To get the most out of a high performance building system, it is beneficial to understand the key components of an enclosure. The enclosure of a building most commonly refers to the walls, roof and foundation systems that protect and provide a controlled environment for the interior.

Since enclosure is all about separating the interior from the exterior environment it means that enclosure systems will change drastically depending on the location and climate of your project. For us here in the Pacific Northwest we expect a lot of rain, but are experiencing increasingly fewer extreme temperatures.

In a climate like the Pacific Northwest a high performance wall assembly would consist of the following “control layers“, each of which helps control a load on the building, whether it comes from the inside such as hot steam from a shower, or the outside such as a heavy storm.

Thermal Control Layer
- Controls heat transfer with insulation materials that have a low thermal conductivity. Often framing members create a large amount of thermal bridging, which can be negated through an exterior insulation layer. Its important to note that the material you use for insulation will change depending on the application. For example exterior mineral fiber insulation like RockWool is vapor and air open, meaning it can vent itself.
- You can get a quick idea of how much energy will conduct through a enclosure using a one-dimensional Fourier’s Law of Conduction.
Vapor Control Layer
- Controls vapor from between interior and exterior, flowing either way to prevent condensation, mildew, and mold.
Air Control Layer
- Neutralizes the pressure difference between interior and exterior from driving water and fluids inside the building.
- Divides the interior air from exterior air, meaning all the energy and money spent on heating or cooling your house isn’t escaping through cracks and openings. Heat exchanges can be used to exhaust stale air, and transfer its heat to incoming fresh air to conserve energy.
Water Resistive Layer
- Stops and controls water from going where you don’t want it, such as flashing or Water Resistive Barriers.
Water Shedding Surface
- The surface the rain will hit, such as cladding or roofing that reduces load on the rest of the building.

For all of these 5 layers to work it is key that they are continuous. This means no gaps, and that seams are taped or sealed. This shows up in the design and engineering process, where you may need to fasten exterior wall cladding through 4” of exterior insulation while minimizing the thermal bridging and holes you create. For this we can use special hardware like a Fero Fast Bracket. It also shows up in the installation and construction stage where control layers can be damaged and create holes in your enclosure.

By integrating designers and engineers on site, as well as routine performance checks we ensure that projects achieve a high performance through proper installation.

Here is an example detail of one such enclosure: