FEMA P-499: Home Builder's Guide to Coastal Construction

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2 PLANNING Building sites or designs resulting in extreme or high risk should be avoided — the likelihood of building loss is great, and the long-term costs to the owner will be very high. Building sites or designs resulting in medium or low risk should be given preference. Siting Note that over a long period, poor siting decisions are rarely overcome by building design. Design Item (Items with asterisk "*" are required by the National Flood Insurance Program (NFIP) and/or local building code.) Cross-Reference to Fact Sheets Design n How much more expensive is it to build near the coast as opposed to inland areas? The table below suggests approximately 10 - 30 percent more. n What about exceeding minimum design requirements in coastal areas? The table suggests that the added construction costs for meeting the practices recommended in the Home Builder’s Guide to Coastal Construction (beyond typical minimum requirements) are nominal. Added Initial Costs2 Required by Code or NFIP Added Initial Costs3 for Home Builder’s Guide to Coastal Construction Recommended Practices Reduce wind/storm damage Effect of Design on Cost A Zone, pile/column foundation 1.1, 1.4, 3.1 High High 4 4 4 V Zone, pile/column foundation* 1.1, 1.4, 1.5, 3.1 High 4 4 Joists sheathed on underside Low Low 4 4 4 Structurally sheathed walls* Medium 4 Corrosion protection* 1.1, 1.7 Low 4 4 4 4 Decay protection* 1.1, 1.7 Medium 4 4 4 4 Hip roof shape 1.1 Low Low 4 Enhanced roof sheathing connection* 1.1, 7.1 Low Low 4 Enhanced roof underlayment* 7.2 Low Low 4 Upgraded roofing materials* 1.1, 7.3 Medium 4 4 4 Enhanced flashing* 1.1, 6.1, 5.2 Low 4 4 4 Housewrap* 1.1, 6.1, 5.1 Low 4 4 Superior siding and connection* 5.3 Medium Medium 4 4 Protected or impact-resistant glazing* 1.1, 6.2 High Medium 4 4 Connection hardware* 1.1, 1.7, 4.3 Low 4 4 Flood-resistant materials* 1.1, 1.7 Low 4 4 4 Protected utilities and mechanicals* 1.1, 8.3 Low 4 4 4 4 4 Estimated Total Additional Cost ($ thousands) 15-30 ±5 4 4 4 4 4 4 Low 2.0% of base building cost depending on the owner’s preference. Notes: 2 Added costs when compared to typical inland construction 3 Added initial costs to exceed Code/NFIP minimum requirements 2 of 2 12/10 Developed in association with the National Association of Home Builders Research Center 2.1: HOW DO SITING AND DESIGN DECISIONS AFFECT THE OWNER’S COSTS? HOME BUILDER’S GUIDE TO COASTAL CONSTRUCTION Reduce flood damage Longer material life Reduce maintenance Lower insurance Lower utility bills
Selecting a Lot and Siting the Building HOME BUILDER’S GUIDE TO COASTAL CONSTRUCTION Technical Fact Sheet No. 2.2 Purpose: To provide guidance on lot selection and siting considerations for coastal residential buildings. Key Issues n Purchase and siting decisions should be long-term decisions, not based on present-day shoreline and conditions. n Parcel characteristics, infrastructure, regulations, environmental factors, and owner desires constrain siting options. n Conformance with local/ state shoreline setback lines does not mean buildings will be “safe.” n Information about site conditions and history is available from several sources. The Importance of Property Purchase and Siting Decisions Siting, design, and construction should be considered together (see Fact Sheet No. 2.1), but know that poor lot selection and siting decisions can rarely be overcome by improved design and construction. Building failures (see Fact Sheet No. 1.1) are often the result of poor siting. The single most common and costly siting mistake made by designers, builders, and owners is failing to consider future erosion and slope stability when an existing coastal home is purchased or when land is purchased and a new home is built. Purchase decisions—or siting, design, and construction decisions—based on present-day shoreline conditions often lead to future building failures. Over a long period of time, owners of poorly sited coastal buildings may spend more money on erosion control and erosion-related building repairs than they spent on the building itself. What Factors Constrain Siting Decisions? Many factors affect and limit a home builder’s or owner’s ability to site coastal residential buildings, but the most influential is probably parcel size, followed by topography, location of roads and other infrastructure, regulatory constraints, and environmental constraints. Given the cost of coastal property, parcel sizes are often small and owners often build the largest building that will fit within the permissible development footprint. Buyers frequently fail to recognize that siting decisions in these cases have effectively been made at the time the land was platted or subdivided, and that shoreline erosion can render these parcels unsuitable for long-term occupation. In some instances, however, parcel size may be large enough to allow a hazard-resistant coastal building to be sited and constructed, but an owner’s desire to push the building as close to the shoreline as possible increases the likelihood that the building will be damaged or destroyed in the future. 2.2: SELECTING A LOT AND SITING THE BUILDING HOME BUILDER’S GUIDE TO COASTAL CONSTRUCTION 1 of 2 12/10 PLANNING 2
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Home Builder’s Guide to Coastal C
Page 4 and 5: G GUIDE 2 of 6 12/10 Fact Sheet No.
