Putting Tightness to the Test

Constructing tight buildings is a requirement in an ever-increasing number of communities, including those that have adopted the 2012 or 2015 IECC as local code. Even where not required, it’s a good idea and it’s not as expensive as you might think. First, you must test your buildings and understand the metrics to know where you stand. Once you’re armed with this basic knowledge, you’ll be able to improve the training of your crews and subcontractors to optimize air leakage control in the homes you build. read more

Water, Water Everywhere: solving the secrets of trapped moisture in walls

It happens every spring. Every build and building inspector knows the script: the phone call comes about the basement leak, a visit to the home is arranged and the inspection takes place. The wet insulation is visible through the ‘plastic stuff’. The plastic stuff is known as the vapour barrier, and in some cases, the air barrier.

During the investigation no leaks are found anywhere. A perfectly installed air gap drainage membrane is present, weeps are fully connected to an active sump, AND there is even a capillary break placed between the footing and the foundation wall (you don’t see that every day!). read more

HRVs vs. ERVs

Some contractors may be hearing or reading mixed messages about the application of ERV technology vs. the older HRV technology. Much of this conversation centers around the appropriate technology for cold weather applications. A quick review is in order. The history of air exchangers, air to air heat exchangers or heat recovery ventilators in residential applications was very clearly tied to excessive winter moisture and window condensation problems as houses became more energy efficient and tighter. HRVs were developed specifically for the removal of moisture in R-2000 and other energy efficient housing programs. Introducing cold, dry fresh air to replace the high humidity exhaust air has the ability to quickly bring down the relative humidity in cold weather. For example, when the outside air is at 0 0C (32 0F) and 100% RH, just 30 L/s (60 CFM) of ventilation can remove approximately 15 liters (3.24 gallons) of water a day. Using an ERV with a latent effectiveness of 50% would cut this moisture removal capability in half.read more