Adding Attic Insulation With Poor Vapour Barrier

[PILOON]

Up here in Quebec code is to completely seal the complete house with vapor barrier. We tape all joints and many builders even go so far as caulking stud pairs.
Outside walls are laid on strips of foam so that air can not get in under the the walls.

Most are building to a year 2000 code.
A code test is to pressurize the entire house and it has to maintain a certain pressure to pass and then the contractor gets code rated to brag about.
Also only a licensed carpenter can work on a building site and contractors need to be licensed as well.
One can expect 2-3 visits on any construction site at any time.

Window holes are now using a 3" sticky membrane to get a total seal.
Naturally we now need to add an air exchange system in order to get fresh air.
Like bring in cold outside air to replace that expensive heated inside air. LOL
It is all 'code'.
We also wrap the whole outside with Tyewrap with all taped joints.
More and more contractors are foaming all the foundation insides rather than wool batts and many use 2" dense foam boards nailed in place with furring strips.
\In any case most will shoot 2" of foam in the spaces between floor joists where the joists sit on the foundation rather than stuffing with wool.

On the other hand I have done rehabs on older buildings that the entire walls were simply filled with sawdust.
I also have had to replace log cabin logs that were rotted out, now that's fun with the chain saw being your main tool. Splicing and fitting followed by staining/aging so that it is not apparent is quite the fun.
Then I once sand blasted an entire 40 x 40 ft log cabin to bring it back to like new. (That's how you find rotted logs, LOL)

Things sure change, and costs sure climb.

 

[Billrog]

Vapor barrier is important walls and ceilings the underside of roofs where there is colder climate will develop mold on the under side of the roof without it. A properly sized furnace, ducting and cold air intake deal with fresh air circulation in the home maintaining a positive pressure.

 

[wawajake]

to the original poster............please be careful taking advice from southern climates where the opposite impacts of heating and cooling have opposite needs in regards to vapour barrier ....the vapour barrier needs in colder climates like our Canada...........even differ between southern Ontario and Northern Ontario . Here is a good website that has various advice in regard to insulation, air barriers and yes and vapour barriers. This link opens on basements (because that was what I was researching) but has tons of university articles on side drop downs on the website about all areas of our northern houses. .
Preventing mold when you insulate your basement | Green Home Guide | Ecohome

 

[Industrial Toys]

Thanks

I know, I have felt bad going into peoples attics trampling down the insulation. I try and be carefull and even try and fix it, but that seems almost futile.

I can't seem to get the blown mineral stuff I like, and don't care for the dust of cellulous. Maybe, I will just go with bats, even though I know it won't make a nice blanket.

 

[teejk]

Thanks

I know, I have felt bad going into peoples attics trampling down the insulation. I try and be carefull and even try and fix it, but that seems almost futile.

I can't seem to get the blown mineral stuff I like, and don't care for the dust of cellulous. Maybe, I will just go with bats, even though I know it won't make a nice blanket.

Maybe instead of a single batt you go with 2 layers and criss-cross them.

 

[Industrial Toys]

Not a bad idea. I am also concerned about making cosy mouse housing. At least with bats, I don't have to get and return a blower which could be 45 minutes away, one way! A good part of the day, in all.

Just thinking about it. I could probably do a good portion of the job in bats, just in the time it takes to get and return the blower.

Save the money on the blower

Get non itchy bats

Be able to do future work . . . and

Not have to build dams for the blown insulation.

Maybe the choice is obvious.

 

[teejk]

Not a bad idea. I am also concerned about making cosy mouse housing. At least with bats, I don't have to get and return a blower which could be 45 minutes away, one way! A good part of the day, in all.

Just thinking about it. I could probably do a good portion of the job in bats, just in the time it takes to get and return the blower.

Save the money on the blower

Get non itchy bats

Be able to do future work . . . and

Not have to build dams for the blown insulation.

Maybe the choice is obvious.

Not so sure you need the "non-itchy" variety, rather just get it done, take a shower and wash your clothes! When you think about it the "criss cross" method might leave a few small holes where the batts intersect but cut on the ground and put in place goes quickly....more expensive but you eliminate that settling problem and lessen the "critter" problem.

 

[topbuilder]

Thanks

I know, I have felt bad going into peoples attics trampling down the insulation. I try and be carefull and even try and fix it, but that seems almost futile.

I can't seem to get the blown mineral stuff I like, and don't care for the dust of cellulous. Maybe, I will just go with bats, even

though I know it won't make a nice blanket.

The BEST way would be to scoop out the existing, lay the R30 in the joist run and then use the left out blow in on top. Of course that is also the most labor intensive... I have never had issues with itching for more than an hour or two. A dust mask is good idea. Not the cheap ones, get the ones you can actually pull air through.

I have a house I'm starting in a couple weeks. My insulator tells me the code has changed to R38 in attics. We might be going foam though making it irrelevant.

 

[teejk]

The BEST way would be to scoop out the existing, lay the R30 in the joist run and then use the left out blow in on top. Of course that is also the most labor intensive... I have never had issues with itching for more than an hour or two. A dust mask is good idea. Not the cheap ones, get the ones you can actually pull air through.

I have a house I'm starting in a couple weeks. My insulator tells me the code has changed to R38 in attics. We might be going foam though making it irrelevant.

Around here R50 is now code on the ceilings. For some reason they don't care about walls much (other than the sill plates in the basement which I guess is now up to 2" foam) but I guess that says heat loss is not a big deal there. Been working with 2 contractors on a house my MIL bought to be closer...biggest problem has been to get them to show up (hence contractor #2) but that's a different story. One would think that we would have some "consensus" on best practices but the 2 are worlds apart...one is traditional (minimal foam), the new guy is a foam nut.

 

[sailfast]

Two words
Spray foam