The Commissioner of Insurance in a hearing held on September 3, 1998, adopted on an emergency basis an amendment to 28 TAC §5.4008, which adopts by reference revisions to the Texas Windstorm Insurance Association Building Code for Windstorm Resistant Construction. The revisions to the building code are effective September 3, 1998. The amendment was adopted on an emergency basis and a permanent rule will be proposed for adoption and will be published for comment soon.
The revisions to the building code expand the standards and specifications of the code to provide additional prescriptive construction methods to be used in the construction, repair and addition of buildings located in the designated catastrophe areas. This expansion of the building code will allow an increase in the building options available to the building industry and consumers. An outline of the revisions for each section of the building code publication is attached to this bulletin. In addition to the expansion of the standards and specifications of the code, an exemption for application of the code to historical structures located in the designated catastrophe area is provided in the building code publication.
Current subscribers to the new Building Code will receive the approved changes as part of their subscription. Those individuals or entities wishing to purchase a copy of the new code with the approved changes should call 512-322-2212.
Alexis Dick
Deputy Commissioner
Inspections Group, MC 103-1A
| TEXAS DEPARTMENT OF INSURANCE Engineering Services / MC 103-3A 333 Guadalupe Street P.O. Box 149104 Austin, Texas 78714-9104 |
Phone No. 512-322-2212 Fax No. 512-463-6693 |
Texas Windstorm Insurance Association Building Code for Windstorm Resistant Construction
| 98WAC-1 | Repairs to historic structures Refer to staff recommendations to exempt historic buildings in Section 201. |
| 98WAC-2 | Limitations on roof systems Staff expanded the limitation to 48 feet for one- and two-story structures. Refer to Section 207.4. This change impacted the majority of the tables in the code. |
| 98WAC-3 | Corrosion resistance standards Staff included specifications for corrosion resistance in Section 211.4. |
| 98WAC-4 | Piling Foundations The advisory committee opted to leave the scope of this section as written. Staff provided clarifications and additional illustrations for this section. |
| 98WAC-5 | Limitation on loadbearing walls The advisory committee voted to take no action on this item. Staff provided an exception for recessed front entryways. Refer to 98WAC-10. |
| 98WAC-6 | Pressure treated sole plates Due to the hazard of termite damage and potential for decay, staff recommends that the requirement for pressure treated sole plates, exterior and interior, remain in the code. Staff was unable to validate that materials such as 30# felt would provide protection against termites. In addition, the existing construction guide requires that exterior sole plates be treated in the seaward areas. |
| 98WAC-7 | Permit Standard grade lumber to be used on the top plates Staff revised the code to permit the use of Standard grade lumber on the top plates. Refer to Sections 303.1.4 and 403.1.4. |
| 98WAC-8 | Use of plywood for both uplift and shear resistance Staff included provisions to permit the use of structural sheathing for wall bracing and uplift resistance. Refer to Sections 303.4.4, 303.4.5, 403.4.4 and 403.4.5. |
| 98WAC-9 | Permit windows to be located at the corner At this time, staff has not developed a solution to address openings at corners, but staff will continue to investigate this issue. |
| 98WAC-10 | Requirement for minimum shearwall segments at the recessed front entryway Staff included recommendations for the recessed front entryway. Refer to Sections 303.1.3 and 403.13 for the wall framing requirements and Sections 303.4.1 and 403.4.1 for the sheathing requirements. |
| 98WAC-11 | Underlayment No action taken on this item. |
| 98WAC-12 | Metal drip edge Staff provided clarification that this is not a requirement. Refer to Sections 307.1.2 and 407.1.2. |
| 98WAC-13 | Application of asphalt plastic cement Staff included methodology for application of asphalt plastic cement at the eaves and at the gable ends including the option for use of bleeder strip along the rake edge. Staff removed the requirement to seal the underlayment to the metal drip edge. Refer to Sections 307.1.3 and 407.1.3. |
| 98WAC-14 | Re-roofing a wood shingle or shake roof Staff included a method for applying structural sheathing over spaced boards. Refer to Sections 312.2.1, 312.2.2, 412.2.1 and 412.2.2. |
| 98WAC-15 | Prescriptive method for plywood shutters Staff included a prescriptive method for application of plywood shutters. Refer to Section 408.5.1.1. |
| 98WAC-16 | Skylights Staff included wind pressure requirements along with requirement for impact resistance in seaward areas. Refer to Sections 308.4, 408.4 and 408.5. |
| 98WAC-17 | Summary of revisions made from suggestions and comments |
General Requirements
| 101 | Scope Change reference from TCPIA to TWIA throughout document. |
| 105 | What the Texas Department of Insurance Will Inspect Editorial, clarify catastrophe area. |
| 106 | Certification By Engineers Change reference from Texas registered professional engineer to Texas licensed engineer throughout document. |
Basic Definitions, Assumptions, and Limitations of the Prescriptive Code
