The correct way to exit the property with 110mm waste?

[Rlove90]

Hi all,

 

First post, so please let me know if I'm missing any key information. I'm far from any sort of expert, but a fairly adept DIYer. 

 

I've recently started a full renovation of my bathroom. The floors are up and we've had a lot of rain recently. I noticed the sub floor / foundation was very wet. It dried out quickly and none of the pipework in the bathroom is leaking, but I can now see where this issue has occurred before, with water marks on some of the debris under the floors. I believe the house is on a raft foundation with a treatment system for waste water (no mains sewer). Built in about 1930, but modern waste system from around 2017. 

 

I found that the waste pipe has been exited through the wall (and part of the foundation (see picture 1). It looks very muddy, but I assure you, there is concrete below the elbow on the pipe. The hole in the wall has then been filled with fiberglass insulation. This cannot be the correct way to do it! But need to know how to fix the issue and get it done correctly to prevent the water ingress. 

 

 

 

Further, on the outside of the property, the concrete slab driveway is built 250mm or so higher than the foundation of the house. There is a join between two slabs where water could pass and I think this is where the water is coming in after heavy rain. (see diagram). 

 

The Green rectangle is the external wall, Purple line is outside ground level. Blue arrows are my guess at the path of the water into the bathroom. 

 

My initial thought is to bring the waste pipe up above ground on the outside the house and then run the wastes for the toilet, bath and sink through the wall, keeping all waste plumbing in the house, well above ground.

 

However, I have a shower waste on the other side of the room, and I'm not sure if I will get the fall I require and still be able to bring the shower waste to the outside and keep it above the outside ground level. (See picture 2). The distance between the underside of the joists in the room, and the ground level outside is 150mm at best!  - I'm sort of hoping that, because shower wastes shouldn't be carrying solids, the fall is less critical? but happy to be corrected. 

 

If the above ground outside idea is a no-go, then is there a correct way to amend what I have to; A. make it compliant/correct/not bodge it?? and B. stop the water ingress??

 

Many thanks in advance. 

 

R

 

 

[markc]

If the water is coming in through the wall penetration you really need to dig out on outside to get access around the pipe, clear out all the mud and insulation then seal up around the pipe to prevent water getting into the wall

Edited February 20 by markc

[Conor]

Change the 90⁰ bend for a long radius rest bend.

[Rlove90]

40 minutes ago, markc said:

If the water is coming in through the wall penetration you really need to dig out on outside to get access around the pipe, clear out all the mud and insulation then seal up around the pipe to prevent water getting into the wall

 Thanks for the reply. And yes, agreed.

 

Before I dig a big hole... What is the correct way to seal around the pipe? Is there a product? or just concrete (a certain mix)?

 

Do I risk doing the work and the water pushing through the join between the existing structures and the new concrete? and is there any way to help mitigate that risk? 

 

8 minutes ago, Conor said:

Change the 90⁰ bend for a long radius rest bend.

Ok, thank you - To aid with flow and rodding I suppose? 

[markc]

@Rlove90 dig the hole and clean around the pipe and inside the wall opening, brush/rinse away any mud and dust. Assuming the hole isn’t huge, a can of foam will fill the voids and seal against the wall and pipe. Will be interesting to see what the ground is like and if drainage can be improved to take water away from the wall - ground level above inside floor level is often problematic

[Rlove90]

Thanks MarkC - Much appreciated. 

 

I'll get cracking next week and post any interesting updates.

 

Thanks