Insulation isn’t just for thermal comfort. When it comes to insulating your building envelope, it goes beyond the roof and walls above grade. Your foundation needs insulation, too. What exactly is required from below-grade foundation insulation panels? In this article, we’ll explore why you need to insulate a building’s foundation and what your options include.
Why Insulate Your Foundation?
Your project’s foundation needs to be protected in the same way as the rest of the building that you see above ground. Things that you need to protect your building envelope from include:
Moisture
Extreme temperatures
Water intrusion
Common problems that building owners face that can be solved by proper insulation at the foundation level include mold, mildew, water intrusion, and shifting of structural elements. When you use foundation insulation panels, you can minimize or eliminate these issues.
Eliminate Condensation
Exterior foundation insulation panels can reduce or eliminate condensation problems. Condensation happens when warm air drops in temperature quickly and the moisture condenses on a cold surface. If your walls are cold and your home is warm, you’ll have an increased risk of condensation problems. Installing exterior foundation insulation panels keeps your walls warm to match your interior space’s temperature.
Protect Your Structure
The freeze-thaw cycle can wreak havoc on buildings. Over the course of a year, most structures will experience extreme temperature variations, leading to the expansion and contraction of each of the building components. Extreme temperature fluctuations can lead to shifting, settling, and other problems in your structure. Protect your structure by shielding it from direct contact with these extreme changes in temperature with exterior foundation insulation panels.
Keep Water Out
Water flows through the path of least resistance. Since a building’s foundation creates a large hole in the earth that displaces soil and water, water will always try to get back in. That’s why waterproofing your foundation is so important. Applying waterproofing materials alone to your basement walls will not be sufficient. Because your waterproofing gets backfilled with soil, you’ll need to protect it. Foundation insulation panels an inch or so thick can do the trick, by ensuring that your waterproofing remains untouched andis able to do its job by keeping the water out of your building’s below-grade floors.
What Type of Insulation to Use on Exterior Foundation Walls?
Exterior insulation comes into contact with the elements directly, so you’ll want to make sure you’re using a compatible building material that will not be destroyed or hindered in the unpredictable below-grade environment. Using board insulation, such as XPS, EPS, or Polyiso—that was manufactured in a controlled environment is essential to making sure you’re applying a consistently high-quality layer of foundation insulation. Plus, it’s quick and easy to install with its modular form.
When comparing good, better, and best options for exterior foundation insulation panels, it ranks like this:
Good: Expanded Polystyrene Insulation (EPS)
Better: Extruded Polystyrene Insulation (XPS)
Best: Polyisocyanurate (Polyiso)
The rationale behind this comes from looking at the moisture absorption properties of each insulating material. EPS performs the worst with a water absorption of 2% or more, XPS is better with a moisture absorption of .3%, and polyiso takes the cake with a water absorption of less than .2% when choosing a foil-faced version.
Superior Foundation Insulation Panels
When shopping for exterior foundation wall insulation, you’ll want a product that will last. Polyiso has many more advantages when it comes to insulating foundation walls. It’s versatile, durable, affordable, and readily available.
Rmax Thermasheath® is a premium foil-faced polyiso insulation used in new construction and renovation projects for exterior foundation insulation panels. It can be placed in conjunction with foundation waterproofing on below-grade exterior walls and with concrete foundations. With an impressive R-Value of R6 per inch, you can achieve high energy efficiency with minimal thickness while still providing protection to your foundation and waterproofing.
Rmax Thermasheath can be used as a Water-Resistive Barrier (WRB) when used together with construction tape at the joints. Polyiso is versatile because it is compatible with multiple attachment methods, including adhesives or mechanical fasteners.
Tapes that are compatible with Rmax Thermasheath® include R-SEAL 3000 and R-SEAL Construction Tape. R-Seal 3000 is an aluminum foil-coated tape with pressure-sensitive adhesive that makes it extremely resistant to humidity, moisture, and mold. R-SEAL Construction tape is a durable mold, moisture, and UV-resistant BOPP film with pressure-sensitive acrylic adhesive.
Rmax Can Help with Your Next Construction Project
Neglecting to insulate a building’s foundation can lead to structural problems, heat loss, moisture issues, and more. Before you break ground on your next construction project or remodel, give your local Rmax representative a call to make sure you’re utilizing the right types of insulation throughout your entire building envelope. From below grade—up to the roof—and everywhere in between, we can provide the best solutions.
Contact us today for advice from the insulation experts!