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-   -   When do people use 15# paper (http://www.diychatroom.com/f9/when-do-people-use-15-paper-9020/)

Malcolm 06-07-2007 03:31 PM

When do people use 15# paper
 
Is it the standard to use 15 or 30# tar paper? I was planning on using double underlayment with 30# paper. Is this overkill? The roof doesn't have a steep pitch that is the reason for double underlayment.

johnny331 06-07-2007 07:43 PM

the few roofers i've talked to say they always use 30# after being burned by using the 15# once in the past. you might even need it to validate the shingle's 20-30year warranty

I imagine there isn't much price difference... and is there really such a thing as over-kill, especially when it's your own roof (is it?)

you don't want to be tearing up the thin stuff as you walk around too...

Ed the Roofer 06-08-2007 08:42 AM

I prefer 30#, but most recomendations are for a 15# due to less wrinkling potential.

I tarp up our roofs every night, so moisture infiltration and the resultant drying out and wrinkling never becomes an issue.

Steeper roofs, a 30# is the recommended choice.

These are the manufacturers and NRCA "Recommendations", not requirements. I prefer to always exceed the "Minimum" requirements mandated in just about every phase of the roof possible.

A flat and tightly installed double layer of 15# is probably better than a single layer of 30#, but at what point do you create the gold plated pig, which will not be cost effective and be able to sell?

Ed

Malcolm 06-08-2007 10:10 AM

Quote:

Originally Posted by Ed the Roofer (Post 48264)
I prefer 30#, but most recomendations are for a 15# due to less wrinkling potential.

I tarp up our roofs every night, so moisture infiltration and the resultant drying out and wrinkling never becomes an issue.

Steeper roofs, a 30# is the recommended choice.

These are the manufacturers and NRCA "Recommendations", not requirements. I prefer to always exceed the "Minimum" requirements mandated in just about every phase of the roof possible.

A flat and tightly installed double layer of 15# is probably better than a single layer of 30#, but at what point do you create the gold plated pig, which will not be cost effective and be able to sell?

Ed


What about double underlayment 30# on 4/12 slope? Is this too much? I'm willing to pay for the material. I just don't want any adverse effects.

Ed the Roofer 06-08-2007 12:16 PM

On a 4/12 pitch, that would be a good idea.

A better idea, as long as 100 % continuous soffit intake and 100 % ridge exhaust ventilation specifications are followed, would be to do a 100 % coverage with Grace Ice and Water Shield protective underlayment.

If you want to know the correct amount ov intake and exhaust ventilation you need, provide the exact measurements of the house and the amount of soffit overhang extending past the walls.

The shadow cast down from the outline of the entire roof structure, would be called its "Footprint". That would be the most helpful for the correct answer.

Ed

RooferJim 06-08-2007 09:06 PM

Full coverage of ice and water shield is standard for slopes 4 in 12 to 2 in 12. under that is considerd flat.
double felt is a waste of time and effort.

RooferJim
www.jbennetteroofing.com

Malcolm 06-08-2007 10:18 PM

Quote:

Originally Posted by RooferJim (Post 48375)
Full coverage of ice and water shield is standard for slopes 4 in 12 to 2 in 12. under that is considerd flat.
double felt is a waste of time and effort.

RooferJim
www.jbennetteroofing.com

My states codes say to use double underlayment for 2 in 12 up to 4 in 12. You can use single underlayment for 4 in 12. Why do you think it is a waste of time? Is ice and water shield only used for areas that have snow/ice?

Ed the Roofer 06-08-2007 10:56 PM

Your state is following the OLD NRCA guidelines. Recent additions more properly address utilizing Ice and Water Shield for the pitces between 2/12 and 4/12.

Ed

RooferJim 06-09-2007 10:43 AM

Massachusetts had that in there old codes also. Once upon a time children they did not have things like I&W or even nail guns believe it or not. Your state needs to update.

RooferJim
www.jbennetteroofing.com

Malcolm 06-10-2007 09:43 AM

I haven't see anybody use ice and water shield in my area. Is this stuff expensive? Do you just use it for the first run then use felt? There is no ice or snow in my location. It will cost me about $120 extra to lay down two layers of felt. Would I just be throwing my money away?

RooferJim 06-10-2007 04:59 PM

Not at all. its quicker on labor than two ply felt and better because it seals around the fasteners like a gasket. It cost a little more on material but not much more, and you will save on labor and better quality. no brainer really.

RooferJim
www.jbennetteroofing.com

Malcolm 06-10-2007 06:57 PM

Quote:

Originally Posted by RooferJim (Post 48512)
Not at all. its quicker on labor than two ply felt and better because it seals around the fasteners like a gasket. It cost a little more on material but not much more, and you will save on labor and better quality. no brainer really.

RooferJim
www.jbennetteroofing.com


It does sound interesting. I was a referring to two ply felt being a waste of money. Would this be a waste of money compared to just using a single layer? The cost difference between 2 layers would be $120. In total I would be buying 12 rolls of 30# for double felt. How much would it cost for 22 to 25 squares of ice and water shield? Any special codes involved with this stuff or is it considered felt (follow same application procedures)?

RooferJim 06-11-2007 12:26 PM

Well its a little different. it has an adheasive on the back and sticks. that is what makes it good. a roofer can put it down just as easy as felt but maybee not so with a DIY or some carpenters. it is more money but its worth it. I buy the stuff by the pallett so Im sure you would pay a bit more. You best bet is to check out a roll at a suppy house. Its like buying insurance on your roof.

RooferJim
www.jbennetteroofing.com

warnerww 06-11-2007 06:09 PM

Quote:

Originally Posted by RooferJim (Post 48630)
Well its a little different. it has an adheasive on the back and sticks. that is what makes it good. a roofer can put it down just as easy as felt but maybee not so with a DIY or some carpenters. it is more money but its worth it. I buy the stuff by the pallett so Im sure you would pay a bit more. You best bet is to check out a roll at a suppy house. Its like buying insurance on your roof.

RooferJim
www.jbennetteroofing.com

My brother is a roofer in the Seattle area where it rains all the time and they put that stuff down and then leave for months to do other jobs then come back and roofs later. They are so busy he told me that is the norm and he has never had a problem. We are talking commercial buildings with hundreds of squares for one job. The stuff really works.

Malcolm 06-12-2007 10:54 PM

I am planning on using double underlayment, but I do not want wrinkles. I will be applying the shingles right after the underlayment is applied. Will I have problems later with double 30# wrinkling and buckling the shingles? I can use 15# if this will be a problem. I am currently looking into gracie ice and water, but it seems like it is 5 times the cost of 30#.


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