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QUESTION: Hello and Thank you in advance

What is one to do with a leaking roof after the constrution hasn't been done correctly?  The new low slope roof is leaking and here is the history.  I hope you can help me. My carpenter (note- not a roofer) is building a porch for me.  There is a skylight and this roof is 3 sided one covering the porch and attached to the house on one side.  He did not use any ice/water shield and the roof is leaking now.  It's a very slight pitch and normally we would have used rolled paper but I'm allergic to the smell so he shingled.  Now it won't stop leaking in the area surrounding the skylight.  He also didn't use any flashing....guy tood 2 weeks, long days to do this job and the room is only 8x14.  Now that the damage has been done..what is the solution?
I look forward to your expert advice.

ANSWER: You can't do a low slope roof with shingles. They are not water tight. They need a slope to drain. If you do what you did it's guaranteed to leak. You have the wrong kind of roof on there and there is nothing you can do except put a sealed type of roof on like modified. It has nothing to do with ice and water shield. It would still leak.


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My front porch was done with shingles, same shallow slop and they used ice/water shield and there is no leakage but it was done by a roofer.  The new back one is leaking as I described.

Are you saying to rip the entire roof off and redo it or am I not understanding what your are saying?  What do you mean by modified and would it go over the existing roof?  This is getting so terribly expensive.  Thanks.

You're just lucky that the other doesn't leak or it might leak without you knowing it. Sometimes you have small amounts of water coming in where it just keeps the wood damp each rain but not enough to drip all the down through the insulation and ceiling below. Many times we rip up a roof and see wet wood but the homeowner didn't know it was happening.

You can either rip it up or just go over the shingles. Modified is a type of roll roofing. Many people call it rubber but that's a layman's term.

You said the other side doesn't leak. Does the other side have a skylight? Because you said it only leaks around the skylight. But a skylight is a big hole in the roof that needs to be done properly. If the slope is too low the skylight is blocking water and can leak simply because it's a skylight and you might not have that situation on the other side.

The basic instructions for shingles are on every single package sold. All you or the roofer has to do is read them and you would find out that you can't install shingles on low slopes. You can't so shingles on slopes below 2/12. From 2/12 up to 4/12 you can but even then you have to use special procedures. Above 4/12 you can do shingles in the normal methods.


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Brad Zacharia


All aspects of residential Roofing. This includes shingles and flat (low slope) roofs. I have knowledge in the installation as well as the design of roofs from an engineering standpoint.


I have been doing roofing for 40 years. This was my father's business and I took it over in 1980.

I have written responses to artcles that I felt needed a response to and those responses have been published in roofing trade magazines.

BSEE Drexel University

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