Home Inspection 101: Inside The Inspectors Head – Information on Strata Rainscreen
Featured Blog Post Written By Aaron Borsch from A Buyer’s Choice Home Inspections
Last blog I was speaking on roofing systems and other sound proofing traits of a strata complex.
Now one of the big things I get asked is about leaking condos, or rain screening.
The term ‘leaky condo’ is pretty specific to the lower mainland, and refers to many of the condo buildings built between the late 1980s and mid 1990s, though not limited to this era.
It came about due to a construction boom that was occurring at that time. Designers from other parts of the world, namely California, were brought to lower mainland to help keep up with the demand for buildings.
The issue with the design during this time, in easy terms, is that moisture would not be allowed to vacate the wall cavity. Instead it would remain in the wall cavity which would cause rot, mould, or other structural issues over time.
A few other matters exasperated things. A material called Exterior Insulation and Finish System (EIFS) was used. Also building code at the time encouraged builders not to include overhangs on a building, therefore there was no shield from the elements.
It was quite prevalent, and resulted in the collapse of the previous non-mandatory home warranty system. It also resulted in the establishment of the Homeowners Protection Office, new standards for construction, and new building code. It also resulted in financial assistance programs available to those that could not afford the levies from their stratas.
A new wall assembly system was developed which commonly referred to as Rain Screen.
Rainscreen – The Solution to a Leaky Condo
This type of wall system essentially, again in easy terms, allows moisture that either penetrates, or remains within the wall system, to escape through a gap.
This gap also allows air to circulate, so that it can reduce the chance of rot forming from consistent contact with moisture.
Rain screening became a requirement in 1996 in Vancouver for all buildings, and in 2006 for coastal areas in the remainder of BC.
How Can I tell if a Building is Rainscreened?
You can easily tell if a building has a rain screen by feeling under the exterior wall. If you feel a gap under it, likely its been updated with a rain screen.
Another way to figure out of a building is rain screened, is observe the exterior wall. If there are what appear to be ‘sections’ separated by flashing, its likely been rain screened. The key is to look for that gap under the wall.
Horizontal plank style cladding, such as vinyl, wood, or hardiboard, naturally act as a rain screen based on how it was installed. They will already have air gaps underneath the material due to the nature of the ‘plank’ style of cladding.
Rainscreen vs. Face Sealed
It’s important not to mix up a building being rainscreened versus face sealed.
Face sealed systems means that the siding (think of it as the face of the building) is water tight from the top to the bottom. In these types of systems, the builders will have caulked and sealed any joints in which water may try to get in to. However, in the case that water does find a way to penetrate in a face sealed system, it can cause hidden and expensive damage as there is no way for the water to release, and as a result of the caulking and sealing there is no air circulation for drying. For a wood frame building (low-rise buildings), failures with face sealed buildings are likely to cause rotting and mold.
Common exterior materials in a face sealed system include:
- Traditional Stucco
- Exterior Insulated Finish System (EIFS)
- Concrete or Masonry ‘Mass’ Walls
Rain screen systems on the other hand take in to consideration that it is a possibility that water may penetrate due to wind driven rains. Therefore, the rainscreen system has three layers of protection to prevent water and moisture damage:
- A durable exterior surface for primary water control and resistance to mechanical damage
- An air gap between the primary exterior and the house structure
- A water resistant membrane installed against the home sheeting.
Vancouver and its subparts have rainy weather all of the time (hence the term “Raincouver”), and it’s often raining for months at a time. Thus, of the two, rainscreened buildings are superior to face sealed buildings as they take preventative measures to avoid moisture and rotting despite some water breaking the exterior.
Risks of not having Rainscreen
If a condo unit has not been rainscreened, then you can expect some talk of it in the strata minutes going forward. Because it is quite an expensive bill, it is important that when you are considering purchasing a building without rainscreen that you take a good hard look at the contingency reserve fund. To add the rainscreen they will most likely take a portion out of the contingency and special levy the rest to the owners, so you could possibly expect a very large bill going forward. If you’re looking at a building older than 2006, always make sure to check whether it’s been rainscreened.
For next blog, more on strata’s. Underground parking, and then some ‘good to know’ items when looking at a strata.
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