Flat Roof Operations

[strask]

When performing roof operations on a flat roof with built up membrane roof on wood joist, do you remove the membrane before cutting the ventilation hole? Why/why not? If so what is the best/quickest way to remove the membrane?

[JohnVBFD]

I miss the Partner saw...Being a local vendor, the Beach and many Hampton Roads departments use Stihl products. The comparable to the K12 is the Stihl T460.

[len1582]

K12 partner saw with a warthog blade. Keep the rpms high and you'll have a hole in a few seconds, on about every surface faced in the fire service.

I second that 100%...Saw has two speeds. All the way on or all the way off.

By screwing around with membrane, tar paper, or whatever you're just waisting time and taking longer to accomplish the task. The crews/victoms inside need ventilation right away so dicking around with that stuff isn't speeding up the process. Also, say your fire's in a 3-story frame. Well, you're standing on top of a 3 story lumberyard that's on fire. Do your job and get off.

[FFPCogs08]

I second that 100%...Saw has two speeds. All the way on or all the way off.

By screwing around with membrane, tar paper, or whatever you're just waisting time and taking longer to accomplish the task. The crews/victoms inside need ventilation right away so dicking around with that stuff isn't speeding up the process. Also, say your fire's in a 3-story frame. Well, you're standing on top of a 3 story lumberyard that's on fire. Do your job and get off.

Yep what he said

[JSMV72]

We have a Sthil saw with just a standard metal blade I have tried talking the
guys into buying a blade such as the warthog for it but they all seem to think they are to expensive. We also have a Shurvent chain saw. Would this work to cut through a flat roof as well?? Out old down town business district all have flat roofs and we need a way to vent them if needed.

[WD6956]

We have a Sthil saw with just a standard metal blade I have tried talking the
guys into buying a blade such as the warthog for it but they all seem to think they are to expensive. We also have a Shurvent chain saw. Would this work to cut through a flat roof as well?? Out old down town business district all have flat roofs and we need a way to vent them if needed.

You can vent a flat roof with a chainsaw. But if you hit metal joists, like Bar Joists, you will kill the chain pretty quick. But on old construction where more then likley it's wood, they work great. Just beware, because of the design of a chain saw, if you are cutting through a thick, multilayer tarred roof, you will be kicking up all sorts or tar that will gum the engine or YOU. Position yourself accordingly. Rotary saws are more popular on flat roofs for these reasons.

If your not using them already, these chains are worth every penny:

http://www.cuttersedge.com/Products/...8/Default.aspx

[CGITCH]

I have seen a chain saw gummed up pretty bad by cutting vent holes at a training. It cut about 5 4x4 vent holes and it was all full of junk. I really dont see this as a problem due to the fact that you are cutting one possibly two holes, or a trench. Then the saw is put away and can be cleaned rather quickly. Rotary saws cut cleaner with less gumming up, but depending on the thickness of the roof it may take two passes to get through which means a smaller hole and more time spent. All in all both techniques will work relatively well, better than using an axe.

[RFDACM02]

Firefuss and Len: You guys have had no issues with rotary saws gumming and binding up when used on "rubber" membrane? I know of a few places that tried this and found that they couldn't make it more than one or two feet before the saw was toast with material stuck to the blade and up inside the guard.

We've always been taught and passed on, that if you can seen the membrane (outermost layer) you cut it with a knife first and peel it back, only if this is the only option and the roof is safe.

In visiting construction sites while the roof was being finished we found many with between 4" and 6" of Styrofoam insulation board over underlayment and topped with the rubber membrane. Of course this is all over the lightweight truss joists as well, and burdened with HVAC units and grease vents. Given this, we determined our rotary saws likely could not be very effective, as we had been taught, though actual experience is the true measure...

WD: A Chainsaw on membrane? Again, it would seem to be possible only if the membrane was fastened between two other layers? I can see a real issue with flapping rubber when it's the top layer and not glued to the next layer down?

[len1582]

[QUOTE=RFDACM02;1130023]Firefuss and Len: You guys have had no issues with rotary saws gumming and binding up when used on "rubber" membrane? QUOTE]

I don't recall ever cutting one of those. The buildings I've dealt with are mostly older ones. Also, any roof repair/replacement was plywood, tarpaper, tar, etc.

[WD6956]

WD: A Chainsaw on membrane? Again, it would seem to be possible only if the membrane was fastened between two other layers? I can see a real issue with flapping rubber when it's the top layer and not glued to the next layer down?

On rolled out rubber membrane not glued, i would just cut it with a knife or razor. It would literally take 30 seconds to get on you knees and crawl back 8 feet while dragging the blade. As soon as you start the next corner, start pulling it back and the OVM can start cutting. No more membrane issue. You could easily cut the section out and toss it to the side before the saw even gets to the third side of the cut. If the membrane is glued, then you just cut through it. It makes a mess, but it can be done.

