We have a two-story home built about 90 years ago. Of course, no insulation anywhere except in the attic and that is marginal!
We have lived here for almost 1.5 years and have already redid the kitchen, (complete gut so we added insulation), redid the living room (did not gut, just removed paneling/wall paper and smoothed out the plaster walls) redid the dining room (again, no gut job just smooth out the walls).
Our next plan is to redo some of the upstairs rooms, one at a time. First, our bedroom. I plan on tearing down the two outside walls simply because we need to insulate them. The ceiling also has some repair spots so I know it must have leaked at one time. The roof is new and there hasn't been any wet spots on anything in the attic so the leaks have been fixed.
My question: Would we benefit by adding a vapor barrier to the outside walls in each room? As we remodel each room I plan on tearing out the outside walls to insulate. Pretty much all the ceilings need to go as well because of the texturing which was probably done to fix any plaster issues when the roof was leaking. In my opinion, textured ceilings/walls is a quick fix to damaged plaster and I can not stand them! So new drywall is in order in all upstairs rooms as far as ceilings and outside walls!
To vapor barrier or not to vapor barrier, that is my question!
Hi michaelsv sounds like you have quite a bit of work ahead of you. There are always a number of questions regarding insulation and vapor are one of the most common. The vapor barrier at it's simplest helps with damp proofing and can be a number of materials, though with insulation paper or foil are the norm.
Commonly insulation vapor barriers for the attic and walls are installed facing toward the interior of the home. The exception to this is that depending on your regional location building codes may require the vapor barrier face the outside of the home or even call for none at all.
The best advice I can ever give is always check your local building codes first. This is a surefire way to save time, money, and future aggravation.
There are a number of insulation discussions on the community as well as an insulation knowledge base with everything from material calculators, R-Value breakdowns, and install videos.
I also found this write up of insulating walls in a previous community post that may be helpful. I hope this helps get you on your way and best of luck throughout your project.
Vapor barrier is not required by code in mild climates such as here in San Diego, CA. Although adding vapor barrier is best even here in these climates as we get some drastic changes - this winter was one of the record cold ones in our area, so I would say yes, go with the vapor barrior.
Another option would be to go with unfaced batt insulation, and then staple a big roll of house wrap like Tyvek - its a longer lasting material then the paper vapor barrier that come with insulation, it breathes just a bit, and provides a better seal, as you are covering the entire wall surface with no breaks every 16"
Huh vapor barriers, my favorite subject :smileylol:
I agree on this one with both Chris and Mark, adding vapor barrier if you don’t have one and you need one it is a good idea.
I'm saying "if you don’t have one" because you may already have one on the exterior side of the wall.
Did you check behind the siding for the felt paper or extruded polystyrene insulation? Both of these mateirals have good perm ratings and are considered a vapor barrier. In other words you don’t want to end up with vapor on the exterior and on the interior of your home. This could result in trapped moisture between the wall cavities.
Check with your local building department for the vapor barrier placement before anything.
Also Tyvek it’s not a vapor barrier (retardant).Tyvek its water barrier and it’s designed to protect a home against damaging wind and rain that can penetrate through the exterior cladding.
Tyvek has perm ratings of 58.0 and 6-mil polyethylene sheeting has a perm rating of 0.06, which means that it does an excellent job of preventing the passage of water vapor.
Hope this helps.
Vapor barriers have become a very debated topic in the construction industry. The use of absolute vapor barriers, such as 6 Mil plastic,, has fallen out of favor, especially in warm humid climates , since the prevalence of air-conditioning. An established builder in Cincinnati was driven into bankruptcy because he had built several hundred homes with 6mil plastic right behind the drywall on the interior walls. During the hot, humid summers, moisture was migrating from the hot, humid exterior and condensing on the cool interior walls inside the wall cavity. It became so severe that the interior carpet was getting soaking wet! The builder could not absorb the cost of rebuilding the walls and was forced into bankruptcy. The presumption is that had that absolute vapor barrier not been present, the vapor would have been able to continue to migrate without saturating the wall cavity.
I personally have 6mil plastic behind my drywall also. But here in Portland,Oregon, the summers are hot, but dry. Fortunately, I do not anticipate such problems.
The present thought is to use vapor retarders, but not absolute vapor barriers on either side of the wall. If you cannot stop vapor from entering the wall, for sure don't put a barrier which will prevent it from drying out! I personally have seen severe damage caused by use of vapor barrier wallpapers. In the past, metalic wallpapers and Mylar papers have been popular. However, these are absolute vapor barriers and can trap vapor in the wall. In this case, porous brick on the exterior had passed vapor into the wall cavity where it was trapped by the wallpaper. The drywall and all the insulation had to be completely removed.
In most situations, a good primer and coat of paint on the interior is sufficient as a retarder. The kraft paper of the insulation gives further retardation of vapor, without totally blocking it.
I live in a 80 year old house in Ohio that was uninsulated prior my purchas3 5 years ago. The weekend before we moved in, we blew in celulose inulation throughout. It made an unbelievable mess, but when done, it really got the job done. A year later we insulated the attic. When I rewired the house, the celulose was not hard to work around, though I did find a few cavities that I missed. I have noted them and sooner or later I will get to them.
We are of course without a vapor barrier, but with a brick facing on the house, aprox 1 inch from the wood structure, any condensation where hot meets cold should evaporate quickly.
So, I ask, is the vapor barrier really critical in your old construction house?