APPENDIX F

DESIGN of RESIDENTIAL BUILDING SHELLS -
Minneapolis and Atlanta

July 17, 2002

Prepared by:

Bo Kasal, North Carolina State University
Pat Huelman, University of Minnesota¹

EXECUTIVE SUMMARY

The objective of this task was to design typical light-frame residential structures for two different climates: a hot and humid climate represented by Atlanta, GA and a cold climate, represented by Minneapolis, MN. The configuration of the structures was based on the most recent surveys conducted by U.S. Census Bureau and National Association of Home Builders. The designs reflected the local building codes valid in pertinent areas, including building envelope design. Alternative steel framing was designed such that the thermal properties matched the ones for the wood frame.

According to recent surveys conducted by U.S. Census Bureau and National Association of Home Builders, the average size of a new house is about 2,225 sq. ft. The predominant type of construction is slab on grade with 56% of new housing starts, followed by basement (29%) and crawl space (11%) designs. The two representative structures were selected to reflect the above surveys.

The Minneapolis structure was designed as a two-story building with a basement, representing a typical construction in the Minneapolis area. All framing members were solid wood with a nominal thickness of 2 in. Wood-based composites (plywood and oriented strand board) were used as sheathing and pre-engineered roof trusses were used as a roof system. The total floor area of the structure was 2,062 sq. ft. The foundation was designed as 12-in thick concrete masonry block walls. Typical wall compositions (from inside to outside, wood frame) was as follows: ½ in gypsum sheet rock, 2x4 in wood studs, 16 in on center, Kraft-faced fiberglass batt insulation, OSB sheathing (could also use plywood), housewrap, vinyl siding. The steel-stud alternative had the following composition: ½ in gypsum board, sanded and taped, 6 mil poly vapor retarder, 2 x 6 steel studs, 24 in on center. (cold rolled, C channel), insulation (R19), 7/16 in OSB, 2 in extruded polystyrene, vinyl siding.

The Atlanta structure was a grade-on-slab single-story design with the area of 2,155 sq. ft. The building envelope was as follows (from inside to outside, wood frame): ½ in gypsum sheet rock, 2x4 in wood studs, 16 in on center, Kraft-faced fiberglass batt insulation, OSB sheathing (could also use plywood), housewrap, vinyl siding. The steel frame wall composition was: ½ in gypsum sheet rock, 2x4 in steel studs, 24 in on center, R-11 batt insulation, ½ in plywood, housewrap, vinyl siding.
The designs serve as a basis for subsequent life cycle analysis of representative structures. The report includes detailed design plans, including dimensions of load-bearing elements. The load-bearing elements such as beams, floor joists or roof rafters can be replaced in the life cycle analysis by elements with comparable capacities. The non-bearing elements, such as siding, can be replaced without consideration of structural capacities but the thermal properties must be considered.

TABLE OF CONTENTS

EXECUTIVE SUMMARY
1.0 INTRODUCTION
2.0 SITE SELECTION
3.0 PLANS SELECTION
4.0 DESIGN
4.1 GENERAL FEATURES
4.1.1 Exterior Wall Systems
4.1.2 Exterior Siding
4.1.3 Thermal Considerations
4.2 LOCATION-SPECIFIC DESIGNS
4.2.1 Minneapolis
4.2.2 Atlanta
5.0 BUILDING PLANS
6.0 FUTURE RESEARCH
7.0 LITERATURE CITED
Attachment 1. One-story design Atlanta structure
Attachment 2. Two-story design - Minneapolis structure
Attachment 3. R-value recommendations for Atlanta structure
Attachment 4. R-value recommendations for Minneapolis structure
Attachment 5. One-story design building envelope - Atlanta structure
Attachment 6. Two-story design -building envelope - Minneapolis structure

LIST OF FIGURES

LIST OF TABLES

1.0 INTRODUCTION

The objective of this task was to design typical light-frame residential structures for two different climates: a hot and humid climate. The designs were intended to serve as a basis for subsequent life cycle analysis of representative structures. The report includes detailed design plans, including dimensions of load-bearing elements. The load-bearing elements such as beams, floor joists or roof rafters can be replaced in the life cycle analysis by elements with comparable capacities. The non-bearing elements, such as siding, can be replaced without consideration of structural capacities but the thermal properties must be considered.

