Advice on repairing roof leak...

I assume the point of water infiltration has not been pinpointed

Could start by running a hose across the lowest row of shingles, slowly, from one end to the other. look for any water leaks on the interior. Repeat on the second row of shingles, then the third and so on until the leak is located. The fix will be dictated by the location of the leak

I notice missing 3-tab shingles in two locations, a plumbing vent penetration whose boot has been either covered of replaced with a large amount of Vulkem or sealant. Note the EPDM used to manufacture the boots deteriorates in the presence of hydrocarbon based sealants. Flashing around the condenser and skylights as well as the woven valley would also be prime suspects for leaks.

A truly hack fix can be affected by using adhesive backed ice/water shield tucked under a row of good shingles above the leak and adhered over the leak. The ice/water shield is not UV resistant and will break down over months, but I used this technique to stem leaks in areas of my roof giving me time to tear-off, re-flash and re-roof section by section.

rizzo said:

I assume the point of water infiltration has not been pinpointed

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Could start by running a hose across the lowest row of shingles, slowly, from one end to the other. look for any water leaks on the interior. Repeat on the second row of shingles, then the third and so on until the leak is located. The fix will be dictated by the location of the leak


Well I'm close to knowing already where the leak is; I know it's coming in right where the valley meets the exterior wall --but your advice is great! I'll give that a try this weekend and see what I find...

I notice missing 3-tab shingles in two locations, a plumbing vent penetration whose boot has been either covered of replaced with a large amount of Vulkem or sealant. Note the EPDM used to manufacture the boots deteriorates in the presence of hydrocarbon based sealants. Flashing around the condenser and skylights as well as the woven valley would also be prime suspects for leaks.

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True but I actually don't think I have any leaks other than the one right at the end of the valley. I already have access to the base of the central air unit, and all the vent pipes. There are no leaks there. I'm assuming my skylight doesn't leak but if it does, it must be a very small leak since I have no drywall damage in the bathroom it feeds. I'm probably going to be gutting that ceiling anyways so I'll find out for sure soon!

A truly hack fix can be affected by using adhesive backed ice/water shield tucked under a row of good shingles above the leak and adhered over the leak. The ice/water shield is not UV resistant and will break down over months, but I used this technique to stem leaks in areas of my roof giving me time to tear-off, re-flash and re-roof section by section.

Click to expand...

Awesome tip! I just Google'd Ice and Water Shield and found some great information on some possible repair techniques. I think I'm going to first remove the bad shingles and determine what's going on underneath, then start my repairs from there... Thx again!!

Michael Thomas said:

For starters it's very difficult to maintain the watertight integrity of a valley with there is something like that evaporative cooler so close to its centerline, and extremely difficult - some roofers will tell you virtually impossible, on a long-term basis - to maintain it when you have a penetration like that skylight as close as you do, at a minimum it's going to require careful detailing with waterproof shingle underlayment on both sides of the valley and up the curb of the skylight.

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Actually, it's a central air / furnace unit I have running there now. I had the swamp cooler removed a few years ago. Still, I have had expert roofers up there to deal with sealing around that unit, the old hole where the old cooler was mounted, and the skylight. They actually don't leak at all right now (but I DO understand that this is just a matter of time). Still, it's good to be reminded that these areas will need attention in the future (until the new roof is built). Thx for your thoughts!

Ok, I started exposing shingles and it looks like I've found the problem alright! Man, I'm beginning to wonder if the people that did the work on this house 30 years ago did ANYTHING right!! Here's a view of the valley from above...[BTW, the felt backing was already gone --I didn't remove any of it myself]



It looks like they figured that the old roofing material they were building OVER would still hold even if they were opening up a side to be exposed [grr]

Here you can see the join up close...


...and here's how I believe the water has been coming in...


There's TON's of water damage in this area! I'm definitely going to have to do a good repair of this valley so that the water drains straight off the roof and not IN to the structure below. It also looks like they didn't use any felt backing below the shingles in this corner...

Here's where I had a professional roofing company do some patching a couple of years ago to plug the hole where the old swamp cooler was mounted...

Do you guys think I can use some of this roll roofing material to help patch up the valley? I think I can tuck it under the good shingles above and thereby creating a solid seal all the way to the edge of the roof? I'm still going to do some structural repairs while I'm here and then lay some good undercoating as well (probably that IAW stuff...

Ok, here's what I think I can do to prevent the rain runoff from getting under the old roof line...


I need to add an underlay anyways as the original work didn't have any type of backing on parts of the valley. Then I can add flashing at the bottom to prevent the water from flowing under the eave and into the walls...


What I don't know is just how to setup the flashing. I'm thinking I'll need to extend the flashing slightly beyond the roof line so there's no chance of water flowing towards the house...

Any thoughts?

> Any thoughts?

Flashing there is a Good Idea, otherwise the concentrated water runoff for the left-hand side of the valley will be scouring the right hand side of the roof.

At the upper right-hand corner of the flashing, it should go under the flashing for the vent stack.

Also, you will find that flashing difficult to form as a single piece as the "top" edge is not actually a straight line. Likely, that will end up as a two piece flashing, with the WSU above serving as the primary water seal in the valley.

................

While you are at it, since you will need to replace the vent's flashing anyway and it's open below, can you re-locate that the vent sack so that its near edge is at least 18-24" from the C/L of the valley? That would make creating a durable water seal much easier.

................

More generally, where's all that water going?

Looks in the picture like it's pouring down onto a slab, I frequently encounter undermined slabs and wet basements and crawlspaces caused by such runoff, here's an example from yesterday's inspection:



and here's a link to an example of problems caused by a valley similar to the one at your roof:

http://paragoninspects.com/basement-water-problems-home-inspection-evanston-chicago-il-copy.html .

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