Builders Technical Session

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Builders Technical Session
Heaving Walk-Out Patios and Decks Joan
Maisonneuve Alberta New Home Warranty Presented
in Partnership with
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Minimizing Patio Movement

• Water Management
• Surface
• Sub-surface
• Pile Patio construction
• Homeowner Education

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Water Soil Facts

• 32,000 gallons of water per year
• Clays holds more water more than sands or silt
• Water increases 9 in volume when it freezes
• In fine soils this freezing action is compounded
  by ice lensing

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Frost Heave
Ice Lenses
Soil
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Consequences of Heaving Patios
Deformation of sidings and trims
Lifting exterior insulation
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Consequences of Heaving Patios
Cracking of the patio slab
Lifting deck stairs
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Pressure Exerted on the Foundation
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Pressure Damage on the Wall
Compressed window trim
Bowed window
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Wall Separation from the Foundation
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Lifting Piles
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Negative Deck Slope
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Negative Deck Slope
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Separation of the Soffit Under the Deck
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Lifting of the Main Floor
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Window Wall Damage
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Window Stress
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What Can Be Done?

• Water Management
• Homeowner
• Builder
• Pile and Patio Design

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Four Areas to Address

• Clay grades
• Downspouts sump discharge
• Foundation drainage
• Pile Design
• Landscape design

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Surface Water Create a Stable Clay Grade
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Consider Compaction at the Patio
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Slope? Compaction? Room to Lift?
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Frozen Soil? Inadequate Starting Grade?
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Water from Many Slopes
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Continue Swales Past the Patio
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Locations of Sump Discharge and Downspouts
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And again
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Discharge to Underground Pipes
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And again.
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And again..
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Can Downspouts Extend?To Where?
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Retaining Walls
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Foundation Drainage
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Foundation Drainage

• Depth
• Connections
• Sump trench

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Sumps and Trenches
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Items to consider in Pile Design Frost Depth

• Typical Frost
• Penetration
• Fort McMurray 3.2 m
• Edmonton 2.3 m
• Red Deer 2.3 m
• Calgary 2.0 m
• Lethbridge 1.7 m

Code states 1.2 for clay, but not less than frost
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Pile Design ConsiderationInsulation

• Grade beams
• Frost walls
• Basement floors

CHBA Builder's Manual
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Pile Design Consideration Soil Water

• What type of soil?
• Is there a water source near it?

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Pile Design and Types
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2
3
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Pile Design Consideration Isolation

• Isolate the piles from the patio

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Pile Design Consideration Pile Overhangs
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Consider Adjustable Columns

• Insure homeowner access
• Educate on their use

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Patio Design

• Allow it to move
• Cushion the movement
• Buffer water expansion

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Level with Free Draining Material
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Educate Homeowners

• Downspouts down
• Sump discharge
• Maintaining clay grades
• Maintaining swales
• Downspouts to underground pipes
• Water features

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In Summary

• Keep surface water from reaching the patio
  piles
• Impermeable, sloped grades
• Downspout management
• Proper retaining walls
• Design piles for frost protection, uplift forces
  adjustability
• Allow for patio movement isolate piles
• Educate your homeowners on altering grades and
  downspouts

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• ANHWP
• Bulletin
• anhwp.com
• Technical
• Resource
• page

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Learn About Soils

• www.albertasoils.com

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ForHome Owners
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QUESTIONS?
Thank You!