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.
A small leak caused the roof sheathing and rafters of this home to rot. Mold grew in the insulation as well. If you have water stains that extend across ceilings or run down walls, the cause is probably a roof leak. Tracking down the leak is the hard part; the fixes are usually pretty easy.