I have had new windows installed in a 5 window bay with stone mullions. We found that the sill on one of the upper windows is quite seriously eroded and has been waterproofed for a short term fix. When removing the ground floor windows we found the stone and wooden lintel were wet, although the wood had not as yet rotted.
I am in need of some guidance as to the options available for repair and what sort of costs are likely to be incurred.
Many thanks
