Recommended Residential Construction for the Gulf Coast 
Building on Strong and Safe Foundations
FEMA 550 / July 2006

Appendix C. Assumptions Used in Design 

Gulf Coast Foundation Designs
The foundation designs proposed in Appendix A are based on the following 
standards and codes:

ASCE 7-02
Minimum Design Loads for Buildings and Other Structures 
American Society of Civil Engineers (ASCE) 

ACI 530-02/ASCE 5-02/TMS 402-02
Building Code Requirements for Masonry Structures 
American Society of Civil Engineers (ASCE) 
American Concrete Institute (ACI) 
The Masonry Society (TMS) 

ACI 318-02 
Building Code Requirements for Structural Concrete 
American Concrete Institute

ANSI/AFPA NDS-2001  
National Design Specifications for Wood Construction 
American Forest & Paper Association (AF&PA) 
American Wood Council  

IRC-2003 
2003 International Residential Code for One- and Two-Family Dwellings 
International Code Council (ICC)

To provide flexibility for the builder, a range of dead loads and building 
dimensions was used for calculating reactions on the foundation elements. For 
uplift and overturning analyses, the structure was assumed to be relatively 
light and narrow, and constructed with a relatively low-sloped roof. For sliding 
analyses, the home was considered relatively deep and constructed with a steeper 
roof slope. For the gravity loading analysis, a heavier structure was assumed.  

Dead Loads 
For Use in ASCE 7-02 ASD Uplift/Overturning Load Combination #7 (0.6D + W +H)

First Floor - 8 psf - Vinyl flooring, 5/8-inch plywood sub-floor and 2 by 8 
joists 16 inches on centers

Second Floor - 10 psf - First floor components plus 1 layer of -inch gypsum 
drywall

Wall - 9 psf - Wood siding, 2 by 4 studs 16 inch on centers, -inch plywood wall 
sheathing, and one layer of -inch gypsum drywall

Roof - 12 psf - 200 lb/sq asphalt roofing, 15 lb/sq felt, -inch plywood 
decking, 2 by 4 top and bottom truss chords 24 inches on centers, -inch gypsum 
drywall ceiling finish

Dead Loads 
For Use in ASCE 7-05 ASD Gravity Load Combination #2 (D + H + F + L + T)

First Floor - 16 psf - Dead loads increased 8 lb/sf to account for additional 
finishes like hardwood flooring (4 lb/sf), -inch slate (7 lb/sf), or thin set 
tile (5 lb/sf)

Second Floor - 18 psf

Wall - 10 psf - Wall weight increased to account for cement composite siding

Roof - 12 psf

Concrete - 150 psf - Normal weight concrete. Footings for continuous perimeter 
walls were also sized to support full height brick veneer at 40 psf. 

Masonry - 115 psf - Medium weight block

Grout - 105 psf

Brick Veneer - 40 psf

Wind Loads 

Designs provided for 120 mph, 130 mph, 140 mph, and 150 mph zones (3-second gust 
wind speeds per ASCE 7-02). Wind analysis used Method 2 for buildings of all 
heights.  

Exposure 
Category C - Open terrain with scattered obstructions generally less than 30 
feet in height; shorelines in hurricane-prone areas

K subscript zt - 1 - No topographic effects (i.e., no wind speedup effects from 
hills, ridges, or escarpments) 

K subscript d - 0.85 - Wind directionality factor (for use with ASCE 7-02 load 
combinations)

K subscript z, K subscript h - Velocity pressure coefficients for Exposure 
Category C  

Flood Loads 

V Zone - Breaking wave load from a wave with height 78 percent of stillwater 
depth (d subscript s) 
Flood velocity (fps) equal to (gd subscript s) superscript 1/2 up to a maximum 
of 10 fps (FEMA 55 Upper Bound)

Coastal A Zone - Breaking wave load from 1 foot up to a 3 foot high wave 
Flood velocity (fps) equal to (gd subscript s) superscript 1/2 up to a maximum 
of 5 fps (FEMA 55 Upper Bound)

Non-Coastal A Zone - Breaking wave load up to a 1 foot high wave 
Flood velocity (fps) equal to stillwater flood depth (d subscript s) (in feet) 
(FEMA 55 lower bound)

Lateral Loads (on stem walls)

Lateral earth pressures from saturated soils - 100 pounds per cubic foot (pcf)  

Surcharge for slab weight and first floor live load - 65 pounds per square foot 
(psf)  

Live Loads
First Floor - 40 psf
Second Floor -30 psf
Roof - 20 psf

Soil Bearing Capacity
1,500 psf Presumptive value for clay, sandy clay, silty clay, 
clayey silt, silt, and sandy silt (CI, ML, MH and CH) (2003 IRC)

Building Dimensions
Building Width - 14 ft (per module)
Building Depth - max 42 ft - min 24 ft
Shear Wall Spacing - max 42 ft
Floor Height - 10 ft (floor to floor dimension)
Roof Pitch Ratio - min 3:12, Uplift and overturning calculation - max 12:12,  
Sliding calculation
Roof Overhang - 2 ft