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JoJoBeans 01-10-2009 06:28 PM

Sealing Trim/siding joint
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I am repairing some water damaged trim along the edge of my chimney outside. I think it was damaged from not being properly sealed where it meets the cementboard siding. Is it supposed to be sealed or open to allow water to have a place to exit? The trim runs diagonally across several lengths of siding so it obviously does not have a snug fit.

I drew a picture of the area in question. Thank you for any suggestions or direction!!!


spaz2965 01-10-2009 07:04 PM

is it possible to take a picture so that we may offer further help?

JoJoBeans 01-10-2009 08:12 PM

Picture added
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Here is a "real" picture! You can sort of see where water was running down the siding at the bottom of the picture. The original trim was not sealed, the gaps are large enough that I would have to fill them with something before I could caulk them. The trim is nailed on top of the siding, not below.

Thanks for your help!


inspectorD 01-11-2009 06:13 AM

Bad design
What you had happen will happen again, it is a bad design.
I would build down the bottom so it ends up flat with a drip edge over a board at the bottom or just a piece of siding which ends at the bottom.
You need to think like the water, the water will find the lowest spot and run there and follow any gaps available. Caulk is only a deterent, it will eventually fail from all the movement of the wood. It may say 50 years caulk, and I agree with that, but it will not adhere to wood which is not there because it rotted away.
If you are going to keep that design, you may need to change the material to aluminum flashing, with some vinyl boards which will not decay.

roofer 01-12-2009 03:49 AM

Caulk it with an exterior sealant,then maintain it

JoJoBeans 01-12-2009 06:13 AM

Yeah, I kinda thought it was a bad design. I would love to be able to replace the siding to go all the way down and flash/trim at the bottom. Unfortunately, I am selling soon and do not have the money to do that extensive of a repair. I also do not want to pass on a problem to the future owner. I have already replaced the damaged trim (the house is 10 yrs. old and the damage was not very bad, just the ends of the board). Is there any type of spray foam that I could fill the gaps with and caulk over that? Is this an issue that I should disclose on the seller's disclosure form?

Thanks again!

inspectorD 01-12-2009 06:16 AM

As long as you fix it, there is nothing to disclose. Paint all sides of the board also. The ends which decayed are the most important, this is where water wicks itself into a board, the same way the tree grows. And do as Roofer suggested

triple D 01-12-2009 06:54 PM

try this....
Go get a piece of 5/4x 3-1/2 cedar, and a piece of flashing that will overlap your 5/4 with a 1/4 lip, and stand up on back side about 1-1/2. Take a pencil and scribe a line across the top of your new trim board you have installed, then remove it. Then slide a piece of flashing up behind siding that is cut to fit. Then lay your old trim on top of new trim, and cut to match. Then slide trim into place and attach. Then caulk the top end and bottom end where they but. This is a cheap, nearly lifelong, honest fix. Good luck....

triordie 01-28-2009 08:30 AM


Originally Posted by roofer (Post 26729)
Caulk it with an exterior sealant,then maintain it

Leak Stopper Rubberized Roof Patches would work pretty well for this.

JoJoBeans 01-28-2009 09:17 AM

Thanks for the replies!

I primed and painted the boards, then caulked as best as I could. It certainly seems like a flawed design. I guess when the market is hot, some builders don't really put as much thought into things as they should.

Thanks again,

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