# Another Flat roof tear off and replace post



## slickgt1 (Apr 1, 2010)

Hi All,
I am going to rip off an entire flat roof soon and need advice if I am on the proper path. I have done 3 torch roofs before, this will be my first time applying it to bare decking. 

1. Is GAF #75 base sheet a good underlayment? Can anyone recommend better, and what are your experiences with this? I would like to get this done right? 

2. I have 2' high brick wall surrounding my roof, should I go up the walls with the underlayment all the way to the wall caps, or should I replace the rotten metal counter flashing that is about 1' high and go up only that high? Same thing for the BUR?

3. If I replace the metal counter flashing, is there any reason why I shouldn't use copper (I know it costs more, but I need this done right)? My local roofing supply can bend 20' lengths and deliver it :thumbup:

FYI, I am not your average DIYer. I have experience with torch down, as well as every other aspect of house building. I just need Pro-Advice on this subject. I cannot get a consistent answer from anyone giving me quotes. I am convinced I am dealing with retards who want to get paid the most they can get for the least amount of work. Most have said that my roof is fine and I just need another layer on top. I have 7 layers already. I can see so many issues with adding another layer that it is not even funny. I need to start checking licenses and proof of insurance, convinced most don't know isht about roofing. Done venting.
 
Thanks in advance.


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## Slyfox (Jun 13, 2008)

slickgt1 said:


> Hi All,
> I am going to rip off an entire flat roof soon and need advice if I am on the proper path. I have done 3 torch roofs before, this will be my first time applying it to bare decking.
> 
> 1. Is GAF #75 base sheet a good underlayment? Can anyone recommend better, and what are your experiences with this? I would like to get this done right?
> ...


Go to GAF/Elk and read up on torch down specs and safety suggestions.
That base sheet is as good as any.

You should have a strip of "cant strip" running along the wall and the base sheet will go just inches above that.
The base sheet has to be fastened over top the insulation, be kinda hard to do that on the brick walls and not needed.
Clean and primer the walls and you can torch directly to them.

No matter if you go to the top of the wall or stop where it is now you need to remove the old flashing.
Going all the way up and wrapping over the top would be the easiest method for detail "flashing" work.

Have a fire extinguisher on the roof with you 100% of the time.
Walk the roof before and after all breaks to look for smoldering insulation, smoke, etc.
Do not leave the roof for at least 60 minutes after you shut your torch down.
Secure your torch when/if you leave it on the roof over night.


P.S. There are entire cities, counties, etc., in the country that have outlawed the use of torch down roofing systems because of the high hazard/risk to both body and property damage related to this type of system.

BECAREFULL.


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## slickgt1 (Apr 1, 2010)

Slyfox said:


> Go to GAF/Elk and read up on torch down specs and safety suggestions.
> That base sheet is as good as any.
> 
> You should have a strip of "cant strip" running along the wall and the base sheet will go just inches above that.
> ...


Thanks for the reply Slyfox. 

No I do not have cant stips on the roof. Yea I know I was shocked about this as well. The current roofing seems to make a 90 deg turn up the wall. 
I am hoping that the supply store will have them, but if not I can cut up my own no problem. Questions about this below. 

All the flashing will be removed. I just didn't go into detail about that above. 

I have 3 fire extinguishers right now, always got a hose with me, and a couple of buckets of water. Usually get my hands hot when folding / applying little flashing peices, nothing better than cooling off the gloves in a bucket of water, :thumbup: . 

I have a couple of more questions. 

What wood should I use for the cant strips, and what are the recommended dimensions for them? I beleive it should be a 45 degree slant, but how wide?

What is better, going up under the wall cap, or re-installing that counter flashing metal? My logic is that going under the cap, I protect the wall from getting water saturated, but not sure if that is the best way to go about it. 

Thanks again for your help. Greately appreciated. 

P.S. Roofers around here are not allowed to use torch products, but every time we hire them, or see them, they always use it. Plus all the supply stores and big box stores cary torch products. I asked around what the deal was. Everyone tells me that the law applies to roofers only, and home ownders can still use this. What? This scares me a little. But I guess that is how roofers get around it as well. 

All in all, I am glad I don't do roofs for a living. I would probably blow a disk or something by now. Really labor intensive work. Don't know how you guys to it all the time.


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## johnk (May 1, 2007)

A 3-4" cant strip would be ideal.You also should strip in or flash the walls using widths cut of of the roll,make the pieces come onto the field 8-10".Do not just run field sheets right up the wall,it will seperate at the transition point.Also make sure to 45 your corners under your endlaps and degranulize any laps.Also prime any drain,pipe or other metal you are adhering to.Any other questions?


