Construction Moisture Prevention – Ten expert tips

All exterior wall surfaces, whether manufactured laminates, plaster coatings or wood logs, need to be treated for moisture resistance, covered before application and installed in 100% dry condition.

Protection and preparation of the structure surface (wall cavity) and finish building materials are critical to the prevention of moisture related problems.

Moisture should be the predominant concern with exterior siding products. Proper treatment of floor, ceiling and wall structures and installation of the finish surfaces that meet the standards recommended by the building materials manufacturers are vital to the success of your construction project.

In the case of natural products such as stone or brick facings or wood logs, extensive preparation and preventative maintenance need to be factored into the homeowner’s budget. These natural building products may appear warm and attractive; however, they do not naturally repel moisture.

Installation instructions accompany all building products; however, they are not always followed by the laborers. Any underlying mildew, dry rot or mold must be removed from the substrate structure prior to the finish siding application. If necessary, any defective areas must be replaced, not repaired. No imperfection in stucco or wood can be overlooked. Poor installation methods usually lead to future problems with moisture and mold.

In order to insure that you do not experience moisture related mold and mildew problems, which can lead to health issues, try to observe the following guidelines during your construction project.

1. Moisture sensitive building materials cannot stored outside or exposed to weather before installation; if they are delivered to the job site wet or corroded, they should be sent back.
2. Roofs should be designed to drain freely and allow water to move rapidly off roofs, through gutters and downspouts and away from the dwelling.
3. Use moisture-resistive barriers, such as Dupont Tyvek, behind tub and shower tile installations so water permeating through tile grout drains back into the tub or shower pan, not into the wall cavity.
4. Gypsum wallboard should be installed only when dwellings are sealed from the weather and the interior relative humidity can be maintained.
5. Before wallboard and other moisture sensitive interior components are installed in dwellings that have been exposed to the weather, provision must be made to dry the framing and substrate. This may be as simple as providing time and ventilation to allow for drying. Depending on the climate, mechanical drying and dehumidification equipment may be required to supplement ventilation drying.
6. All windows, doors, roofs and chimneys need to have flashings installed around them. These flashings, which are not expensive or time intensive to install, are critical in deflecting water away from a building.
7. The ground around the building should graded to maintain at a slope of at least 5% that drains away from the dwelling. This should be checked periodically to make sure that settling or new landscaping does not reverse the grade.
8. In the case of dwellings built on pilings or crawl spaces, cover all earth below with impermeable products so the soils water vapor cannot enter the dwellings floors.
9. Avoid excessive indoor humidity; run exhaust fans over stoves and in bathrooms for at least 10 minutes after use.
10. Watch for water stains or standing puddles in subterranean areas, bathrooms or under kitchen sinks.

Treat moisture problems and water leaks as you would a smoldering fire; find the cause and eliminate the moisture ASAP.

Written by Tom Rosenberger. With more than 25 years of homebuilding experience, 15 of which have been in Costa Rica, construction consultant Tom Rosenberger knows the ins and outs of building and remodeling a home in the Central Valley area of Costa Rica.

Andrew Makarik

to@welovecostarica.com

Andrew Makarik is the main editor of WeLoveCostaRica, a fan of this sunny country. He is also a loving husband and a has a lovely daughter. By being a devoted family man and the biggest Costa Rica fan, he wants to make more people feel at home there. WeLoveCostaRica unites people and helps them find new home or a new travel destination. This website is a friendly community where everyone can find not only information, but also new friends and travel pals. Andrew is also passionate about IT and programming, so he himself maintains a friendly atmosphere in this cozy environment of WeLoveCostaRica.com.