Radon Gas – The Good, the Bad and Ugly

The good news is that radon gas is generally not a problem in the lower mainland. The bad news is that is does still occur in some locations in Metro Vancouver and the ugly news is radon gas is the second leading cause of lung cancer in Canada.

 

In the Metro Vancouver area, radon gas has been known to occur in one house but not the one next door.  Radon is a radioactive gas that is formed naturally by the breakdown of uranium in soil. As a gas, radon is slowly released from the ground and will build up concentrations in well-sealed buildings.  Radon gas is colourless, odourless, and tasteless.

 

If radon gas is found, there are steps that need to be taken.  An upgrade to a more rigorous sub-slab soil gas barrier is one option.  A 6 inch layer of gravel promotes the breathability and movement of gases under the slab.  These gases are then drawn through a pipe in the floor slab that vents through to the roof.  A mechanical fan could be added to increase the draw of the gases.

 

For each home we build, Clay Construction performs a free test to determine if radon is present.  If we find concentrations during our testing, we can take the above measures to mitigate the radon gas.  If radon gas is not an issue, the homeowners have piece of mind at no cost.

The Perfect Wall

Your choice of wall assembly will not only affect the energy efficiency and the longevity of your home but will also affect the air quality through the presence of moisture and mould in your wall. A small investment into this wall assembly will provide benefits to not only the operating costs but more importantly the air quality and longevity of your home.

The wall assembly is comprised of the cladding, framing structure, insulation and air/vapour barrier. When considering the best wall assembly for your home the following issues need to be addressed: how do you prevent water from getting in, how do you keep air from getting out, how do you establish insulation levels as high as possible and how do you construct the wall assembly to increase its ability to dry out in the event water gets in?

One challenge of our traditional wall assembly is that almost ¼ of the wall is comprised of wood that has an R-value of 1.5/inch thus degrading the effectiveness of the R-value of the wall. This leaves only ¾ of the wall to shove our insulation into. The framing lumber acts as a thermal bridge. Since we are limited by how much insulation we can shove between the wood studs, the next generation of wall assemblies will involve moving insulation to the outside of the wall. This will greatly reduce the thermal bridging and moisture in the wall assembly whilst increasing the energy efficiency, longevity and health of the home.

Most of us are familiar with the poly plastic sheeting placed between the insulation and the drywall. This traditional approach has the poly performing two functions: the air barrier and the vapour barrier. Unfortunately, this poly can trap moisture inside the wall assembly. A better approach would be to move the air barrier to the outside of the home sandwiched between the plywood sheathing and exterior rigid insulation. Removing the poly will allow any moisture that penetrates the wall assembly to dry to either the interior or exterior. Since moisture promotes mould, a wall assembly that remains dry will be healthier for its occupants. Cutting edge builders embrace positive change.

Joe Lstiburek a world-renowned building science expert has coined this wall, the “Perfect Wall.” Any builder familiar with building science will be able to advise you on the best wall assembly for your current and future needs.

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