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## AaronB (Jan 29, 2005)

Why do you 45 the corners under the end laps, John?


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## johnk (May 1, 2007)

It minimizes t-seams or joints.Help seal the lap better.Heh Aaron!!Whats up?


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## AaronB (Jan 29, 2005)

Not much, what's shakin, John?

I am pondering this 45 cut, and am thinking it just cuts down on coverage.


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## johnk (May 1, 2007)

The 45 is hidden.The sheet on the bottom gets the cut on the lap edge(bottom) and the sheet on the top gets the 45 on the salvedge.Its standard practice out here and manufacturer specs.No coverage lost.If you don't believe me,ask Kage:no: If you don't like the look of the 45,put an awning over it


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## slickgt1 (Apr 1, 2010)

johnk said:


> A 3-4" cant strip would be ideal.You also should strip in or flash the walls using widths cut of of the roll,make the pieces come onto the field 8-10".Do not just run field sheets right up the wall,it will seperate at the transition point.Also make sure to 45 your corners under your endlaps and degranulize any laps.Also prime any drain,pipe or other metal you are adhering to.Any other questions?


Wow thanks. I never even knew about the 45 at the corners. Gotta make sure I remember to do this on the proper side. 

Other questions would be:

1. What material is best for Cant Strips?
2. My wall caps are ceramic. Can I re-use them, or should I just spend the extra $$$$ and get new ones?

Thanks again, very helpful.


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## AaronB (Jan 29, 2005)

johnk said:


> The 45 is hidden.The sheet on the bottom gets the cut on the lap edge(bottom) and the sheet on the top gets the 45 on the salvedge.Its standard practice out here and manufacturer specs.No coverage lost.If you don't believe me,ask Kage:no: If you don't like the look of the 45,put an awning over it



HA! Maybe a gutter? LOL


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## Slyfox (Jun 13, 2008)

slickgt1 said:


> Wow thanks. I never even knew about the 45 at the corners. Gotta make sure I remember to do this on the proper side.
> 
> Other questions would be:
> 
> ...


The cant strips i have worked with are made up of fiber board insulation,
you could make your own out of lumber, I doubt it matters what type.

If they are still in good shape you can, you'll need to decide that yourself.


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## slickgt1 (Apr 1, 2010)

Slyfox said:


> The cant strips i have worked with are made up of fiber board insulation,
> you could make your own out of lumber, I doubt it matters what type.
> 
> If they are still in good shape you can, you'll need to decide that yourself.


 
They are in good shape. I will have pictures up today of the roof. I just took them. You will see what I am talking about. I am not too sure I want to remove the wall caps anymore. They are cemented on, and I am sure that I will break them taking them off. I might just replace the counter flashing metal that was there before, and add another strip of BUR from that to the wall caps just to protect the brick walls. 

Thanks again. Glad there are people that know what they are talking about on here. I was at a loss before you guys. Thanks.


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## slickgt1 (Apr 1, 2010)

So that you guys can see what I am dealing with

Facing the back of the house

You can see the Drain to the gutters on the left (Square Hole)










Facing the front of the house









Another one facing the front. 









Sorry about quality of pics. Iphone is not the best for this. 

Yes those bubbles are suntunnels. 
Yes I put them in myself
No they don't leak

No, I did not paint my roof silver, neither is most of that patching my work. 
I got a roofer to inspect, and do what he recommended to prolong my roofs life. This is the result. Correct me if I am wrong, but aren't you not supposed to paint gravel roof with that silver paint. By the way, you can see in the pic facing the front, he left the paint bucket on the roof.


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## AaronB (Jan 29, 2005)

slickgt1 said:


> So that you guys can see what I am dealing with
> 
> Facing the back of the house
> 
> ...


That doesn't look like a gravel roof.


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## AaronB (Jan 29, 2005)

It is very difficult to re-use counterflashing unless it is reglet snap on kind.

How thick is your roofing, and how much does it weight per square foot?

I would be concerned with the condition of the masonry since it has been coated/covered. Many time, we end up having to have a mason point or rebuild parapet walls when we tear off this type of building/roof.


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## slickgt1 (Apr 1, 2010)

Hi Aaron,
Yes you are probably correct, I am not sure what the current roofing is called. The roofing is a rolled gravel type of material. I swept a ton of it off. It has been painted silver by a roofer who said it will protect it longer. Guess what, he painted it silver last summer, now it has a ton of cracks and leaking. 

