Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by Shannon » Tue Oct 23, 2018 2:13 pm

Yes insulate well around pipe and use tape to seal poly to pipe. It will stick well to that.
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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by kurt333 » Tue Oct 23, 2018 2:29 pm

Thanks.
Did you mean insulate well around pipe above the poly layer in attic so its touching the pipe?
Or did you mean to insulate the surrounding areas around near the pipe in attic but not touching the pipe?

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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by Shannon » Tue Oct 23, 2018 4:55 pm

Insulated right to the pipe above the ceiling. If you don't you for sure will have drafts, condensation and heat lose in that area
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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by kurt333 » Tue Oct 23, 2018 11:09 pm

Ok, will do, it will be tricky, as it is cutout from the wall, the vent pipe got up through the wall and so no plate above it.
So I forsure should use water proof drywall through the whole bathroom? To be safe.
What was your opinion of the wood panels again?
Did you say the moisture can penetrate it to the back side of the panels?

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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by A. Spruce » Wed Oct 24, 2018 12:01 am

Shannon will be out of the office for the next few days. Please review the questions and answers, you will likely see something that you've missed along the way. 8-)
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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by Shannon » Wed Oct 24, 2018 8:39 am

I'm still hanging out off and on while I'm away.
Do your best to cut insulation and fit it up in there ,then attach some poly or 1x boards to hold it up back in the wall cavity.

I would use moisture resistant drywall in the entire bathroom if it were me ,but as I said earlier you could use paneling or maybe even cedar or pine if you want that look. Stay away from MDF type wood paneling as it will give trouble over time likely with the high humidity conditions of a bathroom.
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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by kurt333 » Wed Oct 24, 2018 2:36 pm

Ok, I will seal it off, maybe can show you pictures of it. I may have to seal right to the actual drywall on the other side or build a little thing to seal too.
Im still a bit unsure of how paneling would turn out, HD sells a nice wood panel, real wood now, new product. But maybe would have to coat it alot to get the white paint to cover?
We know drywall looks good and can work with it?
I dont care about how long it takes and stuff.
And I would not use MDF, that fake board stuff. That doest seem a good idea.

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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by Shannon » Wed Oct 24, 2018 5:12 pm

Just seal it as best you can so it stays in place
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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by kurt333 » Wed Oct 24, 2018 8:53 pm

On it right now. Gonna stuff insulation up there, so no air spaces. And then poly it, and acoustical sealant soon.
Took back regular drywall and got 6 sheets of mold resistant drywall. I wonder how it will work out with cutting all the extra little cuts and stuff. Is that ok practice to join a lot of pieces together, or keep them as big as possible?

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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by Shannon » Thu Oct 25, 2018 3:05 am

As big as possible, nothing worse then doing more taping and mudding then you need to. Stagger joints a couple of stud spaces when possible so they do not line up at bottom and top rows on same
Wall.
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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by kurt333 » Thu Oct 25, 2018 8:00 pm

Thanks, sounds good.
Hey so I am sealing up around the vent pipe, the poly layer, and gonna maybe use acoustic cauld and tape, blue tape or red tuck tape.
Are you sure the insulation above the vent pipe stuffed up against it in the attic should be touching it and it wont get wet? Just having the poly open a bit over night and not taped off around the pipe, it felt a bit wet up there. Is that just because I have not taped it off. Bit worried about it, from all the wetness before. that i had stuffed up there. But maybe this is just because I did not seal it off to attic space. I stuffed alot of insulation up around the pipe in attic space.

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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by Shannon » Sat Oct 27, 2018 3:35 am

Blue tape for vapour barrier if you have it.

This is a tough time of the year if you live where the weather is cooling down. The warm moist air and sewer vents of your home will sweat some because of the temp difference because you don’t have insulation in those areas right now. Get it closed up and insulated and drywalled ASAP.
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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by kurt333 » Mon Oct 29, 2018 2:07 pm

Thanks. It was tricky to tape around the vent pipe, where it will go up to the attic. Here is pics.
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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by Shannon » Mon Oct 29, 2018 2:23 pm

Yup it’s fun to seal around pipes but looks like you got it!
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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by kurt333 » Thu Nov 01, 2018 12:26 pm

I seem to have water getting on other side of poly and insulation, to the right of fan you can see it?
I wonder why?
I Notice this cheaper brand (hampton bay, their in house brand 70cfm) fan from hd drips quite a bit. It seems to exhaust the moisture faster than the Nutone fan, but Nutone fan did not drip at all, but just had a slightly lower cfm rating.
Maybe i should put my Nutone 50 cfm back in..
I bought both new. Its a tiny bathroom under 50 sq ft, and these fans are rated for that, they are 3"
Or do u think i could upgrade to 4"?
Bit worried about putting drywall over this if i have moisture dripping down onto poly. I dont think its dripping on outside of fan housing, it was all dry. I think its coming from inside fan blade part and being spun over to that corner inside and getting past tape. Or somehow its getting past the tape, its getting so wet, it must be dripping past the red tape.. I dont know.
Maybe put my other one in and keep an eye on it.
Is there any point in me sealing all the joints with foil tape on fan housing. I thought the guy at hd told me to, or maybe he just meant the plastic outlet part. and joints where clamp goes...
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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by Shannon » Fri Nov 02, 2018 12:33 am

I really can’t tell in that picture where the moisture is but seal up the housing as bestbuou can and be sure you are using insulated ducting as well and that it is sealed to housing. You really can’t go wrong with a fan rated larger then the bathroom size either. Another important factor is being sure there is a round 3/4” of space under the door to allow for good make up air flow.

We have another bathroom fan thread going on right now that has more info as well that youshould read. viewtopic.php?t=7460
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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by kurt333 » Fri Nov 02, 2018 1:09 am

Thanks.
The water leak is on the right side of the fan housing, to the right of the word tuck on the tape on the pink insulation you can see it is darker with water. Anyhow its wet and I took it apart. I dont see how it could be getting wet, as I sealed the .... out of the fan housing, all joints and holes everything. As you can see. So out that fan goes, and I put the nutone one back in, as I know it did not drip water or nothing. That hampton one must not be exhausting all the water in the housing and its getting hung up in there pooling. I can see it dripping quite a bit.
The ducting is the aluminum type, 3 inch dryer maybe, crinkle, its solid, and bought it new. I ran insulation beside it ontop of it, and small piece under it, as it will be close to the drywall.
I have 3/4 inch gap under the door for sure, all good, I can feel it drawing in air with that other fan.
And this nutone i just put in, i even took it apart, top motor housing off and sealed with foil tape all joints and seams where water could escape or air. Totally over kill probably, but yea, maybe it will help.
I kind of have to run this 3 inch ducting out to outside, as I cant fit 4 inch through over the top plate of wall etc. So if I do upgrade the fan to 4 inch, I would have to buy and adapter to go down to 3 inch. I like your recomendation to go to larger fan. But think its worth it in my case, with adaptor on it down to 3".

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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by kurt333 » Fri Nov 02, 2018 11:57 am

What do you think about a humidity sensing fan? Or humidity sensor installed separately. Is it a big deal to install the sensor on the wall? My fan switch is on the outside of my bathroom on the wall and light too.
Or is there fans that have the sensor built it? Or are they gimicky or not reliable?

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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by Shannon » Fri Nov 02, 2018 1:34 pm

I’m not a fan of the humidity sensor fans I always install timer switches on my fans. Set it so it will run for at least 10 min longer then your shower and you should be good.

The reduced venting size will down grade the CFMs on a larger fan some so it may not be that beneficial to upsize if you don’t wanna change venting.Take note of what I said in other thread about slopeing horizontal vents or using a trap in vertical vents
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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by kurt333 » Mon Nov 05, 2018 8:15 pm

Hey thanks. Yea I read that other post. Mine just runs a couple feet horizontal right above the ceiling and over top plate and down through soffit.
I put this 50 cfm fan back in, no drips at all, it does take over and hour to vent the bathroom so the ceiling poly is dry to the touch otherwise i can feel some moisture on the poly if run it less.
I may just upgrade the fan to the 70 cfm in the exact same model in nutone, apparently the motor fits right into the housing.

And I like your suggestion of using a timer switch, the guys at hd, said the same, seems the way to go. Thanks, next i will get the long awaited drywall job..., if all looks good with fan venting.

