Water – Low Sloped Asphalt Shingle Roof Remediation

garageleakroofshingleswaterproofing

The operative word here is remediation. This isn't a new install, so I'm looking at how to strategically work with what I've got.

The previous owner put a new shingle roof on my garage about 4 years ago, but the problem is that the roof wasn't sloped enough for shingles. Most of the water runs off OK, but some does get through the shingles toward the back. I'm trying to find a good solution that ultimately just needs to prevent this leaking. I'm mostly concerned about cost and hassle. For right now I just have a tarp over the shingles. I'd like to avoid removing the shingles if possible. At this point I'm looking at the following options…

A.) Any solution that would allow me to "patch" or seal the problematic area of shingles, making them less permeable where the pitch is so low that water gets through?

B.) A solution along the lines of removing existing shingles, adding improved waterproofing underpayment, and re-installing existing shingles.

C.) Any overlaying solution that would allow me to avoid ripping off the shingles. For instance, maybe metal or polycarbonate over shingles.

D.) If no good options between A, B, and C, then I'm looking at my material and method options for all out re-roofing. In particular, considering cost, difficulty, one-man-job or not, continuous or piecemeal install, rental equipment, etc.


I'm looking for a good DIY path forward, including any overlooked options and/or particular insights from someone fixing a similar problem.

Bonus: Any alternative uses for relatively new shingles if they're removed?

Best Answer

A) No. Nothing short of an unbroken membrane will resolve the issue. Even if you were to tar each row of shingles, you'd likely miss a few spots and have long-term damage. The right solution is a rolled roof or rubber membrane, possibly underneath shingles if aesthetics are a concern.

B) See A.

C) The question is too broad for the SE Q&A format. Ask for estimates from your local roofers, or price a flat roof solution at your lumber supplier.

D) Sure. If you carefully pop up each shingle nail, you could put them on Craigslist for sheds, hunting shacks, or whatever. Many folks would be glad to have a decent roof for half price (or less). This would take some time, obviously.