The Environmental Design Standards Schedule sets Nature's stage for custom home design and custom home building. What's in your home plan?

An Environmental Design Schedule of some sort is a general requisite, albeit limited in scope, for higher-end designer house plan sets and on rare occasion demanded in some categories as part of a designer house plan set submission by a building authority having jurisdiction. Commonly, these inclusions are not nearly as comprehensive as that which follows, in this custom home designer's opinion.

WHAT'S IN THE ENVIRONMENTAL SCHEDULE?

It's best to do the Environmental Schedule work as early as possibly in the custom home design enterprise. This particular designer home plan Environmental Design Standards Schedule was authored preparatory to a custom home design project in Warrenton, PA. All the entries follow.

1. Latitude 38.68N, 77.76W

2. Elevation: 498-640 linear feet

3. Seismic: Zone = 1

4. Exposure category: B

5. Wind. A) Basic wind speed (3-second gust, 50-year mean recurrence) = 9 MPH; b) Monthly range = 6-9 MPH (1-1.5 MPH below U.S. average); c). Historical tornado activity 15% above U.S. average, higher than Virginia average, predominantly in flatter, open, southern areas [this latter point of predominance having been determined subsequent to initial scheduling, from further, direct inquiry].

6. Precipitation. a) Rainfall ? At I2 (5-minute, 25-year recurrence) = 9 inches per hour; b) Monthly range = 2.-75-4.25 inches (1/2-3/4 inch above U.S. average); c) Snow ? Ground snow load (50-year mean recurrence) = 30 pounds per square foot; d) Monthly range = 0-7 1/4 inches ( U.S. average, except ?-2 inches higher in Q1); e) Average annual, including rain, snow, and hail ? 40.1-40.9 inches [depending on source].

7. Temperature. a) Daily lo = 22-65F (Average); b) Daily hi = 42-85F (Average); c) Average range = 32-75F (Average); d) 24-hour average = 54.3F; e) Average minimum = 43.3F; f) Average maximum = 65.3F

8. Humidity: Morning = 75-89% (Average); Afternoon = 49-59% (Average).

9. Sunshine = 45-63% (2-8% points below U.S. average)

10. Degree Days [variation depends on source's average temperature peg]: Heating = 4200-4795 [former datum's basis undisclosed, latter's is 54F]; Cooling = 517-1548 [former datum's basis undisclosed, latter's is 54F, see 11. below ? this home designer prefers the widest range]

10. Insulation: a) Attic = R-49; b) Walls = R-18; c) Band = R-30; d) Basement = R-11, prefer R-18; e) Slab-on-grade = R-10; f) Heating Degree Days: 4200-4795 [depending on source, see 10 above]; g) Heating Degree Days: 517-966 [depending on source, see 10. above.]

11. Weathering Probability for Concrete: Severe

12. Termite Infestation Probability: Moderate to Heavy

13. Decay Probability: Slight to Moderate

WHERE DOES WHAT-ALL COME FROM AND WHY CARE?

Let's start again, for the rest of the story.

1. Latitude and longitude: Source: http://www.epodunk.com et al.

Use: Google Earth for direct observation; soffit and overhang depth gauge inputs relative to window height.

2. Elevation: Source: http://www.city-data.com et al.. Use: Wide variation inspires more specific jobsite locale; rain, snow, and temperature metrics can be elevation-dependent versus county averages.

3. Seismic zone: Source: International Residential Code map, if it's an easy siting; often, local building departments in Zones 2B and up; scrounging around, otherwise. Use: At Zone 2B, this custom home designer begins turning over some building design elements to engineering latitude, including but not limited to shearwalls, reentrant corner foundation structure, larger roof overhangs, as above porches, taller site walls, etc.; at Zone 3 and up, all structure must be reviewed with engineering latitude.

4. Exposure category: Source: International Residential Code. Use: To determine the extent to which natural elements, especially wind, shall be factored into design; to a lesser extent, at Exposure A and even B, natural light intrusion may be limited.

5. Wind. A) Basic wind speed (3-second gust, 50-year mean recurrence) in MPH: Source: http://www.buildings.chiefind.com/design/MBMA2002.pdf. Use: Wide-ranging application to methods and materials of construction; b) Wind speed - Monthly range: Sources, various including, http://www.city-data.com. Use: Sense of wind variability; again to methods and materials for marginal judgments of home design; c) Historic wind storm activity: Source: http://www.city-data.com et al. including local weather history news reports; clients' awareness and alert. Use: Can spur further investigation as to the generalized statement's relevance ? geographical relationship or topographical similarities to jobsite; tends to shade other wind metrics; can affect wall and roof structure, fenestration, roofing, etc.

6. Precipitation. a) Rainfall rate (I2 = 5-minute, 25-year recurrence) in inches per hour (IPH): Source: http://www.buildings.chiefind.com/design/MBMA2002.pdf. Use: Watershed Schedule; footing drainpipe sizing; etc.; b) Rainfall - Monthly range: Source: http://www.city-data.com. Use: To gauge watershed variability, e.g., tighter range indicates steadier wetness; shading IPH; c) Snow ? Ground snow load (50-year mean recurrence): Source: http://www.buildings.chiefind.com/design/MBMA2002.pdf except in some higher altitudes where data must be sourced from the local building authority having jurisdiction. Use: Primarily roof and deck structure; secondarily, certain design matters of functionality, particularly exterior mobility. d) Snow - Monthly range: Source: http://www.city-data.com. Use: Shade ground snow load metric; e) Average annual, including rain snow, and hail: Source: http://www.city-data.com. Use: Perspective.

7. Temperature (in lieu of the grossly generalized "Design Temperature"): Daily lo, daily hi, average range, 24-hour range, average minimum, average maximum, and comparison to national averages: Sources, various including, http://www.city-data.com & http://www.worldclimate.com. Use: Perspective on controlling daylighting; appropriate materials and methods for convenience of ventilation and heat transfer; materials durability, notably concrete; etc.

8. Humidity - Morning and afternoon Source: http://www.city-data.com. Use: Appropriate materials and methods for convenience of ventilation; materials durability

9. Sunshine: Source: http://www.city-data.com. Use: Jointly with Temperature and Humidity, to assess extents of general and specific design aspects; impacts nature and character of fenestration; to design for daylighting and nightlighting

10. Degree Days: Source: http://www.ornl.gov/~roofs/Zip/ZipHome.html or www.worldclimate.com. Use: HVAC prescription, including SEER (not less than 13 in this custom home designer's opinion)

11. Insulation: Source: http://www.ornl.gov/~roofs/Zip/ZipHome.html. Use: Definitive minimum R-values for ceiling, wall, floor, band, etc. based on zip code, structure; heating and cooling equipment design, etc. developed by DOE, Oak Ridge National Laboratory, Oak Ridge, TN

12. Weathering Probability for Concrete: Source: International Residential Code. Use: To assess sufficiency of surface hardening, other amendments, etc.

13. Termite Infestation Probability: Source: International Residential Code. Use: To assess need for termite shield design specifications

14. Decay Probability: Source: International Residential Code. Use: To assess finish exterior clad durability, ventilate the building envelope, set foundation height over finish grade, etc.