Metal Deck Roof Venting

[JBCat]

Has anyone had any experience with venting a flatroof that is covered with metal deck and rooled tar roofing??? I am looking for the best way to perform the cutting. I did not agree with a recent training but I have not been able to find the answer in any of my text books.

Thanks,

JB

[rds3604]

I'm not sure what your training was but my dept uses a K-12 saw for all vent ops. and I haven't found anything yet it won't cut. Always remeber though, a gas powered saw may not start an AX always runs, be sure to have one with you anytime you get the vent crew.

[Omal52]

Haven't had a chance to try it yet, but our Rep told us that our Cutters Edge will cut metal roof. He showed us a video of a guy cutting the sheet metal "skin" off of a car. We have a few raised seam metal roofs in our area. He told us it will cut through no problem, just not to cut the seams. He said it will cut the seams, just ruin the blade too quickly. So our SOP is to cut the hole in between the seams.

As far as the rolled tar, we had a commercial job couple weeks ago that the roof had 3/4" plywood covered by one layer of paper, two layers of shinges, one more layer of paper, then one more layer of shingles (crazy roofers :rolleyes. Cut through it all like butter . Pain in butt cleaning the saw after, but thats what jrs are for .

What was your training "problem"? Tecnique? Tools used?

[ 07-10-2001: Message edited by: newasstchief ]

[jizumper-5]

In May I helped coordinate a ventilation practices class and got the chance to cut and observing cutting a commercial roof. Here is a little background of what we had. The commercial flat roof was about 6" thick and was composed of (top to bottom) rolled tar/tar paper, felt paper, about 16 layers of tar shingles, metal flashing, and wooden decking. We has a carbide toothed chain saw, and "K-12's" with different blades.

Results:
1) Chain saw--worked really well. Had no trouble cutting through and of the material. Really gunked up after several uses and took a while to clean.

2a)K-12 w/carbide tipped blade--worked just as well. Did not bog down much at all and was a bit less messy than the chainsaw.
2b)K-12 w/Warthog blade--cut similar results to the standard c-tipped blade.
2c)K-12 w/a diamond tipped multi-blade (looks like rocks welded to the outside, can cut wood as well as metal)--poor results. Since it cut by grinding it melted the tar shingles and got bogged down. Once the shingles were removed it was able to cut the metal flashing and wooden decking just fine.

3)had a few swings of the axe, very rough and labor intensive, recommend finding another saw...

Now remember that the types of structures these roofs are usually found are commercial or industrial. The operation is very labor intensive and the instructors recommended at least a 4 man team to perform the operation.

Any other questions just send me a personal message. I hope this will help.

[JBCat]

We had a commercial building scheduled for demolition. We had a chance to cut it up before the demo. The roof construction consisted of gravel on top of rolled tar roofing then over an insulating material. All of that then being supported by a metal decking ontop of steel bar joists. It was suggested to try the K12 with a metal cutting blade. Bad choice, it would gum up and go only about an inch/ min. It was then suggested to clear the gravel, use an ax to cut the roofing. We then had to peel the roofing up with flat shovels. Once all of the roofing is peeled back, we then cut the decking with the K12 with the metal cutting blade. I,m sure there is a better way but I have not been able to find one.

JBCat

[FireCapt1951retired]

The best tool for this job is the K-12 with a carbide blade. Works very well for ventilation on a flat roof with metal and tar. Cuts through it like a hot knife through butter.

[PAVolunteer]

We cut a commercial roof w/ rocks over rolled tar over wood over insulation. Removed the rocks w/ a shovel and then cut right through w/ the cutter's edge. Yes, it was a pain to clean, and to cut a decent sized hole we needed to use two saws (the chains got too loose), but it didn't gum up and did the job. Sounds like a cutter's edge will take you down to the metal decking, then depending on how thick it is, it sounds like you might need a K-12 w/ the metal blade to get through that.

Stay Safe

[ 07-10-2001: Message edited by: PA Volunteer ]