External Insulation Air Barrier Systems in Toronto
Today we’re going to cover external insulation air barrier systems, one of the elements that makes a building sciences approach to home improvement a success. We’ve covered various related topics on the blog already (such as our article on control layers), but we think that both external insulation air barrier systems and house wrap air barrier systems warrant a closer look.
If you’re just arriving to this series now, take a look at our articles on How Building Science Affects Home Comfort for an in-depth explanation of the building science approach, or our article titled The Importance of the Building Envelope for some preparatory information on this area of insulation and building science.
Exterior Insulation Air Barrier System
What are external insulation air barrier systems? In this kind of control layer, you see the air barrier and vapour barrier separated, with the insulating layer towards the exterior of the building. Usually this type of control layer is made with a rigid material - it needs to be able to withstand changes in air pressure and should be installed continuously over the entire building structure or unit. Unlike other things, it needs to be able to withstand the rigours of construction and last the expected lifetime of the building - it’s not something that’s going to be easy to replace, so doing it right the first time is essential!
How it Works
Your external insulation air barrier systems are located anywhere towards the exterior of the building enclosure. In colder climates like Canada, we generally find interior air barrier systems controlling the exit of moist interior air, and exterior air barrier systems controlling the opposite - the entering of exterior air.
There are a number of different materials that are used in external insulation air barrier systems, such as:
- self-adhering membrane sheets (often made out of modified bitumen)
- concrete panels (either precast, site-cast, or tilt-up)
- breathable insulated structural sheathing products
There are many great advantages to choosing rigid external insulation air barrier systems.
- Ease of installation: because they go on the exterior side of things, there’s less detailing needed and more complete coverage. Fewer intersections mean fewer areas where wind and weather can penetrate over time.
- Controls wind-washing, the effect of air movement through and around homes that diminishes your thermal performance.
- Easily repaired or replaced if damaged during construction.
- External insulation keeps internal parts warmer - like your framing - which reduces the potential for condensation.
- Withstands air pressure and help form a pressurized equalized rain screening system.
- Allows earlier air tightness testing.
House Wrap Air Barrier System
If external insulation air barrier systems aren’t a viable option for your renovation or new home build, having a house wrap air barrier system installed will help to keep external air out of your home as well. Like the name implies, a house wrap is like putting cling film over a bowl - it creates a surface, or lid, that keeps the air out. The main purpose of a house wrap is preventing the entrance of air or moisture into the wall cavity, where it can wet construction materials (like wood, insulation, electrical, etc) and cause damage.
Driving past construction sites, you’re likely familiar with the logos of two of the most popular types of water resistive membrane products - Tyvek and Typar. While both of these products are meant to act as breathable vapour barriers, when installed correctly they can also be an effective air barrier. A house wrap should provide continuous coverage around all cracks, gaps, and openings between the exterior and interior of your home.
Modern house wrap products replace the asphalt treated papers that were common in homes built in the first half of the 1900s. Some house wraps today are installed using a peel and stick method, making for a much better air seal that won’t stretch out or sag over time. House wraps are installed over sheathing but behind exterior sidings of materials such as wood, vinyl, concrete, or brick.
The advantages to choose a house wrap air barrier system are:
- They eliminate the need to air seal interior detailing, like electrical and plumbing outlets.
- House wraps don’t interfere with the usual scheduled of contractors (ie, electrical, plumbing, etc).
- Reduces the effect of wind and rain
- Attached correctly to the structural sheathing, it can be a part of pressure equalized rain screening system.
Testing your External Insulation Air Barrier Systems
After installation, the best way to check if your new air barrier system is working effectively is by performing an airtightness test. This test measures how quickly the interior air of your home is replaced by exterior air, and this is one of the few tests where you don’t want to score 100 - the slower the air change the better. An airtightness test can help you determine how well your home is retaining conditioned air or, in a newly built or renovated home, alert you to areas that need further attention.
The reason we recommend installing external insulation air barrier systems is that increased air tightness leads to:
- Lower heating and cooling bills.
- More energy efficiency.
- Less drafts or hot or cool spots.
- increased longevity of HVAC appliances.
Learn More about Air Barrier Systems
Older homes often have little to no air barrier installed, leading to all sorts of problems with air infiltration, moisture, mold growth, drafts, and other uncomfortable and potentially damaging weather related issues. Getting to know the parts of your home and how they’re constructed can help you more effectively troubleshoot when problems arise, and give you great insight into the remediation and repair process.
At EcoStar, we’re committed to helping our customers understand the how and why of their home renovations, so that you feel confident when choosing our products and services. Knowing a bit more about the external insulation air barrier systems and house wrap installations that we offer can help make it easier for you to choose what’s right for your home. For more information on how these services might fit into your renovation or insulation project, get in touch! We’d be happy to explain more about the advantages, return on investment, and energy savings that you can have when installing external insulation air barrier systems.