A building envelope is the physical barrier between the conditioned and unconditioned, or interior and exterior, environment of a building.  The building envelope is made up the material components in the roof, sub floor, exterior walls, windows and doors which protect the interior environment from wind, precipitation, heat, light, and noise. The building envelope is your home's climate control to keep the interior dry and temperature controlled.

A building envelope serves many functions. These functions can be split into three categories:

•      Support: these building materials provide structural strength and support against internal and external loads.
•     Control:  these building materials control the exchange of water, air and temperature between the inside and outside of the building.
•      Finish: these building materials make the building look attractive on the interior surfaces and exterior surfaces.

Water, Air & Thermal Control:

The foundation is the structural component made of a combination of concrete footings, slabs and walls that transfer the building's load to the underlying substrate. The foundation must also control the transfer of moisture and temperature into the interior space.

Waterproofing membrane products include sheet membranes, liquid membranes, cement coatings, and built-up systems used directly on the foundation.

Perimeter drainage must be provided to protect the waterproofing membrane used directly on the foundation such as a French drain or a sump pump system.

To control thermal energy transfer through the foundation install insulation.  Most of the time, insulating a foundation is done with rigid foam.  Insulation can be  installed vertically around the perimeter, or under the concrete installed horizontally.

 Water, Air & Thermal Control:

The wall assembly includes multiple products that are used for support, water control, air control, thermal control and finishing the building envelope. The order in which each product is used will vary in each climate, however all are typically used in a wall assembly.  Products include exterior cladding, exterior sheathing and/or sheathing membrane, interior sheathing, vapor barrier, insulation and the structural components.

 Water, Air & Thermal Control:

The largest "holes" in the building envelope are your exterior doors and windows Exterior doors and windows that are airtight are imperative as they are key to air control, water control and thermal efficiency of the building envelope.

Typical doors are not thick enough to provide very high levels of energy efficiency on their own. Glass inserts and poorly installed or damaged weatherstripping can add to the inefficiency of energy conservation.  Properly installed weatherstripping is crucial in maintaining the best insulation for your door. 

Look for windows which are gas filled with low-E coatings and a low U-factor for better thermal resistance. The U-factor is the rate at which a window conducts non-solar heat. SHGC  (solar heat gain coefficient) measures the solar radiation emitted through a window.  When looking at a window's SHGC look for whole unit U-factors and SHGCs as they more accurately reflect the energy performance of the entire window. 

Water, Air & Thermal Control:

A roofing system is more than just the shingles. Each component contributes to protecting your home from sunlight, wind, rain, snow and hail.  The layers of a roof include decking, ice/water barrier, underlayment, starter strips, shingles and ridge caps.  Each product will control water, air or thermal properties of the roof system. Chimneys, skylights, and plumbing or venting openings are areas  where leaks would likely occur. Installing the weatherization materials and flashing correctly is important for an airtight, waterproof seal.

     Building Envelope

     Windows

     Doors  

     Insulation 

     Building Envelope Continuing Education