Fred W. Hargis Jr

Hanging vapor barrier, any tips?

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Posted (edited)

I mentioned in another post my drywall guy isn't going to hang the plastic vapor barrier on the ceiling of my shop. That leaves it for me to do, or skip it (I don't want to skip it). I've done this once before on a much smaller and lower ceiling, and it was a pain in the butt. I stapled it up only to find in the early going the plastic would tear off the staples while I was working it into place across the span. I did get it done, but that was me only and it took all day to do a 24x20 section of the ceiling.  If I do this I'll ask the S-I-L and maybe a GS or 2 to help. I'm guessing 6 mil plastic (last time it was 4 mil) will help. What if I fasten the starting point with a furring strip holding the plastic to the trusses, then work across the span stapling it. Is there any easier way?

Edited by Fred W. Hargis Jr (see edit history)

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Fred, I don't know how you are going to insulate, but the other option is to put your vapor barrier between the joists from the top.  Either is a pain.

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Posted (edited)

Thanks Ron. I did that once before as well. Wasn't real happy with how that worked out, though I guess it's still an option. I'll blow in loose fill for the attic. I've also read there are vapor barrier paints, I guess I could let the plastic go and use that.

Edited by Fred W. Hargis Jr (see edit history)

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Posted (edited)

Paper faced insulation is an option.   House wrap could be used too and might be easier to work with than the plastic.

Edited by HandyDan (see edit history)
steamshovel and Gene Howe like this

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10 minutes ago, HandyDan said:

Paper faced insulation is an option.   House wrap could be used too and might be easier to work with than the plastic.

Certainly would be less prone to ripping off the staples. Probably cheaper, too.

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paint the back side of the sheets that you are gonna use on the ceiling...
Vapor Barrier Primer Sealer

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Is the space above your ceiling well ventilated? For example, properly sized continuous ridge and soffit vents. Are you using blown-in fiberglass insulation (no batts)? Insulation providers indicate that a vapor barrier in the ceiling is not needed in these situations. I would not install a vapor barrier in the ceiling if these conditions existed. In hanging the drywall to the ceiling, I would use glue and screws. At interior walls, where truss lift issues could exist, I would not apply glue within in two feet of interior walls. 

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Well, the drywall will be done by a contractor, so I'll let him do it as he usually does. That also means I couldn't paint the back side with the vapor barrier primer as Stick suggested, but I could do the interior side after it's up and finished. As for the attic, yes...I had a full length ridge vent installed and the soffits are perfed. I've already put in those foam baffle thingys that keep the insulation from blocking the air flow. I'll be doing the insulation myself (probably) and at the moment I'm thinking it's blown in cellulose, though I may go fiberglass before this is all over. I'm aiming for R30. But I think there may be a problem with truss movement, so the one partition wall I have is fastened to the trusses with truss clips. Dan had mentioned paper faced insulation. I had considered that and decided not to make this too complicated. My early thought was to install R13 kraft faced between the trusses just for the vapor barrier, then blow in more loose fill on top of that. I have to admit, right now the vapor barrier paint seems like the leading candidate, though if I don't need a vapor barrier at all I'd like that even better.

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Posted (edited)

That was my thoughts too,do you need a vapor barrier? the paint on option sounds great, never knew there was one.

 

I helped a friend awhile back use OSB and he painted it (Latex) on the saw horse before we installed it and saved having to have paint drip all over everything after it was installed.. Are you getting it taped and finished too?

 

Herb

Edited by Dadio (see edit history)

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3 hours ago, HandyDan said:

Paper faced insulation is an option.   House wrap could be used too and might be easier to work with than the plastic.

 House wraps let the moisture vapor go through but not liquid water.  They are not a vapor barrier.  Roly

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Herb, yeah...the installation is everything, hang and finish. I even offered him the opportunity to prime it, but it wasn't on the estimate.

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5 hours ago, Roly said:

 House wraps let the moisture vapor go through but not liquid water.  They are not a vapor barrier.  Roly

Didn't know that, Roly. Thanks. 

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Well, I've shifted through the suggestions and did a lot of looking around on the innernet. Can't say the searching was all that useful, the opinions vary so widely. No matter what I do, I'll find supporters or dis tractors. But I think I have a plan, I'll wait for the drywall to be finished and use the vapor barrier paint. Considering the wide range of options suggested, this seems to be an easy way out but still be effective.

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Interested in finding out your solution.   I was in the finish room today trying to figure out how to get plastic on the joists above.   I'm thinking some 1/4" furring strips stapled over the 6 mil plastic sheeting???

HARO50 and Fred W. Hargis Jr like this

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1 hour ago, kmealy said:

Interested in finding out your solution.   I was in the finish room today trying to figure out how to get plastic on the joists above.   I'm thinking some 1/4" furring strips stapled over the 6 mil plastic sheeting???

I don't envy you on that one, it is a real neck twister, you will be sore for days.

 

I often thought about an easy way to do that, and wondered if stapling it to the back of a 4'X4' sheet of masonite and leaving the edges an inch long and installing those like tile.  But then I always ended u fighting the sags and bags in the plastic and tearing the temporary staples trying to get it tight for the furring strips.

 

Herb

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It's going to be a pain no matter how you do it, but the 1/4" fur should hold well.

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Is the shop a building by itself.  Why do you think the shop requires a vapor barrier at all?

That I know of shops do not transmit enough water vapor to need a vapor barrier.

In fact you probably want all that vapor to escape upward and out of the roof.

If you succeed and let's say you have a shower in the shop (not likely)

So you generate a lot of vapor you may and I stress may create a mold space between the poly film and the drywall.  But it would be best to ventilate the shower thus eliminating and condensing vapor between the drywall the barrier.

If fact the drywaller is probably forcing you to do this so that when or if you have and issues with vapor build up it is your fault and he does not get called back.

 

 

 

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