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Parapet drip…

monchgreen | Posted in General Questions on
Hi – We live in an energy efficient house without eaves in Olympia, Washington. We like the design of the house, but having second thoughts about low slope membrane roof. Major problem is coping material atop parapet wall directs rain to the outside of the house in several locations showing negative effect on siding and windows. I have located a door drip edge manufactured by PEMKO that fits nicely over window framing and may help keep windows dry. You can see photos of the house here: Also considering adding gutters to catch water running off coping. Any suggestions would be appreciated. Thanks!

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  1. Expert Member
    Akos | | #1

    Unfortunately the nice clean look of no overhangs and siding durability don't go hand in hand. Your house does look great.

    A couple of things you can do to help. Get the caps made to slope towards the flat roof and include a larger drip on the siding side.

    If you don't want to touch the coping, you can get a L shaped larger drip edge (2" to 3") bent up and install under the bottom edge of the coping. As long as the bottom of the drip edge is the same color, you won't really notice it from the ground.

    The window details look fine in the pictures, maybe post a picture of the problem areas.

    1. monchgreen | | #3

      Hi Akos - thanks for your reply! Yes part of the problem is that water running off the outside of coping doesn't fall far enough away from the siding so your idea about drip edge is very good. Regarding the windows - water falling from coping rolls over the flashing above the window frame then hangs and drips from underneath onto the sill and splashes the windows. Attached photo shows this. I added a 2" drip edge over one window (seen in photo) and seems to help. Thanks again!

      1. monchgreen | | #5

        Hi Akos - would I be correct to assume that the flashing originally installed above the window seen here should have a more pronounced drip edge or outward bend as in the attached diagram that would move water away and not direct it to run over and under the wood frame where it then drips on the sill? Thanks again.

        1. Expert Member
          Akos | | #6

          That right. Even a small 3/8 drip edge would keep most of the water away. The larger one you installed would make a much bigger difference.

          Unfortunately with wood finishes, once the paint starts cracking it won't last long, fixing the drip edge will buy you some time but most likely that trim will need to be refinished down the road. Instead of re-painting, for long term durability, might be better get somebody to wrap it in color matched aluminum.

  2. brendanalbano | | #2

    If the primary problem is that your parapet caps direct water to the outside in some spots, why not tackle the problem at its source and replace those parapet caps with ones that correctly direct water to the inside? Have you reached out to Artisans Group? It seems like they would want to make sure that their projects were continuing to function well over time, given that "high performance" is a key part of their brand!

  3. monchgreen | | #4

    Hi Brendan - thanks for your reply! Yes Artisan put me in touch with the roofing company. While I have read on building science website that coping should slant to the inside, I've gotten mixed messages about whether or not it can be done in this situation. Roofer recently added caulk to joints where coping pieces overlapped each other, but no change in drip - still working on a solution. Thanks again!

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