Vapor barriers / Guides

The difference between air barriers and vapour barriers
Air and vapour barriers

The Difference between air barriers and vapor barriers

...barriers and vapor barriers The job of a vapor barrier is to prevent vapor diffusion, and the job of an air barrier is to stop air leakage through differences in air pressure. A wall system should have one vapor barrier, but can have many air barriers. A vapor barrier can act as a very effective air barrier, but an a...

Vapor retarder latex primer instead of polyethylene sheet
Air and vapour barriers

Replacing polyethylene vapour barriers with latex paint vapor control

...vapor semi-permeable interior finishes. The following main principles are recommended: Avoid vapor barriers where vapor retarders will work, avoid vapor retarders where vapor permeable materials will work. Avoid the installation of a vapor barrier on both sides of the wall assembly. Avoid using poly, foil fac...

Poly vapour barriers in air conditioned houses can cause mold and rot
Healthy indoor air quality

Why you should Never Install Air-Con in a Home with a Vapor Barrier

...vapor barriers in wall assemblies in all but the coldest of climates, or at least change their location within the wall assembly to avoid the possibility of interstitial condensation damaging wall structures . Moisture-impenetrable vapor barriers work great in winter and, before air conditioning and heavily insulated...

Crawl Spaces or Slab on Grade Foundations?
Foundations and Basements

Slab on grade or crawlspaces, which is better?

What is the difference between a slab on grade & a crawl space? A slab on grade, or ‘frost protected shallow foundation’ is exactly that, a slab of concrete on the ground. There’s more to it of course, but let’s start with a ‘win’ in the comprehension department shall we? A slab on grade rests directly on the grou...

Crawl Spaces or Slab on Grade Foundations?
Crawl spaces

Should I Build on a Slab on Grade Foundation or a Crawl Space?

What is the difference between a slab on grade and a crawl space? A slab on grade, or ‘frost protected shallow foundation’ is exactly that, a slab of concrete on the ground. There’s more to it of course, but let’s start with a ‘win’ in the comprehension department shall we? A slab on grade rests directly on the gr...

Air barriers are essential to a properly functioning wall system
Air and vapour barriers

What is an air barrier?

...vapor is carried into our walls by air leakage than is carried by vapor diffusion. That makes air barriers 100 times more important than vapour barriers, so why is no one talking about them? We don't talk about air barriers because we are too busy talking about vapor barriers. An air barrier is not something you walk...

Radon and vapour barrier below slab on grade floor
Radon in Homes - Mitigation

Vapour / radon barriers below slab floors

How to Install a Radon Barrier - Slab Floors If in the kind of area where it's a good idea to install a vapor barrier against radon ingress, (check out the Radon maps by state and province page to find out here) we can't stress enough how important it is to test for radon, or better still to continually monitor for ...

How to Insulate Exterior Walls from the Outside US Canada Ecohome
Walls and Roofs

The easiest way to insulate walls from the exterior in older homes

...vapor retarder or vapor barrier, it’s important not to add another vapor-impermeable layer on the opposite side of the wall that could trap moisture in the middle along with organic materials such as insulation or wood framing members. Some rigid insulation boards have integrated air barriers, some have vapor barrier...

What is Interstitial Condensation? (And how to stop it!)
Walls and Roofs

What is Interstitial Condensation in Walls or Roofs? (And how to stop it!)

...Vapor control layers (VCL) or membranes should be positioned on the warm side of insulation, however, these layers must be carefully sealed and penetrations avoided to prevent air leaking. (See here to understand the difference between air barriers and vapor barriers .) Materials with low vapour resistance should be ...

Tyvek home wrap left exposed to wind and UV rays
Air and vapour barriers

Choosing the right house wrap / weather barrier, which is best?

...barriers and rainscreens play in a wall, choosing the right products and installation tips for optimum performance. They're officially known as water-resistive barriers or WRBs, sometimes weather-resistive barriers, but in practical terms they are more commonly called housewraps and weather barriers. With so many opt...

Interior sheathing as air & vapor barriers in wood frame construction
Air and vapour barriers

Interior sheathing as an air and vapour or vapor barrier

...vaporate and eventually become brittle and peel. The most durable tapes on the market contain no such solvents, so they actually do the job they were intended to do. They won't come cheap, but they work. Find out more about Weather Barriers, Rainscreen & Vapor barriers here , from the EcoHome Green Building Guides