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TOPIC: Flashing

Valley Flashing/Sealing

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What is the proper way to prevent water from jumping across the valley on steep pitches? I am continuing to have a leak and the contractor can't seem to fix it.
Guest User

4/18/2006
Sorry to say but thiss is not a very good detail. You have a vallet transition onto a lower roof. The valley metal should exit out on the lower sheet not into the gutter. The gutter should be cut back at least 12-24 inches. The valley roof sheets removed. New valley metal should be installed such that it is 1 minimum of 12 " under the metal and that it terminates on the next sheet past where it is now. This sheet needs to have the upper part removed and a new sheet installed lapping the valley metal and lower sheet. Straighten out the sheet cuts into the valley wider at the bottom and narrower at the top so snow or debris can flush out. Usa a profiled foam sealing strip and butyl tape it to the valley metal to stop water.
Allan Reid
Dura-Loc Roofing Systems, Inc.

4/19/2006
Thanks. The solution to most of the leaks that I have experienced have been corrected using a liberal amount of sealant. As you can see from this photo of the dormer. I am concerned that the life of the sealant is less that the life of the metal. Am I correct to assume that the sealant should be under the metal where it would be protected, instead of being in directed sun? The Pro2000 datasheet says to apply a bead smaller than 1/2" and does not appear to be intended for extreme prolonged exposure to UV.
Guest User

4/20/2006
That is correct. The sealand is to "bed" the overlapping parts into and the detail in the attached photo is not correct as the valley metal terminates into a partially cut sheet and then the sealant exposed. This detail is sealant dependant.
Allan Reid
Dura-Loc Roofing Systems, Inc.

4/20/2006
Appers the metal roof rubs are at near perdicular to the valley and if so that can not be. the system must have the rib ends closed of and running near verical with the up and dwon sslope. Suggest removing all the lower system and running verically in bermuda panels and roll solidly by roll the bermuda around the valley. Must use Butly tape mastics combined with butyl tube sealant as in Sica #65 tape and Sica #511 tube butly caulking. All seams and laps must be sealed and no metal to metal contact should ocur with out installing the butyl sealants in such locations. seal up under the upper edge metal where it will lap the bermuda panels as wind can drive water under that location as well. the Install underlayerment of Grace ice and watershild under systm and double the valley. this is the best advice based on just the one photo of the condition. C W Bennett, Sr.
Guest User

7/4/2008
USE BUTYL SEALANTS AT INTERNAL METAL INTERFACING LAPS AND SEAMS -- BUTYL SEALANTS ARE NOT TO BE USED IN UV EXPOSURE -- USE ONE PART URETHANES SELANTS AS WITH SONNEBORN NP-1 WHERE SURFACE SEALANT CONDITION OCCURS -- BUT THE SYSTEM MUST ALWAYS BE SEALED AT ANY METAL TO METAL INTERFACINGS AND NEVER RELY ON SURFACE SEALS -- WHEN HAVE END TERMINATIONS AS SHOWING IN PHOTO MUST ALWAYS BOX OFF BY FLASHING LOCATIONS WIHT END CAPS ALL SEALED IN THE LAPS WITH BUTYL AND NP-1 TO ANY SURFACE APPLICATION C W Bennett, Sr.
Guest User

7/4/2008
Thanks. Todd Miller
Todd Miller
Isaiah Industries, Inc.

7/13/2008
Try using a W shaped valley flashing instaed of just a straight V shaped as they have a better tendancy to block water from shooting up the other side of the roofing panels. keep the metal a min of 2-3 inches away from the centre of the W valley.
Guest User

5/13/2009
Would a crosslinked butyl tape work in this application as some of the higher ends crosslinked butyl tapes remain flexible and are UV stable?
Guest User

5/13/2009
I opened up the photo after my reply...what a mess
Guest User

5/13/2009