I learned about a company called BRINC Building Products, Inc a couple years ago. They had developed a solution for how to attach windows when using exterior insulation. Normally we would build a wood buck to move the rough framing out to the plane of the exterior insulation. This works, but we end up with a thermal bridge conducting cold or hot temperatures into the home and we would have to carefully plan how to manage water and air. Their product, ThermalBuck solves these issues. I used ThermalBuck on the Concreteless Slab on Grade project in 2019. Read about that project here.
BRINC Building Products released a new product recently. ThermalTight is an exterior insulation system with an adhered water resistive barrier (WRB). A clever idea where you only need one trip around the house to install both the exterior insulation and WRB.
Let’s start with the type of insulation that is used in the ThermalTight system. GPS or Graphite Polystyrene is manufactured by BASF with the brand name Neopor. According to the Neopor website:
“Silver-Grey Neopor GPS is comprised of many small pockets of air within a polymer matrix containing graphite. The graphite reflects radiant heat energy like a mirror, increasing the material’s resistance to the flow of heat, or R-value. Most polymer-based foams exhibit a greater ability to slow the movement of heat as the temperature decreases. Neopor GPS is in a unique class because it increases in R-value as the temperature outside drops.”\
The GPS used in the ThermalTight system is a Type II with a 15 lbs. per square foot compressive resistance and an R-value of 4.7 per inch at 75°F. The R-value increases to nearly 5 as the temperature decreases to 40°F. Neopor also has a perm rating of 3.5 which will allow some drying potential outward. Better than extruded polystyrene (XPS) which is often used as exterior insulation in my area. The insulation is available in 1.0625” R-5, 1.5” R-7, and 2.125” R-10. If you need thicker exterior insulation, for instances if you are building a 2 x 6 wall in my very cold climate, climate zone 7 and want to move from a class I or II vapor control layer to a class III, you will need to install a layer of R-5 Neopor exterior insulation to the wall sheeting before installing the R-10 ThermalTight. This increase in the exterior insulation R-value will warm the exterior wall sheeting enough to prevent it from becoming a condensing surface. The ThermalTight sheets are available in 4 x 8’, 9’, or 10’ and can be installed either vertically or horizontally. You can find more information about Neopor at the BASF website.
We know a little about the insulation, let’s look at the Water Resistive Barrier part of the system. The WRB is a non-woven, non-perforated polypropylene membrane with a perm rating of 42 using the ASTM E96 method A test, or dry cup method. This means the WRB is watertight but vapor open, exactly what you want in a Water Resistive Barrier in a cold climate. Definitely the type of WRB I would be looking for if installing a mechanically attached product. The nice thing about the system is the WRB is already bonded to the insulation, eliminating one step in the installation process.
Installing ThermalTight is not complicated. First install the window bucks, ThermalBuck, per the BRINC Building Products directions. A detailed video showing this installation can be found here. Each insulation panel has a two-inch flap on all four sides. Install the panel on the wall, attaching with either a cap nail or screw. If I were designing a wall system using the ThermalTight panel, I would plan on also installing a vented rain screen. Because 1x lumber will be screwed on top of the insulation panels for cladding attachment, I would use as few cap fasteners as possible. After the panel is set, the excess flap of WRB is cut from the top and one side of the panel. This will allow the WRB flap from the adjacent panel to lap onto one side and lower panel creating a shingle lap. This lap is sealed using a double-sided tape that is supplied with the ThermalTight panels.
The ThermalTight insulation with integrated WRB is a great way to install exterior insulation and a water resistive barrier in one trip around the home. Add ThermalBuck, and you have a great system. I am hoping to use the ThermalTight system in a future build, should that build happen, I will be blogging about the experience. Stay tuned.