But, composition shingles, cedar shakes, cedar shingles, and other materials that are installed in rows or courses typically require step flashing at vertical junctures.
If you enjoyed this post, make sure you subscribe to my RSS feed! Each piece of step flashing laps over the shingle below and under the shingle above. Before we get into the retrofitting we first must discuss roofing over existing shingles. Sidewalls on roofs covered with asphalt shingles, wood shingles, shakes and slate should be flashed using step flashing, like you see here.
Some contractors prefer to nail flashing to roof deck only because this allows the flashing to be replaced later when re-roofing. Proper sealing is necessary to protect the shingles from wind damage. On his website, Rob uses his knowledge and experience to help and educate on best practices in the remodeling industry.
Failing to replace step flashings when a cedar shake roof is replaced with a composition shingle roof. It is possible to install new shingles over old shingles. Wind-driven rain can enter at these gaps, causing roof leaks.
Except where walls are brick, the vertical part of the sidewall flashing should extend up behind the exterior wall covering, just like with headwalls. Enter keywords like roof leak, bookcase, deck, etc to find your topic. The recommended length of step flashing is typically a minimum of 2-inches longer than the exposure of the roofing material.
Installation of a continuous sheet of metal flashing from the top of the roof to the bottom of the roof in lieu of step flashing is not a correct method of installation in many instances.
In my opinion the advantages for tearing off the old shingles far out weigh the three reasons to roof over. Manufacturer warranties do not usually cover a new shingles being layered on top of old ones. This series covers roof framing, roofing materials, the attic, and the conditions that affect the roofing materials and components, including wind and hail.
Robert Robillard is a general contractor, carpenter and operates a remodeling company located in Concord, MA. This method of installation relies upon the step flashings of the underlying roof to continue providing a water tight connection with the adjoining sidewall.
The gap can be present but difficult to see on tile roofs. While I do not advocate doing this there are a few reasons why people do this, they are:. This flashing is typically field fabricated from a sheet of 26 ga. In certain instances flashing may need to be installed on the exterior of siding. Flashing should overlap the roof-covering material, but on asphalt shingle roofs, for aesthetic reasons, the part of the headwall flashing that extends down over asphalt shingles is often covered with a course of shingle tabs.
Once the step flashing was installed we primed all of the cut clapboard ends and installed a drip cap flashing under the clapboards.
Headwall flashing should extend up behind the exterior wall covering and down over the roof-covering material, as you see here. All shingle manufacturers require step flashing at sidewalls for both asphalt, wood and slate. Frankly these contractors, and many homeowners, do not want to deal with the added work scope or the increased cost.