Dealing with VOCs

Volatile organic compounds (abbreviated as VOCs) are gases that emanate from some solids or liquids and  include a range of chemicals which may have short or long-term negative health effects.

A big problem is that the concentrations of VOCs are  consistently higher in the interior spaces. Up to ten times higher than outdoors. They are readily found in most homes, which most people think of as their safe place in the world, the sanctum-sanctorum of private life.

The number of products emitting VOCs run  in the thousands, and all them release VOCs not only when in use but also when stored.

Most people is aware that organic chemicals are widely used in household products, fuels of all types, varnishes and wax, cleaning and disinfecting products, cosmetics, degreasers and more.

However, many homeowners don’t realize how often VOCs are introduced to the home when it’s being built or renovated. Construction materials,  paints, and adhesives, among others, are high on the list of VOCs emitting products, and poor designs in terms of air flow often compound the issue.

According to the EPA some of the health effects of exposure to VOCs may include eye, nose and throat irritation, headaches, loss of coordination and nausea, damage to liver, kidney and central nervous system. Some organics can cause cancer in animals, some are suspected or known to cause cancer in humans.

The same source cites a variety of symptoms associated with exposure to VOCs, which range from conjunctival irritation, to nose and throat discomfort, headache, allergic skin reactions and more.

For these reasons, it is of paramount importance to make sure the reduction of VOCs in the household starts right at the beginning, with the planning and construction process.

Clay Construction in Vancouver, British Columbia, works with their clients to ensure this issue is taken very seriously at every step of the way. For this purpose they closely monitor the construction materials, and implement designs that permits for better ventilation in order to reduce harmful toxins and minimize their effects.

Air Quality Starts at the Foundation

To improve your home’s air quality, start at the foundation.

I received a call from a woman who had placed an offer on an expensive home in Vancouver. She wanted a renovation to this home, since she could not be in this home without quickly feeling sick. The home smelled musty, and she couldn’t bear the thought of living there. I concluded that a band-aid fix would not be satisfactory, considering her health issues.

I phoned my friend and ventilation expert, David Hill. David lives locally, yet his expertise takes him all over Canada and the U.S. for speaking engagements. He confirmed my suspicion that the smell and mould/mildew originated from the basement.

Nearly all new homes are built to the lowest common denominator – the BC Building Code. With respect to the foundation, let me show you what you get when you only build to code. We have two problems.

Firstly, traditional construction places the footing on dirt or clay. Footings, much like snow shoes, increase the surface area and spread out the load. The foundation wall sits on top of the footing. This footing, when sitting in water, can wick up 3 pounds of water per day per square foot. This moisture finds its way to the basement wall assembly.

Secondly, traditional basement wall assemblies are a victim of building science principles.

Allow me to illustrate my point.

Take one cold coke out of your fridge and put it on your counter. Take another one out of the pantry and put it beside the first coke can. Wait 5 minutes. What do you notice? The can out of the fridge has accumulated condensation on the outside of the can, while the other is dry. Moisture in the air condenses on cold surfaces.

Concrete is cold. Once moisture in the air gets past the vapour barrier, it condenses on this cold concrete wall. Furthermore, the poly sheeting prevents adequate breathing of the wall assembly.

What can be done?

Firstly, place your footings on a thick bed of ¾ inch free draining clear crushed rock. Water may wick up through sand and dirt through capillary action, but water will not wick up through ¾ inch clear crushed rock. Placing poly at the base of the footings will also prevent footings from making contact with water.

Free draining clear crushed rock and poly under the footings will prevent your foundation from making contact with water.

Secondly, choose a basement wall assembly that prevents air vapour from making contact with the cold concrete wall. Insulated Concrete Forms is one solution. Another would be to place rigid insulation on the interior/exterior of the foundation wall. Eliminate the poly vapour barrier and replace with a vapour barrier paint. This increases the breathability of the wall assembly.

foundation2

Insulated concrete forms prevent air vapour from making contact with the cold wall.

When building a custom home, you have one chance to get it right. Strategically, build above code. Spend a little extra money and build a home that is healthy, comfortable, durable and energy efficient.

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.

vapor

Effective vs Nominal R-values

The City of Vancouver has recently implemented their new Vancouver building code. One small change affects the insulation of exterior walls. Previously, exterior walls needed to be at a nominal R22 insulation level. The new code requires effective R22 insulation levels. What difference does this make?

Nominal insulation is the R-value of the insulation batt we stuff between the wood studs. This is the R-value we see printed on the bag. Don’t be fooled, this is not the R-value of the wall. Wood has an R-value of R 1.5 per inch and makes up approximately 23% of a traditional framed wall. A 2×6 stud will have an R-value of 6 while windows range from R2-R5. Relative to the insulation property of fiberglass, wood and windows are poor performers.

What will it take to achieve Vancouver’s R22 effective insulation values in exterior walls? Here are three options.

1. The traditional 2×6 wall insulated with R22 batt will achieve R17.89 effective. Fail!

2. A 2×8 wall insulated with R28 batt will achieve R22 effective. Pass!

3. A 2×6 wall with R22 batt and 1” exterior rigid insulation achieves R22 effective. Pass!

There are many variables at play to achieve R22 effective. Make sure your builder considers the many options and doesn’t default to what is easiest. There is one wall assembly considered by the world experts to be the perfect wall assembly. Check back for my next blog post on the “Perfect Wall” and its many advantages.

architecture plans for custom home

1. Starting Smart

Introducing The Clay Way

Clay Construction takes pride in building right, right from the start. We call it The Clay Way. In our blog posts we’ll share in-depth knowledge of our building style. Issues facing home owners as they navigate new home builds and renovations will be discussed. We’ll explain what to look for and what to watch out for and how Clay Construction gets it right. We start with the aptly name Starting Smart, the first in our series.

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Larry Clay at the Georgie Awards

Georgie Awards Winner

Georgie Awards come in all sizes with 45 categories ranging from best renovation under $100,000 to the best overall builder in the province. These awards, bestowed by the Canadian Home Builders’ Association of British Columbia (CHBA), reflect the dedication of the winner to have done their best whether the job was big or small.

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