# Installing sill adapter for replacement windows...



## Windows on Wash (Aug 30, 2011)

Same thing I said on the other board for me.

Foam, allow to cure, then cut to fit and install.


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## Yodaman (Mar 9, 2015)

AllGoNoShow said:


> Looking to install my Seaway replacment windows which come with a sill adapter that snaps into a channel in the bottom of the window (it is flat and just terminates where it hits the existing sill-it is not in an L shape like others i have seen).
> 
> Ive seen it done two ways , install the sill adapter before installing window and then putting a strip of low expansion foam on the sill right before install. Or install the window without the adapter, insulate underneath, then install sill adapter. With the second way i am concerned because i would have to cut the adapter to fit in between the exterior stops (i am doing inside install) and it will not extend the full length of the actual window opening. Is there a best way to do it?
> 
> ...


The difficulty with pre-installing the sill adapter is that often they need to be cut to width. But there is no way of knowing where to cut it until the 
window is installed. I cut it to fit inside the stops after the window is installed. And then run a bead of silicon across the top and down the 2 sides, continuous to the to the sill. No Silicone across the bottom. Regarding shimming up to to meet the top. I would prefer to leave that 1/8 to 1/4 gap at the top and then fill it with spray foam. Also if you move the window up it creates a larger gap at the bottom.


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## Yodaman (Mar 9, 2015)

Windows on Wash said:


> Same thing I said on the other board for me.
> 
> Foam, allow to cure, then cut to fit and install.



Could you elaborate a little, thanks


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