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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by kurt333 » Tue Nov 06, 2018 10:00 pm

Should the poly be dry to the touch in less than and hour, say half hour or so?
Maybe that means I need a more powerful fan?

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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by Shannon » Wed Nov 07, 2018 1:59 am

Well first off the poly surface will likely have more condensation then an actual drywall surface . Once the drywall is on you will likely have less condensation to start with as the surface will be slightly warmer.

How much condensation can be different based on many factors. The top two IMO would be length of shower and temp. of water. These two will determine the amount of steam / humidity in the air . That’s why i say to go with bigger fan then just the recommended size based of sq.’ of room.
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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by kurt333 » Wed Nov 21, 2018 5:22 pm

Thanks.
I did up the vent fan to the 70 cfm nutone, seems good.
Now when I screw the drywall to the ceiling, can I screw it right to the rafters that are on 16"?
Theres no need to use strapping is there? in such a small bathroom.
I just have been watching a number of youtube videos on how the drywall, and guy doing basement used strapping, but then he had ventilation and things, so maybe that is what decided that.
Also, when I fill in all the gaps on first coat, before taping, do I use a coat of quick set, sheet rock 45 mud? This is what he seems to recommend but his video is not super clear.
It has a hardener in it and sets up in 30 mins apparently.
So try and avoid butt joints? Where I can. But dont cut another sheet specially to avoid it? I guess there is not rule, and maybe many different ways of getting the job done.
Thanks

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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by Shannon » Wed Nov 21, 2018 6:37 pm

Screwing right to the rafters/trusses is fine.
You can pre fill gaps with 45 if you want. It will get you to taping quicker.Some people will use 45 for taping as well but I don't. Guess I just have never tried it for that. Only mix what you can put in place in about 15 mins or it will set to quickly to work with.
Butt joints are just a little more work to make them look great ,I avoid butt joints when possible.
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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by kurt333 » Wed Nov 21, 2018 9:37 pm

I guess with my small bathroom, small scale job, I maybe dont need to buy drywall in the bags?
I just need a small bucket to do all the jobs?
I think i will just do what you do, what works. So just use a smaller pail premixed. I dont have a mixer but have big drill that could mix it.

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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by A. Spruce » Thu Nov 22, 2018 12:14 am

kurt333 wrote:
Wed Nov 21, 2018 9:37 pm
I dont have a mixer but have big drill that could mix it.
A paint mixer will do the trick, and it's cheap enough.
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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by Shannon » Thu Nov 22, 2018 7:21 am

Yup just buy A pail of all purpose drywall mud and mix according to the application you are doing. You will need the mud for taping to be sloppier then for coating. The mixer will work or if you buy a larger one you will find uses for it or sell it later.
this is the one I prefer: https://www.amazon.ca/Goldblatt-G15303- ... wall+mixer
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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by A. Spruce » Thu Nov 22, 2018 11:14 am

Shannon wrote:
Thu Nov 22, 2018 7:21 am
this is the one I prefer: https://www.amazon.ca/Goldblatt-G15303- ... wall+mixer
That's definitely the better choice, but it's not as useful to those who don't do drywall or need to mix heavy materials on a regular basis, hence why I suggested the paint wand instead.

Mud can also be thinned and creamed by the pan full with a drywall knife, should one not want to buy a mixing wand at all.
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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by kurt333 » Fri Nov 23, 2018 4:44 pm

Thanks guys. I will just use small pails of drywall and mix a bit of water in by hand, for such a small scale project, i think this makes sense. But both those mixers look good too. Probably would go with the smaller mixer if I did, so I could do paint containers too maybe.
Is adhesive needed behind drywall board on walls or ceiling?
I see other guys in videos using it. But then again, I did not see poly behind there drywall boards. And I have poly vapor barrier on outside walls and ceiling.
Thanks for the great videos on drywall, simple and easy to follow.

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Re: Main Vent Stack ABS Pipe Sweating Moisture Buildup-Insulate?

Post by Shannon » Fri Nov 23, 2018 5:06 pm

adhesive is not needed and it would not work over the poly anyways.

Mix some water into mud you place in your pan as you work, that will be easier then mixing by hand into your small pails.
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