Folks, I was about to insulate a wall cavity in my basement finishing project when I forgot to do something critical. My basement has 8’9″ load-bearing walls in it, and there are a couple of them that run parallel to the first floor’s joists and use a 12″ high knee wall.
Well, in one of these walls (load-bear 2×6 wall topped with a 2×4 knee wall) there is a PVC vent pipe that enters into the basement, but only as far as to come through the top-plate of the knee wall. In order for me to extend this PVC vent pipe, I need to go through the knee wall’s 2×4 bottom plate, and through a double top-plate of the load bearing wall.
That’s three layers of 1.5″ of wood I need to go through in order to extend a 3″ PVC pipe. How on earth am I going to do this? This knee wall, that sits on top of a load-bearing wall, is situated between two joists. On one side of the knee wall is a staircase, and the other side only has about 6″ of room. Even using a right-angle drill would not work in this confined space.
Someone suggested I just use a reciprocate saw (sawall), but that would be my last resort as this would only be is I was going to completely severe the double top-plate of the 2×6 wall and the bottom-plate of the knee wall. And yes, this is a spec house and I now know why the plumbing sub stopped where he did.
BTW, local building code will not allow build and offset vent path around the plates as we would be walking at least 4 bends, and that’s a no-no in my county. I can provide a picture in the morning if this would help.
Replies
I'm having a hard time picturing that in my head. Ouch.
Two possibilities come to mind. Can you use a hole saw with a drill extension to get above the treads of the stairway and drill down through the plates? If so you will just have to pull the holesaw out after each 1.5" layer is penetrated and clear the waste core. Otherwise it may be time to get the chisel out. A good mortise chisel will make shorter work of it than you might think. I am sure that I could chisel it through while you were still trying to explain to me why it wouldn't work.
"Tiger Claw" Porter Cable multi-articulated recip saw sounds like it could get in there. Not cheap though, about $300. Buy it for the job and sell it to me for 1/2 when you're done!
Sounds like you are in a tough spot. If you're careful I'd seriously bet you could do a decent job with a regular recip saw. Maybe it would be easier to start it off with a jigsaw and finish up with the recip.
Another thought is one of those flexible shafts that mounts in your drill and bends around like an old oil funnel. Not sure if it up to a hole saw of that size however.
Tight spot...good luck bro. There's always chisels and patience.
Just had an after thought...could you get an angle grinder in there to hog away and decent amount of the material and finish up with a chisel? One way or the other, I'm confident it can be done.
Edited 3/11/2003 9:49:24 PM ET by dieselpig
Had to cut a 2" hole thru a bottom plate 8" above a finished ceiling. Hole saw on extension wouldn't hold. torsion would keep the set screw from holding. Drilled series of holes around the circumference and used a chisel to finish bobl Volo Non Voleo Joe's BT Forum cheat sheet
If, and this is a big "IF", I visualize the problem correctly, cut the PVC pipe out of there temporarily and drill up from the bottom (yes, I know you end up with some extra holes; but, just sister over them when you're done). If I've misread the problem with knee wall, maybe you don't even need the extension(s), or maybe you don't need to drill any extra holes; but, from the bottom seems to be the direction of choice here. Use a hole-saw (deep socket version), unless you already own a self-feeding bit, and a bit extension. I've only seen 18" Greenlee extensions in HD, but I've seen 24" and 36" extensions around.
Phill Giles
The Unionville Woodwright
Unionville, Ontario
Idle question, not meaning to side track:
Where does one find these drill extensions? And/or how are youse supposed to use them with a holesaw? I mean, the guy's gotta drill out for a 3" pipe. The only drill extensions I've seen will accept either the installer's bits, a la Greenlee, or spade bits. Biggest shank size I've seen them accept is about 1/4"; but my Milwaukee hole saw kit has a mandrel that requires a 1/2" drill. What am I missing here?
(Kartman, I have no advice for you. Sorry.)If everything seems to be going well, you've obviously overlooked something.
Milwaukie has 3 5/8" self-feed bits and extentions from 5 1/2" through 24". Preferred drill motor would be a 1/2" hole hog or equivalent but would do the trick in less time than it takes to dig out the drill and mount the bit.
Easy for me to say cause I have one. Do you know a plumber or other tradesman that would loan you the above for a few minutes? If not, drill and chisel away!
And I hate it when stuff like that happens! You have my empathy.
I was just thinking, most of the local rental places, including HD, rent the self-feed/Hole-Hog/extension set-ups; but I have no idea they cost..
Phill Giles
The Unionville Woodwright
Unionville, Ontario
A carpenter who I have had the pleasure of working around, the guy knows his stuff and is always looking for ways to help the other trades out, keeps a pneumatic chisel, the type commonly used by muffler shops to split joints, with a modified set of chisels on hand. He gets into some very tight spots and moves quite a bit of wood in short order. Its quite noisy but it works wonders.
What is going on with this forum? I've had problems all morning trying to access the forum, and then authenticating. It wouldn't take my original password so I went and got another one. It then complained that the new one wasn't true.
We;;, now I am at work. I had taken some pics to post. Tomorrow?
If I'm understanding the situation correctly, you're going to have to open up the lower 2x6 part of the wall to install the pipe anyway, so do that to start with, and drill up from the bottom.
-- J.S.
John, let me get home tonight (half-past Midnight) and I'll post a picture. The wall is unfinished, but ...
This photo shows the three layers of wood I will need to bore through.
I don't suppose you have another picture showing the next 2' below this picture ? What's the inhibitor from below ?.
Phill Giles
The Unionville Woodwright
Unionville, Ontario
Phill asked the right question: Can you get at this from below? If so, it's just a hole saw job. It also looks like the top piece is modern 1 1/2" thick material, and the next one is old fashioned full 2" lumber. Or is that a trick of perspective?
-- J.S.
They are all 1-1/2" thick. I think its a condition of lumber grade between the 2x4's and 2x6's. Some of that lumber (nail header) I added for framed soffets.
Would it be easier to just not seal this cavity and then the next time the builder's plumbing comes comes in to ask them to cut the hole for $20 under the table?
Seriously, the actual bathroom completion is the last thing that is going to occur in the basement finishing project (budgeting money wisely, and for a home with two buttholes we already have four toilets).
BTW, I've tried four times to post another picture, but the forum locks the browser. I know the image file isn't corrupt because I can view it in several programs without a hitch and its under the file size and type specified by the forum moderators. Really wierd.
Now, this forum will no longer remember my password even when I check the appropriate box at the login screen.
I'm not sure if I fully understand your situation, but if this pipe is being extended so you can vent a bathroom in the basement, could you use an air admitance valve instead. Stud-r-vent is a common name brand for this type of vent. It might save you alot of trouble. Just a thought.