My Victorian house has an enclosed porch with a double opening-outwards churchtype door. The doors are rebated so they overlap where they meet, which helps keep the draughts out. But there is a large gap under each door through which the wind whistles. My question is can I add an internal cill to block that gap? I have a suitable length of 2 inch oak. Would that do? And how do I seal under the cill if I can install it?
