New Construction Moisture Control

Throughout the course of new building construction, contractors are often confronted with adverse weather conditions that can generate an excess amount of moisture within the unfinished building.

Excess moisture presents a unique problem when it comes to new construction. If the interior framing or sub-floor exceeds the IICRC standard of 12% moisture content, it is very easy for mold to grow on these surfaces. Once covered with carpeting or drywall, the existing mold will quickly begin to feed and grow.

What does this mean for a contractor?

Imagine a scenario where your firm constructs a building for a client, only to have them file a lawsuit sometime in the future because of mold growth within the building. There are numerous court cases in which homeowners and major companies have successfully sued contractors for negligence during construction that led to mold growth.

Typically, the building owner claims that the contractor permitted excessive levels of moisture to enter the building prior completion. And as discussed above, the now completed building created a sealed environment in which mold could quickly reproduce.

How do you prevent a costly lawsuit?

Mold cannot develop without sufficient moisture levels, either in the air or on the surface of materials. The surefire method to removing moisture from the interior of the structure is to use structural drying techniques.

We’ve come across a number construction firms that understand the nature of the moisture issue, but feel that they can adequately remove the moisture themselves. Typically they use propane heaters and cook the inside of the structure. This method uses a large amount of guesswork; nor does it have a method to determine if all the surfaces are below 12%. It’s simply not scientific enough to guarantee success.

Novos follows the nationally established IICRC standards for structural drying. We utilize thermal imaging and moisture measurement equipment to ensure that the interior of the structure is below the 12% moisture threshold. Once the entire interior structure has been confirmed to be below 12%, the interior walls and carpeting can be installed without fear of future mold growth.

But what about the crawlspace?

When construction necessitates a crawl space beneath the first floor, moisture levels must be controlled to prevent excess moisture from entering the building. In our experience, mold contamination is typically the result of a damp crawlspace without proper climate and moisture control.

Importance of moisture control in a crawlspace

These days, polyethylene sheeting is laid in the crawlspace of a building to act as a vapor barrier between the sub-floor/floor joists and the exposed dirt. The vapor barrier is the only protection that a crawl space has from excess moisture; so you can see the importance of a properly installed barrier.

If the vapor barrier contains gaps or doesn’t sufficiently cover the side walls, ground moisture will envelop the exposed floor joists and sub-floor. This situation provides the perfect conditions for dry rot to occur. Once mold forms on the floor joists, it will penetrate into the beams and destroy their structural integrity. Only costly removal and replacement of the floor joists can fix this issue.

Clearly, the best method to prevent a mold growth or dry rot issue is to properly encapsulate the crawlspace after building construction is complete.

Crawl space encapsulation method

Prior to the building being completed and released to the owner, Novos will undergo a multi-stage process in the crawl space that will essentially eliminate moisture and the conditions necessary for mold growth. This encapsulation system creates an environmentally-controlled air space beneath the main floor.
– Channels are opened around the inside of the foundation to direct any surface water to flow to a lower collection point. Any collected water is pumped out of the crawl space by a sump pump.
– Heavy duty, low permanence polyethylene sheeting is placed over the exposed dirt surfaces. Proper overlapping of the sheets ensures that moisture does not bypass the vapor barrier.
– Chemical sealant containing fungicide is applied to the floor joists and the underside of the sub-floor.
– Commercial dehumidifiers are installed to remove moisture from the air and expel the water from the crawlspace.