Page 6 and 7: G GUIDE 4 of 6 12/10 Fact Sheet No.
Page 8 and 9: G GUIDE 6 of 6 12/10 Category Categ
Page 10 and 11: 1 GENERAL What Should Owners and Ho
Page 13 and 14: Summary of Coastal Construction Req
Page 15 and 16: Foundation Orientation of Lowest Ho
Page 17 and 18: Certification Elevation NFIP 60.3(b
Page 19 and 20: Coastal Construction Requirements a
Page 21 and 22: Coastal Construction Requirements a
Page 23 and 24: Using a Digital Flood Insurance Rat
Page 25 and 26: Sample DFIRM This map is a portion
Page 27 and 28: Lowest Floor Elevation HOME BUILDER
Page 29 and 30: V Zone Design and Construction Cert
Page 31 and 32: Designing for Flood Levels Above th
Page 33 and 34: FIRMs depict the limits of flooding
Page 35 and 36: Figure 6. Mold and biological/chemi
Page 37 and 38: Other Considerations As previously
Page 39 and 40: Coastal Building Materials HOME BUI
Page 41 and 42: Location of Material Use Name of Ma
Page 43 and 44: n Metal-plate-connected trusses sho
Page 45 and 46: Non-Traditional Building Materials
Page 47 and 48: Things to consider if building with
Page 49 and 50: Figure 5. An example of a wall cavi
Page 51 and 52: Moisture Barrier Systems HOME BUILD
Page 53: How Do Siting and Design Decisions
Page 57 and 58: Foundations in Coastal Areas HOME B
Page 59: prohibited in V Zones but are recom
Page 62 and 63: 3 FOUNDATIONS Table 1. Example foun
Page 64 and 65: 3 FOUNDATIONS Additional Resources
Page 66 and 67: 3 FOUNDATIONS 2 of 6 12/10 Figure 2
Page 68 and 69: 3 FOUNDATIONS 4 of 6 12/10 Figure 4
Page 70 and 71: 3 FOUNDATIONS Additional Resources
Page 72 and 73: 3 FOUNDATIONS Piers vs. Piles Pier
Page 75 and 76: HOME BUILDER’S GUIDE TO COASTAL C
Page 77: If a stemwall and floor slab system
Page 80 and 81: 4 LOAD PATHS If a connection fails,
Page 82 and 83: 4 LOAD PATHS Gable end wall - cut c
Page 85 and 86: Use of Connectors and Brackets HOME
Page 87 and 88: Important These are examples of typ
Page 89 and 90: Housewrap HOME BUILDER’S GUIDE TO
Page 91: n Improper integration with flashin
Page 94 and 95: 5 WALL SYSTEMS 2 of 3 12/10 Figure
Page 97 and 98: Siding Installation in High-Wind Re
Page 99 and 100: n Use aluminum, galvanized steel, o
Page 101 and 102: Figure 8b. Wood siding installation
Page 103 and 104: Energy Conservation and Air Barrier
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Attachment of Brick Veneer in High-
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Construction Guidance The brick ven
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Table 1. Brick Veneer Tie Spacing N
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6 OPENINGS Although not discussed i
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Protection of Openings- Shutters an
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What Types of Shutters Are Availabl
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Are There Special Requirements for
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Roof Sheathing Installation HOME BU
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Common Sheathing Attachment Mistake
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7 ROOFING 5. Apply a single layer o
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Asphalt Shingle Roofing for High Wi
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After the shingles have been expose
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7 ROOFING Design and Construction G
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Minimizing Water Intrusion Through
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Checking Soffit Material Installati
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Figure 8. This metal ridge vent was
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Gable Rake Vents Key Issues n Gable
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Metal Roof Systems in High-Wind Reg
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Construction Guidance n Consult loc
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Additional Resources For general in
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8 ATTACHMENTS Space Below the BFE
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8 ATTACHMENTS n Siding used on the
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Decks, Pools, and Accessory Structu
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uildings. Pools can be designed to
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Purpose: To identify the special co
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Fuel n Fuel tanks should be install
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9 REPAIRS n Pre-FIRM or post-FIRM b
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9 REPAIRS n If a lateral addition c
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9 REPAIRS Enclosures of Areas Below
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Repairs, Remodeling, Additions, and
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Vertical additions may also impose
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n Soffits should be inspected follo
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References and Resources HOME BUILD
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FEMA. NFIP Technical Bulletin 5-08,
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FEMA P-499: Home Builder's Guide to Coastal Construction

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