For some homeowners, it’s currently too late, as Winter Storm Mateo lingers over the top half of the continental U.S., bringing unrelenting snowfall and, in some cases, high winds. In moments when your home seems completely besieged by severely inclement weather, it quickly becomes apparent how important it is to outfit your abode with a strong, durable, and weatherproof membrane, especially around your windows.
It’s an unfortunate reality that most windows, regardless of their construction, have several shared points of vulnerability that make them susceptible to air and moisture intrusion. In past posts, I’ve paid special attention to installation practices and unit fit as key instigating factors, but the space between your windows and siding can also provide an opening for leaks and drafts.
What is Window Flashing?
To protect this pivotal space between a home’s siding and window frames, builders and renovators will use a thin strip of material, often vinyl, metal, or tape, with an adhesive backing. This strip is carefully lined along the opening in the wall that contains the target window(s), which means installation is an involved process.
You’ll have to remove your window frame, not only to correctly apply the flashing, but to ensure that you have enough room to apply rolling pressure to further improve the seal. Also, in many cases, contractors will also apply a thin lining of caulk to further reinforce the seal, because a breach in either your flashing or building paper will lead to worsening insulation and likely repair.
What Type of Flashing is Best?
With multiple types of window flashing material, it would be comforting to know that there was one preferred option, but unfortunately, it’s not that simple. Tape flashing is the most popular choice because it’s relatively more affordable and easier to apply, but it also has a higher degradation rate. Vinyl flashing offers durable protection and low application difficulty, but will snap in extremely cold weather. Metal flashing offers the most reinforced barrier, but its inflexibility and sharp edges present obvious hazards and frustration for first-timers.
The most important takeaway is that every flashing material has specific strengths and weaknesses, so you must balance them against your particular location, climate, and home situation. That said, some exterior remodeling companies are developing window flashing that incorporates multiple membrane layers and provides a weathertight seal without the application of foam or caulk.
What Are the Risks of Not Flashing My Windows, or Flashing Them Improperly?
All of the same risks you’ll incur with a warped or porous window—most importantly, moisture intrusion and air leakages. Over time, these can create a host of costly problems for your home, including:
Poor Insulation and Hiking Utility Costs: When you can’t keep heated air in your home, your HVAC systems have to consume more energy to keep your interior comfortable.
Rot, Mold, and Mildew: Small beads of condensed moisture can either coat adjacent walls or pool on wooden floors and create the perfect conditions for rot, mold, and mildew.
Flimsy Seals: If your flashing adhesive is inattentively or messily applied, it can create gaps for air and moisture leakage. What’s worse is that, because flashing protects the space between your windows and siding, that moisture may end up stagnating inside your walls.
Uncomfortable Drafts: Cold air passing freely through your windows will make areas of your home too chilly to enjoy.
Little Tasks Like Window Flashing Make a Huge Difference For Your Home
It may not be the most noteworthy aspect of maintaining your windows, but investing in great flashing material—and applying it properly—will go a long way towards keeping your home insulated, comfortable, and free of unwanted moisture, drafts, and precipitation.