Can I cut top plate

[Steven JP]

I need to run a 3 inch DWV pipe through the top plate in my house. I pretty much need to cut a whole 4 inch section out for this to work. It is an external wall on the gable side of my two story house. The pipe will be right next to the 2 by 4 on the right. The picture is the bottom of the second floor.

Also want to know about doing the same thing from second floor to attic.

 

[Jadziedzic]

On a load-bearing wall if the cut-out exceeds 50% of the width of the top plate, then the top plate must be reinforced with metal sized as per building code specifications, typically 16 gauge metal 1-1/2" wide extending 6 inches past the cut ends onto the remaining top plate.

 

[Sponsor]

 

[Steven JP]

Where do you think would be best place to get that metal piece?

 

[Jadziedzic]

Simpson Strong-Tie brand at a big box store; models MSTC or RPS are suitable. The generic name is "structural strap" if you are looking at other brands. A plumbing supply store would also stock the straps.

 

[Steven JP]

Simpson Strong-Tie brand at a big box store; models MSTC or RPS are suitable. The generic name is "structural strap" if you are looking at other brands. A plumbing supply store would also stock the straps.

Cut that top plate and kind of figured this might be a problem. Guessing I cant cut this joist that is on the outside wall? I plan on tieing a shower and a toilet into this vent pipe. Can I reduce it to 2 inches above where everything drains into?