The four front windows in the Bungaloft project were original cottage style, double hung, single pane windows. A while back we replaced the sashes with Marvin Tilt-pack units that made a tremendous difference both in thermal efficiency and noise transmission. But it was clear at that time that the window frames were a bit marginal. So as part of the remodel process, I have taken out the windows and done restoration to improve matter a bit.
One of the windows had significant damage to the "horns" at the outside of the sill. So a replacement front edge was made from material reclaimed from the house demolition.
I devised a plan to attach flanges fabricated from pressure treated plywood to each of the windows to facilitate installing them with the insulated, ventilated rainscreen siding. Each flange strip has an edge of fir (also reclaimed from the house) attached to the inner edge that will be visible under the final trim. The PT flanges are the same thickness as the furring strips for the rainscreen so they will also provide a place to attach siding adjacent to the windows.