People are wondering if they have to cover the insulation already installed. The answer is no. It is unnecessary to put a vapor barrier over the insulation because it does not require any protection from moisture.
Many people wonder if it is OK to put plastic over unfaced insulation. The answer is yes. You can use a vapor retarder or a vapor barrier on top of the unfaced insulation, but this would be an added expense, and you will have to remove the plastic when you want to access the space below the ceiling for other reasons.
Let’s find out more in this article!
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Can you put plastic over the faced insulation?
The answer is yes. You can put plastic over unfaced insulation. But I don’t recommend you to cover faced insulation because it will trap moisture.
However, it depends where you live. Check with your inspection dept. Where vapor retarders are required, 4mil will.
Every contractor I spoke with was very positive about Kraft-faced insulation. They all talked about the consequences of using plastic – it is known to cause problems with retaining moisture in houses.
Drywall is water vapor permeable as concrete is to other materials. Drywall’s permeability level is approximate 1/12,000th the levels found in common building material.
The water provoked the first plastic. The first plastic now accumulates on the drywall. It sounds like the insulation companies haven’t thought about code requirements during their assessments. Then, We put plastic on the insulation to prevent water or condensation from getting into the paper.
With the heat turned on, outside temps below freezing, and condensation noted in various homes- it’s not hard to diagnose what causes this. Slow down the venting time for outside air intakes, humidify the inside air with humidity control systems, or install a moisture vapor retarder rated above 1.0 perms. All of these will work to stop.
Do you put a vapor barrier over faced insulation?
There are some benefits to putting a vapor barrier on top of unfaced insulation. The vapor barrier will help protect the insulation from water damage and keep the attic dry.
It should not create condensation on the other side of the wall unless you have a problem in letting interior air hit the exterior side of the insulation without a vapor barrier. With Kraft-faced insulation, air leakage from the interior of a building can leak into and through the insulation.
One thing to think about is the air quality in this tight space. It would be best to look into the air to air heat exchangers, and proper venting for baths and kitchens is essential.
It is essential that you only use this technique on the exterior of your building and do not apply it to any interior walls. If you are using kraft paper-backed insulation, please make sure to slash the kraft paper before applying your new paint.
The CMHC website is an excellent resource if you’re looking for proper procedures. It’s pretty much the online version of what you need to follow when building a house.
I use poly as a vapor barrier for kraft-faced insulation. I have not had any callbacks concerning the practice. Just make sure it’s kraft lined, not foil-lined insulation.
What’s the use of vapor retarder?
Vapor retarders prevent water vapor-laden air through the wall assembly. It stops the passage of water vapor-laden air through the wall assembly.
To ensure that any assembly is adequately insulated, you must single line of vapor barrier. If two separate lines of vapor retarder are provided in a group, moisture cannot disperse.
The critical component in depressurizing a wall is the vapor barrier. Moisture-laden air migrating from warmer areas to cooler ones will cause problems without this necessary measure.
Assembly detailing for stick framed buildings typically calls for unfaced batt insulation between wood studs with six mil poly inside.
Our company specializes in building and detailing office buildings, and we’ve been doing this for over 30 years. If you visit Southern Ontario, you will see many successful examples of our work.
I have found assemblies that were rotting. They had insulation without a vapor retarder and others that were rotting. It was because someone had carved a big hole in an otherwise tight and well-insulated wall.
I’ve also examined the moisture levels in old buildings with no vapors, insulation, or heat. Moisture appears to condense at points where it quickly evaporates.
Main building types here include concrete block, concrete, stone, and a lightweight kind of building I’m going to use for my home called autoclaved aerated concrete (or AAC – r1.2 per inch). I will insulate the walls to reach r30 + with most of the interior surface area.
Masonry construction for the insulation
Local reliance on masonry and concrete may be due to termite or hurricane concerns.
The winds of hurricanes are howling outside my house, but they’re not a problem for me. Labor is inexpensive, and I think our regional building materials are of high quality. I’ll finish the exterior with a stucco-type affair or something like that, or an actual second.
Masonry may not be susceptible to rot, but the accumulation of moisture will usually lead to the deterioration of your insulation. It is only for low-rise exterior wall detailing.
190 concrete block. Need a clean, even, and dry surface, complete with ties to support the masonry veneer. We typically call for veneer ties every 400 vertically and every 600 horizontally.
There are plenty of reputable manufacturers of vapor or air retarders in Canada. You should pay particular attention to the joints in the construction and expansion process.
Polyisocyanurate insulation boards are 400×1220 sheets up to 4″, which you can apply in sheets of the thickness that suits you best. They provide up to three times more insulation than 1″ of polystyrene board, among other benefits.
Airspace for ventilation and drainage in the insulation
The exterior of your house should be brick or stone with standard units. Connect the shrubs well to the backup wall to ensure there are no gaps. Some often misunderstood points include flashing units that flash from behind insulation across to the footing and under the veneer brick.
The cavity is the primary operating principle of an assembly. Not only does it allow for bricks to be dry on both sides, but it also has an equally important function.
The wall’s protection is ensured by veneer, insulation layers, and membrane. Much like water that passes through a window, it invades past the outer layer of porcelain enamel known as the veneer. It is redirected towards the weep holes. Then, it evaporates from either wet surface.
Our project consists of polystyrene, polyurethane, and mineral wool. I was concerned before about insect & vermin problems but should be less now. We also have bitumen products as well as a torch on offer.
We use stucco to insulate a concrete block wall when it is the backup. Although there are a lot of factors involved, it can be outstanding if you make all the right decisions.
A few of the stucco finishing options we can specify for clients are Sto, Dryvit, and Durock. All three offer training programs.
