste from the sink and bath. The roof pitch would cross just where there waste for toilet comes out and joins svp and be too much going through the roof. Feel this would lead to leaks in the future.

I'd planned on re-routing the pipework internally but any issue with two 90° bends on toilet soil to get to the new svp position? One straight out the back of then toilet and anothet to get through the wall or a better solution?

I've added a pic of current situation and design.

 

[CBW]

I’ve seen soil pipes with more than one 90 on them, and afaik don’t have issues. Any reason you can’t use x2 45 degree bends?

 

[denso13]

I'd planned on re-routing the pipework internally but any issue with two 90° bends on toilet soil to get to the new svp position?

That's fine, use a 90° pan connecter then a soil pipe bend through the wall.

 

[bmb4cjt]

I’ve seen soil pipes with more than one 90 on them, and afaik don’t have issues. Any reason you can’t use x2 45 degree bends?

Hadn't thought of it tbh. Felt I needed a 90 pan connector to turn in the space between back of toilet and wall and then other 90 straight into the back of the SVP with easier core hole to bore I guess, but 2 x 45's at the SVP end poss less prone to clog.

Thanks both tho, nice to know what I planned wasn't going to cause too many problems

 

[bmb4cjt]

Any ideas how best to get divert the bath pipe to the new stack?

I was gonna go with the toilet soil into the svp at far point under the bath but this would mean soil runs straight across where bath waste currently goes and don't think joining straight into the side was the best idea incase back ups into the bath?

 

[Hugh Jaleak]

Where will the new stack position be, I'm assuming you want to move it outside the footprint of the new extension?

You've already laid the oversite, with the existing drain underneath it, personally I'd have relaid the drain and put a temporary soil run in first, then got rid of the redundant drain before laying the concrete.

 

[bmb4cjt]

Hey @Hugh Jaleak,

Yeah gonna move the SVP outside the footprint of the house.

In hindsight, think we should have done that but it's only really come to light for me one the walls are up and can see the position of the roof at the front.

The new SVP will be further forward, corresponding with the far corner of the bathroom (past where the bath waste runs out). Might keep the original run in use to run the washing machine and dryer through now as it goes through where the utility is going to be

 

[Hugh Jaleak]

Thanks for the clarification. No wish/ability to box existing soil pipe in internally?

If you do need a new soil pipe run, could you drop into the floor immediately behind the WC and come out through the wall slightly lower than the existing position, run inside the new roofspace area and out at the lower level. Run bath and basin waste across to new SVP position, common basin waste in if preferred, (fit anti vac trap on basin).

 

[bmb4cjt]

I'm happy to box the pipework in internally and think that's gonna be best option, running the bath/sink into the svp in the current position leaves them horizontally passing through roof and think it's asking for leaks.

Would you have the soil pipe run past the area where the bath waste comes out and 90 through wall to pipe and have the bath waste run alongside and join svp lower down outside? Just trying to figure how to divert the bath waste as don't think join to horizonal soil pipe is a wise idea

 

[Hugh Jaleak]

Wastes are a lot easier to route internally than 4" soil pipe. If you're now leaving the soil pipe where it is, (albeit boxed in), then rerun the wastes internally, come through the wall at a suitable point and join the stack in the roofspace. Unfortunately the joist run the wrong way to allow you to lose it under the floor.

 

[bmb4cjt]

Sorry for confusion meant I was happy to box in the soil pipe across the wall in the bathroom tbh.

It'll run where the black mark is on the image above. Think although it'll be a bigger box internally it'll lead to less hassle long term. Just puzzling how to join the bath waste but think it'll have to be some bending around and down past the soil to join the SVP outside. The sink waste can just be twisted back on itself on the outside and join the stack as it's higher than the roof pitch will be.