Originally Posted by inspectorD
My opinion, don't install any wood to the block. your asking for trouble from somewhere down the road with condensation or wicking water.
When we trim a block area, usually around a basement window around here, we build the interior trim box.
The window will need extension jambs to get the trim out flush to the interior wall because of the thickness of the block. Build a box to fit the window size where the reveals are good. Then shim the box with a few cedar shims.
The last thing is to foam the box in place with low expansion foam in the can. Just be sure to cut a few sticks to keep the jambs in place while the foam sets up, or the foam will bow the jambs inward.
I have had great results with this method, and actually it is less work.
I have the same issue, concrete block home with tile. It was good info to hear about the condensation and wicking effect, but I honestly do not understand the rest of your post! Are you suggesting we remove the window and build a windowbox, then replace the window into the box? My windows do not sit on the tile, yet I don't like tile or marble and miss the look of a wood interior sill.
I like the idea of seating the sill on a treated plank. This would seem to take care of the condensation/wicking effect. What do you think?