thermal-barrier / Green Building & Sustainable Home Renovation Information & Advice

There has been a steady evolution in the way we build homes over the last couple of decades, and the old standby wall recipe of 2x6s, fiberglass insulation and polyethylene doesn't measure up anymore with building codes, nor the trend towards high performance housing. One aspect of wall assemblies that is garnering som...

A technical guide to understanding the role weather 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...

Vapor Barriers in walls, why polyethylene can be problematic It would probably surprise many home builders to hear what really causes moisture accumulation in walls, and what to do to prevent it. An understanding of how water vapor moves through walls is important, so a good place to start would be with our page explai...

The difference between air 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 effect...

Vapor Barrier + Air-Con = Damp Moldy Walls So here's a little known fact that most HVAC installers won't tell a potential new client for central air; Polyethylene vapor barriers in combination with air conditioning in homes can rot walls because of the condensation they may cause. This is why if you have a newer home w...

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 groun...

Insulation slows the rate of heat transfer, helping keep homes warmer in winter and cooler in summer. How well-insulated your home is will determine how comfortable it is and how much you will spend on energy for heating and cooling, and in some respects, how durable it will be. The transfer of heat (or heat loss) occu...

LEED Platinum V4 Wall Design: Building Science  The wall we designed for the Edelweiss house, Canada's first LEED Platinum V4 Home is best categorized as a 'REMOTE' wall, a high performance building envelope developed by the Cold Climate Housing Research Centre in Alaska. REMOTE stands for 'Residential Exterior Membr...

Approximately 100 times more water 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 ...

The Ecohome Demo House has a vapor permeable exterior air barrier, and with an ACH rate of .69 it is  several times more airtight than the average new home. Air leakage can be responsible for up to 1/3 of the total heat loss of a home and cause significant moisture damage in walls, as one small hole can be responsible ...

First published in ecoHouse Canada The thermal performance of wall assemblies and insulation products has long been characterized using R-value, a metric which describes thermal resistance. While R-value is useful, it doesn’t tell the whole story about heat flow through building enclosures such as walls and roofs. Rece...