lstevensuk Posted June 15, 2022 Share Posted June 15, 2022 Trying to work out if it's possible to take a foul water pipe from first floor ensuite down inside my hallway and then through the existing externall wall and under my new extension (block and beam floor)? Can I simple put a 90 degree bend at the bottom of the stack and core through? I'm trying to avoid going through extrenal wall as it would then need to come up through the middle of my roof in an awkward spot. Thanks! Link to comment Share on other sites More sharing options...
Jenki Posted June 16, 2022 Share Posted June 16, 2022 I Think you will struggle to get this tight into the corner. You really need to use a swept rest bend at the bottom of a stack, this aids both solid and liquid to exit together, with sharp 90 deg. bends you can get separation of liquid from solid, i.e. leaving the solid waste behind, ultimately resulting in blockages. Poor drawing time... but this might work, run a rest bend along the internal wall(under the floor, then put a sweeping bend to exit in to the extension under the beam and block floor. Link to comment Share on other sites More sharing options...
lstevensuk Posted June 16, 2022 Author Share Posted June 16, 2022 Thanks @Jenki that's a good idea, I've been looking for an excuse to dig up the hallway and put new floor down anywa and it would bring the pipe more central on my extension. Can I core through for the long radius bend or do I need to a bit more in depth brick removal and small lintel do you think? Link to comment Share on other sites More sharing options...
ProDave Posted June 16, 2022 Share Posted June 16, 2022 Isn't the stack pipe in the corner of the original 2 storey house so it would emerge through the original roof not the lower roof with the velux windows? I don't see why a rest bend could not go at the bottom, but the opening and lintel in the wall would have to be much higher and the bend would intrude into the floor make up of the extension so that would have to be formed around the bend. Link to comment Share on other sites More sharing options...
lstevensuk Posted June 16, 2022 Author Share Posted June 16, 2022 (edited) 5 hours ago, ProDave said: Isn't the stack pipe in the corner of the original 2 storey house so it would emerge through the original roof not the lower roof with the velux windows? I don't see why a rest bend could not go at the bottom, but the opening and lintel in the wall would have to be much higher and the bend would intrude into the floor make up of the extension so that would have to be formed around the bend. I could pass it through the external wall directly from the ensuite and then down into the extension but was trying to avoid having the pipe in my front rooom. As it is an attic truss could try and squeeze in the void but a bit tight, and then I believe I'd need to go up through the roof for the ventilation. Hence trying to keep it inside and up into the existing loft with a durgo. Edited June 16, 2022 by lstevensuk Link to comment Share on other sites More sharing options...
Temp Posted June 16, 2022 Share Posted June 16, 2022 18 hours ago, lstevensuk said: Can I simple put a 90 degree bend at the bottom of the stack and core through? I'm trying to avoid going through extrenal wall as it would then need to come up through the middle of my roof in an awkward spot. As others have said.. It needs to be a rest bend which has a larger radius.. I would make a scale drawing. I don't see why it can't go where you propose. It might just mean you need slightly taller hole in the wall. eg drill higher up and remove brick below. The dimensions of a typical rest bend (Marley) are here.. Link to comment Share on other sites More sharing options...
Mr Punter Posted June 16, 2022 Share Posted June 16, 2022 Use one like @Temp suggests. You will be best stitch drilling at an angle as you will need to take off part of about 4 courses. I would not bother with a lintel. 1 Link to comment Share on other sites More sharing options...
lstevensuk Posted June 16, 2022 Author Share Posted June 16, 2022 Brilliant thanks @Mr Punter (great scaling) and @Temp Just a bit of extra drilling and I'm sorted then. Link to comment Share on other sites More sharing options...
ProDave Posted June 16, 2022 Share Posted June 16, 2022 1 hour ago, Mr Punter said: Use one like @Temp suggests. You will be best stitch drilling at an angle as you will need to take off part of about 4 courses. I would not bother with a lintel. That is what I was trying to describe but without the luxury of doing a drawing. The lintel bridging the hole through the wall has to be higher to allow for it. I still don't understand if the stack pipe goes straight up from where it is shown in the corner of the existing hall behind the front door, how it is going to exit the lower roof with the velux windows? Surely it would just go up in the corner of the room above? Link to comment Share on other sites More sharing options...
Mr Punter Posted June 16, 2022 Share Posted June 16, 2022 50 minutes ago, ProDave said: The lintel bridging the hole through the wall has to be higher to allow for it. I would not bother with a lintel. The opening will be less than 140mm wide if it is done carefully. Fill and bed with sand cement mortar. Link to comment Share on other sites More sharing options...
PeterW Posted June 16, 2022 Share Posted June 16, 2022 21 hours ago, lstevensuk said: I'm trying to avoid going through extrenal wall as it would then need to come up through the middle of my roof in an awkward spot. why would it..? If it’s a new WC then fit a stub stack and AAV and nothing comes through the roof. Link to comment Share on other sites More sharing options...
Jenki Posted June 16, 2022 Share Posted June 16, 2022 1 hour ago, PeterW said: why would it..? If it’s a new WC then fit a stub stack and AAV and nothing comes through the roof. ++ For above. Stub stack durgo / air admittance valve. My suggestion to go parallel and a sweeping bend was due to being unsure where the beam and block in the extension was height wise . My solution only requires 5 inch. But if it fits taking a few courses out then great. Link to comment Share on other sites More sharing options...
lstevensuk Posted June 17, 2022 Author Share Posted June 17, 2022 15 hours ago, PeterW said: why would it..? If it’s a new WC then fit a stub stack and AAV and nothing comes through the roof. Sorry I'm confused where the stub stack would go, should it just be inside the bathroom? I was going to run the pipe up into the attic with durgo there. Maybe this image will help. Link to comment Share on other sites More sharing options...
ProDave Posted June 17, 2022 Share Posted June 17, 2022 Run the stack up the corner of the hall behind the front door as planned. Up into the right corner of the bathroom where it will branch off to the WC. It must continue about 1 metre higher where it terminates in an AAV. That corner bit will be boxed in, but if your drawing is accurate you have a back to wall WC so you will be boxing in a section of wall anyway to hide the cistern. This reinforces my earlier belief, if you had just carried the stack all the way to the roof it would have emerged through the original roof not the lower roof with the velux windows. Link to comment Share on other sites More sharing options...
lstevensuk Posted June 17, 2022 Author Share Posted June 17, 2022 Thanks @ProDave I understand now. I think that was just in case it was easier to run the pipe through the existing external wall first then down into the extension. But as you say much better to hide away in the hallway 😀 Link to comment Share on other sites More sharing options...
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