Expert: Bruce E. Johnson - 11/12/2008

Question
Hi,
I have to run a stack vent vertically (3 inches abs pipe ), coming from the slab, then through one wall downstairs, then through one wall upstairs to the roof.
These walls are made with 2x4, each has one baseplate and a double top plate, both are bearing walls (space between studs 12"o.c)
The pipe is in a corner of 2 bearing walls.
Is it allowed by code to cut the base plate upstairs and  the two double top plates for this ?
How to attach the walls together after I cut them ?
Thank you very much.

Answer
Hi Regis, yes it is allowed otherwise there would be no vents in half the plumbing in the country.  Use a hole saw to make the cuts and you can buy heavy duty protection plates that screw into the wood on each side of the pipe.  These plates keep the wall secure and also prevent anyone from putting a drywall screw into the pipe. Also your trusses or rafters located on each side of the pipe and secured to the wall will keep the wall laterally stabilized so no need to worry about the wall being flimsy in this area.  I hope this information helps feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com