International and Texas Building Codes: Flashing Requirements
Below are the international building codes for one and two family homes. To view photos and examples of flashing issues as they relate to the Texas building code, please refer to my newsletter on flashing problems in homes.
International Building Code Section R703.7.5 Flashing
Flashing shall be located beneath the first course of masonry above finished ground level above the foundation wall or slab and at other points of support, including structural floors, shelf angles and lintels when masonry veneers are designed in accordance with Section R703.7. See Section R703.8 for additional requirements.
International Building Code Section R703.7.6 Weep holes
Weep holes shall be provided in the outside wythe of masonry walls at a maximum spacing of 33 inches (838 mm) on center. Weep holes shall not be less than 3 /16 inch (4.8 mm) in diameter. Weep holes shall be located immediately above the flashing.
International Building Code Section R703.8 Flashing
Approved corrosion-resistive flashing shall be provided in the exterior wall envelope in such a manner as to prevent entry of water into the wall cavity or penetration of water to the building structural framing components. The flashing shall extend to the surface of the exterior wall finish and shall be installed to prevent water from reentering the exterior wall envelope. Approved corrosion-resistant flashings shall be installed at all of the following locations:
- At top of all exterior window and door openings in such a manner as to be leak proof, except that self-flashing windows having a continuous lap of not less than 11/8inches (28 mm) over the sheathing material around the perimeter of the opening, including corners, do not require additional flashing; jamb flashing may also be omitted when specifically approved by the building official.
- At the intersection of chimneys or other masonry construction with frame or stucco walls, with projecting lips on both sides under stucco copings.
- Under and at the ends of masonry, wood or metal copings and sills.
- Continuously above all projecting wood trim.
- Where exterior porches, decks or stairs attach to a wall or floor assembly of wood-frame construction.
- At wall and roof intersections.
- At built-in gutters.
I have only scratched the surface on Texas building codes and practices, and the issue of residential construction flashing. The idea is make you aware of just how important it is. I believe that it is far and away the most overlooked component of construction today. As our systems get more and more complicated, it seems that pride in construction has become less common. It is up to me to try and help you and the builders understand the importance of quality construction. It is up to you to be aware of these issues so that you can monitor or correct them in your own homes and hopefully avoid more serious issues in the future.
Additional Resources About Flashing and Building Codes:
Through Wall Flashing of Brick Veneer (Journal of Light Construction)
Stucco Construction Guidelines
Stucco Flashing (Journal of Light Construction)
Making EIFS Watertight (Journal of Light Construction)
Flexible Flashing (Journal of Light Construction)
Trouble Shooting Roof Leaks (Journal of Light Construction)
Sealing and Flashing Metal Roofs (Journal of Light Construction)
The Masonry Society Home Page
The Northwest Wall & Ceiling Bureau Home Page
Exterior Design Institute
Hardie Plank Siding Installation Guide
If you have a question about Texas Building Codes or the 2000 International Dwelling Code, please contact Advanced Inspection Service at (512) 818-4164.