Hammering a nail close to the edge of a piece of a board may cause it to split. This problem can be solved by using the nail to open up the split, them filling the crack with glue. Wipe off any glue that runs over. Remove the nail, then clamp board as the glue dries. To avoid these splits in the future, use a drill to bore a pilot hold.
By simply caulking, sealing, and weatherstripping around all your windows, outside doors, or where plumbing, ducting, and electrical wiring penetrate exterior walls, floors or ceilings, you can save 10 to 25 percent of your heating bill.