On Nantucket, decay and rot due to moisture infiltration may be the most prevalent cause of wood deterioration. Most problems with moisture can be resolved with routine maintenance, but identifying the cause of hidden moisture problems can sometimes be time-consuming and frustrating.
So what is a homeowner to do? Moisture invades most houses from time to time and the problem can usually be solved if it is weather-related or caused by leakage. Here are few tips to assist you. First, keep an eye on potential problem areas to see if the issue can be corrected by simple steps, such as installing new flashing, replacing broken shingles, or directing a downspout away from the foundation. Routine maintenance can often solve the problem. Don’t obsess about stopping all air leaks in your old house—you don’t want to trap the moisture inside. The best-preserved houses, ironically, are those that may not be the most energy efficient. There is enough movement of air in most old houses so that moisture trapping can be avoided by weatherstripping windows and doors.
Second, address potential problems associated with ground-related moisture and rain run-off:
- Are the gutters and downspouts in good order or are they filled with debris?
- Is there vegetation such as ivy on your walls—and is it trapping moisture?
- Does the ground slope away from the building as it should?
- Or does it direct water run-off under the structure?
- Check up on your other exterior weatherproofing.
- Is the exterior caulk around your doors and windows in good order?
- Are there shingles missing from the roof?
- Is the chimney capped and is the flashing in good repair?
Fix pipe leaks immediately. That small bathroom leak may be doing more damage than is obvious, allowing moisture to collect under flooring or in the walls and creating potential mold issues. Investigate musty smells. Is there outside ventilation for your appliances,such as the clothes dryer? Open windows and doors to generate air flow whenever practical. Is the dirt crawl space allowing moisture to penetrate the living area? A simple plastic vapor barrier laid on the dirt floor might do the trick (although some think this long-used method might trap moisture at the edges and along the walls). Consider using a dehumidifier in your basement if it tends to be damp. If problems persist, there may be a hidden moisture problem that can be identified and corrected by a contractor familiar with such issues.
Finally, if you opt for insulation, make sure it is placed in the correct areas and correctly installed. Older homes often were constructed with an air space between the exterior and interior walls to help ventilate. If practical, the attic floor is the best place to place insulation. Insulation in the wrong area can be a serious mistake, as moisture could get trapped in the walls, causing major problems. The best approach is to proceed carefully and eliminate possible problems with actions that will not compromise the historic fabric or do more damage.