advanced wood framing - woodworks

Designing Multi-story Wood Structures

Advanced Wood Framing

Scott Nyseth, PE

ADVANCED FRAMING

The Genesis:

“Operation Breakthrough”

(Not a code name for a military offensive)

• HUD sponsorship – started 1969• “stimulate the private housing industry by

promoting volume industrialized housing production, particularly through modular construction. “

• “not a program designed to see just how cheaply we can build a house, but a way to break through to total new systems of housing production, financing, marketing, and land use.”

“Operation Breakthrough”

• Terminated in 1979.

• Positives:• The National Association of Home Builders

(NAHB) along with the USDA Forest Products Laboratory (FPL)

• proposed construction methods for Optimum Value Engineering (OVE) which is also know as the Advanced Framing Method.

Operation Breakthrough How does Advanced Framing fit into our current approach to sustainable design?

LEED for Homes gives credit for using Advanced Framing Techniques

LEED for Commercial gives no direct credit for Advanced Framing Techniques. The benefit will show up in energy savings in the energy model.

There should be some incentive to save the material though…

Some jurisdictions recognize this material saving benefit –

The City of Portland Office of Sustainable Development and the PDC both got it right: The Green Building Resource Manual requires, 24”oc framing, 2 stud corners, engineered lumber, and box headers. These are “threshold” or required strategies which reflect the savings of an important natural resource, as well as energy.

The Building America program is a US Department of Energy (DOE) program which utilizes the Whole Building approach to energy efficiency, where an overall energy consumption savings is targeted, and the details of how you get there do not matter (Energy Star Rating). Advanced Framing is an important tool to achieve energy savings, but it is not required. That being said, almost all buildings in this program utilize Advanced Framing Techniques.

Details of Advanced Framing

Elimination of unnecessary wood framing in a structure

Simply =

Image from Cost Effective Home Building: A Design and Construction Handbook by the NAHB

Not So Advanced Framing


Advanced Framing


Advanced Framing AlignmentAdvanced Framing

• Studs at 24” o.c.• Two stud corners or other means to fully

insulate corners• One stud is used to support each header• R-10 headers• Fully insulated interior/exterior wall

intersections• 17% of the wall is studs and headers• Conventional = 23% studs/header (�=35%)

Advanced Framing System

• 2 Stud CornersAdvanced Framing System


• Hardware used to eliminate cripples at wall openings


•Single Top Plate

Energy Saving Details

• Insulated headers

• No header necessary at non-bearing walls


• Recessed Header

• Trusses & Joist “Stacked” over studs


• Full and even insulation depth to the outside edge of the exterior walls

• Raised heel or oversized trusses


• Airtight electrical boxes in exterior walls and ceilings


• Seal ALL penetrations to the outside

Pearl Family HousingOwner: Ed McNamara/Turtle Island DevelopmentEngineer: Miyamoto InternationalArchitect: Ankrom Moison Associated ArchitectsContractor: Walsh Construction Company

Fire and Life Safety

Parking Level Meets the definition of a basement , does not contribute to area or height limitation.

Ground Floor Type IA Construction – Occupancy S2, B, E, A2.

Allowable Height - Unlimited

Allowable Stories - One Story

Allowable Area - Unlimited

Podium (2-6) Type IIIB Construction – Occupancy R2

Allowable Height - 55’

Allowable Stories - Four Stories

Allowable Area - 16,000 sf

Modifications to height

Use automatic sprinkler system to add one story and 20’ to allowable height.

Modified height Allowance (fire and life safety) = 75’

Structural height allowance for plywood shear walls = 65’

The Structural height limitation controls the building height!

Type IIIB details

2hr Exterior Bearing Walls – Fire retardant treated wood req’d

• Galvanized or Stainless Steel fasteners required

• Reduce structural properties of wood

Exterior Bearing Wall

Case Study – Advanced Framing Quantify lumber savings for various

Advanced Framing details:

Douglas Fir can produce 1000 bd ft of lumber per year per acre such that every 30 years approximately 30,000 bd ft can be logged.

Wall Studs Wall Studs –

Conventional Advanced Savings

Exterior Walls45,000 s.f.

33,750 BF 22,500 BF 11,250 BF

Interior Walls75,000 s.f.

56,250 BF. 37,500 BF 18,750 BF

Note:2x6 @ 16” o.c. = 0.75 BF/s.f.2x6 @ 24” o.c. = 0.50 BF/s.f.

Top PlatesTop Plates -


Exterior 2x6 Walls

1,200 LF/Floor

2,400 BF/Floor 1,200 BF/Floor1,200

BF/Floor

Interior 2x6 Walls

2,000 LF/Floor


BF/Floor

Interior 2x4 Walls

4,400 LF/Floor


BF/Floor

Totals

(5 Floors)46,750 BF 23,375 BF 23,375 BF

Window Trimmers -Conventional Advanced Savings

Under Header (4) 2x6x8’ studs (2) 2x6x8’ studs 1,620 BF/Floor

Under Sill (4) 2x6x3’ studs (2) 2x6x3’ studs 540 BF/Floor

Totals(90 windows/floor)

10,800 BF

Miscellaneous Reductions -

** Savings based on 70 windows / floor @ 5 floors


Headers in NL Bearing Extr.

6x6x5’ (20 BF) 2x6 Flat (5 BF) 5,250 BF**

Wall Corners & Intersections

(3) 2x6x9’ studs (2) 2x6x9’ studs ~10,000 BF

Totals 15,250 BF

Approximate Lumber Savings –

Equivalent to about 2.9 acres of 30 year old Douglas Fir (~ 2x4x23 miles long!!)

Savings

Wall Studs 30,000 BF

Top Plates 23,375 BF

Trimmers 10,800 BF

NL Bearing Headers

5250 BF

Corners/

Intersections10,000 BF

Totals 80,000 bf

Delivery or Disposal?

Challenges (Design Opportunities)

• Application. Advanced framing requires stacked and modular construction to be most effective. This may not work well with certain project types

• Layout Control. Advanced framing requires tighter control of framing layout, which may be difficult to coordinate between subcontractors.

• Different. Advanced framing methods differ from standard wood construction practice. There may be ‘growing pains’ associated with implementation.

• Availability. Custom cut studs (94 1/8” vs. 92 5/8”)

Advantages• Cost Savings. Both upfront and long-term

• Reduction in shrinkage. For multi-story buildings, a single top plate will result in at least one third less total shrinkage

• Reduce waste. Wasted materials are paid for 4x, once to get, once to move around, once to move scrap to dumpster, and once to haul away

• Sustainability. Material and Energy savings

Advanced Framing just makes sense

Contact

Scott Nyseth, PE

Miyamoto International

www.miyamotointernational.com

advanced wood framing - woodworks

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