Replies

1. 
   Rebeccah_ | Jul 12, 1999 02:22am | #2

   *
   Thanks for the response. This is for new construction, and as I understand it the builder plans to step flash the roof portion, but suggested this one-piece method for the counterflashing part -- the piece that comes down from the chimney and overlaps the flashing. He expressed concern about wind-driven rain getting behind the vertical edges of stepped counterflashing. I don't know if this is a common problem, or if his solution is an accepted one.

   Rebeccah

2. 
   Guest_ | Jul 12, 1999 05:45am | #3

   *
   If I understand your question correctly both methods will have step flashing.The difference is in the style of counter flashing,either a stepped counter flashing or a diagonal counter flashing.The stepped counter flashing is superior in my opinion although slightly more time consuming to fabricate and install.The problem with the diagonal method is that to insert the counter flashing into the masonry it will be necissary to cut a saw kerf diagonally accross some brick courses instead of just cutting into mortar lines.I don't feel this can be good for the brick and with copper flashing you are gonna want a traditional appearance of stepped flashing anyway.I have sometimes seen the diagonal method used on sort of "low end "housing,but I can not imagine that anyone willing to pay for copper flashing would then accept this (diagonal)type of installation.Unless there is something with the roof/chimney intersection I am not aware of, the stepped counterflashing ,properly installed,will be VASTLY SUPERIOR.

   I suspect that your roofer may not own a sheet metal brake capable of the precise bends needed for this job,and consequently, may not be the best guy for
   this job.If I have misjudged him I opologize for the unfair slur.

   Best wishes,Stephen

1. 
   Guest_ | Jul 12, 1999 06:35am | #4

   *Rebbekah,I'm glad you cleared that up, I thought you were talking about NO counterflashing. Stephen's right the diagonal looks cheesy and is inferior to the stepped counters. Why would anyone want to cut a riglet into the face of new brick? Go for the copper steps.RM

1. 
   Guest_ | Jul 12, 1999 08:15am | #5

   *Rebeccah, Functionally I have found no difference with either method when done correctly. Around here we call the diagonal diamond cut method a "reglet"(Actually, it doesn't have to be a diagonal cut. We sometimes cut reglets horizontally). Twenty-five years ago it was something we only did on commercial jobs with long runs-it is a time saver compared to installing 30 or more individual counter pieces. We used a big gas powered Partner saw. Impracticle for a small chimney. But now with diamond blades for mini grinders it makes cutting the reglets very easy. Personally, I prefer the traditional look of stepped counter flashing on residential work, but I wouldn't judge the competency of the roofer on his choice of flashing. I repeat, each method is equally functional when done correctly. You should go with the look you prefer. I find that most homeowners don't give it a thought one way or the other. John

3. 
   G.LaLonde | Jul 12, 1999 04:09pm | #6

   *
   Fred, I completely agree with you. I use the method you describe and I think it makes a much neater, cleaner and far more waterproof counterflashing than doing it the other way. You can fabricate all of the components on the ground and easily install them on the roof. Stepped counterflashings are notorious for leaking from wind driven rain.

   As for appearance, keep the counterflashing low, ( 6" is plenty ). Put a slight bend on the bottom to give it rigidity and fold the lip that sticks into the cut and let it float in the groove so it doesn't kink. I fill the cut with clear silicone first. I use copper rivets on the corners. They look beautiful !!

4. 
   Guest_ | Jul 13, 1999 01:43am | #7

   *
   I have been accused of having to have the last word so I will make one more point and then bow out of this thread.

   In my area i have done to many flashing repairs to count on chimneys that were flashed using the diagonal method.In almost every case the diagonal flashing was merely nailed onto the side of the chimney and a little caulk applied. This method does not hold up.(in my area anyhow).

   I have never, ever, been called back on a job where I flashed a chimney with inlet,stepped,counter flashing.EVER.Also,I have never had a peice of my flashing blow off to my knowledge.So if you are having problems with this type of work I suspect(maybe erroneously)that the problem is not with the materials or technique but with the worker.

   When I do a average chimney using this method it takes me about 3 1/2 hours including tear off of old materials.I am meticulous as hell about this aspect of roofing and probably slower than average,but my customers are paying for results not theory and projections.I have seen others use the diagonal method or improperly use the stepped method and do the same size chimney in under an hour.My flashing takes longer,costs more but it ddefinitly holds up.

   JRS,sorry but I got to disagree with you.A roofers flashing is the best place to evaluate competency since it is the area wich takes the most skill amd costs the most.If he short cuts on flashing a leak prone area I can only assume he shortcuts elsewhere.

