Design
Transitions
Roofing, connections, building form.
First Principles of Building Envelope
1. Design the connections.
◦ Simplicity, compatibility, and practical.
2. Design transitions.
1. Walls to Roofs and Parapets (Parapet - what is that?
Web Link)
2. Foundation to exterior cladding.
3. Walls to windows or openings. (fenestrations) Web
Link
4. Holes, changes in the surface and features that
interrupt a cladding or wall system.
(penetrations)Web Link
5. Material Changes.
© 2016, Southern Alberta Institute of
Technology
Residential Transitions
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Technology
Commercial Building – Transition @ Parapet
A parapet is a barrier (wall) which is an upper
extension of the wall at the edge of a roof, terrace,
balcony, walkway or other structure. Why?
• Hides roof, hides roof equipment, retains a
specific amount of water (overload storm),
connection and protection.
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Technology
Parapet Detail Example 1
Parapet Difficulties are Dependent on Wall System Used.
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Technology
Parapet Detail Example 2
Parapet Difficulties are Dependent on Wall System Used.
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Technology
Water Retaining and Risks and Water Entry
through Parapet.
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Technology
What Controls the Water Storage?
• Control flow drains and scuppers.
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Technology
Scuppers and Why?
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Technology
Scuppers
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Technology
Transition to roof and openings - scuppers
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Technology
Ponding in areas at drains.
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Technology
Large Parapets with Ponding.
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Technology
Plugged drains, what’s the back-up plan?
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Technology
Long term ponding, stains and what happens?
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Technology
Commercial - Transitions at Windows and Base
of Walls
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Technology
Commercial - Roof Drains
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Technology
This Detail is difficult – Why?
• Lets look at Valley Ridge Fire Station
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Technology
Hidden Gutter - Residential
Nice looking but…..
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Technology
Hidden Gutter
What about Thermal control layer?
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Technology
Hidden Gutter
Looks neat and clean. Are we confident we
don’t need eaves and the protection they
provide?
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Technology
Hidden Gutter
Neat and clean looking….
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Technology
Building Form – “monopoly house”
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Technology
Complexity of building shape
- How does this affect our control layers?
- Presence of water is tricky.
- More joints lead to water and or air
leakage.
- Issues may become compounded with
fluctuating ambient temperature,
building aspect, variable heat-loss
through different parts of the building
envelope.
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Technology
Cantilevers
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Technology
Cantilevers
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Technology
Continuous layers
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Technology
Example …
Warm roof meets cold roof
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Technology
Surface area to volume ratio
• Even the most energy-efficient homes lose
heat through walls, windows, doors and
roofs. Minimizing this heat loss means
higher efficiency homes. The shape of a
home also impacts heat loss.
© 2016, Southern Alberta Institute of
Technology
Surface area to volume ratio
• The relationship between the volume of a
building and its external surface area is
known as its form factor. Homes with an
optimized form factor generally perform
better, use less insulation and fewer
construction materials. This means that
buildings with better form factor will save
money on construction plus have less
embodied carbon.
• It also generally make the buildings
control layers simpler and less prone to
leaks - thermal, air, and moisture. (control
layers)
© 2016, Southern Alberta Institute of
Technology
Surface area to volume ratio -SVR
• The surface area-to-volume ratio (SVR) is
the ratio between a home's total outside
envelope area (EA) and its total volume
(V).
• A building’s envelope area is the sum of
area for all external faces of the building.
This includes all the wall and roof areas as
well as the foundation.
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Technology
Surface area to volume ratio -SVR
• SVR is calculated as ;
SVR = EA / V
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Technology
SVR
• So lets think of building as a cube 10m x
10m x 10m
• The cubes volume is calculated by Length
x Width x Height.
• 10x10x10=1000 cubic meters
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Technology
SVR
• The cube's envelope area is the same as
its outer surface area.
• To calculate the surface area, you need
to find the area of each of the six sides
and add them together.
• Each side is 10mx10m = 100 square
meters.
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Technology
SVR
• The building has 6 sides (4 walls, 1 roof,
1floor)
• Total Surface Area 100 square meters X 6
= 600 Square meters
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Technology
SVR
• Then we put this information into our SVR
Formula:
• Surface area to Volume Ratio (SVR)=
Envelope Area / Volume
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Technology
SVR
• For the cube this translates to:
• SVR = 600m2 / 1,000m3 = 0.6 m2/m3
• The SVR for the cube is 0.6 m2/m3.
• The cube is the most efficient standard
shape that you can build a building in.
© 2016, Southern Alberta Institute of
Technology
SVR
• The lower the SVR, the less potential
energy is required to heat the building.
This means that homes with basic
geometry such as simple square shapes
often have low SVRs compared to
buildings with more complex geometry
such as complicated floor plan, perimeter
shapes and cantilevers.
© 2016, Southern Alberta Institute of
Technology
SVR
• Another way to look at it is that the higher the
SVR, the less compact a home or building.
• Buildings with a higher SVR have more
surface area where heat and air can escape.
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Technology
Building form
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Technology
Building Form and Energy
• A 2,000 ft2 home with a basic square
shape would have a SVR of 0.66 m2/m3
and an annual heating energy demand
in Calgary of 31,020 kWh/a.
• A 2000 ft2 home with a more complex
design would have a SVR of 0.74
m2/m3 and an annual heating energy
demand in Calgary of 36,797 kWh/a.
• This is a 19% increase in heating energy
demand.
© 2016, Southern Alberta Institute of
Technology
Building Form and Energy
• The energy demand was calculated of
both these homes have the following
assembly insulation values:
Basement slab = R 8 (RSI 1.41)
Foundation walls = R 20 (RSI 3.52)
Above grade walls and exposed floors
= R 40 (RSI 7.04)
•
Roof assemblies = R 60 (RSI 10.57)
•
•
•
© 2016, Southern Alberta Institute of
Technology
Video Example
• Monopoly Faming - A NEW? way of
framing
• Monopoly Framing – Roof
• Monopoly House - Walls
© 2016, Southern Alberta Institute of
Technology