The one piece cap flashing is inserted into a reglet and held by lead wedges. The base flashing extends a minimum of 4" up the wall and onto the roof. The lower edge is held 1/2" above the butts of the succeeding course. The upper edge of each flashing piece extends 2" above each course of shingles. One type uses pieces of copper base flashing installed with each course of shingles. There are two approaches to stepped flashings. The details shown concentrate on such chimney flashings, but apply to other wall conditions. A typical occurrence is where a brick chimney rises above a roof. All joints between base flashing sheets are soldered.Description: Stepped flashing is used where a sloped roof meets a masonry wall. Copper cap flashing then covers the upper edge. It extends at least 8" up the wall and at least 4" onto the roof, on all sides of the chimney. Chimney Flashing – Flat Roof Copper base flashing is attached to the roof deck before installation of the roofing. The cricket can be a one piece design or a two piece, joined by a standing seam at its ridge.Į. Chimney Cricket Flashing This detail illustrates the use of a cricket to divert water above the chimney to either side. Chimney Flashing – Alternate **This detail shows a second method of stepped flashing as described above.ĭ. The water is conducted instead to the end of the base flashing, over the apron, and onto the roof below. Note the hooked edge on the base flashing to prevent water from running under the roofing material. The other one uses the single piece base flashing with a two-piece cap flashing. The one on the left uses individual copper base flashing sheets, and a one-piece cap. Alternate Step Flashing Methods These sections illustrate two methods of stepped flashing. Flashing at Base of Chimney This detail shows a typical installation using individual copper base sheets, as described above.ī. bad form.Īs Bob indicated, standard yes, right no. the top view of the shingles may lay pretty, but pretty isn’t going to keep the weather out or keep them on in high winds. and since the installer doesn’t care about what is plainly visible display of his work, i’d question what what hidden – underlayment, overnailing, crooked nailing, missing nails. although counter flashing is sometimes surface applied and sealant applied, this is not a suitable application. That’s poor execution of an unacceptable detail. It kinda looks like upside down drip edge. Shouldn’t there be some sort of counter flashing, maybe a step flashing grouted in to the mortar joints? This flashing flares out at the top and is just filled with different types of sealant. I expect to get calls from my client and both agents on this one!!! With this method of flashing, I would expect regular maintenance to be necessary. They are called step flashings because they look like steps as they follow the mortar joints going down the roof. Its actually more complex than I make it sound. The step flashing is sealed at the mortar joints. Step flashings are then recessed into the chimney at the the mortar joints and bend down over the base flashing.
The proper way to flash a chimney is to install a base flashing that goes beneath the shingles on the sides and back of the chimney and bends up on the vertical walls of the chimney. Maybe why there is water damage at the ceiling above the fireplace. I suspect that this has been a problem area in the past.
You can see the different colors of sealants used. This is just begging for water to run between the flashing and the chimney, and down into the roof structure, ceiling, and wall. See where the top edge of the flashing tilts out and away from the chimney. The material they used looks like upside down drip edge. I have never seen it done like this before.
The chimney appears to be improperly flashed.