   Also Fred L, Lead flashing may be common in your area but I think I have seen it here ONCE.Even copper is pretty rare and pricey

   Best wishes all,STEPHEN

1. 
   Guest_ | Jul 13, 1999 02:32am | #8

   *Now that we have thoroughly confused poor Rebbekkah. I will reiterate "although both methods will probably work, the step method has stood the test of time". I have to agree with Stephen on every point. I don't trust silicone caulk in the riglet. I've been able to peel it out in long strips when doing repairs. I have also never had a call back on steps or seen a blow off. A roofer should be judged by his flashing work. It's the flash points that are the critical part of the system. And around here the lead or leadcoated copper to copper ratio is about 1 to 50. I'm all for new techniques but in this case I see no advantage to the new method versus the old proven one.Richard Max

1. 
   Guest_ | Jul 13, 1999 04:52am | #9

   *I've seen two additional variations.One is individual, stepped counter flashings with the vertical overlap soldered to the piece of counter flashing beneath. I've also seen these solder joints that have failed. (Vertical, plain lapped solder joinst have to be the most difficult to do right.)Another is a stepped counter-flashing made from a large single piece of copper. In this neck of the woods copper is seen much more frequently than lead. I have seen copper, single piece, unstepped counter flashings on the diagonal. On the face of it they seem like theyed be quicker to install and maybe less failure prone (at least the sheet metal part). I do wonder about the strength of those diagonally cut pieces of brick (assuming it's a brick chimney) particularly if very far off the center of a brick. But I suppose it it's well mortared all around it's OK. Both the stepped and unstepped versions I've seen have been let into grooves cut into the masonry, not merely tacked on and caulked. I've seen them mortared in and I've seen them caulked in and the caulking usually looks sloppy and doesn't inspire confidence. A lot of the chimney cleaning guys seem to sell caulking "touch ups with our super nifty 50 year silicone/polyurethane space age you can't buy it only us pros can" stuff. They seem to sell it by the foot. They do the same by the way with the joints in the firebrick of the fireplace... "oh this is special firebox cement in a tube, you can't get it. $5.00 a foot, oh, well OK just today I can give you a special at $2.50 a foot because I need to use up this open tube." My mother's 1938 house has the original copper step flashing (no counter flashing as near as I can remember) in or on a fieldstone chimney. It appears to be sealed with some sort of red lead putty. It's never leaked and I've never touched it to see if it's actually let into the masonry.Another detail I've seen is the counter flashing standing an inch or so proud of the chimney surface with a bend back to the chimney. The area above the bend is filled with a sloped mortar cap.

1. 
   Guest_ | Jul 13, 1999 08:38am | #10

   *Ditto FredStep flashing is archaic. The one piece counter flashing has no seams to leak. The top edge that is inserted into the seam cut into the brick has a "z" shape or I believe the term is standing seam that prevents water entry. The caulking is usually colored to match the flashing and is for added protection as well as sealing the cut. The one piece design on top of the roof flashing cannot let any water in. Water would literally have to stand on the roof to get through this assembly. We are using this method here in Louisiana (50+ inches of rain a year) on both high and low end houses without problems. You may want to consider a cricket though behind your chimney if conditions warrant.

5. 
   Rebeccah_ | Jul 14, 1999 10:15pm | #11

   *
   Wow, thanks for all the opinions!

   It seems that both methods are fairly common, and if done right they work; if done sloppily they don't. By the way, I have the utmost confidence in my builder. He has a reputation for excellent quality work, and has been a joy to work with as we decide on the details. Since he has seen more leakage problems with stepped than with diagonal counterflashing around here, I'll probably go with the latter. Brian's description sounds like what he was trying to describe to me.

6. 
   Guest_ | Jul 14, 1999 10:15pm | #12

   *
   Which is a better method for chimney counterflashing and why (masonry chimney for masonry fireplace, 5:12 roof slope, asphalt 3-tab shingles)?

   1. Individual pieces of copper, stepped and embedded in the mortar of the chimney

   2. One piece of copper, with an angled groove made in the side of the chimney, the copper tucked into the goove and secured with some type of caulk or adhesive.

1. 
   Guest_ | Jul 12, 1999 01:35am | #1

   *Rebbekah,I suppose either method would work, but I don't think I've ever seen the second method used. the first has certainly stood the test of time. Even though it's more pieces and not continous I would have to vote for the steps. The fact that the steps and counterflashing are able to move individually is part of it, and also relying more on the physical barrier of the metal to stop intrusion rather then on a sealant which will fail over time. You don't say the age of the house ,but I've seen roofs settle around chimneys and unfortunately vice versa. The step and counter method gives your roof system a better chance of surviving that. Whatever you choose make sure you apply generous overlapping strips of ice shield underneath it all, it's good cheap insurance.Good luck,Richard Max