Canadian Contractor


Code changes that could save thousand$ Why they can’t—or won’t—get done even when they are smart, cost effective and timely

"It’s a small wonder that many manufacturers of innovative products privately feel they are held hostage to the approvals agencies perpetuating their existence along with numerous fees, delays and other impediments to innovation."

By Paul Duffy, M.A.Sc., P. Eng.

Most people have little understanding of the need for Building Code change and if they can imagine it they see it as something that is primarily of interest to Engineers and Researchers. They never conceive of how archaic Code requirements might be limiting innovation or adding unnecessary cost when new materials or design solutions are brought forward. The status quo is ensconced in “the Code” and the pace of change can be glacial.

There are some mechanisms available that allow innovation provided both in legislation and practice by most Authorities Having Jurisdiction (AHJ’s). For instance:

  • In Ontario, the Building Materials Evaluation Commission (BMEC) will provide an evaluation of an innovative product for compliance with the Ontario Building Code.
  • Nationally, the Canadian Construction Materials Centre (CCMC) provides evaluations of innovative materials and systems to the National Building Code.
  • In several municipalities and Provinces, a myriad of commissions, committees and boards will review plans and permits for a “one of” approval or rulings, usually based upon a supporting engineering evaluation, third party tests and research.

The net result of these processes can be thousands of dollars of extra cost added to the work of builders, designers, manufacturers, and ultimately, building owners.  Worse yet, the approval agencies are under no obligation to drive Code Change to streamline approvals as more becomes known and more successful applications of the technology become implemented locally.  The added costs typically become a permanent fixture in the costs of doing business.

It’s a small wonder that many manufacturers of innovative products privately feel they are held hostage to the approvals agencies perpetuating their existence along with numerous fees, delays and other impediments to innovation. There is a curious relationship between manufacturers and these agencies however—few manufacturers would venture forward in open criticism of regulators.  Once you get through the arduous process and know how the system works, the delays and costs become impediments to competitors thinking of entering the market. As one manufacturer once said to me “You get through the process and then you want to slam the door tightly behind you!” The whole mess can seem disheartening if you believe that innovation is crucial to maintaining a healthy construction sector in the years ahead.

There are many factors driving the need for innovation, ranging from energy and environmental imperatives to limits on raw material resources, or simply finding more effective ways to build, reduce cost or improve affordability, etc. We have all seen the workings from researchers, policy analysts, lobbyists and the like. To continue building without new systems and technology advances is nothing short of crazy.

To illustrate the point, it really takes a couple of examples.

Slab on Grade Construction

Firstly, consider slab-on-grade construction.  Why do we build foundations a minimum of 4 feet below grade in Canada? The answer is simple—to get footings below the frost line. But, what if you insulate the footings so that frost does not penetrate the ground, how far down do you need to go?  Well the Code does not tell you.

No big deal… you have to go down four feet, so insulate the walls and turn the basement into living space. It’s not the best solution—moisture ingress can be an issue and the view underground is less than ideal, but, creating living spaces below grade does kind of turn a lemon into lemonade, as the expression goes.

But wait, suppose you are building a home for seniors, or someone who has mobility problems.  You don’t want a house with stairs.  You can add an elevator, I suppose, with all the associated costs. Or, you can simply build a slab-on-grade house.  But that is not described in the Code particularly well, so you will need to hire an engineer, and because the Code doesn’t help much, be prepared for delays getting a building permit because most municipalities will balk at a house that does not have a basement or at least perimeter footings that go below the “frost line”.

Not convinced that this is important to you?  Slab-on-grade houses are not common in this part of the world so is it a real issue or am I just making a mountain out of a molehill? How about building a house near a lake or river… chances are you will hit the water table close to the surface of the land… do you really want to go down 4 feet to avoid frost? Do you want to drain the lake?  I have seen lots of folks try to solve the problem by moving in soil, sometimes hundreds of cubic meters of soil to raise the grade and protect their foundation.  You can easily see lots of situations where tens of thousands of dollars are added to the cost of a construction project because the builder needs to place footing below the frost line. Does that sound more sensible than a slab-on-grade foundation?

Still not convinced? Maybe you simply want a basement walk-out at the rear of the home.  If there was a simple solution that could save you thousands of dollars, wouldn’t you want to hear about it or at least have that option?

The interesting thing is that most of the world builds without basements. Yes, it is true that you don’t need to go down below the frost line in places like Florida or Texas so the way they build might not necessarily work in Canada.  But consider the way they build in places like Sweden. Swedes often build with insulated slab-on-grade construction and they have done so for years. Here is the crazy part…their Code was based on research partly done right here in Canada!  In the 1960’s, a Professor by the name of Fred DeLory at the University of Toronto did pioneering research into insulated slab-on-grade construction and his work made its way into Nordic Building Codes, but the Codes for foundation design right here in Canada never did change. It’s hard to say whether we should be proud or embarrassed.

It’s a pretty important (and ironic) gap in our Codes but is it the only area where we are lagging? Sadly, no it is not.

