I recently experienced a roof leak on a heavy raining day in the east coast. Picture 1: This is the interior ceiling.

I tore open the ceiling sheetrock and could see that water was dripping from the horizontal wood beams. When I checked with a flashlight between the horizontal beams I can see a tiny hole on the black material (above the beams). Water was leaking from that tiny hole.

Picture 2 : This is the outside/exterior roof of my building from where the water is coming in.

I am assuming its right under the red shingles but not exactly sure. How do I exactly know where is the leak/hole from outside ? I guess once I find the hole I can patch it up with flashing cement.

Any advice on what is the best way to fix this leak. enter image description hereenter image description here Thanks in advance.

  • I'd agree with jwh20, what is currently there does not look properly done to me. And you shouldn't have standing water, even on a flat roof. I too will say remove and rebuild that section of roof. You can try some silicone to do a temporary patch to at least stop the dripping for now, but do not rely on it long term.
    – Phaelax z
    Dec 29, 2020 at 18:29
  • @Phaelaxz the best way to "agree" with an answer is to give it an up vote. Since jwh20's answer doesn't show any vote activity (as I'm typing this), then you haven't done so. Go ahead and give him a vote for his efforts & to show your agreement properly. The rest of what you typed could have been a comment on the answer instead of the question.
    – FreeMan
    Dec 29, 2020 at 18:52
  • Do you have the resources to do it better? Adding some fall to that roof would make it so much better - specially with all the red shingles draining in from the right hand side. Comment because its not answering the question, but does address the long-term need.
    – Criggie
    Dec 30, 2020 at 8:11
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    A littte bit of history...I am the home owner and i dont do construction. This is a 110 year old home which is my primary residence since 2012. 4 years ago i decided to do some addition to the house. The red shingles are where the original house actually ended. The square corner is the new addition. There were no leaks prior to the addition. 2 years after the addition, i started experiencing the leaks, so i called the same construction company, they came over and i think they applied some flashing cement. It was fine for couple of years and this winter i am facing the same problem.
    – Jay Roy
    Dec 30, 2020 at 15:42
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    Boarding is present on top of ceiling joist and asphalt layer is present on top of it but boarding is missing across the border line of the new addition and I can directly see the sparkly black asphalt layer. That is what you see in the first picture as well. The hole is on that black asphalt right above the water droplet that you see in first pic.
    – Jay Roy
    Dec 31, 2020 at 1:25

5 Answers 5


Clearly this has been a problem for a while and also the standing water and patch job on the flat section of the roof is to blame.

There is no real shortcut here, as you can see, so the solution is to remove the roofing, repair the water damage, and then have it re-roofed properly. There are ways to apply a flat roof so that it will not leak but slathering it with roof patch is not one of them.

  • "Re-roofing properly" needs to include insulation: if there isn't any, then condensation on the underside of the roof will eventually degrade any boarding, causing it to sag. That will cause the felt to stretch, pool and allow water in. Insulation can go between the ceiling and the roof, or between the boarding and the felt. Or even both. Slathering it with roof patch will help get through a winter, but it's definitely not a permanent solution. Dec 31, 2020 at 8:47

Your problem is going to be finding where the leak is coming from. I have found leaks that came in more than 10’ from the entry point. The water can travel under the rolled roofing and drip down at a seam then run on the rafters especially double plates prior to finally coming down.

Today I use a FLIR camera I can see the water when it is traveling between boards because of the temp difference.

The only way to patch in wet weather is a patch like Henery’s asphalt or other brands of similar type. I would stick with asphalt as that is the best material and the base of the rolled roofing.

I used to do hot tar as a kid and for patches we used Henery’s you might have the leak up in the valley or to the side that is running down so identifying the entrance point will be the most critical part and sealing that point. Asphalt patch can even handle standing water and most brands I have used can be put on in standing water but you have to work it a bit to get it to seal and it works better on dry surfaces.

I used to use a leaf blower to dry roofs off before sealing it helps.

  • Ed mentioned the method used by consultants. Infrared camera sees the water making it's way in through the roof. Clearly this was a bad install/patch. Needs to be done right with the whole roof for the longest leak free lifespan. Bandaid fixes will fail with the right circumstances.
    – user68386
    Dec 29, 2020 at 20:36

One option which I used long ago when I did not want the cost of a new roof ; I got a gallon of liquid roofing tar and brushed it on every suspicious spot . I had a few damp spots in the roof decking plywood . It stopped the leaks for a couple years until I sold the house. It was ugly to see when on the roof but not so noticeable on the dark shingles from the street level.

