Soil Stack alteration

[Madrid]

I'm about to add an extension to my 1960's house. I'm putting in a complete new central heating system and refitting an existing bathroom and removing a small cloakroom in the existing house. In the extension will be a new shower and utility and kitchen. My builder suggests replacing a section of the cast iron soil pipe with a plastic soil pipe. I'm getting conflicting opinions from some of the tradesmen. I can't proceed until I make a decision on whether to keep the existing pipe or replace it with plastic. I've had one plumber in to quote on the bathroom refurb and he would like to put in an AAR.

 

[John D v2.0]

Not touching anything is ideal, but as soon as you start altering you need the tools and experience and there's always a chance of issues. Plastic is pretty easy to plug together so I can see why they would favour changing part.
In our case it was an easy choice as the old one was cracked in the dry part and the stack needed moving slightly anyway and taking through the foundations, but in a situation where it will be half and half is tricky because any joints in the system can be a risk.

 

[Nige F]

I've had one plumber in to quote on the bathroom refurb and he would like to put in an AAR.

AAV ? can you post some pics. or a drawing of what's existing and proposed. What can be left could depend on new connections.

 

[ReganAndCarter]

For me the decision would be made by looking at the condition and location of the current ci stack. If it was in good condition and could be easily replaced in the future without disturbing surrounding structures and access was good I would poss leave it. If there was any doubt, I would replace as it's a sounds like small beer in the scheme of work you are undertaking.

 

[snb]

AAV he could mean durgo or air a 32/40 air admittance valve

 

[Hot&Cold]

I'm putting in a complete new central heating system and refitting an existing bathroom and removing a small cloakroom in the existing house. In the extension will be a new shower and utility and kitchen.

leave it all to your builder,they will instruct building control when as necessary.

dont forget to get building regulation approval sign off certificates as the project progresses

yes they cost

 

[Madrid]

The soil pipe is currently exposed in the bathroom because all the plasterboard has been removed. The pipe follows the internal side of an external wall. At ground floor level it is currently imbedded in an internal wall - but it will be exposed when they knock the ground floor wall down next week. This same internal wall will remain an internal wall at floor level in the new build. This is really our only chance to change the soil pipe from cast iron to plastic. After the renovation and extension, the soil pipe will be imbedded in an internal wall - either behind plasterboard or tiles.

 

[John D v2.0]

I'd just go for it and change the lot. Admittedly ours was nearly 100 years old, so you might get a while longer out of it, but with modern materials you can just slot it together

 

[Madrid]

Thank you for all your replies - It is a lottery to replace something that may not need replacing at this particular point in time - but where the window of opportunity dictates that it may be now at a reasonable cost - or later at very great expense! I hate to spend money unnecessarily - as does everyone - and was really concerned that by hacking into a perfectly good working stack I might be setting myself up for future unnecessary problems. It's really the flip of a card I think. My builder for the current house is old school and reliable and will do a good job. My builder for the new extension is also old school - but inclined to embrace current design.

 

[John D v2.0]

If you make a decision and you never know whether it was the right decision, should it matter?

Never mind diynot, hour about philosophy

 

[Hugh Jaleak]

If replacing cast with plastic, I'd replace all above the section you need to replace. Cast is extremely heavy, and relies somewhat on the pipework below for support, as well as the wall fixings. For what plastic costs, £100 in the grand scheme of things for a new stack is pretty small.

If existing stack is vented to atmosphere, then do not cap the new stack off with an AAV. Ventilation is required for the drains to breathe, effectively sealing off an existing vent with an AAV can create more problems than it solves.

 

[Madrid]

Work being done this weekend - I am most appreciative of all your combined knowledge. If you didn't post this information here, I wouldn't know. I expect my guys will do what they call a 'proper' job. But there are lots of jobs ahead in this new extension and I need to be more knowledgeable.

 

[John D v2.0]

When our extension started I didn't have a clue about anything. By the time it finished I knew more than I expected.
Perhaps by that time it was too late, but I think it's normal!
Just pick your topics and don't get too stressed! Good luck and you know where we are, good advice or not

 

[Nige F]

I'd just go for it and change the lot. Admittedly ours was nearly 100 years old, so you might get a while longer out of it, but with modern materials you can just slot it together

Agree with John, you never know what might be altered in future - particularly in the bathroom, upstairs

 

[HERTS P&D]

Also make sure you have access points to clear the stack of any blockages in the future.

https://www.toolstation.com/shop/p7...MIluqD_O-52QIVTrHtCh19tA5UEAQYAyABEgJ3Z_D_BwE

Andy