Texas Administrative Code › Title 28 - INSURANCE › Part 1 - TEXAS DEPARTMENT OF INSURANCE › Chapter 5 - PROPERTY AND CASUALTY INSURANCE › Subchapter E - TEXAS WINDSTORM INSURANCE ASSOCIATION › Division 1 - PLAN OF OPERATION › Section 5.4007 - Applicable Building Code Standards in Designated Catastrophe Areas for Structures Constructed, Repaired or to Which Additions Are Made Prior to September 1, 1998

Current through Reg. 49, No. 28; July 12, 2024
(a) Areas Seaward
					 of the Intracoastal Canal.
(1) Applicability.
					 This code contains requirements for the construction of buildings to minimize
					 damage to such buildings by severe windstorms which occur along the Gulf Coast.
					 Where specific requirements for particular devices or methods of construction
					 are specified, alternate methods or practices which are considered equal may be
					 used. Such consideration is to based on sound engineering practice and
					 experience. The degree of protection against damage from windstorm provided by
					 these requirements cannot be assured for tornadoes, but such compliance should
					 be helpful to some degree in reducing tornado damage. The requirements herein
					 are applicable only to properties located seaward of the Intracoastal Canal on
					 the Texas coastline (or seaward of the boundary authorized to be established by
					 the Commissioner by the Insurance Code, Article 21.49, as amended). The
					 requirements herein shall apply, on or after October 10, 1988, to May 31, 1998,
					 to new construction of, and additions or repairs to, structures located seaward
					 of the Intracoastal Canal in areas previously exempt from the requirements of
					 this subsection. The property previously exempt was that property protected by
					 a sea wall constructed by the Corps of Engineers.
(2) Building code standards.
(A) Wind pressure.
(i) When considered. All buildings and
					 structures shall be designed to resist a horizontal wind pressure on all
					 surfaces exposed to the wind, allowing for wind in any direction, in accordance
					 with the following table. No allowance shall be made for the shielding effect
					 of other buildings or structures. The height is to be measured above the
					 average level of the ground adjacent to the building or structure.
Attached
						Graphic
(ii)
					 Exterior walls. Exterior walls shall be designed to withstand the pressures
					 specified in clause (i) of this subparagraph, acting either inward or
					 outward.
(iii) Roofs.
(I) The roofs of buildings and structures
					 shall be designed and constructed to withstand pressures, acting outward normal
					 to the roof surface, equal to 1 1/4 times the pressures specified in clause (i)
					 of this subparagraph. The height is to be taken as the vertical distance from
					 the average elevation of the ground adjoining the building to the average
					 elevation of the roof.
(II) Roofs
					 or sections of roofs with slopes greater than 30 degrees shall be designed and
					 constructed to withstand pressures, acting inward normal to the surface, equal
					 to those specified in clause (i) of this subparagraph and applied to the
					 windward slope only.
(III)
					 Overhanging eaves and cornices shall be designed and constructed to withstand
					 outward pressures equal to twice those specified in clause (i) of this
					 subparagraph.
(iv)
					 Chimneys, tanks and towers. Chimneys, tanks, solid towers, and similar
					 structures shall be designed and constructed to withstand the pressures
					 specified in clause (i) of this subparagraph multiplied by the following
					 factors:
Attached
						Graphic
(v)
					 Other structures. The design wind pressures for structures not covered in this
					 paragraph shall be in accordance with generally accepted engineering practice
					 and shall be subject to the approval of the building official.
(vi) Stability. The overturning moment due to
					 wind pressure shall not exceed 50% of the moment of stability due to the dead
					 load only, unless the building or structure is securely anchored to the
					 foundation to resist this force.
(vii) Roofing materials. Roofing materials
					 must pass the U.L. Standard 997 or a comparable test certified by the
					 Commissioner and be installed as required by the Department, to promote wind
					 resistance of the materials.
(B) Anchorage.
(i) Heavy timber construction (as defined in
					 the Texas Commercial Property Rating Manual in effect prior to September 1,
					 1994). Every roof girder and every roof beam shall be anchored to an exterior
					 or interior wall or to a properly designed interior column. Wall beams and
					 plates shall be anchored to the wall with approved type anchors not more than
					 four feet apart. Roof planking where supported by a wall shall be anchored to
					 such wall at intervals not exceeding four feet. Roof trusses shall be securely
					 anchored to masonry walls at point of bearing. Monitor and saw tooth
					 construction shall be anchored to the main roof construction. Anchors shall
					 consist of steel or iron bolts or straps of sufficient strength and ample
					 anchorage to resist vertical uplift of the roof as required in subparagraph
					 (A)(iii) of this paragraph.
