What is that lip along the top back edge of (timber) window boards

[Draughtsman]

What is it for?

Thank you.

 

[chappers]

It slots into a groove on the back of the window to prevent a crack line showing if the timber shrinks.
Though not all windows will have them

 

[Draughtsman]

Are you referring to timber frame windows? I have new Upvc windows, I should have mentioned it - they don't have grooves.

I would like timber sills though, presumably I just order without the lip.

 

[JohnD]

or if you have a circular saw (or a plane and a lot of time) I suppose you could whizz the tongue off.

 

[crank39]

Deleted

 

[bobsuerita]

with pvc windows they are normally fitted with a channel for the the window board

 

[chappers]

Are you referring to timber frame windows? I have new Upvc windows, I should have mentioned it - they don't have grooves.

I would like timber sills though, presumably I just order without the lip.

yep or just but them up anyway