PVC Waste Vent Pipes

[T-ProGuy]

As I mentioned in my post about PEX tubing, I am finishing my basement and putting in a second bathroom. We had the builder rough-in the bathroom a few years ago when we bought the house, but now are running into a situation that poses a question.

Currently, the waste vent pipes are hanging about 5" below the floor joists, which means we will have to furr the ceiling in the bathroom down below the pipes, unless they can be moved. Do any of you know if we can safely cut 2 1/2 to 3" holes in our 12" floor joists to run the pipes through, or I am going to have to build the ceiling lower?

I have tried to contact the inspector several times but have yet to get a response...I am hoping that some of you very knowledgable people here can help!

Thanks!

[Shack]

How much of a span does the truss cover? I think if you cut a hole in truss (not a U), you should be safe. How many truss's do you have to go threw? I have seen old houses that the plumers hacked huge section's out of truss for cornering 4" black pvc and the floor has never buckled. I think a little reinforcment would take care of your concern.

Try a couple of steel struts, with 2x4 over and under passes on both side of truss (about 3' length's). Good luck.

[sparcebag]

Thats why carpenters call plumbers hacks,you can drill circular holes in the joists however theres a code that keeps the holes within a certain distance from a bearing wall,It depends on hole size.And its to save the structural integrity of the joist!Better get the inspector involved,If you dont want inspection post again.

[minneman]

consider the pipe is where it is for the flow of water to keep moving down hill.

[T-ProGuy]

The joists span the entire width of the basement, (maybe 30') but there is a load bearing wall less than 6' away. I would definitely be looking to cut a hole just big enough to put the pipe through...no "u's" would be cut. I would only have to cut through two, maybe three joists to move the pipe completely out of the way.

[Shack]

If tube is a vent pipe, you can bend at a 90 deg. with out worry of flow specs. I think?

[sparcebag]

T-Pro I'm not positive,I was a Carpenter for over 25yrs and a building inspector lisenced in Mn. & California.I'm retired.You have a older house and made it sound like the attic was 20' span now the basement is 30' span,you are the guy who was thinking 9' wall opening.first I would assume your floor joists are undersized.But acode does allow holes in the bottom 1/3d of a joist just for your purpose, the bottom of that hole has to leave 2" of joist.and I beleive it must be within 6' of bearing.If you want no inspection,I'd suggest ply gussets each side of each joist.nail there edges so no nails are drilled through,drill and nail off ply gussets.I'm guessing you have 2x8 joists thats gettin small 2x10 I'd say go for it.but either way do the gussets! 1/2" ply nailed 2"OC I went back and read you have 2x12 joists GO FOR IT! leave 2&1/2" of joist bottom.GOOD LUCK

[Shack]

sparcebeg,

Way to help out. Good advice. Your a true F.Mer. I would saw the 1/2" ply. would be better that a 2x4. I did notice a 2x4 had broke in one of my span trusses during construction and bulider put a 6"x3' 1/2" ply. gusset (could not rember term last nigh. Thanks) on one side and it pass final inspection.

[T-ProGuy]

Sparcebag,

I am a different guy than the one asking about opening up a wall. I have a newer townhouse, less than 6 years old and am finishing off the basement. The joists are 12" and appear to be OSB sandwiched between some sort of laminate. They are very sturdy and nearly impossible to drive a screw into. I thought about supporting with plywood in the area around the holes, just to make sure. I am on day four of waiting to hear back from the city building inspector for a definitive answer...

Thanks for the info.

[sparcebag]

Prefab I joists; some have pre partial cut circular holes in them.But for code on those,circular holes are even more acceptable.and only have to be placed in the OSB.You should have no problems.Also you could go to Menards and get a pamphlet for I joists it will explain your choices,dont worry about brand name there all pretty generic.

[T-ProGuy]

Finally got everything figured out...

I was just about ready to start working on cutting the holes and moving the pipes when the instector showed up at my house to take a look at what I was doing. He said there really shouldn't be any problem cutting a 3" hole to run the pipes through, but did suggest that I get some 3/4" plywood to reinforce the area of the hole just to be safe. Needless to say, I quickly got to work, got the pipes moved and can now look forward to a much easier job of building the new bathroom. Thanks for all the advice...it seems that most of it was right on track!