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I have a roof slants away from a brick wall. I need to cut a groove in the brick to install the counter flashing. What’s the best way to cut the groove? What do you use to hold the counter flasing in place, morter or something else?
The brick in question is very uneven, it’s more like a rough cut stone.
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Replies
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hi caleb,
in ireland we deal with a lot of masonry block, brick and stone. solution almost always the same, rent a con-saw or stone disc in a grinder. with this cut a half to 1 inch deep slot along 2 inches above the intersection and for an inch or two beyond each end.
roll out the lead flashing, (joins should overlap by 4 inches), and push into the slot. then cut small pieces of lead, like toast soldiers, and fold them until they give good resistance when you tap them in on top of the flashing at 12" O.C. you can them point out the slot with the matching mortar. there for a lifetime.
good luck.
*Caleb, what you are talking about is commonly refered to as a riglet(sp?). In new construction it is usually a raked out motar joint. Many times the masons forget to do this and the bed joint has to be cut. A 4" angle grinder with a diamond blade on it makes pretty fast work of the job. It is easier to control than a circular saw, for me at least.The joint is generally cut to a depth of 1 to 1 1/4" and the the counter flashing is inserted in the joint. The top of the counter flashing should be bent into a "V" shape and pushed into the riglit. Try to make the V slightly smaller than the depht of the joint , but not to shallow. After the flashing has been snugly fit in the joint use small pieces of the flashing folded over on itself several times to wedge the V securly in the joint. Make sure the wedges are not so large that they project outside the plane of the brick. This whole assembly can then be pointed up with new motar, or my preferance is to use an architectural grade of caulk to seal the joint.If the counter flashing is a long run, I would work in no more than 4 to 6' pieces and lap them at least 2". This allows the flashing to expand and contract in smaller controllable sections. Larger section will tend to wrinkle or "oil can" when they expand. It is the expansion and contraction over a period of seasonal changes that causes most flashing to work loose from the riglet whether they are caulked or mortared in.If you have access to a brake the flashing should be formed with it. Make a couple of test pieces whith different "standout" lenghts from the brick face, since you brick does not have a uniform face plane. The one that fits the higest spot is the size you want to bend the whole run to. If you don't have a brake, then your best bet is to have it fabricated by shop that specailizes in flashing.You also need to decide what material the flashing is to fabricated from.The latest issue of FHB, November 2001, no. 142 has a good article on falshing brick veneer. I probably should have said that first, and save you reading this long winded post.Hope this helps.Dave
*Eddie...what in the name of all that is Holy is a "toast soldier"? Must be a regional thing. I'm of Irish descent, but that is one I've never heard.
*Caleb: Dave has summarized the reglet technique of attaching flashing very well. One thing to keep in mind if you live in a freeze zone is to grind your reglet groove with a slight upward slant to avoid risking water infiltration into the masonry. Good luck.
*keith,toast- bread which hsa been burnt, controlled like, for extra taste.soldier- is a piece of toast cut into 1 inch slices across the bread.ha ha ha. good stuff!
*CalebI agree with most of Dave Richeson's post with a few additions. I make my reglet cut 1 3/4" inch deep using a 6" grinder. I would grind off any surface irregularities that are under the counter flashing before I installed the base flashing. This surface prep is a judgment call, but will greatly ease the flashing installation and final look of the job. On a smooth surface wall I bend my counterflashing 2" into the reglet. I then bend it with a 3/8" hem on the top side. I dry fit it in the reglet, remove it and open the hem with a putty knife. This results in a locking mechanism for the flashing when it's installed (open the hem until it's tight in the reglet). It's installed by using the putty knife and a dead blow hammer. The knife is set into the bottom of the hem and the flashing is worked into the reglet with even hits spaced along the length of flashing. A smooth installation is key, but use of locking shims is unnecessary and the final look is clean and smooth. Finally I caulk with a structural caulk (Owens Corning 795).Terry
*Caleb, I cut miles of these.If you rarely do this just put a masonry wheel in a circular saw and cut away.If you are gonna be doing this a lot get a little 4 inch grinder with an diamond blade.I used a circular saw for years.I didn't realize that the 4 inch grinder would pay for itself in just over a week. Now I would give up my coil nailers and go back to hand nailing shingles before I would give up my grinder.
*Terry, can yuo post a drawing of your profile? It sounds interesting enough to try.Steve, what is you reccomendation for flashing type and gauge? I have mostly used copper in commercial applications, but once had 0.024 coated alum. spec. The alum. was the worst job I every did. The architect wanted as few joints as possible, and when the 10' lenghts oil canned they went nuts. To make matters worse it was a 10" high counter flashing and also had to step around an insde radius wall. I grew to dislike brown coil stock and the architect at about the same ratio on that one.
