# Undersill trim



## joecaption (Nov 30, 2011)

Depends on where your talking about.
It needs to be under and window sills to keep it from buckling.
I also use it at the top of the wall inside the J.
I use a snap lock tool to punch rectanguler shaped hole that leave a tab that locks into the undersill trim so it never comes loose.
One other use is up under the drip edging when the fasias is being wrapped with coil stock.
With those punched holes it locks in place with no face nails needed, on the bottom where the folded over lip is I use another punch that makes tiny oval holes for the trim nails.


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## begal (Jul 23, 2014)

I guess over time it will buckle. Could is use another piece as a shim?
Does the undersill have to be the same color as the siding?


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## joecaption (Nov 30, 2011)

Not going to work.
Why do you not want to do it right?
We still have no idea where your going to use it.
How would you hold the shim in place?
No it does not have to be the same color as the siding, but would be better if it was if this is on a second story where you would see it more.


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## ron45 (Feb 25, 2014)

I use pieces of foam the same thickness as the J channel 2" wide by the length of widow. The foam is pushed up into the jay and nailed, this makes the siding look full and not crimped and will not buckle.


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## ParagonEx (Sep 14, 2011)

According to VSI you need under will trim. Then you use a punch lock on your siding piece that is cut along the top so that when it is pushed into the undersill trim, it locks.


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## joecaption (Nov 30, 2011)

I agree 100%, why do you not want to do it right.
Under sill is cheap to buy and simple to install.


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## Yodaman (Mar 9, 2015)

joecaption said:


> I agree 100%, why do you not want to do it right.
> Under sill is cheap to buy and simple to install.




And the punch tool is probably only $10 or $15


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## Yodaman (Mar 9, 2015)

Yodaman said:


> And the punch tool is probably only $10 or $15


http://www.homedepot.com/p/Wiss-Snap-Lock-Punch-WSLP1/204158890


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