Originally Posted By: psmothers This post was automatically imported from our archived forum.
Whats everyone’s view on this chimney flashing through the metal roof. They installed a raised metal triangle to divert the water. The old cracking tar application behind it is lower than the metal flashing. This is my first metal roof with a chimney. Is this how they do crickets on metal roofs?
Opinions???
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Originally Posted By: aleleika This post was automatically imported from our archived forum.
There is debris on both sides of the flashing on the cricket…this is indicating to me that there is ponding…which is showing the water is not easily flowing away from the chimney. Also Todd is right, there is a rule for the height of the ridge on the cricket. Just looking at this installation brings out a red flag to me…Like Todd said a piss poor installation…at the very least it should be evaluated.
Originally Posted By: aleleika This post was automatically imported from our archived forum.
jonofrey wrote:
If it's not leaking why would you call it out?
If there was Reverse Polarity in an electrical receptacle, but it presently wasn't causing a fire...wouldn't you call it out to be fixed?
If a gas water heater was improperly installed in a garage (under 18" clearance), but didn't explode yet from igniting fumes....wouldn't you mention it?
If there were roof shingles installed upside down, but the roof wasn't leaking...Wouldn't you call it out?
Originally Posted By: jonofrey This post was automatically imported from our archived forum.
That white vertical flashing probably doesn’t need to be there but the cricket looks all metal with tar slathered on it. Probably don’t need the tar on the metal cricket either. Kinda looks like over kill if you ask me. If the tar is cracking but you didn’t need it in the first place, is that a problem?
Originally Posted By: rcooke This post was automatically imported from our archived forum.
Bald tires also do not leak I would never drive on them .
Cricket incorrect to low slope
Tar should never be used over metal
Incorrect caulking Should be a type that can expand and move .
Recommend immediate further evaluation by Qualified person.
Originally Posted By: hziegenbein This post was automatically imported from our archived forum.
I don’t see any reason to call out the cricket, but the flashing appears to not go up high enough on the chimney. Chimney flashing should extend a minimum of 6" or 1/6th the width of the chimney, whichever is greater. If those are standard bricks it would appear that the chimney is about 56" wide, which means the flashing should extend about 9.5 inches above the roof. It might be close but it’s hard to tell from a picture.
The specific job of the cricket is to divert water around the chimney, which it appears to be high enough to do.
Unfortunately with a ridged type metal roof there’s really nothing (that I know of) that you can do to avoid some pooling at the base of the chimney. Any roof penetration wider than the width between ridges will lead to some pooling. It should be pointed out to the client and noted that while it’s not leaking currently it should be monitored and re-tarred as necessary.
I’ve never seen a rule for how steep a cricket should be, if one of you guys has please do post it. I’d like to know.
Originally Posted By: rcooke This post was automatically imported from our archived forum.
jonofrey wrote:
I'm really getting a kick out of these alarmist analogies with regards to health and safety that have little or nothing to do with crickets.  I guess I'll play the roll of the seller.
rcooke wrote:
Cricket incorrect to low slope
My cricket diverts water away from and around the chimney. What low slope? How high should it be? What is your reference?
rcooke wrote:
Tar should never be used over metal.
My roofer put roofing tar over exposed nails at the metal flashings. Is that wrong too? Never is a pretty strong word. Are you sure it's never?
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YES I AM SURE , I guess your roofer was away from class the day they taught to use ELASTOMERIC caulking
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rcooke wrote:
Incorrect caulking Should be a type that can expand and move .
Now that's a stretch. No pun intended.
rcooke wrote:
Recommend further evaluation by Qualified person
I thought you were a qualified person.
I am a generalist no much about a lot, but not every thing about many things.
Originally Posted By: jonofrey This post was automatically imported from our archived forum.
NRCA recommends a cricket be used behind a square curb or penetration on a metal roof system if a curb or penetration is 24 inches (600 mm) wide or wider.
Because square penetrations impede water flow, water can collect above a penetration. This can result in leaks and corrosion of metal flashings. Water above small penetrations is more likely to evaporate within a reasonable time period. Large penetrations retain more water because of minor deflections in their flashing components, which create areas that will collect and retain moisture.
If you are concerned about ponded water behind curbs less than 24 inches (600 mm) wide, you can install water diverters. Water diverters typically are "L"-shaped metal pieces secured to roof panels. You should select a fastening method that does not create potential leak locations (e.g., fasteners through the pans).
To eliminate the need for crickets or water diverters, rotate a curb 45 degrees so one of its corners points upslope. The curb will divert water and eliminate the need for a cricket or water diverter regardless of the curb's size.
Roof system designers should note that curbs and penetrations should be installed between panel seams wherever possible. If a curb or penetration is wider than a panel and a seam is interrupted, the interrupted seam should be held back from the upslope side of the curb or penetration. This creates an open area upslope from the curb or penetration, which allows water to flow around the curb or penetration unimpeded by the seam.
Water diverters and crickets should be installed in open areas upslope from curbs or penetrations. Do not install them in a manner that traps water against panel seams that run alongside curbs or penetrations.
Providing positive drainage is critical to optimum roof system service life. And installing crickets or water diverters and having a 1/2-in-12 (2.4-degree) minimum slope help achieve positive drainage.
James R. Kirby is an NRCA director of technical services.
Copyright ? 2004 National Roofing Contractors Association