*Dave SorryI'm to illiterate to post a drawing. I just got a digital camera though so I'll e-mail you a picture of my work. I which I could post it for everyone but I haven't straightened the learning curve on that one. To keep out oil cans I put in V shaped kicks every 2 vertical inches. 10 inch tall flashing gets 4 lines of kicks. This adds strength and style.Going around a radius requires a different approach.I make the top a separate piece cut to the desired radius. I hem my 3/8" lock on the top and hem under a 3/8" on the outside. I put a 90 degree 5/16" kick out on my vertical piece and lock it into my 3/8" under hem. A lot of work but we do what we have to.Terry
*I know the feeling Terry. DW has to teach me the posting routine. I bought her a digital camera, so that is another hi-tech gizmo I need to learn to use.The bad a*s flashing job was circa 1981, but every time I pass that bank, my eye is drawn to that sorry flashing. The architect accepted it, but we knew it could have been a lot better. I did a lot of the interior trim on that job that I am very pleased with. Multiple radius wall and natural white oak trim, and I didn't screw up a piece of it.If I get by there in the near future, and have that new camera with me I'll post a pic of the roof/flashing.Dave
*Dave,virtually all my work is in residential settings.Around here aluminum is the usual material. I buy 24 inchx 50 ft coils from my roofing supplier. I don't know the gauge but it is a good deal thicker than lumberyard coil stock.I would try to drop down at least one brick course to avoid a 10 inch high piece.I would also try to do it in 6 ft long pieces to controll expansion.I bend a slight kick at the bottom to keep it straight.flashing chimneys etc. is about my favorite work.I have just about convinced myself to specify copper on chimney flashing starting in the 2002 season. It is very rarely used here,but it will add only a nominal amount to the total cost of the job while making it really stand out.Copper has a pretty high expansion rate so I would be leery of using long pieces.I have also been thinking about some leadd coated materialsBtw, Terry's 1 3/4 inch reglets would be a real concerrn on a lot of the buildings I work on. Especially a 1 3/4 inch reglet running 10 ft. plus along one mortar joint.
*StephenPlease detail your concerns with my 1 3/4" reglet.Terry
*Terry, I think a 1 3/4inch kerf cut into the mortar of a lot of the buildings I work on would be a structurally un-wise technique.Quick example ----a common house around here is 80 years old and has a 10/12to 12/12 roof. a chimney located at the bottom edge of a roof will have well over 10 ft. of masonry above it.A 1 3/4 inch kerf accross the back ,front and stepped up the sides could easily be the cause of the chimney ending up blown into the driveway( A tall single flue chimney can be pretty tipsy).A 1 3/4 inch kerf cut 10 plus feet long into a wall above a porch isn't likely to improve the longevity of the wall either.I would much rather see the kerfs cut much shallower---just deep enough to permit wedging the counter flashing in place.If you have a 3 3/4 inch brick with the mortar joints raked back maybe 1/2 inch you now have a bond 3 1/4 inch .cut 1 3/4inch into that the brick is under cut pretty far.Less than half the depth of the brick is supporting everything above.
*Before I started working for my present company, I was a superintendent for relatively small commercial contractor. Most of my exprerience with flashingwas in the commercial field, where copper was the norm.On new commercial work I like the two part counter flashing system. A piece of lead coated copper shaped like: -I wonder if a similar system coud be used in residential? replacing damaged counter flashing would be greatly simplified. Just ory open the punched down peen points and insert a new piece of counter flashing.what do you think?
*StephenI agree with your concerns. The depth of reglet is a judgment call, based on the structural integrity of the masonry. The best design (from a watertight standpoint) is a through wall flashing that has an internal vertical lip. With the deteriorating masonry that you describe, water going directly through the brick becomes a real concern. I agree with you on the shallower reglet in this instance, but I'm always apprehensive in a hard driving rain. I've experienced leakage through the wall in new work.ThanksTerry
*Terry ,you are too modest. You are the guy in the slate article back in june'95 ain't ya?I have a zillion questions for you ......We do no new construction work here,so everything is a series of compromises based on the existing situation.Occasionally we are able to convince the customer to have the chimney re-built from the roof line up.We also are now taking multiple before and after flashing pictures of "suspect" masonry conditions.We can then provide the customer with pictures and notes of possible problem areas and potential leaks above and beyond the flashing area.( of course we keep copies of this type of thing in the job file if any problems or questions arise later)One of my most memorable jobs was one I was called in on after the excitement. A chimney on an upper roof had a tv ant. attached to it.Chimney came down in a storm,slid off the upper roof and was suspended above a lower kitchen roof----actually hanging by the tv wire.Boy do I wish I had pictures of that one!The fire department beat me to that job though and before I got there had dismantled the chimney and thrown it down into the yard.Best wishes to you,I am more than envious of your work and materials.
*Reglets are over-rated...just skip them all together. Instead, just slather a bunch of roof patch that comes in th caulk tubes onto the flashing and smoosh it against the brick. Then shoot some more in to fill any remaining voids by the mortar joints, and bingo...you're finished, no mess or hassle.At least, that's how many around here have done it over the years...maybe its just a Pittsburgh thing ;)Q
*Thanks for all the great advice. I'm still trying to picture some of this, put I think I think I have the idea now. I've attached a picture of what I think you all mean. Do I have it right?
*caleb... it won't display for me...
*Won't display for me either.
*CalebDisplayed for me, and yes that's how I do it. I also hem the bottom edge under. Adds stiffness and a cleaner edge.Tight lines Terry
*Hey guys - I couldn't open the picture either. So I did this: Copy it and Paste in Word. It opened there. And yeah, it looks right.Don
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I have a roof slants away from a brick wall. I need to cut a groove in the brick to install the counter flashing. What's the best way to cut the groove? What do you use to hold the counter flasing in place, morter or something else?
The brick in question is very uneven, it's more like a rough cut stone.