I will definitely not reuse the counter flashing. The pictures don't show it, but it is heavily damaged, has rot holes in it, and I don't want to take chances with it. I am going to replace it with copper 100%. 

When I cut out the holes for the suntunnels, the roofing looked to be about 1" thick. I tried to count the layers, and it seemed to be about 7. I am not sure if I counted correctly, but it looked like too many layers. The hole was 14" diameter, I didn't weigh it, but it felt massive. I cannot even guess how heavy it was, as that was nearly 3 years ago. 

You can see I put down the torch roofing around the suntunnels and all other protrusions. At the time I had a bad feeling about putting another layer of roofing throughout, due to my suspicion of already having too many layers, I think I was right. Those sections with the torch roofing are the only ones that do not have any cracking, bubbling, or any visible damage. 

I can grind out and re-point the walls no problem. I am also thinking of putting a strip of BUR between the wall caps and the counter flashing, do you think that is a good or bad idea?


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## AaronB (Jan 29, 2005)

If you're going to re-point the walls properly, then there should be no need for a membrane at that point.

A through-wall flashing may be a good idea, though.


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## slickgt1 (Apr 1, 2010)

AaronB said:


> If you're going to re-point the walls properly, then there should be no need for a membrane at that point.
> 
> A through-wall flashing may be a good idea, though.


Thats good too. 

Do you see that skylight by the roof entrance? I plan on replacing that, and making a proper roof access door as well (something that will just open on hinges, not something I have to move to the side every time). Do you think it is a good idea to get something that is curb mounted? Or should I replace with something similar?

Thanks again. Almost done with the planning stage. Planning to get this started sometime May 19th.


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## AaronB (Jan 29, 2005)

There are curb mounted hatch cover for this purpose that swing upwards and lock open/closed.

They may seem a bit pricey, but IMO worth every penny. Some even come with safety rails designed so that it is much more difficult to accidentally fall in.


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## slickgt1 (Apr 1, 2010)

AaronB said:


> There are curb mounted hatch cover for this purpose that swing upwards and lock open/closed.
> 
> They may seem a bit pricey, but IMO worth every penny. Some even come with safety rails designed so that it is much more difficult to accidentally fall in.


That is exactly what I am looking for. The one I currently have is BS. Even with going up on the roof a couple of times a year, I don't like that I have to put that cover on the roofing, and then drag it back to close it. Plus for some reason it weighs a ton. 

Do you know of a brand that I should look for? I know of Velox and thats pretty much it. Do you think they carry what I need, and would I be able to get a custom size? Thanks again.


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## AaronB (Jan 29, 2005)

http://www.bluewater-mfg.com/App_Roof-Hatch.htm


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## slickgt1 (Apr 1, 2010)

Thank you very much.


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## slickgt1 (Apr 1, 2010)

Hi guys. Was at the roofing supply this weekend. 
Ordered cant strips, GAF base sheet, Firestone top sheet, copper counterflashing, primer, nails, flashing cement, and silver paint. 

The owner suggested I get insulation panels under the base sheet. Should I consider this? I have insulation between beams on the inside of the house. It could be a good idea as far as leveling out any missperfections on the decking once I tear off the old roofing. 

Thanks in advance.


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## AaronB (Jan 29, 2005)

If you have a space between the celing and roof deck, then insulation would most likely be a waste of money. Cover board would do the same thing for deck preparation as insulation boards and at a fraction of the cost.


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## slickgt1 (Apr 1, 2010)

AaronB said:


> If you have a space between the celing and roof deck, then insulation would most likely be a waste of money. Cover board would do the same thing for deck preparation as insulation boards and at a fraction of the cost.


Hi Aaron, 
Thanks for the reply. 
Inside the house, I have the roof deck, right under it is Bat Insulation, under that are the ceiling joists, under that is sheetrock. Bat insulation is against the roof deck, about an 1-2" between insulation and roof deck. 

I am going to upload pictures of this during the construction phase. I hope it will show this for better understanding.


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## slickgt1 (Apr 1, 2010)

Ok, insulation between roof joists. You can see the metal studs for the sheetrock. In this area, the space between the roof joists and ceiling is big, about a foot. That gets less as you go toward center of the house. I am not sure if this is what you are talking about. 

You can also see the roof thickness in this picture under the skylight curb. 










So should I do insulation panels on the roof, or just cover board? Thanks again, you've been great help.


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## slickgt1 (Apr 1, 2010)

TTT, Thanks.

Oh forgot to add. There is spray foam insulation between all the metal, ceiling and walls. Don't have a picture of that. Pictures were taken for locations of wires and pipes, once the insulation was sprayed, everything is white. Sorry.


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