| 201 | Applicability Included recommendations for exempting historic structures. Clarified that the primary intent of the document is for the design of structures to resist wind loads. |
| 206 | General Building Nomenclature- Editorial, define mean roof height. Add illustrations showing mean roof height. |
| 207 | Limitations of the Prescriptive Code 207.1 Building Dimensions (207.1.1) Provided clarifications and illustrations. (207.1.2) Expanded limitations for building dimensions. 207.4 Roof Systems - Expanded roof span limitations for one- and two-story buildings. |
| 208 | Design Loads 208.2 Dead Loads - Editorial; replace item numbers with bullets for consistency. Clarified dead load criteria for heavier roofing materials, such as roof tile. 208.3 Live Loads - Editorial; replace item numbers with bullets for consistency. |
| 211 | Materials 211.1 Lumber - Add reference for finger jointed lumber. Editorial; delete last bullet. 211.3 Gypsum - Add specifications for gypsum wallboard. 211.4 Fasteners - Provide clarifications on corrosion resistance. |
Prescriptive Requirements, Area Inland of Established Dividing Line
&
Section 400
Prescriptive Requirements, Area Seaward of Established Dividing Line
| 301 | Foundations - (301 & 401) Add text to define structural requirements for slab. 301.1 Monolithic Slab on Grade Foundation (301.1.1 & 401.1.1) Provide options and equivalencies to welded wire fabric. Clarify cover for minimum thickness of slab. Clarify requirements for tying rebar. (301.1.2 & 401.1.2) Add alternatives and specifications for other anchorage systems. (301.1.3 & 401.1.3) Editorial; clarify dowels. 301.2 Piling Foundation |
| 302 | Floor Framing 302.3 Floor Deck (302.3 & 402.3) Eliminated blocking requirements. Provide option on nail size. |
| 303 | Wood Stud Wall Framing 303.1 Wall Framing (303.1 & 403.1) Clarify species of lumber for loadbearing walls. Provide option for use of lower grade lumber for the trimmer and cripple studs. (303.1.4 & 403.1.4) Provide options for alternative grades of lumber for top plates. 303.2 Uplift Connections 303.3 Framing Around Openings 303.4 Wall Bracing 303.5 Chimneys - (303.5 & 403.5) Clarify bolt dimensions. |
| 304 | Masonry Walls 304.1 General Requirements - (304.1 & 404.1) Clarify requirements for wood framed interior walls. 304.4 Shearwalls - (304.4 & 404.4) Clarify requirements for minimum shearwall segments. Revise illustrations to clarify the application of shearwall segments and definition of pier height. 304.5 Lintels - (304.5 & 404.5) Revise tables to reflect new roof spans. 304.7 Interior Walls - Include section for interior walls. |
| 305 | Ceiling Framing 305.1 Ceiling Joist - (305.1 & 405.1) Editorial Clarifications. 305.2 Ceiling Diaphragm |
| 306 | Roof Framing 306.1 Rafters Systems (306.1.1 & 406.1.1) Add rafter span options for tile roofs. Add rafter span options for ceilings that are attached and not attached to rafters. (306.1.2 & 406.1.2) Clarify bracing and purlin requirements. Investigate options for hip splices. (306.1.3 & 406.1.3) Include minimum ridge board requirements. (306.1.4 & 406.1.4) Include option for replacing collar tie with ridge straps. (Figure 306.1.4) Revise illustration to show correct lap. (Table 306.1.5 & 406.1.5) Clarify application of ridge strap and expand table. (306.1.6 & 406.1.6) Clarify application of straps and address thrust load. (306.1.7 & 406.1.7) Expand uplift table for larger roof spans. 306.4 Roof Deck |
| 307 | Roof Coverings 307.1 Composition Shingle Roof (307.1.3 & 407.1.3) Editorial; clarify slope limitation and nailing requirement. |
| 308 | Doors and Windows - (308 & 408) Clarify wind pressure options. 308.2 Garage Doors - (308.2 & 408.2) Editorial; delete last bullet and clarify fastener requirements. 308.3 Exterior Windows - (308.3 & 408.3) Clarify fastener requirements. 308.4 Skylights - (308.4 & 408.4) Provide wind pressure and impact requirements for skylights. 408.5 Protection From Windborne Debris (408.5.1.1) Added windborne debris protection using wood structural panels. |
| 309 | Exterior Coverings 309.1 Wood Structural Panel Siding - (309.1 & 409.1) Clarify underlayment requirements. 309.2 Horizontal Board Siding - (309.2 & 409.2) Specify shear requirements. 309.3 Vertical Board Siding - (309.3 & 409.3) Specify shear requirements. 309.4 Diagonal Board Siding - (309.4 & 409.4) Specify shear requirements. 309.5 Brick Veneer or Stone Veneer - (309.5 & 409.5) Specify shear requirements. 309.10 Turbine and Ridge Vents - (309.10 & 409.10) Added requirements for turbine and ridge vents. |
| 310 | Mechanical and Exterior Equipment 310.1 Exterior Air Conditioner Equipment (310.1.2 & 410.1.2) Specify treated lumber. (310.1.3 & 410.1.3) Specify treated lumber. |
| 311 | Miscellaneous Construction 311.3 Patio Covers (311.3, 311.4 and 411.3, 411.4) Editorial; combine awnings with patio covers. 311.4 Awnings, Overhangs, and Covered Porches - (311.4 & 411.4) Add illustrations on construction. Specify species and grade of lumber for the support beams and posts. Clarify overhang limitations. |
| A | Windstorm Offices - Update information. |
| B: | Glossary - Add and revise definitions. |
| E: | Texas Department of Insurance Standard TDI 1-95 - Clarify definition of porous systems. Clarify acceptance criteria. |
| G: | Reference Material Sources - Add several references to National standards. |
| H: | Shearwall Examples - Revise examples for clarification. Clarify requirements for masonry shearwalls. |
| I: | Fastening Schedule - Add options for additional fasteners. |
| J: | Figures - Add illustrations noted above. |