Roofing/Roof Repar


QUESTION: Hello Joe:  My friend has a 4 season porch attached to a double wide.  The porch roof runs 3/4 of the way over one side of the double wide roof.  My friend noticed a leak in the roof porch.  When I took down the ceiling discovered the lower right corner of the roof sheathing and several of the rafters were rotten.  I suggest she replace the entire porch roof.  However, she asked me to just replace the damaged section of the roof.  The roof slope is maybe 2/12.  So, I replaced the damaged rafters and sheathing and added felt paper per a low slope application and installed three tab shingles.  The area of the repair is 9'7" x 7'  and I was doing this work several weeks ago in 35F weather in upstate NY.  I ended up with vertical and horizontal seams because discovered the existing shingles were too brittle to slide the new shingles under the old shingles.  So, spread Black Jack All Weather roofing cement in the seams and then added a layer of 6" roofing fabric over the seams, spread another layer of BJ roofing cement, added another strip of roofing fabric and a final layer of BJ cement.  I ended up using 4 gallons of the BJ Cement.  Yesterday, I was informed the roof is still leaking and I'm assuming using the cement in the seams did not work and I need a Plan B?  Would very much appreciate any ideas you might have to save this situation.  Thanks, Frank

ANSWER: Hi Frank,

First of all you are very generous to help your friend out like this.

Sometimes we just can't do what the customer asks no matter what the their budget is, in this case, there's no easy fix. You were right in the beginning. At the very least, the entire roof should have been replaced, and with a Torch on material not comp shingles.

Here is a little known fact:
Comp shingles need at least a 4x12 pitch to function properly. Everybody does it on much lower pitches but it's not correct.

The solution:
Put a tarp on it for now and at some point replace the entire roof and or structure. Affordability is irrelevant, there's only one way to do this.

Good Luck

Joe Ronstadt

---------- FOLLOW-UP ----------

QUESTION: Hello Joe:  Thanks for your reply.  If you don't mind would like to to run a few additional questions bye you.  I'm wondering if before I go to the tarp option should either remove seam patch and add a final course of new shingles and attempt to get them under the original shingles or attempt to run flashing under the original shingles and over the repair seam tacking the flashing to the new shingles?  Concerning the tarp assume I have to run the tarp from the highest point where the porch roof joins rests on the double wide roof?  Also, am concerned about nailing the tarp into the existing shingles?  Thanks again Joe.  Frank

Hi Frank,

Long story short, it's best to extend the tarp over the top ridge and use wood battens like 1x2. Nail through battens and into shingles. You can later seal the holes.

Sorry Frank, this is the last question I have time for. My time is very limited these days. I don't even have time to get to all of my stuff, there's not enough hours in the day.

Good Luck

Joe Ronstadt SR  


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Joe Ronstadt SR


All questions related to residential roofing and roof repair.


In Business Since 1980, over 34 years as of 2014. Specializing in residential re-roofing and roof repairs.

OC Register and San Clemente Journal.

relevant construction credentials are: Licensed Contractor since 1980 by the C.S.L.B. 390685 - roofing 452151 - general, frameing, painting, concrete special coatings.

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