Internal or External Waste water pipes?

The_Bullman

I've been looking around but couldn't find an answer for this.


In a 2 storey house, is it better to have waste pipes inside the building down through the ground floor slab or out through the walls?

North West

The Bullman
Upstairs they are normally out through the wall. Downstairs kitchen sink out through wall / whb are down through slab as they are not usually on outside
wall.
NW

DOCARCH

internal pipes are better from an aesthetic point of view (i.e. you don't see pipes on the outside). From a technical point of view it does not make too much difference other than it may be easier to make house airtight if pipework is internal...but...on the other hand pipework/junctions can be more in accessible if something goes wrong.

Drift

Aesthetically they aren't great outside but my opinion is that the waste pipes should be brought outside as quickly as possible to allow for future repair work and to lessen any damage that might occur from leaks etc. It's also easier to rod/clean drains that don't have turns inside the sub-floor / foundation.

It's possible to appropriately vent soil points with both methods but I have found that the venting tends to be done more poorly when internal pipes are used. - But that's easily avoided by good detailing and supervision.

So to sum up: Both are possible. I prefer to lessen risk and take them outside but that is at the expense of aesthetics!

The_Bullman

That's grand then so.

I thought that it might be necessary to bring them within the building's envelope for airtightness or cold bridging reasons.

Through the walls it is.

Thanks all.

sky6

I've had internal pipework for nearly 40 years, never had a problem and the house looks so much better than having them on the outside. It's inside a 6 x 6 inch box in the corner of the Bathroom upstairs and Kitchen downstairs.

poor farmer

sky6 wrote: »

I've had internal pipework for nearly 40 years, never had a problem and the house looks so much better than having them on the outside. It's inside a 6 x 6 inch box in the corner of the Bathroom upstairs and Kitchen Bathroom downstairs.

Internal pipework in my current house .I haven't had any problems in
16 years and that,s with four small children.
I suppose it depends on the orientation of the house,most of the pipework ends up on the back of a house and it depends how visible this is.
I personally find external pipework unsightly.