January 4, 2019

In many cases, crawlspace waterproofing will involve complete encapsulation of the crawl space. This means that the crawl space is closed off from the outside environment. Nothing gets in and nothing gets out; not even air.

The only problem with this is that moisture may build up in the air in the crawl space. You'll need to find a way to deal with this. The following are some of the options you may want to consider:

  1. Venting to the outside
This was once the most common practice in crawlspace waterproofing. However, it has been shown to be a poor method for ventilating the crawl space. This is because the air in the environment (especially in humid areas) is humid. It will therefore bring moisture into your crawl space and cause moisture problems.

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This is therefore the worst option if you do not live in a dry climate.

  1. HVAC System
Another common option used is supplying air in the crawl space via the HVAC system. Many homeowners opt for this as the duct work of their HVAC system already runs through the crawl space. It is therefore an easy and inexpensive option.

The only problem with this option is the development of a positive pressure in the crawlspace and negative pressure in the house. Great care should be taken to avoid this as it may not achieve the desired result of drying out the crawlspace.

  1. Exhausting air to the outside
This is becoming a common way to deal with air in the crawl space. It involves the installation of an exhaust fan in the crawl space. The fans exhaust air from the crawl space to the outside thus getting rid of stale and humid air.

The problem with this method is that replacement air is needed to fill the vacuum created. This air is expected to come from the house above. However, air doesn't always follow this pathway. This is especially true if the subfloor has been insulated. On the other hand, if the band joists aren't sealed properly, too much air may be drawn in from the outdoors.

  1. Use a dehumidifier
This method involves the use of a standalone dehumidifier. The dehumidifier will help to control the levels of moisture in the air in the crawl space. It only works to control the conditions in the crawl space.

This is the best option currently available for controlling the conditions in the crawl space. Ensure you get a professional contractor to properly size and install a dehumidifier.