roll roofing / flashing a stone chimney
Hi – first time on BT.
I have a shed roof (2/12) over my garage/bonus room. Currently has roll roofing that is failing. Local roofing supply house recommends modified bitumen roll roofing. I’m having trouble understanding how to install it. Do I nail down roofing felt first (if so, what weight -15 or 30)? If I nail down felt, do I glue the bottom edge of the roll to the felt and nail the top? Gluing to the felt doesn’t sound too sturdy.
Also, how do I flash the roll against the cedar siding? The garage roof is against a higher cedar sided wall for the main house.
And, worst of all, I have a large (3x8ft) stone faced chimney about 6 ft down from the peak and against the side of the main house as well. When I removed the old tar (lots) from around the chimney I found failing aluminum counter flashing under the first course of stone facing and cut into the brick and cinderblock base of the chimney. No idea how to properly flash there. Hoping some one knowledgeable can help.
Thanks
Replies
Bump
I have to get off to work right now, but can you post a photo of the chimney and roof? You have quite a challenge so I have a lot to write - wanna get it right - but gotta go now
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Here are some photos of my problem.
1433 shows the top of chimney and cricket against side of house
1434 is the rear of chimney and side of house
1428 is the side of chimney showing counterflashing embedded in the brick and block mortar lines
1434 shows the top corner of chimney and cricket (should the cricket not extend all the way to the edge of chimney?)
1436 is a close-up of the counterflashing
Thanks for your help!
groan,I hate to sound like a complainer since you seem like such a nice guy.but those of us on dial up find files larger than about 150-200KBs to be impossible to deal with.But I think you have most of your answers above.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Sorry about that...still learning the ropes.
When I step flash against the chimney and the side of the house with roll roofing on it, does the flashing go on top of the roll material? And do i cover it with something (another layer of roll or roofing tar?
Thanks
should the cricket not extend all the way to the edge of chimney?)
It should.
counterflashing embedded in the brick and block mortar lines
In this case, re-use the same reglets where the block ends instead of doing a parallel reglet as I described above. View Image
Thanks. I'm confused about how to attach the step flashing to the roll roofing along the chimney. Do I lay the roofing, then attach the flashing above it, and then lay another piece of roll roofing to secure it? Sorry, I know it sounds kind of basic, but I can't find the answer anywhere and I have the whole chimney and side wall to flash.
Also, what is the correct way to cover the cricket and how do I flash between where the cricket meets the chimney? As you may have seen, the previous roofer's opinion was to add a lot of roofing tar.
Typically, the modified is turned up the side of the wall. There is no seperate "step flashing".
If you do use an ELL shaped metal base flashing, it would go on top of the modified and be sandwiched with another strip of modified which in turn would be melted to the bottom layer. This requires a torch or a heat welding gun.
The cricket would also have the membrane run across it and up the wall. You want to create as few seams as possible.View Image
got it now...makes sense...thanks.
What do I do at the corners of the chimney? Caulk the seam where the membranes meet?
Is the cricket installed correctly in the corner or should I replace it?
What do I do at the corners of the chimney? Caulk the seam where the membranes meet?
Without the proper tools, that's about your only option and it's gonna be a maintainence item. I don't see modified as very DIY user friendly. I've got the proper tools and I still don't like it.
If I were you, I'd look into EPDM. Doesn't require any $400 heat welders. The only product specific tool necessary is a hard roller - $25-$30. View Image
I'm a bit like CU, thinking this could have you in over your head, but I'll try to add some to your understanding.do the roof material first to the chimney. I can't see what you have but would consider having you add a cant strip to run the roofing up a bit.Flashing goes over the roofing and is then stripped in with about a 9" wide piece over it.
Flashing in this case is NOT a step flashing, but a continuous base flashing. Steps are for shingles on a greater pitch and are placed one step at a time between shingle courses. Base flashing on a low slope functions differently and must have the joints caulked or soldered, and as few joints as possible, preferably at the corners only. After the base flashing is in, then the counterflashing is let into the masonry as CU described above, again with joints sealed.This is one of the more skilled operations in roofing, and yours is one of the most difficult type chimneys to do, complicated further by the intersection with the adjacent wall, if I understand it all correctly. Good luck.
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I can't see what you have but would consider having you add a cant strip to run the roofing up a bit.
He doesn't have room for a cant if he uses the existing reglets where they switched from block to stone. They're down pretty close to the roof. I'm not sure, but I think maybe he's got a real stone veneer on a block chimney.
complicated further by the intersection with the adjacent wall
Yeah - what he's got is a sided wall along one side with a chimney bumping out from the wall. There's a poorly realized half cricket above the chimney. I'm suspecting he has a flashing detail to deal with at the top of this roof plane as well. View Image
Thanks. Reason I had asked for photos was to see if he had options for a cant and what was going on behind the chimney. Sounds like one I would hate to have to do myself.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Yeah - on top of that, the tar had not been spared.View Image
My builder used this company's product on the flat part of my roof. It is self-adhering, but he used a sticky underlayment too.
http://www2.polyglass.com/
Here's the skinny on modified:
http://www.mulehide.com/product/samb.aspx?Graphic=CONT
As far as the flashing goes on the stone chimney:
We usually lay a 2x4 on the roof next to the chimney with the wide side verticle. The 2x4 is used for a guide for a 7" grinder. Let the blade guard ride on top of the 2x4 and cut as deep as possible. Then we fabricate a counter flashing with a 3" leg going back into the kerf you just made. Slide that flashing into the kerf and mark and trim until it sets as tight against the face of the stone as you can get it. Caulk the kerf with high quality roofing caulk - Geocel 2300 or equivalent.
The base flashing will be the modified turned up the chimney.
View Image
flash .... you need a course in flashing 101.........
but , like piffen said..... you would help yourself if you show all your pics in .jpg
and about 240 x 480 ( about 100K - 150K )
if you download a program called Irfanview... that is what the majority of the world use to resize pics
Thanks Mike. I saved them as pdfs because the original files were 5-6MB each, I'll look into the irfanview.
And sorry, I understand flashing with shingles but can't find any info on flashing roll roofed areas. Bought a couple of good Taunton books, but no mention of roll roof flashing. I realize that roll is usually used on sheds, etc. where flashing wouldn't come into play, but...I'm trying to play the hand I've been dealt.
thanks for your help