  • 2
    +1, not tar though. fibered aluminum roof coating aka silver coat. I do it every couple of years on a +100yo roof.
    – Mazura
    Dec 29, 2020 at 19:36
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    @mazura I fully agree but silver coat needs dry weather , asphalt patch like Henery’s can be done wet, then silver coat when dry.
    – Ed Beal
    Dec 29, 2020 at 20:45
  • Thank you for the suggestions.
    – Jay Roy
    Dec 30, 2020 at 15:24

I would ask a few more questions, like, is this a home you plan on living in for years or just a long term Airbnb that you want to patch ?

Maybe I'm misunderstanding your comment about the hole, but couldn't you just insert a stiff wire at that point and have someone up on the roof look for it?. If not measure the distance from a known exterior wall from inside and add 6-8" outside and you have a closer measure of finding the spot of the leak.

Since you have the end point of the leak... work backwards and start removing the interior framing and that will likely lead you to the wetspot ie the hole in your roof which TBH looks like a drunken toddler was your roofer. You can slowly work your way up, since water really only goes down, you will find many wet boards along the way and you won't have to tear a hole in your roof looking for it. Then patch that hole, reroof that job and if you can salvage the framing otherwise put in new boards.

I recently had to fix a bad dry rot problem that was patched so poorly by the previous owner that they tore off the rotted siding, sheeting and installed a new piece of plywood as a nailer strip. Then they reinstalled new plywood over dry rotted framing, installed siding and sold the house. $22,000 later we found/solved the issue and am suing the previous owner for lack of disclosure of the repair, fraudulently sold a house claiming there was no repair as we now know he knew there was an issue but covered it up in addition I have testimony from neighbors they witnessed the work being done the prior summer.

If you are skittish about swinging a hammer or doing repairs blindly, I have a few options to fix this once you find the leak, you can get someone with 15+ years experience in roofs who will happily supply you five different references of old jobs where the customer is happy. Ask that roofer to come over and give you advice, I've had so much luck making friends with contractors, beer and pizza go a long way to get advice. Its likely that this is a common occurence and the contractor has a way to deal with this that you can benefit from.

Next option you can repeat the mistake of the previous person and try to patch this job by draping a tarp over an area or doing other half measures, this is not undoable but its hit or miss and will waste time. Then you become the same type of person who does a half way job and there is a special place in the underworld for people who half ass things.

I guess a nerdy option would be to draw squares on your roof and use different colored water to pour onto that area, when you get that color water into your wood framing you have at least a vertical start point.

  • 1
    Thank you for the suggestions. - This is my primary residence, i plan to live here another 5 to 7 years. - Yeah, insert a stiff wire from interior was my next step
    – Jay Roy
    Dec 30, 2020 at 15:15
  • 1
    The problem with poking a wire up or making another hole the actual leak can be quite a distance away from the drip point. I would measure to get an approximate starting point.
    – Ed Beal
    Dec 30, 2020 at 16:17
  • I already measured the distance from inside (hole to exterior wall) but i do not see any hole on the exterior roof.
    – Jay Roy
    Dec 30, 2020 at 16:34

If your sure of the leaks location or general vicinity here's a couple of alternative suggestions:

If the leak is coming from the red shingles on the pitched section of roof there's a roof product called "Kool-Roof" which is an elastometric rubber coating. It is applied with a brush or roller. I goes on as a thick liquid and dries to a flexible skin that fills holes and stops leaks. It can be applied to damp surfaces, but not in standing water.

My last suggestion to locate the leak would be to closely examine the shingled roof. Look for any signs of failure (torn or worn shingles, nail heads pushing up through bottom, shingle joints that line up over an exposed nail head). If the leak is reoccurring look for the plywood sheathing to be swollen from water and bouncy when walked on. Zero in on those areas and you will have the general vicinity of the leak. From there you can remove rows of shingles to expose the leak source.

  • Thank you for the suggestions.
    – Jay Roy
    Dec 30, 2020 at 15:23

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