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.
The forces that cause windows to leak fall into three categories: house design, installation, and maintenance. Turning to the wisdom of industry experts, we can identify nine of the most common errors that occur during window installations, which can lead to window leaks â and now you can too.
When a snow load melts on a roof and re-freezes at the eave areas. Ice dams force water to back-up under shingles and cause leakage. L Flashing. Continuous metal flashing consisting of several feet of metal.