[FWDbuff]

I miss the Partner saw...Being a local vendor, the Beach and many Hampton Roads departments use Stihl products. The comparable to the K12 is the Stihl T460.

A few years back, we purchased a K950A Partner. There was one older guy on the Department who didn't like it because "it had a compression release" (his words.) We won't mention the fact that he ran all Stihl equipment for his personal business, and that his neighbor was a Stihl sales rep. Eventually, he talked the powers that be into selling the K950A in favor of the 12 pound heavier, larger, less horsepowered TS450........What a piece of crap boat anchor!

[RFDACM02]

On rolled out rubber membrane not glued, i would just cut it with a knife or razor. It would literally take 30 seconds to get on you knees and crawl back 8 feet while dragging the blade. As soon as you start the next corner, start pulling it back and the OVM can start cutting. No more membrane issue. You could easily cut the section out and toss it to the side before the saw even gets to the third side of the cut. If the membrane is glued, then you just cut through it. It makes a mess, but it can be done.

This is basically how we've trained for these roofs. In the last few years (5-10) This method of roofing has been the predominant one on commercial buildings in our area. Almost all the chain restaurant buildings and large strip malls have done this as well as some downtown re-roof jobs.

[HeightsFF]

You can vent a flat roof with a chainsaw. But if you hit metal joists, like Bar Joists, you will kill the chain pretty quick. But on old construction where more then likley it's wood, they work great. Just beware, because of the design of a chain saw, if you are cutting through a thick, multilayer tarred roof, you will be kicking up all sorts or tar that will gum the engine or YOU. Position yourself accordingly. Rotary saws are more popular on flat roofs for these reasons.

If your not using them already, these chains are worth every penny:

http://www.cuttersedge.com/Products/...8/Default.aspx

wouldn't you be worried about cutting a joist w/ the chainsaw?

[len1582]

wouldn't you be worried about cutting a joist w/ the chainsaw?

Not if you don't plunge it too deep. Also, when you're cutting with a chainsaw you'll feel some resistance (for lack of a better word) as you touch the joist. Just pull back on the saw a bit.

[CowboyD Eng6ine]

so if we have a cutters edge and a k12 on the truck, would it be our best bet to pull the k12 and take it with us to play it safe not knowing the age of the building and what materials we may be cutting into?

we have a warthog on our k12.

[RFDACM02]

so if we have a cutters edge and a k12 on the truck, would it be our best bet to pull the k12 and take it with us to play it safe not knowing the age of the building and what materials we may be cutting into?

we have a warthog on our k12.

We usually base our decision on the pitch of the roof. I like the K saw on low pitches where I can stand without the assistance of a ground ladder or other purchase. Anything steeper I like the chainsaw. Luckily this sort of coincides with the roofing materials in most cases.

[RFDGloWorm]

Works like a champ; http://www.carbidechain.com/cobracarbidechain.php

[jakesdad]

You can vent a flat roof with a chainsaw. But if you hit metal joists, like Bar Joists, you will kill the chain pretty quick.

Forget the chain...if you hit a bar joist with ANY type of saw, you can likely kill YOURSELF.

You should NOT be sinking a saw into a membrane roof with steel bar joist construction!

There can be as much as 8 feet of spacing between steel bar joists. So either the ventilation hole you are making is being supported by NOTHING on either side of the cut, or worse, the cut is directly over one of the bar joists and you cut the top chord of the bar joist, which is a truss, therefore rendering it useless and prone to failure.

[BKDRAFT]

Works like a champ; http://www.carbidechain.com/cobracarbidechain.php

This is what we run on all of our chainsaws. They are so much more effective than bullet chains.

On flat roofs with drop ceiling also be sure not to plunge too deep or you will end up with a wire wrapped chainsaw.

Nothing holds up to commercial flat rood ventilation like the Partner K-12 with Warthog blade.

http://www.youtube.com/watch?v=XLqLht7DC1Y

http://www.youtube.com/watch?v=vFGAoACoISc

[Rescue101]

Forget the chain...if you hit a bar joist with ANY type of saw, you can likely kill YOURSELF.

You should NOT be sinking a saw into a membrane roof with steel bar joist construction!

There can be as much as 8 feet of spacing between steel bar joists. So either the ventilation hole you are making is being supported by NOTHING on either side of the cut, or worse, the cut is directly over one of the bar joists and you cut the top chord of the bar joist, which is a truss, therefore rendering it useless and prone to failure.

Guess we don't know anything about roofs.Been cutting 'em for over 40 years with a SAW,all types. You need to know WHAT you're cutting to know HOW. For membrane roofs, it's the K12 960 with a Warthog here.If not available it will be the 550 Stihl. Steel trussed roofs can be swiftly and easily cut with a rotary saw and it doesn't take a genius to figure out where the Chord is and avoid it. If you're VENTING the roof,real GOOD chance that truss is going to be exposed to a failure element anyway. Get it done and get OFF. T.C.