Building Enveloppe Flashcards
What is a Building Envelope?
- Separates the interior from the exterior
- Protects buildings from climate
- Maintains an indoor environment according to use/occupancy
What are the Building Envelope Requirements? Name all 12.
- Control water vapour flow
- Control rain penetration
- Control light
- Control heat flow
- Control airflow
- Control sound
- Control solar radiation
- Control noise
- Control fire
- Provide strength and rigidity
- Adjust to movement
- Weather gracefully
What are the basic principles and key elements of a building envelope?
The basic principle is an insulated exterior wall with air and vapour barriers to control the flow of air, heat, and moisture.
- Roofing materials that provide a water-resistant covering
- Flashing materials that prevent water ingress and leaking
- Exterior walls that provide protection from the weather
- Insulating materials that control heat loss and heat gain
- Air and vapour barriers that control the flow and air moisture
- Expansion joints that allow building materials to expand and contract due to temperature variations
Building envelope design is a process that merges _________, __________, and ___________.
- Art
- Science
- Craft
The first line of defence against the movement of water vapour is called the ____________.
Vapour Barrier
When designing a building envelope, how do you arrange the materials according to their permeability?
a. From inside to outside: Most permeable to least permeable.
b. From inside to outside: Least permeable to most permeable.
b. From inside to outside: Least permeable to most permeable.
Water vapour can move in two ways. Name them.
- Air Current
- Vapour Diffusion
Must an air barrier membrane be vapour permeable? Why/Why not?
Yes. An air barrier can be a vapour barrier, but a vapour barrier can’t be an air barrier.
Name the 3 principal methods of heat transmission.
- Convection
- Conduction
- Radiation
What is the basic principle of how thermal insulation works?
Heat moves from warmer to colder areas.
What are the 3 requirements for a vapour barrier?
- Interior humidity levels
- Exterior temperature
- Wall assembly
What are the 3 sources of water in any wall?
- Studs
- Concrete
- Ext. and Int. moisture
Define “R-value”
The R-value is the measure of the ability of a material to resist heat flow.
Define “U-value”
The U-value is the measure of the ability of a material to conduct heat flow.
What is a vapour barrier?
A vapour barrier is any material used for damp proofing, typically a plastic or foil sheet, that resists diffusion of moisture through the wall, floor, ceiling, or roof assemblies of buildings and of packaging to prevent interstitial condensation.
What is the function of an air barrier system?
Resist the flow of air across the building envelope, wether it be caused by wind, stack effect or fan pressurization.
What are the requirements for an air barrier?
- Must be airtight
- Must be continuous
- Must resist wind loads
- Must be durable
- Must stop liquid water intrusion
- Must be sufficiently vapoured permeable
- Must promote drying of the wall cavity while allowing the water vapour barrier to be excluded out of the house.
What is the difference between nominal R-value and effective R-value?
The Nominal R-Value is the “estimated” level of performance, while the Effective R-Value is the “actual” level of performance in real conditions.
What is “Thermal Bridging”?
It is any material that conducts hot/cold at a higher rate than insulation.
Where would you find thermal break being used?
Windows
What are the insulation requirements for a 2x6 @ 16” spacing o.c?
23% framing and 77% insulation
Name some of the insulating materials.
- Rigid polyisocyanurate board
- Closed cell sprayed polyuerthane
- extruded styrofoam board
- Rockwool batt
- Expanded polystyrene board
- Cellulose fiber
- Fibreglass batt
- Open cell spray polyurethane
Name the 4 newer methods of insulation.
- Cotton Blue Jeans
- Wood Fibre
- Seaweed
- Sheep’s Wool
Name examples of rainwater management strategies.
- Overhangs
- Flashing
- Downward slope