(ii)
					 Ordinary construction (masonry).
(I) All
					 trimmers and at least one beam or joist in every four feet resting on masonry
					 walls shall be secured to such walls by approved metal anchors attached at or
					 near the bottom in a manner to be self-releasing. Each end of a trimmer, beam,
					 or joist that is supported by a girder shall be secured or tied in an approved
					 manner to such girder or to a trimmer, beam, or joist correspondingly supported
					 from the opposite side of such girder. Anchors and ties shall be so arranged as
					 to form continuous ties between opposite masonry walls.
(II) Where floor or roof joists or beams run
					 parallel to masonry walls, such walls shall be secured to four or more joists
					 of the floor or roof construction by approved metal anchors at maximum
					 intervals of eight feet for dwellings, and six feet in other
					 buildings.
(III) Wall plates and
					 roof construction shall be anchored to the walls at least every six feet,
					 except that wall plates and roof construction shall be anchored at intervals of
					 four feet to hollow concrete masonry walls which do not have cast-in-place
					 reinforced concrete tie beams.
(IV)
					 Wooden girders shall be anchored to the walls and fastened to each other with
					 suitable steel straps placed near the bottom of the girder.
(V) At least every third rafter shall be
					 anchored to the ceiling joists or partitions directly beneath by not less than
					 the equivalent of one-by-six-inch boards securely nailed. Such braces shall be
					 attached to the rafters at their midpoints or at the third points if two are
					 used per rafter. In peaked roofs opposite rafters shall be laterally braced to
					 each other at the ridge in a manner satisfactory to the building
					 official.
(VI) Roof trusses shall
					 be securely anchored to masonry walls at points of bearing.
(VII) Anchors shall consist of steel or iron
					 bolts or straps of sufficient strength and ample anchorage to resist vertical
					 uplift of the roof as required in subparagraph (A)(iii) of this
					 paragraph.
(iii) Wood
					 frame construction.
(I) Sills shall be
					 anchored to the foundation walls to develop a strength equivalent to 1/2-inch
					 bolts with proper washers embedded six inches in concrete foundation walls and
					 spaced six feet apart.
(II) Rafters
					 shall be anchored to the wall plate by approved metal anchors attached to at
					 least every other rafter or shall be otherwise anchored in an approved
					 manner.
(III) In all buildings 20
					 feet or more in width where joists run at right angles to the rafters, the
					 rafters shall be tied to the ceiling joists with wood or metal ties nailed to
					 the foot of alternate rafters and extending across four joists well nailed to
					 each joist.
(IV) Girders resting on
					 masonry foundation walls or piers shall be anchored thereto with not less than
					 1/2-inch bolts embedded at least six inches in masonry.
(V) Wooden columns and posts shall be
					 securely anchored to their foundations and to the members which they
					 support.
(VI) At least every third
					 rafter shall be anchored to the ceiling joists or partitions directly beneath
					 by not less than the equivalent of one-by-six-inch board securely nailed. Such
					 braces shall be attached to the rafters at their midpoints or at the third
					 points if two are used per rafter.
(VII) Each rafter shall be laterally braced
					 to the opposite rafter at a point underneath the ridge, in order to form a
					 brace known as the "A" type of "collar beam," except that roof construction of
					 the "exposed cathedral type" or "exposed shed type" may have such bracing
					 omitted when the rafters are securely anchored and braced in an approved
					 manner. Roof framing and trussing of all other types of roof construction shall
					 be anchored by an approved method.
(C) Roof covering installation.
(i) General requirements for all roof
					 coverings. Roof coverings shall be securely attached to the roof in accordance
					 with the manufacturer's installation instructions and specifications and with
					 the methods approved by the building official. Nails, clips, and similar
					 attaching devices shall be galvanized or otherwise suitably corrosion
					 resistant.
(ii) Prepared shingle
					 roof coverings.
(I) Wood roof decks to which
					 prepared shingles are applied shall be solidly sheathed. Sheathing shall be
					 well seasoned and dry. Sheathing boards shall be at least one inch nominal
					 dimension boards not over six inches wide. Plywood sheathing shall be at least
					 5/8 of an inch thick.
(II) Attic
					 spaces shall be vented with vent openings so placed as to circulate air in all
					 parts of the attic.
(III) Nails
					 shall be of sufficient length to extend through the roof deck
					 (sheathing).
(IV) Thick-butt
					 asphalt shingles shall be nailed in the thick portion of the shingle.