2.0 SITE SELECTION

Two sites were selected for the initial life cycle analysis: Minneapolis, MN and Atlanta, GA. The rationale for the selection is as follows:

1. Minneapolis represents the cold climate

2. The University of Minnesota cold climate housing program provided assistance with envelope design for both Minneapolis and Atlanta

3. Atlanta represents the hot and humid climate

4. Financial constraints limited the analysis to the two cities

3.0 PLANS SELECTION

The configuration of the structures was based on the most recent surveys conducted by U.S. Census Bureau and National Association of Home Builders. The designs reflected the local building codes valid in pertinent areas, including building envelope design.

According to a national survey [1], the average size for new home construction is 2,225 sq ft (based on U.S. Bureau of Census, www.census.gov). Data from the National Association of Home Builders (NAHB) [2] shows typical designs in the U.S. as indicated in Table 3.1.

Table 3.1. Typical Foundation Designs and their Proportions for Residential Construction in the U.S. [1,2].

Based on the above table and representativeness of local building practice, slab-on-grade (Atlanta) design and basement design (Minneapolis) were selected.

The design parameters as shown in Table 3.2 were selected for the two structures:

Table 3.2. Design Parameters for Representative Structures

4.0 DESIGN

4.1 GENERAL FEATURES

4.1.1 Exterior Wall Systems

The software package SOFTPLAN [3] was used for the design. Softplan, Inc. provided the two designs as an in-kind contribution to the CORRIM work. The two houses have slightly different areas. Three different exterior wall systems were considered:

5. wood frame

6. steel frame

7. concrete masonry

4.1.2 Exterior Siding

According to US Bureau of Census [1], the market share of the exterior siding in 1999 was as shown in Table 4.1.

Table 4.1. Market Share of Exterior Siding Used in Residential Construction

4.1.3 Thermal Considerations

The recommended R-values are shown in Attachments 3 and 4. The values were obtained via interactive program available at http://www.ornl.gov/roofs+walls/. The building envelope configuration designed by the University of Minnesota cold housing program is in Attachments 5 and 6. The building envelopes were design to meet local building codes for all possible materials used in the structures. No consideration of thermal bridges due to the studs was made.

4.2 LOCATION-SPECIFIC DESIGNS

4.2.1 Minneapolis

The Minneapolis structure was designed as a two-story building with a basement, representing a typical construction in the Minneapolis area. All framing members were solid wood with a nominal thickness of 2 in. Wood-based composites (plywood and oriented strand board) were used as sheathing and pre-engineered roof trusses were used as a roof system. The total floor area of the structure was 2,062 sq. ft. The foundation was designed as 12-in thick concrete masonry block walls. Typical wall compositions (from inside to outside, wood frame) was as follows: ½ in gypsum sheet rock, 2x4 in wood studs, 16 in on center, Kraft-faced fiberglass batt insulation, OSB sheathing (could also use plywood), housewrap, vinyl siding. The steel-stud alternative had the following composition: ½ in gypsum board, sanded and taped, 6 mil poly vapor retarder, 2 x 6 steel studs, 24 in on center. (cold rolled, C channel), insulation (R19), 7/16 in OSB, 2 in extruded polystyrene, vinyl siding.

4.2.2 Atlanta

The Atlanta structure was a grade-on-slab single-story design with the area of 2,155 sq. ft. The building envelope was as follows (from inside to outside, wood frame): ½ in gypsum sheet rock, 2x4 in wood studs, 16 in on center, Kraft-faced fiberglass batt insulation, OSB sheathing (could also use plywood), housewrap, vinyl siding. The steel frame wall composition was: ½ in gypsum sheet rock, 2x4 in steel studs, 24 in on center, R-11 batt insulation, ½ in plywood, housewrap, vinyl siding.

The framing of all structures was a typical 2x4 framing, 16 in on center. Solid lumber was used throughout the structures with the exceptions where the loading required composite or steel girders. Alternative steel framing was designed such that the thermal properties matched the ones for the wood frame. Typical wall framing diagrams are shown in Appendices A and B.

