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-   -   Flashing repair (http://www.diychatroom.com/f9/flashing-repair-70690/)

Squash_Pro 05-06-2010 09:08 PM

Flashing repair
 
I have an 18 year old house with a concrete tile roof. Over the past two years I have developed some leaks from valleys in my roof. I have oak trees in my front yard that are a ways from the house. However, some of the leaves from these trees make it onto the roof and get caught between the tiles in the valleys. Over the years the leaves have accumulated to the point where I believe they restrict the water flowing down the valley flashing. My theory has been that the leaves are causing dams which cause the water to go over the edge of the valley flashing onto the roof felt underneath. I have occasionally lifted the roof tiles and cleaned out the leaves from on top of the valley flashing. This seems to help for a while but the leaks seem to come back. Today I removed all the tiles along the flashing so that I could do a thorough cleaning and perform a closer inspection. I noticed that one edge of the valley flashing in one area was bulged up off of the felt by more than 1/4 inch. It is clear that water could go under the flashing at this point if it could get to this area. Is this the likely culprit? Does the flashing need to be sealed somehow with the felt for the roof to work properly? If so, what should I use to reseal the flashing in this area? The flashing is bulging and really doesn't want to go flat in this area. I could put some screws in it to try to flatten the edge to the felt but I'd probably still need some caulking or something to make it seal properly. Please let me know if the flashing edge needs to be sealed with the felt and how to do this given my bulging flashing. Thanks in advance for your advice.

seeyou 05-06-2010 09:54 PM

Cut strips of ice & water shield (peel & stick) to seal the sides of the valley. Don't make any more holes in the metal.

AaronB 05-06-2010 11:08 PM

Does the edge of the valley flashing have a water return? A water return is a feature bent into the edge of the flashing to keep water from running over the edge of said flashing in the event that wind or debris cause water to flow in that direction.

The edge of the flashing should be bent up at about a 135 degree angle.

Squash_Pro 05-07-2010 02:36 AM

Thanks for the replies.

Yes, the flashing has a lip that is curled over to keep water from flowing over the edge. The lip is U-shaped with the width of the U being 1/4 to 3/8 inch in most places. However, in some places this lip has been flattened to 1/8 inch or less by the concrete tiles that rest on top of it. Should I try to open up the U to what appears to be its original shape?

I'll look for the ice and water shield to seal the flashing where it has separated from the felt. Is this something that I would find at a Home Depot or would I need to go to a specialty store to find it? The flashing in some spots along the edge is 1/4 to 1/2 inch off the felt and simple pushing on the metal doesn't get it to lay flat. I could probably use some screws to pull the flashing down against the felt. However, this would require putting a few screw holes in the flashing. The flashing is currently held down by nails that are just inside the U shaped lip mentioned above. Should I use a few screws to pull the flashing back down against the felt (along with the ice and water shield) or should I just fill the existing gap with the ice and water shield?

Thanks again.

seeyou 05-07-2010 05:34 AM

Yes, the flashing has a lip that is curled over to keep water from flowing over the edge. Should I try to open up the U to what appears to be its original shape?

Won't hurt.

I'll look for the ice and water shield to seal the flashing where it has separated from the felt. Is this something that I would find at a Home Depot or would I need to go to a specialty store to find it?

Should be available at the big boxes.

The flashing in some spots along the edge is 1/4 to 1/2 inch off the felt and simple pushing on the metal doesn't get it to lay flat. I could probably use some screws to pull the flashing down against the felt. However, this would require putting a few screw holes in the flashing. The flashing is currently held down by nails that are just inside the U shaped lip mentioned above. Should I use a few screws to pull the flashing back down against the felt (along with the ice and water shield) or should I just fill the existing gap with the ice and water shield?

Since the valley metal has already been nailed, a few more screws/nails probably won't hurt. When we install metal valley for tile roofs, we hook strips of metal with opposing bends into that "hem" and nail through them. This allows the valley to slide if it needs to expand or contract from heat change and keeps holes out of the metal. We then add I&WS as mentioned over either side of the valley, just shy of the reveal line.

Squash_Pro 05-07-2010 10:59 AM

It sounds like the roofers took a short cut when they nailed down my flashing without using the hem technique. The bulge probably occurred due to uneven heating/cooling without allowing the flashing to move.

I'm not quite sure where to put the ice and water shield based upon your last message. You mention putting it over both sides of the valley just short of the reveal line. Is the reveal line the raised v-shaped bump in the exact middle of the flashing? If so, does the ice and water shield extend from close to this point over the outside edge of the flashing and onto the felt, thereby sealing the edge so that water can't get underneath the flashing from the side? (Such an approach would cover the entire u-shaped hem). My felt along the flashing is pretty dusty where dirt and leaves have gotton onto it in the past. Is there something that I should use to clean the felt before applying the ice and water shield in order for it to stick?

Thanks again for all your help. Your advice has been great.

seeyou 05-07-2010 11:10 AM

It sounds like the roofers took a short cut when they nailed down my flashing without using the hem technique. The bulge probably occurred due to uneven heating/cooling without allowing the flashing to move.

I've seen it done that way and bulging or tearing is sometimes the result if the valley can't move. It's more of an issue with copper than steel. They didn't necessarily do it wrong, just different from the way I do it.

I'm not quite sure where to put the ice and water shield based upon your last message. You mention putting it over both sides of the valley just short of the reveal line. Is the reveal line the raised v-shaped bump in the exact middle of the flashing?

No - the reveal is the exposed portion of the valley metal.

If so, does the ice and water shield extend from close to this point over the outside edge of the flashing and onto the felt, thereby sealing the edge so that water can't get underneath the flashing from the side? (Such an approach would cover the entire u-shaped hem).

Yes. The I&WS is widening the valley, so to speak. Since the hem has been nailed through, it's no longer completely effective at doing what it's designed for. The I&WS will negate the nail holes and the function of the hem. I'd cut the 3' width in half and install each 18" strip on each side of the valley.

My felt along the flashing is pretty dusty where dirt and leaves have gotton onto it in the past. Is there something that I should use to clean the felt before applying the ice and water shield in order for it to stick?

A broom.

Thanks again for all your help.

My pleasure. Good luck.

AaronB 05-07-2010 01:33 PM

Since you already have the valley dis-assembled, I would recommend going ahead and replacing the metal with new, and using the fastening method that CU described.

I differ from him in the opinion that your valley isn't necessarily wrong. Your valley IS fastened improperly, and should be done as CU describes.

AaronB 05-07-2010 01:38 PM

Also, if you do end up replacing the valley, you might consider two, maybe three rows of IWS, with one being centered in the valley, and one additional on each side, overlapping properly, to catch any water that does get pushed in by debris.

Also consider making the valley out of a wider sheet of metal with the water returns.

seeyou 05-07-2010 01:50 PM

I differ from him in the opinion that your valley isn't necessarily wrong. Your valley IS fastened improperly, and should be done as CU describes.

I can't believe I said that. I was in a mellow mood earlier, but it passed. Replacing it while it's open would be the best solution. I get caught up in offering band aid solutions to DIYers that don't have the ways and means sometimes. Thanks for getting me back on track.


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