The sill nose on my dining room window is partially rotted and I have removed it. I noticed that the face of the sill and the back of the sill nose have some grooves. I am thinking of replacing the sill nose with PVC which is a different size from the previous wood sill nose I removed. Is it important for the grooves on the sill and sill nose to interlock or does it matter.
I ask this because the face of the sill also contains some rot so I may not be able to get the groove on the back of the sill nose to fit into the slot in the face of the sill