5.0 BUILDING PLANS

Building plans are presented in Attachments 1 and 2. The plans contain the geometry of the structures as well as sizes of individual members. Note that the designation of the envelope materials is valid for the particular design and can be easily changed in the life cycle analysis. However, the geometry and sizes of load-bearing elements must be retained. The load bearing elements include

1. wall studs

2. headers above openings

3. floor members

4. roof members

5. foundation

At this stage of the research, most of the load-bearing elements were designed as solid sawn members with the exceptions of certain girders with high loads where wood composite sections or steel members were used.

6.0 FUTURE RESEARCH

The following activities are proposed for the next phase of research:

1. Include more sites across the U.S. to obtain more representative samples

2. Include designs containing wood-based composite materials-OSB, composite I-beams, glulam, and parallel strand lumber.

3. Include additional plans and elevations.

4. Include other non-wood materials such as concrete filled EPS.

5. Include analysis of various systems from the thermal insulation point of view

7.0 LITERATURE CITED

Crist, Dean. 2000. New Home Characteristics. Housing Economics. February 2000:19-21.

Crandel, Jay. 2000. NAHB Research Center. Personal Communications.

Softplan, Inc. 2000. Architectural Design Software. Version 10. http://www.softplan.com
    SoftPlan Systems, Inc. 214 Overlook Ct. Suite 220 Brentwood, TN

Oakridge National Laboratory web site http://www.ornl.gov/roofs+walls/.

ATTACHMENT 1. ONE-STORY DESIGN ATLANTA STRUCTURE

Figure A 2. Atlanta house - floor joists.

Figure A 3. Atlanta house - main floor plan.

A 4a

A 4b
Figure A 4. Atlanta house - elevations.

A 5a

A5b
Figure A 5. Atlanta house - elevations.

Figure A 6. Atlanta house - elevations.

A 7a

A 7b
Figure A 7. Atlanta house - typical wall framing diagrams.

Figure A 8. Atlanta house - wall framing diagrams.

Figure B 1. Minneapolis house - foundation plan.

Figure B 2. Minneapolis house - main floor plan with floor framing.

Figure B 3. Minneapolis house - main floor plan.

Figure B 4. Minneapolis house - main floor plan.

Figure B 5. Minneapolis house - wall-framing plans.

Figure B 6. Minneapolis house - typical wall framing.

Figure B 7 Minneapolis house - typical wall framing.

Figure B 8. Minneapolis house - main floor plan with roof and floor framing.

Figure B 9. Minneapolis house - main floor plan with roof and floor framing.

Figure B 10. Minneapolis house - 2nd floor joist framing.

Figure B 11. Minneapolis house - 2nd floor framing plan and wall topology.

Figure B 12. Minneapolis house - 2nd floor framing diagram.

Figure B 13. Minneapolis house - roof plan.

Figure B 14. Minneapolis house - front elevation.

Figure B 15. Minneapolis house, - left elevation.

Figure B 16. Minneapolis house - rear elevation.

Figure B 17. Minneapolis house - right elevation.

Figure B 18. Minneapolis house - section A-A.

Figure B 19. Minneapolis house - roof plan.

ATTACHMENT 3. R-VALUE RECOMMENDATIONS FOR ATLANTA STRUCTURE

DOE/CE-0180
September 1997

Department of Energy
Assistant Secretary
Energy Efficiency and Renewable Energy

R-Value Recommendations for New Buildings

Heating System: Heat Pump
Cooling System: Electric Air Conditioning
First 3 digits of ZIP code: 303
Location: Atlanta, GA

* R-values have units of F-ft²-h/Btu. The recommended R-values were produced using the ZIP-Code computer program. The recommendations are based on an analysis of cost effectiveness, using average local energy prices, regional average insulation costs, equipment efficiencies, climate factors, and energy savings for both the heating and cooling seasons.

