An Ordnance Survey cut mark in the UK. The term bench mark, or benchmark, originates from the chiseled horizontal marks that surveyors made in stone structures, into which an angle-iron could be placed to form a bench for a leveling rod, thus ensuring that a leveling rod could be accurately repositioned in the same place in the future.
9 Causes of Leaky Windows. One of the main reasons to ensure your windows are watertight is to keep moisture out of the walls. Once inside your walls, moisture can cause rot, mold and pest problems. Keeping water at bay would be easier, of course, if our homes had no openings for doors and windows.
This is typically what it takes to prevent roof leakage from ice dams. Random ceiling stains, no roof leaks. Condensation that occurs in the attic is a common cause of ceiling stains. When enough frost builds up in the attic, it can leave enough water when it melts to create stains in a bunch of random places.