Taping plastic sheeting

[Easy Livin’ 3000]

What's the best way to tape plastic sheeting together? It'll be used for an airsealing project in the attic under (over?) cellulose insulation and for a vapor barrier in the crawlspace.

 

[johneh]

We use tyvek house wrap tape .
Tyvek is a brand name any house wrap tape would work

 

[vinny11950]

I would not put plastic sheathing in the attic under/over the cellulose insulation because there is a good chance it will trap moisture, condense it in the colder climate of the attic and you will have a moldy mess. To seal the attic you have to seal the wire/duct holes at the top of the wall frames, the wall joints and any other gap/hole that allows air to move from living space to attic space. It's a pain in the you know what, but it works. You can also open up your electrical boxes and seal them them, or at least try using the plate gaskets they sell.

Not sure about the crawlspace.

 

[vinny11950]

But if you insist on using a wrap, like Johneh says, use Tyvek house wrap because it allows for moisture to pass thru. Can't guarantee it won't condense moisture.

 

[johneh]

I don't know how it is done in the US but here plastic sheeting is used
on walls and ceilings of the building envelope but all ways on the warm side
to seal air infiltration . As long as it is on the warm side there is no condensation
It is part of the Ontario building code

 

[sportbikerider78]

I don't know how it is done in the US but here plastic sheeting is used
on walls and ceilings of the building envelope but all ways on the warm side
to seal air infiltration . As long as it is on the warm side there is no condensation
It is part of the Ontario building code

Yes...typically the sheeting is put on the inside of the framing under the sheet rock. As you said, on the warm side.

 

[cd36]

Ya code in Manitoba as well on the warm side of the insulation. It really does seal up houses tight and no condensation issues as it can still breath to the outside.

You can either use tape to seal it, it's red semi translucent stuff, often called tuck tape. It isn't the best to use though but will work by code.

I think k code also allows you to overlap edges by 12" with no sealing but again wouldn't recommend it.

The best stuff to use is acoustical sealant. It comes in a tube and you use a caulking gun to apply it. It is black and horribly sticky and doesn't harden. It is what is used the majority of the time to seal the vapor barrier.

Sent from my LG-H812 using Tapatalk

 

[Easy Livin’ 3000]

Mine is a relatively unique problem, it's an old stone house, so it's essentially an 18" thick stone shell with a stick frame fully inside the shell. My main issues are the gaps between the frame and the wavy, uneven stone walls. My current plan in the attic is to build a knee wall around the perimeter, maybe 18" wide, line the bottom and sides of the knee wall with plastic sheeting, then fill with cellulose. That'll take care of the gap and still allow for use of the attic. The space between the joists is filled with blown-in fiberglass.

 

[johneh]

Build your e wall but fill it with expandable foam . Air and moisture tight
This is what we do with stone wall basements here . Makes the basements warm and dry

 

[Easy Livin’ 3000]

Build your e wall but fill it with expandable foam . Air and moisture tight
This is what we do with stone wall basements here . Makes the basements warm and dry

I considered that, and I'm sure it is the best idea, but the idea hurt$!

I'm having trouble picturing what you describe in the basements. I'm imagining a box at the intersection of the basement wall and ceiling? If I have this right, what are the dimensions of the box?

 

[johneh]

The interior of the basement is framed with 2x4 from concrete pad
(gasket between floor and wood ) to the 1st. floor joists . Closed cell
foam is then sprayed into the cavity note the framing is set 2 in away
from rubble wall so allowing for 4 in. of foam .
Yes it costs but the benefits are unreal . my basement went from 55
all year around to 70 this decreased my wood use by 50%
My home was built in 1858 and the basement walls are 3 ft. thick dry
stacked stone. We lowered the floor 2 ft and benched the walls so a
person of 6 ft. can walk down there. It is still classified as a craw space

 

[Easy Livin’ 3000]

The interior of the basement is framed with 2x4 from concrete pad
(gasket between floor and wood ) to the 1st. floor joists . Closed cell
foam is then sprayed into the cavity note the framing is set 2 in away
from rubble wall so allowing for 4 in. of foam .
Yes it costs but the benefits are unreal . my basement went from 55
all year around to 70 this decreased my wood use by 50%
My home was built in 1858 and the basement walls are 3 ft. thick dry
stacked stone. We lowered the floor 2 ft and benched the walls so a
person of 6 ft. can walk down there. It is still classified as a craw space

Got it, thanks! If I did this in my basement, there'd be about 4' of space left. It's a small house.

Foam makes an enormous amount is sense. I might spring for a few of the diy tanks for strategic areas (the big tanks, not the small Great Stuff aeresol cans) , like the sill in the addition that is stick framed where cold air pours in, and some of the worst places in the attic. If I do this, I'll pull up the floor boards so I can really get to the gaps.

 

[DickRussell]

For insulating stone foundations, here's a good read on addressing water issues: https://buildingscience.com/documents/insights/bsi-041-rubble-foundations.