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11echo 04-05-2004 12:14 PM

Roofing my shop...
Hi Guys ...need some help here Please. I'm in the process of tar papering the shop roof so I can start on the singles. My question is this ...How much overlap is needed on the tar paper for a "good" job? ... I have a friend that used to do roofing tell me 50% over lap ...then the store guys said 3 or 4 inches. I live in and area that doesn't get lots of rain, but I'll like to do a "good" job on my shop ...without going over board. Any help would be appreiated! ...Mark

poncho62 04-05-2004 02:33 PM

A lot of todays roofers don't even use the tar paper. Don't know if the shingles are better quality today, doubt it. I would say that a 4 in overlap is fine.

Gearhead forever 04-05-2004 02:36 PM

As far as I know there should be a line present along one side of the roll to act as an overlap guide. There is on Ice and Water shield anyway.

5window 04-05-2004 03:02 PM

How much overlap you need really depends on the slope of your roof. Most roofing material will have the manufacturer's recommendations printed on the paper that wraps the roll together. "Fifteen pound" tar paper is really just an underlayment and should not be used as finish roofing. It just won't hold up. There are roll roofing products made to be used as a finish layer. Most of these have a coating-chips and bits-attached to about half the width, making the required overlap easy to gauge. The lines on the tar paper are generally guides for applying shingles on top of them, but may help you gauge your overlap. Shingles come rated in pounds per square (100 sq ft coverage), usually 3 bundles of shingles per square. The higher the weight, usually the longer the guarantee. The best ones are now 40 year. Shingle overlap, drip edge requirements etc., are also printed on the shingle package, or on a fact sheet available from the dealer. You might also look into metal roofing. It comes in widths that typically cover 3 feet and can be ordered to fit your roof-maybe even 30' long. Goes on fast and lasts 2x what shingles do. Again, what kind of roof material you do is related to the slope of your roof. And your budget. But a tarpaper roof won't last a year.

11echo 04-05-2004 03:17 PM

this is a 1:3 slope roof. I don't plan to just leave the tar paper uncovered, I've got singles ready to go. This tar paper is marked "ASTM 30" ...seems heavy, not sure what #15 paper looks like. But I have 1280 sq. ft. of roof to cover.

adtkart 04-05-2004 08:00 PM

I have done a few roofs. What I usually do is put the bottom row on. The next row is overlapped to the line on the paper of the forst row, and so on. The tar paper will seal itself from the heat in the summer, but don't leave it uncovered for an extended time period. I have never had one of my roofs leak doing it that way.

dinger 04-06-2004 12:21 AM

Adtkart is right on, Ca. weather that should hold up fine. Don't forget the flashing on the edges. :D Dan

Kevin45 04-06-2004 01:46 AM

Mainly the felt paper is a precautionary measure until you get your shingles on. 3"-4" overlap is fine. Just staple along both edges or use the tab nails to hold it good along the edge until you get the shingles on. Also when you start your shingles...quite a few just take the starter row and turn it upside down. The way I do it is to cut off the three tabs and put the glue strip at the bottom for the starter. Then when the next shingle goes on top the three tabs are glued down. Have fun!!!! I hate roofing with a passion and seems like every year I end up having to roof something. Oh yea...don't forget the drip edge like Dinger stated.


BigMac 04-06-2004 08:00 PM

Kevin is right. Only 3-4 inches overlap on the tar paper is fine. Use the three tab shingles upside down for your starter row. Don't forget the drip flashing and if you can overhang the first row about an inch. That should do it. For the ridge row, make them out of three tab shingles and start on each end and work to the center then your final shingle will seal it up and look good.

daimon1054 04-06-2004 10:20 PM


The way I do it is to cut off the three tabs and put the glue strip at the bottom for the starter.
That is also the way I do it, but I also add some black roof cement that comes in a caulk tube. What happens more often than not in high wind is the first row lifts and wind gets under, if you glue it down you lessen that risk.

If the building is not heated or cooled then you do not need tar paper as it is mostly a vapor barrier but I always use it because you never know what you will do in the future. Again as said the overlap is not that big a thing as no rain will ever get to it unless you did a bad shingle job.

BigMac 04-13-2004 08:48 PM

The higher the pitch, the less chance you will have for it leaking. The felt paper is cheap enough that you should really use it no matter what the pitch.

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