Jump to content

Plumbing help


Potter64
 Share

Recommended Posts

Just need a bit of help, daughter has just bought another house needs new bathroom the previous owner had boxed the soil stack 300mm deep 800mm wide enough to sit the toilet against with the sink in a recess back to wall. She wants to fit a vanity unit with matching toilet back to the wall, this is where the problem is the down stairs cloakroom is directly below the bathroom so the soil stack runs the full height of the house into the loft and up to roof ridge 

what I want to do is cut the stack above the toilet outlet upstairs  reduce the pipe diameter to say 50mm until it's in the loft then back to 110, this would mean I could make the boxing in as small as possible allowing a bit more wall to fit units I know I may have to cut the units at floor level 

so the question is would a 50mm pipe allow enough air into stack to stop it vacuuming 

Edited by Potter64
Link to comment
Share on other sites

Air admittance valve is not always the answer. The stack is not just for drawing g air in but venting too.

If possible reroute inside the rear of the vanity to a corner where you can get it into the loft. 2" 50mm pipe should be ok.

You can try a durgo and see if it works, I have had the toilet water bounce up and down in the pan as the air in the pipe had no where to vent to basically the durgo created a sealed system with no where to vent the pressure of water wanting to push the air along the pipe. Depends if your underground has a trap in it.

Edited by figgy
Link to comment
Share on other sites

The stack does go up the corner of the bathroom into the loft and to the ridge of roof the diameter of the pipe (4") just makes it a bit tight to get the units in. I just thought if I could half the pipe diameter but still allowing it to draw air and still vent I might get away with it I have found some offset reducers that I could fit leaving what's in the loft 4" and reduce it to 2" in the bathroom itself 

I can give it a go and see if it's ok I can always reinstate back to original. Good idea the anti Syphon on the sink that will help 

Link to comment
Share on other sites

10 hours ago, figgy said:

Air admittance valve is not always the answer. The stack is not just for drawing g air in but venting too.

If possible reroute inside the rear of the vanity to a corner where you can get it into the loft. 2" 50mm pipe should be ok.

You can try a durgo and see if it works, I have had the toilet water bounce up and down in the pan as the air in the pipe had no where to vent to basically the durgo created a sealed system with no where to vent the pressure of water wanting to push the air along the pipe. Depends if your underground has a trap in it.

If you do decide on the Durgo, don't forget that it needs to be accessible for maintenance as they can sometimes stick and also need permanent vent to the room in the boxing/vanity unit allowing air to enter. Just a 50mm hole or slot is sufficient.

As figgy says, probably best to go the 50mm pipe into the loft, which sounds like what you have already decided upon.

OB

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...