Basics of Building Envelope Construction

Your building envelope is just as important as the interiors. Keeping the weather out and the comfort in is the primary role for your envelope. As a builder you should be focused on quality to this vital building component, holes and improper installation can lead to discomfort for the building occupants.

We won’t pretend to be fancy building scientists, we’re far from it. But as a project manager or site super intendent it’s your job to know the basics and the right questions to ask. We’re here to help with that.

What Makes Up The Building Envelope?

The building envelope is really any exterior facing component of your building. It can be the walls, slabs, roof and parapet. It could be clerestory windows or skylights. Anywhere the weather could come in your building envelope is there to protect you.

In general the building envelope is made up of three components – slab, walls and roof.

What The Various Construction Techniques for each Building Envelope Component?

For each component there’s a long list of materials and systems that can make up your assemblies, so lets list a few of them:


  • Concrete
  • Metal Deck
  • Insulation
  • Air Vapour Barrier


  • Curtainwall
  • Window Wall
  • Panelling or Siding System (ceramic, metal, composite, precast etc)
  • EIFS
  • Studs
  • Insulation
  • Air Barriee
  • Vapour Barrier
  • Metal Flashing
  • Bricks / Masonry
  • Stone
  • Exterior Sheathing


  • Slab
  • Metal Deck
  • EPDM Roofing
  • Inverted Roof System
  • Green Rood
  • Mod Bit Roof
  • Vapour Barrier
  • Flashing

As you can tell theres a lot to know about the different types of systems. The terminology can really add up and get confusing so just try to keep things within the three main components until you get more comfortable with the terminology.

Focus On Quality In Envelope Construction

Given there’s alot to know your main focus should be constructing with quality in building envelope construction. If this is your main purpose you’ll stand a better chance at doing so. How do you start, there’s a few main concepts you can follow or generally always keep in mind.

Vapour Barrier On The Wet Side, Air Barrier On The Warm Side – one of the golden rules of construction. The intention of this is to keep the insulation free from moisture. By putting the vapour barrier on the outside of the wall cavity it keeps any vapour from the exterior from getting inside. The air barrier is intended to stop the movement of air. Because warm air condensates when it gets cold, you want to block the cold air from getting warm. Therefore if you live in a cold climate it goes on the inside (warm air gets cold on its way out) and in warm climates it goes on the outside (warm air tries to get in).

Focus On Transitions – how many times have you heard of a roof leaking at a joint in it, or a window leaking around the perimeter casing? 90% of all facade problems originate from where two materials meet. Generally products that are applied across large areas, unless applied incorrectly, are designed to perform well. Where you run into issues is where two different products meet. Spend extra time on these details and focus on making sure they are water tight and sealed. Before installing the products it’s recommended you check with both to make sure they are compatible. For example – asphalt that is used to apply blueskin can eat away at certain PVC products used in roofing.

The Newest System Isn’t Always The Best – in construction vendors are always trying to sell their newest system. The newest isn’t always the best. Sometimes proven systems are the best way to go. You never know what the elements will throw your way and taking a chance on something that is new could go horribly wrong. In envelope construction replacing a product if it’s failed can be incredibly costly so relying on something that has a proven quality and track record can be a good thing.

Mockups Are a Man’s Best Friend – seriously. Everyone always wants to see what the interior lights or finishes will look like but doing mockups to understand how different products will fit together can be equally useful. Leave time in your schedule to build samples and mockups to get sign off and allow your trades to coordinate between the different vendors.

Envelope construction is a challenging task and getting it right can be a trial and error process. By focusing on quality, understanding the basic concepts and relying on the expertise of others you can succeed in your building.

What’s your biggest lesson learned in facade or envelope construction? Share some of your stories with us below.

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