(V) All butts or tabs of asphalt shingles
					 shall be securely spotted or tabbed with a plastic, fibrous, asphalt cement or
					 anchored by clips or locks, and all edges at eaves and gable shall be set in
					 such cement three inches back from the edge.
(VI) Metal drip edges shall be nailed to the
					 roof deck with nails not less than ten inches on centers.
(iii) Built-up roof coverings.
(I) For built-up roof coverings cant strips
					 shall be provided at the angle of roof and vertical surfaces.
(II) Built-up roof coverings shall be carried
					 at least six inches above the cant strip to a reglet in the parapet and covered
					 with metal flashing caulked into the reglet. Reglet may be omitted at parapet
					 walls provided two layers of felt or the equivalent are carried across the top
					 of the parapet under coping and down the parapet to the lower edge of the cant
					 strip. The said layers are to run vertically, properly lapped and cemented to
					 the parapet.
(III) All resinous
					 places in the wood roof deck shall be covered with sheathing paper or
					 unsaturated felt.
(IV) The first
					 layer or anchor sheet shall be not less than 30-pound felt nailed six inches on
					 center along with a two-inch lap and nailed 12 inches on center both ways in
					 the area between laps with tin caps and one-inch nails; or shall be not less
					 than two layers of 15-pound felt lapped 18 inches and nailed through both
					 sheets on six-inch centers along the lap and on 12-inch centers in the area
					 between laps with tin caps and one-inch nails; or where the underside of the
					 roof sheathing is to be exposed and its appearance considered, the first layer
					 shall be not less than a 30-pound felt or two layers of 15-pound felt nailed
					 six inches on centers along the rafters with tin caps and 1-1/4 inch nails, and
					 nailed 12 inches on centers both ways, between rafters, with tin caps and 3/4
					 inch nails.
(V) Each additional
					 sheet above the anchor sheet shall be thoroughly mopped between layers with a
					 bituminous compound so that no layers touch an unmopped layer. Bituminous
					 compound for mopping plys together shall be air refined asphalt or coal tar
					 pitch but shall not be any type of emulsion, cold or cut back liquid cement,
					 oil, or grease.
(VI) Gravel stop
					 and drip strips, and eave and gable drips shall be not less than Number 26
					 gauge galvanized metal, 16 ounce copper or 0.024 inch aluminum, with not less
					 than three-inch flange on roof and nailed with not less than 3/4 inch nails
					 spaced not more than six inches apart.
(iv) Roll roofing.
(I) Roll roofing shall be applied only over a
					 smooth surface. Roll roofing shall not be applied over shingle roofs.
(II) Roll roofing applied in a shingle layer
					 shall be spot mopped and applied by concealed nail method with a minimum three
					 inch head lap and a minimum six inch end lap properly cemented. Nail spacing
					 shall be not less than four inches on centers.
(III) Nails that secure roll roofing to the
					 roof deck shall be driven at least 3/4 of an inch from the edge of the
					 sheet.
(v) Tile roofing.
(I) Tile roofing shall be laid over not less
					 than one layer of 30-pound asphalt felt securely fastened by nailing with tin
					 caps.
(II) All tile shall be
					 thoroughly watered with a hose before application.
(III) Every tile shall be laid full length in
					 portland cement mortar and in addition the first three horizontal courses shall
					 be nailed. Under certain conditions additional nailing may be required to
					 prevent the tile from slipping. Mortar shall be not less than one part cement
					 and three parts sand and not more than 25% lime by volume.
(IV) All nails for flashing and tiles shall
					 be copper.
(vi)
					 Corrugated metal roofing, protected metal roofing, corrugated and flat sheet
					 asbestos cement roofing.
(I) When roofings of
					 the previously mentioned types are applied to wood roof decks, they shall be
					 secured with drive screws of sufficient length to extend through the roof deck.
					 When applied directly to purlins and other roof members they shall be secured
					 with bolted strap fasteners. Properly designed clip fasteners that are approved
					 may be used in accordance with the conditions of such approval. Drive screws at
					 least four inches in length may be used to secure these roofings directly to
					 wood purlins.
(II) Aluminum roofing
					 when fastened to steel roof structures shall be insulated against
					 electrogalvanic action.
(vii) Insulated steel deck roofing. Insulated
					 steel deck shall be secured by spot welding of clips or spot welding the sheets
					 to the steel purlins, or by equivalent means.
(D) Construction walls. During erection
					 masonry walls shall not be built higher than ten times their thickness unless
					 adequately braced or until provision is made for the prompt installation of
					 permanent bracing at the floor or roof level immediately above the story under
					 construction.