Building Envelope Research

Oak Ridge National Laboratory

For more information, contact the facility manager for Building Envelope Research:

Andre O. Desjarlais
Oak Ridge National Laboratory
P. O. Box 2008, MS 6070
Oak Ridge, TN 37831-6070
Voice (423)574-0022; Fax (423) 574-9338
E-mail desjarlaisa@ornl.gov

Revised: August 28, 1998

ATTACHMENT 4. R-VALUE RECOMMENDATIONS FOR MINNEAPOLIS STRUCTURE

DOE/CE-0180
September 1997

Department of Energy
Assistant Secretary
Energy Efficiency and Renewable Energy

R-Value Recommendations for New Buildings

Heating System: Heat Pump
Cooling System: Electric Air Conditioning
First 3 digits of ZIP code: 554
Location: Minneapolis, MN

* R-values have units of F-ft²-h/Btu. The recommended R-values were produced using the ZIP-Code computer program. The recommendations are based on an analysis of cost effectiveness, using average local energy prices, regional average insulation costs, equipment efficiencies, climate factors, and energy savings for both the heating and cooling seasons.

Building Envelope Research

Oak Ridge National Laboratory

For more information, contact the facility manager for Building Envelope Research:

Andre O. Desjarlais
Oak Ridge National Laboratory
P. O. Box 2008, MS 6070
Oak Ridge, TN 37831-6070
Voice (423)574-0022; Fax (423) 574-9338
E-mail desjarlaisa@ornl.gov

Revised: August 28, 1998

ATTACHMENT 5. ONE-STORY DESIGN BUILDING ENVELOPE - ATLANTA STRUCTURE

Ceiling/Roof Systems

All house types will include the following components (inside to outside)
5/8 in gypsum board, taped and sanded
Engineered Trusses
Blown cellulose insulation to R30 (or high density blown fiberglass to R40)
½ in OSB sheathing
Rolled asphalt impregnated roofing paper (one layer, shingle style)
Rolled moisture protector on eve (one layer, 5' in width)
240# asphalt shingles

Basement Walls and Floors

8 in x 20 in concrete footings
12 in concrete masonry block walls
Vapor retarder installed on block wall (typically 6 mil poly)
2 in x 4 in wood stud frame wall (16oc) on treated plate
R13 fiberglass batt insulation
6 mil flame retardant poly vapor retarder
3 ½ in - 4 in concrete floor over sand (aggregate is preferred, but often used)

Walls - Wood Frame (above grade)
(inside to outside):

½ gypsum board, taped and sanded
6 mil poly vapor retarder
2 x 6 inch stud, 16 o.c.
Insulation (most common insulation is 5 ½ inch fiberglass batts)
Sheathing (most common is OSB)
Housewrap - recommended but not used much
Siding (most common is horizontal vinyl)

Walls - Steel Frame (above grade)
(inside to outside)

½ in gypsum board, sanded and taped
6 mil poly vapor retarder
2 x 6 steel studs, 24 in o.c. (cold rolled, C channel)
Insulation (R19)
7/16 in OSB
2 in extruded polystyrene
siding (most common is horizontal vinyl)

Windows

Double glaze, low E, wood frame with cladding (vinyl or aluminum)

ATTACHMENT 6. TWO-STORY DESIGN -BUILDING ENVELOPE - MINNEAPOLIS STRUCTURE

Ceiling/Roof Systems

All house types will include the following components (inside to outside)

5/8 in gypsum board
Engineered Trusses

Blown cellulose insulation to R30
3/8 in OSB sheathing
Rolled asphalt impregnated roofing paper (one layer, shingle style)
240# asphalt shingles

Basement Walls and Floors (Slab Construction)

Monolith footings and reinforced 4 in slab floor
6 mil polyethylene
gravel

Walls - Wood Frame

½ in gypsum sheet rock
2x4 in wood studs, 16 in oc (may also see a fair amount of 2x6, depending on loads)
kraft-faced fiberglass batt insulation
sheathing (most common is OSB)
housewrap
siding (most common is horizontal vinyl)

Walls - Steel Frame

½ in gypsum sheet rock
2x4 in steel studs, 24 in oc
R-11 batt insulation
½ in plywood
housewrap
siding (most common is horizontal vinyl)

Windows

Double pane vinyl windows (some low E)