Roll Insulation Question

[RWebb]

I want to use it above an unheated (or rarely heated) lower floor room. The room above is heated space.

The lower room is a guest bedroom and storage area for wine.

I plan to put up a sheet rock ceiling the lower room when I'm done.

Now, which way should I face the kraft paper (vapor barrier on the roll)? Should it face down like is usually done, or do I face it up which would put it towards the more heated space?


2nd Question: The lower room is on a corner of the house and so is exposed to heat loss. I already used a can of spray foam to seal all crack, crevices, etc. at the top of the walls where they are exposed.

Is there anything else I can do to make it better insulated than just putting up the roll insulation, then the sheet rock?

[TimT]

Vapor barrier toward living space.

In this case the living space that will be used more.

[RWebb]

my thought was that the floor and subfloor (plywood) would act as a vapor barrier (?)

[GWN7]

Look at spray foam insulation. It has a higher insulation value than fiberglass. Acts as it's own vapour barrier. The closed cell type doesn't absorb water like fiberglass. Seals the smallest cracks. Only down side is it's not DIY.

[RWebb]

thx but this has to be DIY (and using cheap materials)

[MysticLlama]

I really like the recycled industrial cotton batts. They are slightly more effective than fiberglass for heat transfer, quite a bit more effective for blocking sound.

Easier to get than rockwool, which is also a good alternative.

Another bonus is that it's not all nasty and itchy.

This is what I used a package of:
Bonded Logic UltraTouch Recycled Cotton Insulation > Green Products, Green Building Materials | Green Depot

They have a warehouse in Portland where you could pick it up.
Green Building Materials in Portland, OR Green Depot

Will cost a touch more, but shouldn't be outlandish for the amount you're looking at.

[trekkor]

have you already bought the rolls?



KT

[masraum]

I put roll insulation in my attic this past spring. It's definitely helped this year.

I got mine at Lowes. It's Johns Manville Comforttherm. It was cheap and is completely encased in a thin plastic membrane except at each end where it was cut. It makes putting the stuff in much easier and more pleasant since there's less exposed fiberglass, and it makes your main question moot.

[MysticLlama]

Originally Posted by trekkor

have you already bought the rolls?



KT

Good question most of us missed on our tangents.

[RWebb]

I had one old roll and used it - I'll need a few more. BTW, PDX is a 5 hour roundtrip.

I can get the FG batts or rolls for "free" at the Home Despot here (I turn my credit card points into HD gift cards, and put everything I can, even lip balm on the my credit card now...).

no cotton batts at HD...

[MysticLlama]

Ah, fiberglass it is then.

Since it's interior space, and the vapor barrier isn't an urgent thing, I'd put the faces down for ease of installation, or go for those cool enclosed ones.

For both a little extra insulation and sound deadening, you can use 5/8"s drywall when you get that far and seal up the edges.

If you look up airtight drywall, there will be some good tips for sealing corners and such a bit better than just typical taping.

[Burnin' oil]

I finished a basement and installed the insulation with the kraft paper down. I don't know what possible difference it could make. Of course, I usually do things incorrectly so factor that into your decision making.

[wreckersteve]

The paper is a vapor barrier. It should be put towards the heated side. This keep the moisture from evaporating and geting in the insulation, causing possiable mold. By putting the vapor barrier in the cold side, you now trap the moisture good. The best woud be to use the type with out the tar paper and use a breathable product to hold it in place. Sort of like house wrap. Lets moisture espcape but not in.

[wreckersteve]

Insulating Unconditioned Crawlspaces - Residential Insulation - Owens Corning

[MysticLlama]

Yeah, that's the correct way with a vapor barrier.

I may have been thinking about it wrong though, my unheated lower bedroom and wine storage area are always about 60 degrees either way, so they aren't really crawlspace grade cold, so it wouldn't make that much of a diff.

This case might be different though, so good point.

[Instrument 41]

As far as spray foam insulation..there is a DIY kit that you can buy . Its about $600 to cover about 1000 sg ft.

[RWebb]

Thx, but I am trying to do this for zero $$.


Here is a pic of the ceiling after I flipped the insulation so the kraft paper was up:






There is 10" of depth in the cells formed by those joists, and this insulation only fills about half of it -- I'm thinking I may just put a double thickness in there, and then buy or "gift card" thicker batts for the rest of the cells.

The expansion spray foam can be seen over on the side, tho the 1st cell (bay?) has spray foam all over the edge.

[MysticLlama]

If you don't do full thickness (10" is a lot), then cut another bit for placement at the header.

But full depth would sure work well.

[wreckersteve]

Also remember not to stuff it in. You want to cut it big enough that it just stays. When compressed, it will loose some of the R value. But looks good.