Moisture issues are a problem in many homes, but basements especially have a reputation for damp conditions and musty smells. If you're hoping to finish the basement space in your older home, you need to be realistic about potential moisture and mold problems before you undertake any finishing. Here are the initial steps you should take before you begin.
1. Remove any and all mold that is currently present in the home.
Old houses have a long history of owners who have made changes to the home's materials, finishes, and even the footprint. Before you begin a serious renovation project that will close off plumbing and access to floors and walls, have a mold remediation company inspect for any mold that might be present in the home—especially in the basement. Pay specific attention to older laundry rooms and bathroom fixtures (solitary sinks or showers) that might be located in the otherwise unfinished basement area. You don't want to inadvertently cover up mold that is flourishing, only to face a much more expensive remediation later.
2. Assess actual moisture levels.
Even if you've never had an actually flood in the basement during a rain storm or with spring run-off, you still need to address these "slight" moisture problems. Check the foundation walls for signs of water—old whitewash will yellow from water leaks. On bare brick, water will leave white mineral deposits. Windows could have slightly warped frames. Concrete could show pitting, and mortar in between old rubble or brick foundations could be cracked from exterior water pressure in the soil surrounding the basement. Make a note of even the most minor signs of water—you'll have to assess each one before finishing can begin.
2. Run a vapor barrier test.
Tape a large sheet of clear plastic on the bare masonry of your walls in different areas of the basement. Water vapor that leeches in will condense and pool on the plastic, showing that moisture is more of a problem than you may have anticipated. If you have dry plastic after a few days, you know you'll be mostly in the clear to apply spray insulation, framing, and sheetrock. If the plastic is not dry, you'll need to contact a waterproofing company for advice on how to best remedy the problem—it may involve waterproofing the foundation exterior of your home. They will need to run more extensive and precise vapor barrier tests.
3. Use interior waterproofing products.
Once you've filled gaps, fixed exterior drainage, and installed a sump pump in case of flooding, it's time to apply interior waterproofing—even if your basement seems dry. Interior waterproofing products work quite well as a preliminary measure to improve your vapor barrier test results. In older homes, however, applying this barrier can be more time consuming because it often needs to be applied over bare brick, concrete, or stone. This means removing the preliminary white washing or other paint that is common to basement walls of historic homes. You can also apply it to the floor. It can take time to remove this layer, and if you're not up to the DIY task, leave it to a waterproofing professional.
4. Use subfloor panels.
Laying carpet or any other flooring directly on concrete traps condensation and leads to moldy flooring. Mold quickly spreads once it starts, so this is easily prevented by installing an elevated subfloor over the concrete that allows for better airflow over the foundation. This is also a good way to level out any uneven settling in an older home.
5. Build with mold-resistant materials.
Opt for treated lumber if you're using wooden framing. Do not use paper-covered drywall for interior finished walls. Look for paper-free sheetrock, or use cement board to finish the walls. Finally, use engineered hardwoods, tiles, or laminate flooring instead of hardwoods in the basement. Engineered hardwoods are much more moisture resistant, and they adapt better to a damp basement environment.
For additional info on completely removing and preventing mold growth in the basement, contact a mold remediation company in your neighborhood.