Water Management: Part One

Poor water management is a house killer. Acute, catastrophic failure is not the main concern, and from our experience seems to rarely happen. The real danger is the small and consistent leak that allows bits of water beneath your siding, beyond your window and onto your rough window sill where it is trapped. This water has little potential to dry or drain away and if it consistently collects in a vulnerable area over a long period of time it will almost certainly lead to mold growth and even to wood rot that can be devastating if the volume is great enough.

You have heard the stories of rotted walls and floor joists, or even severe structural damage caused by poor roof flashing. Rotted sills, wet and moldy insulation and drywall enabled by poor detailing around windows/doors and other penetrations into the home.

This series of blog posts will cover Water Management. We will explain the details, why they work and how to integrate them into existing systems.

The nature of renovations is such that sometimes we can only do so much. We are at the mercy of our clients’ budgets and so we always do the best we can, when we’re able for the good of our clients and the houses we work on.

This post will be a short non-comprehensive introduction to basic concepts and typical products that homeowners should be aware of.

1) Think like a drop of water

This means that when we are installing an exterior door we imagine how water running down different planes of the wall may behave. Where is it likely to go if unobstructed? Yes, gravity will pull it down. So ideally we want to slope horizontal surfaces away from the house to encourage water out.

But our houses don’t exist in a vacuum. Water will move down, but in windy conditions water can also traverse. It can move horizontally across surfaces. So not only are the head and sill of a window opening vulnerable, but so are the legs of the window openings.

Winds driving directly at a wall can also force water inside and even up. Surface tension and the right wind conditions can actually cause water to move vertically up into areas that conventional wisdom may say are not vulnerable.

In summary, think like a drop of water but assume that water can get everywhere and plan to enable adequate drainage and drying potential and to kick water back out from the inner layers (beneath your cladding) to the outer layer (outboard of the cladding) whenever possible.

2) Install protective layers “shingle-style”

Best practice when installing any protective products is shingle-style installation. That means working from the bottom, up. If your house has a mechanically fastened WRB like a Tyvek, start at the ground and work up, overlapping subsequent layers over top of lower layers. Similar to how roofers will apply roofing membranes from the eaves, up or how they shingle from the eaves up to the ridge. This simple practice dramatically reduces the total points for water intrusion beneath your protective layers.

Even taping seams working on integrated systems like a ZIP panel it is ideal to tape from the bottom, up always lapping seams to encourage water exfiltration and prevent water infiltration.

3) Kick-out

Whenever possible, kick water out and away from the roof/wall etc… Kickout flashing at valleys to divert heavy flows of water off a roof directly into the eavestrough; flashing at butt joints in siding to kick water that finds that joint out onto the surface of the piece below and not into the wall; step flashing on your roof to kick water out onto the surface of the shingles; or metal head flashing above a window or door to kick water out beyond the frame/trim to have it drip down and away. All of these types of kickouts divert water out and away to discourage infiltration.

Products typically used today will include membranes like Tyvek/Typar. These are products that wrap the house and are mechanically fastened with staples or cap fasteners. On older homes, felt paper was common and served the same purpose. There are peel-and-stick products that serve as WRB (weather resistive barrier) as well. Popular options include Blueskin, where walls are primed and the release paper is removed and the product is adhered to the wall. There are also bonded sheathing products with the WRB integrated onto the surface of the wall sheathing like Zip System where once the joints between panels are taped and rolled the system is considered water tight. And less common still is fluid applied, where a water resistive product is sprayed or rolled onto the house to form a WRB.

Other products that will be critical to good water management include high quality sealants, liquid flashing, rigid flashing, flashing tapes, vent strips, and drainage membranes.

There is much to know, and we will continue to contribute to this blog series as opportunities arise to showcase different products, different methods, and helpful tricks/tips.

As always, thank you for reading. We value our clients and anyone who takes the time to engage with our content. If you are looking for a General Contractor operating within the Halton Region - specifically in Acton, Georgetown and Milton and surrounding areas please reach out by phone at 416-930-3724, or email at info@whiteoakhomes.ca or follow a link to fill out a contact form.