I am putting rolled roofing on a new construction garage with a 4:12 roof. This is a DIY job in the desert SW (Phoenix metro area).
My questions are about the techniques people use for applying the cement.
1> What do you use to physically apply the cement? I was planning on a couple of putty knives and just dipping into the bucket and spreading from the lap line upward. Spread on a couple feet and move the bucket along.
2> Between courses, how far up do you apply the cement? Just to the top of the underlying roll or do you continue up onto the felt?
3> How do you gain access to the lap area to be cemented. The rolls are already nailed across the top. I was planning to just lift and cement. Is it easier to lift a small section and tar? Or flip the whole course over and hold with something weighted and then tar the full length of the lap before flipping back down? In the future, is it better to apply the cement to each course as it is installed? Seems like that would invite much more oportunity to make a mess.
4> As luck would have it, the top courses of roofing are just shy of the peak by a few inches. Being a frugal-skate, I was not wanting to use a whole roll to cap the peak. But if I cut a roll in half the cut edge will look bad. So is there such a thing as a half-width roll out there?
4-1/2> And speaking of cutting a roll in half… I cut a roll in half to create the starter course. I used my sawzall. The resulting rough edge is hidden so not an issue. As expected the cutting process gummed up the blade quickly and I sort of knawwed my way through the remainder. Is there a better way to cut a roll?
5> Do you add extra cement to the cap piece or keep the lap width the same as the courses in the field?
Thanks in advance
-dch
Replies
Golly, but it's been a Looooonnnng time since I've had to mess with that stuff! Let's see what I can remember here...
"3> How do you gain access to the lap area to be cemented. The rolls are already nailed across the top. "
This has you sort of screwed already. The action of lifting is going to be hard on the material without damaging it. I imagine you will need lots of help to flip it back so you can spread the tar.
There is two kinds of adhesive. lap cement and the other less fibered which I forget the name of. I would use a heavy nap roller to spread it and then roll the roofing into it, nailing at the top enough to hold it in place. The more far up you apply it, the better wind resistance you have. At 4/12, in phoenix, leaks from snow backing up is not an issue!
It sounds like you have Selvedge double coverage roofing which laps 18" rather than roll roofing which has about a 2-4" lap.
For spreading the plastic roof cement or lap cement I used a 3" pointed mason trowel both to scoop out of the bucket and to spread.
To cut material, I roll it out on a clean smooth surface like a plywood subfloor ( or a slab) snap a line, and use a utility knife. Straight blade or hook blade depending on the temperature.
Then roll it back up and place it where needed.
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If i recall the non fibered lap cement was called cold process cement. We always used a brush on a broom handle, they always have them by the roofing materials for coating. I have never seen one nailed first though, he is gonna have all types of fun.
That's why we do this... for the fun!
Thanks for the tips. This is rolled roofing. 39" wide with a 2" lap. The directions on the packaging said to cut one in half so that the starter course was 18" wide.
Looks like I'll be packing one of the heavy (!@*# back off the roof and rolling it out on the slab to cut for the cap. I guess the bright side is that it will only weigh half as much on the way back up.
Thanks,
-dch
It's kind of an obsolete material------probably 10 years since i have bought any---but to cut a roll in half---what I used to do was unroll it on a clean driveway----snap an appropriate chalkline---and cut it with a hook blade.---it's one of the roofing materials that actually cutscleaner when its cool than when it's warm---when its warm it gums up the hookblade and more tears than cuts---sharp blade,cool roll-your cut edge will look just like the factory edgewe used old drywall knives--or cheapo plastic drywall knives..---pull a bread bag over your hand up to your elbow---hold it in place with a rubber band---use THAT like a glove--will keep your hand and sleeve clean----then all you have to worry about is a stringy karnack tar booger snapping over and goobering up your shirt front,your face, the adjacent siding, a car down in the driveway....etc.
stephen
Thanks again for the great suggestions.
Does anyone have any details on how to flash in a vent stack/pipe? Of course the vent will penetrate the roof in the middle of a course, not near an edge.
Should I patch around the flashing jack with pieces of roofing and then run rolls for that course up to each side of the vent area and have lap seams. Or is there a slick way to make a few cuts to incorporate the jack but keep the roll continuous?
Because it falls center of course and is a 4/12, do it this way - cut off a piece about 18" wide or so and fit it to the line below, and cut around the pipe.Then seal the flashing boot down onto it with the cement and nails. Then run to it from either side cutting over and around and sealing that lap down as well.This way all the laps face downhill and no water traps.
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i have done a bunch of jobs with cold process SBS Modified Cement and it is a wonderful product. We use lead boots anywhere we have a stack coming out of the roof and they have held out water for as long as i have been in business. If you can get lead boots, use them! Just cut the hole in membrane and mush that boot into a small amount of the cement.
Don't try that professionally, or you will spend more time fixing your own leaks than making money doing new jobs.
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you seem to have too many answers for everything-----------unlike you, i am actually out there working and doing these jobs----------------------this way does work and never has leaked on numerous jobs------------------maybe you should research every contractors methods and come up with a success ratio--------------seems that you have all of the answers for everything---------------you must be the contractor of the milenium------------------is your company the most recognized outfit in the country
I spent twenty years doing nothing but roofing, so I know exactly what I am speaking of in regards to this. I've had plenty of chances to fix leaks caused by installing the way you describe - after the original contractor/installer was long gone.Seating it in the cold process is only the first of three steps when you want to do it that way.
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