Water is not always a building’s friend. The battle to stay dry is essential to a healthy and low maintenance building. A good building envelope and drainage controls direct water infiltration and moisture when properly done. Beyond controlling water, there are equally important controls for moisture, dehumidification, and airflow. Determining the source of moisture and water can be a challenge, but the right professional can diagnose and remedy the issue.
Direct water can be an easier diagnosis. The signs of direct water could be paint peeling to bare wood, rot, plaster or drywall damage, or just by observing water pouring through or out of something. Most times, direct water can be obvious, like from failing gutters, roofs, and flashing, although there are times it can be a bit more elusive. The best way to find a failing system is in the rain, especially directional or hard rain, or when conditions are extreme enough to allow water in.
Beyond observations, there are several diagnosis methods that are very effective. Non-invasive methods include moisture meters and infrared cameras. Typically, the natural moisture content of exterior wood is about 15%, and interior is about 12%. Anything above that suggests water is trapped or the element is becoming saturated.
More invasive methods include destructive methods, where material is removed to see if flashing or caulking has failed and has trapped moisture. Products like caulk can be great in preventing infiltration, although they can trap more water than prevent it. Areas under trim and siding should never be wet, not even with condensation.
Exterior caulking should be reserved for vertical seams, and only appropriately used for active movement or incompatible materials. Caulking over a quarter inch wide requires a backer rod; never caulk into an open deep gap, since it just falls in and does not bond. Horizontal seams should be caulked sparingly as to not trap water, like under windowsills or at the bottom of trim. The reality is good flashing and water management should not require caulk.
Synthetic wood, vinyl, aluminum, and other non-wood siding or trim can hide water issues, since they do not “rot” or show damage like wood. Many non-wood products reveal trapped moisture or water from staining, mildew, or movement. While many sidewall products are systems to control water and moisture like vinyl siding, they can be improperly installed causing rot to the wood underneath. Hidden water infiltration can be even more damaging since the failure is not seen. We have replaced a 15 year old home’s rotted framing that had fiber cement siding, and the siding was showing only a bit of flaking.
The bottom line is observe your building and signs for water and control it. Sometimes it’s as simple as making sure your gutters are clean and rainwater drains away from the house, or window flashing is replaced. Caulk can be a fine as a stopgap solution, but caulk can crack and trap even more water.
A good construction generalist should inspect issues like persistent mold and lichen, peeling paint to bare wood, and rotting wood. They can determine how your building is performing and isolate the issue. Only then can they fix the problem, or recommend a specialist like a roofer or gutter company.