Misc. Articles
What's Wrong with this Picture?
By Dan Turner
Dec 6, 2001

The proper method of applying step flashing where a roof butts into a vertical masonry wall or chimney is defined in almost all the codes.

RR905.2.8.4 SIDEWALL FLASHING. FLASHING AGAINST A VERTICAL SIDEWALL SHALL BE BY THE STEP-FLASHING METHOD.

RR903.2.1 LOCATIONS. FLASHINGS SHALL BE INSTALLED AT WALL AND ROOF INTERSECTIONS; WHEREVER THERE IS A CHANGE IN ROOF SLOPE OR DIRECTION; AND AROUND ROOF OPENINGS. WHERE FLASHING IS OF METAL, THE METAL SHALL BE CORROSION-RESISTANT WITH A THICKNESS OF NOT BE LESS THAN 0.019 INCH (NO. 26 GALVANIZED SHEET).

Both of the these paragraphs are cited from the 2000 ICC and deal with the fine art of protecting the materials gap between two different material surfaces.

The other issue with this photograph that is not readily seen will be the fact that the builder chose not to watch his minions in action in the process of installing the angle iron to carry the masonry load as partly supported by the immediate rafters. It became apparent that the roofers brought the asphalt shingles to the angle iron and actually thought that by involving the roofing to the base leg of the angle would aid in the base-flashing process. Which is a good assumption until the shingles weather and crack and the structure movement opens up huge gaps for rainwater to flow. At present the brickwork in this gable is resting immediately upon the asphalt shingles, so the re-roofing work will involve not only cutting the shingles free from the masonry, but installation of the base/counter and step flashing at an extended cost to the purchaser.

BE SPECIFIC!!! Either cite the codes or draw the symbols for step, counter and/or cap flashing in your designs. As 3rd party defendant, you can always point to your drawings that the builder chose to overlook, ignore or use his/her discretion.


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