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.
Skylight Leaks. If your skylight leaks, chances are good that the problem is the seal between the flashing and the roof. Identifying where the leak is originating is the first step. For more about troubleshooting a roof leak, please see How to Find & Fix a Roof Leak.or this, you can use the same roofing cement. 4 Also check the seal where the skylightâs glass meets the frame. If you see any signs of leaking, seal this with clear silicone caulk. Keep in mind that some skylights, notably those in bathrooms, can drip moisture from condensation.