Section 321.24. Exterior covering.

 

(1)   General. The exterior walls shall be covered with a permanent weather resistant finish.

(2)   During construction. During construction, wall cavity insulation may not be installed until a water-resistant covering is in place over the wall cavity and windows, doors and a roof with at least underlayment are installed.

(3)   Flashing.

(a) Corrosion-resistant flashing shall be installed in the exterior wall to prevent water from entering the wall cavity or coming in contact with the structural framing components.

(b) The flashing shall extend to the surface of the exterior wall finish and prevent water from reentering the exterior wall.

(c)

1. Any joints between 2 pieces of flashing that form a vertical joint shall be lapped a minimum of 6 inches and sealed.

2. Any joints between 2 pieces of flashing that form a horizontal joint shall be lapped a minimum of 2 inches and sealed unless otherwise specified by the flashing manufacturer.

3. Sealants used for flashing shall be exterior grade and shall be compatible with the materials being sealed.

(d) Flashing shall be provided at all of the following locations:

1. At the top of all exterior door and window openings, unless using self-flashing windows that provide at least one inch of flashing around the opening, including the corners.

2. At the intersection of chimneys or other masonry construction with frame walls.

3. Under and at the ends of masonry, wood or metal copings and sills.

4. Continuously above all projecting wood trim.

5. Where porches, decks or stairs attach to a wall or floor assembly of wood frame construction.

6. At wall and roof intersections.

7. At built-in gutters.

8. Along the bottom of door openings that are elevated above-grade.

(e) For a roof that intersects with an upper-lying head wall and rake wall, such as where a dormer is provided, the vertical metal flashing along the rake wall shall extend down the roof at least one-half inch past the vertical flashing on the head wall.

(f) For a roof eave that intersects with a sidewall, the end of the roof flashing shall be installed so that it diverts water away from the sidewall and onto the roof or into the gutter.

(4)   Water-resistive barrier requirements.

(a) General.

1. Exterior walls of wood or metal frame construction shall be provided with a water-resistive barrier from the highest point to the bottom of the permanent weather-resistant covering.

2. Structural products with an integral water-resistive barrier may be approved by the department as a complete assembly.

(b) Material compatibility. The water-resistive barrier material shall be compatible with the other materials in the wall with which it will come into contact.

(c) Performance requirements.

1. Polymer-based house wraps shall meet all of the following requirements:

a. A water vapor permeability rating of 5 perms or higher when tested in accordance with ASTM E96.

b. An acceptable water-resistance rating determined in accordance with ASTM D779, AATCC 127 or CCMC 07102.

2. Spray-applied water-resistive barriers shall be approved under the International Code Council Evaluation Services.

(d) Application.

1. Horizontal seams in sheet or strip material shall be overlapped such that the upper layer extends over the lower layer at least 2 inches.

2. Vertical seams in sheet or strip materials shall be overlapped at least 6 inches.

3. Any rips, tears or voids shall be patched in accordance with subds. 1. and 2.

(e) Penetrations.

1. Penetrations caused by fasteners of the water-resistive barrier or the weather-resistant exterior covering do not require sealing.

2. Penetrations of 5 square inches or less with an annular space of no more than ½ inch shall be sealed with caulk or similar material.

3. Penetrations of greater than 5 square inches shall be flashed in accordance with sub. (3) .

Cr. Register, November, 1979, No. 287 , eff. 6-1-80; r. and recr. Register, March, 2001, No. 543 , eff. 4-1-01; CR 02-077 : cr. (3) Register May 2003 No. 569 , eff. 8-1-03; CR 08-043 : am. (2), renum. (3) (c) to be (3) (d), cr. (3) (c) and (4) Register March 2009 No. 639 , eff. 4-1-09; CR 15-041 : cr. (3) (e), (f) Register December 2015 No. 720 , eff. 1-1-16; CR 15-043 : cr. (3) (d) 8. Register December 2015 No. 720 , eff. 1-1-16.

Note

An example of acceptable water-resistant covering for a wall is foam sheathing with permanently taped joints. Microsoft Windows NT 6.1.7601 Service Pack 1 Flashing placed along the bottom of a door opening that is elevated above-grade can subsequently accommodate adding a deck outside the door. Microsoft Windows NT 6.1.7601 Service Pack 1 A head wall as addressed in this paragraph intersects a sloping roof at a horizontal line along the top of a roof segment. A rake wall intersects a sloping roof along the side of a roof segment. Microsoft Windows NT 6.1.7601 Service Pack 1 See s. SPS 321.26 (5) for additional flashing requirements with masonry cavity walls and s. SPS 321.28 (7) for additional flashing requirements with roofing. Microsoft Windows NT 6.1.7601 Service Pack 1 See s. SPS 321.26 (8) for further requirements relating to flashing for masonry. Microsoft Windows NT 6.1.7601 Service Pack 1 Acceptable water-resistive barrier materials include polymeric-based house wraps and spray-applied water-resistive barriers installed per the manufacturer's instructions, #15 or greater asphalt-saturated felts that comply with ASTM D 226 for type I felt and extruded foam sheathing with permanently taped joints. Duct tape or similar will not result in a permanently taped joint. Microsoft Windows NT 6.1.7601 Service Pack 1 Spray-applied water-resistive barriers may not be compatible with foam plastic insulation. Microsoft Windows NT 6.1.7601 Service Pack 1 Asphalt-saturated felt or "tar paper" is not a polymeric-based house wrap. Microsoft Windows NT 6.1.7601 Service Pack 1 For more information on the water-resistance tests and their results, see the International Code Council Evaluation Services Acceptance Criteria AC 38. Microsoft Windows NT 6.1.7601 Service Pack 1 For approval criteria, see ICC-ES acceptance criteria AC 212 or successor document. Microsoft Windows NT 6.1.7601 Service Pack 1