Shed made with tar paper & roll roofing needs replacing

Can I just place new tar paper & roll roofing over existing structure or do I have to tear off all the old material. I'm thinking that trying to get all the old tar paper off might be a problem. Any suggestions? Thank you
  9 answers
  • Junk Gypsee Junk Gypsee on Jun 19, 2013
    The general rule is, no more than 3 layers of roofing. In some cases it's best to leave the old roof. If there are any more than 3 layers, it could cause structural damage.

  • Code states only two layer then tear off required. Ideally if at all possible doing a tear off is preferred. It assures that any hidden defects that may have occurred from perhaps leaks that went undetected are found and corrected. Also installing a new roof over an old one shortens the life of the new roof over all. If the roof is currently a roll style roof it will come up pretty fast and easy. Using a pitchfork or roofing removal tool such as this will remove the roofing material in short order and remove the nails as well. Also it always gets more and more expensive to do a roof. When this new roof your putting on needs to be replaced the cost of removal will be even more then then it is now. Add that to removal of two roofs combined with the shortened life span. It is cheaper now to tear off and replace then not to.

  • Euroshake Euroshake on Jun 20, 2013
    Code states no more than 2 layers. If you do roof over alternate seams by at least 16 inches. If the walls are tar paper alternates seams by at least 16 inches or stud width whichever is greater. Spent many summers with Uncle in his tar paper shack

  • KMS Woodworks KMS Woodworks on Jun 20, 2013
    I've done a handful of re-roofs. The "tear-off" is not really that hard, just pick a day when it is not 90 degrees and baking hot.

  • Al C Al C on Jun 20, 2013
    Hey, Thank You everyone for all the input. I really appreciate it

  • Junk Gypsee Junk Gypsee on Jun 21, 2013
    State laws vary apparently...good to know guys. Thank you!!

  • The feds create the laws with the industry. It is up to the states and local towns to adopt them. Or then can make them harder, but BOCA and CABO are the two governing bodies that develop them.

  • Carol S Carol S on Aug 01, 2013
    I just caught your post today. I took off 3 layers from my shed last month and then the rains came. So, I covered it with a trap until the weather was appropriate. They, (previous owners) had siliconed every gap in the shingles, sandwiched between rolled roofing and the were a zillion nails. It still leaked everywhere. It really was a pain to rip up but it was well worth the effort, because I was able to repair the problem areas and sealed the plywood. I will be posting the work and end results in Aug.,2013.

  • Rocky Catt Rocky Catt on Feb 14, 2016
    usually 2 layer's are accepted cut out the buckled spots and go over if this will be second layer and if the roof boards are not rotted if so replace them and shim with rolled goodds