How we build homes in Canada has changed very little in the last 35 years: until very recently we were still using the same wall systems with the same insulation as we were in the 1980’s.
In 2015 a new energy efficiency requirement was introduced into the building code. The recent introduction of defined energy efficiency requirements in the building code is likely the 1st step in a series of code changes over the next 15 years. These changes will see new homes become so energy efficient that they will use 75-80% less energy than a code built home of today. This will enable many homes, with the addition of solar panels, to produce as much energy as they consume. Homes that meet this standard today are referred to as Net Zero homes.
Recently, the Canadian Home Builders Association (CHBA) launched a labeling program to help identify homes that could produce as much energy as they consume. RDC has qualified themselves to be able to label our new homes under the CHBA Net Zero Energy Label: I am very excited to announce that we have just begun construction on the 1st home that will qualify for this new designation.
Net Zero Energy Label projects are required to achieve a high insulation number to reduce the homes overall energy use. To help achieve this RDC has partnered with a number of our Holmes Approved Homes product partners on this demonstration project. We are also showcasing some innovative products that we believe are key to building a better home, Our key partner when it comes to reducing energy will be BASF and their new HP+ Wall System.
This new wall system will allow us to achieve a very air tight home with great insulation values for a reasonable price using standard materials. One of the great advantages of this wall system is that BASF has extensively tested it and offers a 10 year limited warranty; no other manufacturer of insulation offers a warranty on the durability of their system. The 10 year warranty is double what builders in BC are required to offer as part of the provincial mandated warranty program.
Over the next 9 months I will write regular posts with photos chronicling the progress of this exciting new project describing the products and features that make this home affordable, comfortable, healthy, durable and energy efficient.
This week we started work on our footings, note the plastic under the forms. This is to keep moisture from wicking up into the concrete foundation: while we do this on all our builds this site is of particular concern as there is significant water that come out of the hillside during heavy rains.
Moisture wick in concrete is the key cause of that musty basement smell we all most likely grew up with. What you are smelling is the mold and mildew collecting on the framing and insulation behind your drywall, not a very healthy condition to be living with. You will notice the Insulated concrete Forms (ICF) in the photo as well.
For more information on the benefit of ICF please see our blog Insulated Concrete Forms – 5 Steps to a Better Built Home
The goal of these progressive building code changes will be to achieve a Net Zero energy standard for new homes (and all buildings) in BC by 2032.
RDC agrees with and is excited about these changes and is working in partnership with a number of key industry partners to build a demonstration home highlighting how a Net Zero Home (a home that produces as much energy as it uses) can be built. This project is not without its challenges in that the home design and orientation is not optimal for a Net Zero outcome; the design was not optimized for solar orientation, rather the home was designed to take advantage of the lot topography and the view corridors.
As you can see from the EnerGuide Home Owner Information label shown at the top, the home as modeled by the energy software Hot 2000, with the solar panels on the roof would produce as much energy as it uses. This satisfies the goal of designing a home that would be considered Net Zero. In our case we are not planning on installing the solar panels right away and so would achieve a Net Zero READY status.
While most of the emphasis on these type of super energy efficient homes is placed on energy saved there are numerous other benefits – From improved thermal comfort to better indoor air quality an energy efficient home will give back in so many more ways.
In today’s post I will give an overview of the steps we are using at the foundation stage to improve thermal comfort and indoor air quality at the same time as we make sure we can reduce our energy use to meet the Net Zero standard.
But first, here are some details about our Net Zero ready home:
Up until recently basements required very minimal insulation and crawlspaces had no requirement for insulation at all: additionally, traditional concrete foundations only require minimal waterproofing strategies. Unfortunately this can lead to damp moldy smelling below ground spaces that often are turned into living space. I am sure all of us have lived in a home (or suite) that was cold damp and smelly. This condition can not only be uncomfortable but also can make the occupants much more susceptible to colds and flus.
This is what we recommend:
Here you can see the various layers applied to the foundation wall. The foundation itself is poured using an Insulated Concrete Form and then to bump up our insulation values and improve our air tightness and waterproofing we have added 2″ of Halo Subterra provided by Standard Building Supplies, a graphite impregnated expanded polystyrene foam. The ICF foundation blocks have an effective insulation value of R 24, the Subterra will add R10 giving us a total effective R value of 34.
Concrete is like a sponge and if exposed to water will very quickly wick moisture that can then transfer to interior framing and insulation. The high moisture/ humidity levels then begin to promote mold and mildew and that bad musty basement smell we all know so well!
In the photo above, if you look closely, you can see that the base of the foundation/footing itself is wrapped in plastic. This plastic is wrapped under the footing and will be sealed to the interior under slab insulation ensuring that the entire foundation is protected from moisture. The plastic is connected on the exterior with a layer of peel and stick membrane (Nudura) and the whole assembly will be protected by a plastic dimpled membrane designed to eliminate any hydrostatic pressure. Of course, we will have the required perforated pipe as a perimeter drain.
Foundation forming will be complete this week and framing of the revolutionary HP+™ walls, XR series system will begin March 13.
Today, I am going to focus on the wall systems and insulation we will be using to achieve the insulation values required to build a home that can produce (with the use of solar photo voltaic panels) as much energy as it uses.
When considering building a home that is designed and modeled to produce as much energy as it might use it is very important to reduce energy use as much as possible; the biggest energy demand in a Canadian home is for heating and cooling, so it is important that we design and build a home that is air tight with very good insulation.
The wall system that you choose therefore has a big impact on your energy consumption. When RDC looked at the new BASF HP+ wall System we knew we had found the right formula for exceptional insulation performance and building air tightness.
The BASF HP+ advanced high-performance wall system uses the following products:
How does HP+ help make a home better? In addition to energy reduction, a high performance wall system will also provide the following benefits:
The HP+ wall, at 1st glance, looks much like a conventional framed wall, Until you look closely! Rather than a typical 2X6 stud this system uses a 2X4 on a 2X6 top and bottom plate with a 2″ horizontal strapping (to make up the difference between the 2X4 stud and 2X6 plates). This significantly reduces the thermal bridging typical of a conventional stud wall, as we now only have a thermal bridge where the strapping connects to the 2×4’s. We use 2.5″ of Waltite spray foam on the inside of the assembly to seal between the strapping and the 2×4 studs.
The NP1 is used to seal all the framing connections, studs to plates, plates to floor etc. These 2 elements combine to give us our air tight seal for the walls.
So you might be thinking that 2.5″ of spray foam does not give us very much insulation and you would be right. We would now have an effective R value of about 12 – a long way off of where we need to be.
This is where the Neopor ridged insulation comes in. We will use 4.5″ on the exterior of the home giving us an additional R20 for a total R32. This is right where we need to be for our climate zone to achieve or energy reduction standard to achieve a Net Zero Ready energy footprint.
– Bob Deeks & The RDC Team