Why are soil pipes run internally?

[flanagaj]

I am trying to understand why soil pipes are run internally these days.   When I renovated a property in 2006, I ran the pipes externally and never had any problems.  Plus, I didn't have any boxing in to do internally.   So is there a reason why this is done, or is it simply for aesthetics?

[Big Jimbo]

In my last house i had 4 internal vertical soil pipes. I was being posh, and didn't want them outside spoiling the look of my stunning render.  On the new house i will probably have 4, but this time outside, although to the sides of the house. I wouldn't want One on the front elevation.

[flanagaj]

4 minutes ago, Big Jimbo said:

In my last house i had 4 internal vertical soil pipes. I was being posh, and didn't want them outside spoiling the look of my stunning render.  On the new house i will probably have 4, but this time outside, although to the sides of the house. I wouldn't want One on the front elevation.

Ok, so it is more for aesthetic reasons?

The bathrooms on the property are all on the side of the property and won't really be visible.   

[bassanclan]

Visually it looks better and you don't want to spend time and money making an air tight insulated house then put loads of holes for pipes in it

[Big Jimbo]

For me it was aesthetic, and wanting to be like the big posh houses i worked in. Having to have points internally to rod etc, was a right pain. If you can get them on the side where they are not really seen, i would do that.

[Dave Jones]

9 hours ago, flanagaj said:

I am trying to understand why soil pipes are run internally these days.   When I renovated a property in 2006, I ran the pipes externally and never had any problems.  Plus, I didn't have any boxing in to do internally.   So is there a reason why this is done, or is it simply for aesthetics?

 

they still are in low quality/value houses where the extra time and expense aren't worth it.

 

bit like sticking go faster stipes on a 911 porker.

[SteamyTea]

On one my houses had a external soil pipe.

It froze up one winter.

[flanagaj]

5 hours ago, SteamyTea said:

On one my houses had a external soil pipe.

It froze up one winter.

I think that is very rare

[joe90]

Cold bridge and aesthetics, I think they spoil the loook of a house. My pet hate is kitchen pipes running at an angle down an outside wall to a drain.🤯

[AliG]

They look awful. Don't do it.

 

However, builders should put more effort into putting sound insulation around them.

[ToughButterCup]

16 hours ago, flanagaj said:

... So is there a reason why this is done, or is it simply for aesthetics?

 

Why? Because I was told to. Why ? Keeps the tigers away. And it looks pretty (ier). 

[ash_scotland88]

It appears gone are the days of running them outside to show off your fancy indoor plumbing and drainage system!...

[Timedout]

Inside, so much a better look. 
a couple of years ago I was talking to a lady who had moved to the U.K. from a Central European country. She told me that they laugh out loud at our drainage and soil pipes being slung outside. Where she comes from it gets to -30 and they would all freeze for the winter.  She had even sent photos to her father back home to prove we really did it. 
 

Think about all those frozen condensate pipes we had here in 2009 and 2010 winters. The drainage pipes froze in our utility room those winters too. I had to put a heater (60W incandescent bulb) under the internal bits to keep the traps from freezing. It was a horrible rental. 

[George]

- Prevents freezing

- Looks better

- Fewer wall penetrations (best will in the world bricks don't seal perfectly to a circle)

- Less susceptible to damage and corrosion 

- Allows for toilets to be placed anywhere in the building / avoids long horizontal runs internally

 

No reason not to

[flanagaj]

Consensus does seem to be that you should run them internally.

[TonyT]

Do you run your rain water

pipes internally too?

Edited September 7, 2023 by TonyT

[Alan Ambrose]

I get the conventional logic of rain water pipes on the outside for single dwellings.

 

But, it occurred to me recently that pretty much all commercial buildings and blocks of flats etc have the rain water pipes on the inside.

 

So, there's really no reason that internal pipes can't work great. Sure, iron pipes rather than cheap plastic, but yes, that works.

[Dave Jones]

7 hours ago, Alan Ambrose said:

I get the conventional logic of rain water pipes on the outside for single dwellings.

 

But, it occurred to me recently that pretty much all commercial buildings and blocks of flats etc have the rain water pipes on the inside.

 

So, there's really no reason that internal pipes can't work great. Sure, iron pipes rather than cheap plastic, but yes, that works.

 

if they can be routed outside of the thermal envelope of the building but you dont want them breaching it and acting as a giant cold radiator leeching the expensive heat out of the building.

[saveasteading]

13 hours ago, Alan Ambrose said:

pretty much all commercial buildings and blocks of flats etc have the rain water pipes on the inside.

Errrm....no.

I built about 250 such. The only ones with internal drains were where the client had an architect who insisted. 

 

They add a large element of leak risk at the gutters and downpipes. What warehouse or factory owner wants that?

And the gutters might freeze.

Plus there is the sound. Offices and leisure buildings don't want  that, or leaks.

[Crofter]

I'm a bit surprised about the freezing comments.

The only place where there should be standing water is in the traps, and surely they are all inside the building?

[saveasteading]

Gutters freeze  and can block the outlets. Then it rains and water runs to the nearest escape, which I like to be overflowing to ground.

Edited September 8, 2023 by saveasteading

[Crofter]

Btw, talking about soil pipes, when I was building the cottage I learned that the 110mm standard stack is mandated for anything from a single WC up to four bathrooms.

I found it hard to imagine that a single toilet could generate so much of a vacuum that it needed a 110mm vent.

So I didn't fit one. I wasn't bound by building regs and this was one of the only places where I deviated deliberately.

I used a 50mm pipe instead, which meant I could run it hidden behind the larch cladding.

Five years on and it's working perfectly.

[saveasteading]

13 minutes ago, Crofter said:

working perfectly

Good.

But the airflow through that will be much faster than in 110mm. Water and air are fluids so it depends on layout, bends and so on.

A smaller pipe with bends may not allow enough air in, and restrict the drainage flow.

Hence 110mm avoids the need for calculations and proofs.

[Crofter]

15 minutes ago, saveasteading said:

Good.

But the airflow through that will be much faster than in 110mm. Water and air are fluids so it depends on layout, bends and so on.

A smaller pipe with bends may not allow enough air in, and restrict the drainage flow.

Hence 110mm avoids the need for calculations and proofs.

Yes I'm not recommending it as a solution to other people. And I was a bit wary of it to start with. The backup option would have been an AAV on the rodding eye, but that seemed like extra complication. I was really loathe to install a big clunky soil stack on a fairly visible elevation.

[Alan Ambrose]

@saveasteading

 

>>> pretty much all commercial buildings and blocks of flats etc have the rain water pipes on the inside.

>>> Errrm....no.

 

I guess I was thinking of office commercial buildings rather than industrial:

 

https://www.google.com/search?sca_esv=563740992&rlz=1C1CHBF_en-GBGB689GB689&q=office+building&tbm=isch&source=lnms

 

https://www.google.com/search?sca_esv=563740992&rlz=1C1CHBF_en-GBGB689GB689&q=apartment+building&tbm=isch&source=lnms

 

Maybe there's some height where external doesn't work for some reason.