Venting of Roofs

Consider the way we build roofs.  In most houses, you frame a sloped roof and place your insulation at the floor of the attic. Then, because air leakage driven moisture can often penetrate through the insulation, you add venting through the roof to get rid of it. Conventional wisdom is that there are a lot of penetrations including electrical outlets, plumbing stacks, vent fans and pot lights that make it difficult to air seal the ceiling area. Venting is the brute force solution that solves the problem.  When all else fails, ventilation gets rid of the problem. Or at least that is the primary way many people defend the need for ventilating roofs.

However, the Code provides two examples of roof assemblies that do not require venting:

  1. The lower portion of a mansard or gambrel roof is specifically called out as not requiring venting in the Code. (See Sub-section
  2. The Appendix to the Code identifies that some roof assemblies in some factory built houses have “over time, demonstrated that their construction is sufficiently tight to prevent excessive moisture accumulation.” (ref. Appendix A-

It’s unfortunate that the Code isn’t more prescriptive about how you need to design things when venting can be eliminated. You almost have to infer design requirements from the nature of the exceptions given.

For instance, some people suggest that venting is needed to protect shingles from overheating.  But if that were the case, why would (shingle clad) unvented mansard roofs be allowed?  In any event, research done by people like Armin Rudd in the U.S. researched the whole shingle overheating issue and found little to worry about.  Using an unvented design raises shingle temperatures only 2 to 5 degrees.  The fact is that there are much greater effects seen when you change shingle colour (black vs. white) or home location (Arizona vs. Canada).  Shingle manufacturers don’t void their warranties on certain colours of roofs, or on roofs built with more sun exposure, or in certain climates, why should they if the roof is unvented?

So the key issue, as far as the Code is concerned, is moisture—venting is provided to get rid of it.  Why not stop the moisture getting into the vulnerable components like the roof deck in the first place?

Conventional roofing materials are intended to keep moisture out, coming from the top side, but what about the underside of the roof deck. What if you applied insulation at the roofing level on the underside of the roof deck as with spray foam or maybe a SIP panel? Wouldn’t that eliminate a number of penetrations that lead to air leakage driven moisture problems? Wouldn’t the fact that these products meet code requirements for air impermeability help limit moisture accumulation at the roof level? Would that be enough protect sheathing and structural elements? Would venting still be required? What if you used materials like closed cell spray foam, or foil-faced polyisocyanurate board? Would the fact that these materials act as vapour barriers as well meet Code requirements for a continuous Vapour Barrier as well as Air Barrier be enough? Or could a conventional polyethylene air barrier or a spray-on coating as a vapour barrier be added to vapour permeable materials to make the assembly work?

I have posed the design process as a bunch of unanswered questions but wouldn’t it be nice if the Code gave more complete answers as to how you build without venting a roof? At present, it does not, so many building officials (wrongly) assume that an unvented roof cannot be built and they give you a rough ride if you try to build without venting.

If you go to other jurisdictions, (this time in the U.S.,) again you find they are using building codes that give prescriptive requirements for unvented attics and these requirements have been in place for more than 15 years. (That’s six “Code review cycles” and not only do the unvented attic code provisions appear to be working, they have been expanded!)  In U.S. Codes, they give specific guidance on where and how you insulate, the types of materials that will work, R-values, design criteria by Climate Zone, etc.

The really interesting thing about this example is that, we think of the U.S. as being generally warmer than Canada, but, the U.S. Climate Zones do include areas like mountains in Washington State, places like North Dakota, and of course Arctic climates in Alaska. The U.S. Climate Zones include lots of jurisdictions that have climates that directly parallel Canadian climates and the U.S. Building Codes include provisions for unvented attics in ALL CLIMATE ZONES!  The science doesn’t change so as to prohibit unvented attics in cold climates. Why don’t we have Code provisions that describe how you build an Unvented Attic in Canada?

Why is this change important? It would sure make it easier to achieve higher R-values and energy efficiency in a cathedral ceiling if you could eliminate the vent space and add more insulation. It would also make it easier to add more high quality living space in attics by insulating at the roof line, maximizing insulation, minimizing re-framing and adding valuable living space on the interior.

Or maybe you live in one of the millions of post-WW2, 1 ½ storey houses that CMHC helped build in cities all across Canada.  If you look at them closely, most have poorly insulated attics and extremely leaky knee walls on the second floor and chronically high energy bills. Wouldn’t it be nice to fix the problem by sealing the attic and knee walls by insulating at the roof line with a continuous layer of an air sealing, air impermeable insulation solution?

Again, we have another potential Code change that could save thousands in construction costs and produce substantial improvements in energy efficiency and comfort.

A Fresh Start

I am recognizing that there are huge opportunities here to build more affordably and better aided and encouraged by better Code language. Perhaps we need a resolution to do the heavy lifting and get the job done.

For change to occur, it will take advocacy on the part of industry associations where competitors can collaborate in less threatening ways. It will take receptive ears in the regulatory community. I even believe builders and designers need to speak up.

If you are working closely with your local Building Officials you have to make it known that this is a high priority for you.  This isn’t just a technical discussion best left to housing researchers and engineers.

Paul Duffy and Associates Inc.


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