Posted on Leave a comment

4 Pro Tips for Wall Cavity Drying

by Jocelyn Hare; e-published in R&R Magazine

There are multiple ways to dry affected walls, each with different benefits depending on the severity of the loss. It is often recommended to start with the drying process that requires the least amount of demolition. When you remove affected materials that could be dried, you decrease the amount of drying equipment needed. Drying walls allows you to minimize your labor costs while maximizing the amount of drying equipment on a job.

1.  A common step to drying affected walls is to remove affected baseboard. By detaching baseboard from wet walls, capillary action (stage 2 of the drying process) can occur. While baseboards may impede the dry-time of wet walls, this is also the case with wall coverings such as calcimine (often referred to as “cal-cote”), gloss and semi-gloss paints, and wallpaper. Once the baseboard is removed, and nearby flooring is dry, bound moisture in the walls may “wick” out through the bottom of the walls. Contractors often leave a small gap between the wall material and the subfloor.

Pro Tip#1: To reduce secondary damage to affected walls, carefully score the top of the baseboard to disconnect it from the wall or wall covering.

2.  When materials become wet, the moisture becomes bound within the materials, including the inside of wall cavities. To dry materials that contain bound water, the drying process goes through the third and final stage of drying, “vapor diffusion”. The best way to allow airflow to access the affected wall cavities is through wall cavity drying. By removing the baseboard and creating one 5/8” hole every 14-16 inches (or in between each stud bay), the decrease in vapor pressure will allow moisture trapped inside the materials to turn into vapor and evaporate into the drying chamber. Wall cavity drying can help reduce the overall dry-time of affected materials.

Pro Tip #2: Use an aerator, like the one created for restorers by Restoration Tools, to create the holes for wall cavity drying. It is 15 times faster than the current method and leaves no debris to clean up.

Pro Tip #3: The process of creating holes for wall cavity drying can typically be added to estimates. (ex: Xactimate users, use WTR WALLH)

3.  In some cases, the process of wall cavity drying may require the use of specialty drying equipment. Unlike typical wall cavity drying, where the vapor evaporates into the drying chamber through the cavity hole, the injected airflow helps to inject drier air from the chamber into the cavities.

wall cavity drying
Aerator being used to make holes for wall cavity drying.

Pro Tip #4: Using injected-air drying systems can be advantageous in drying hard-to-reach spaces or sensitive areas such as server/computer rooms.

As with any water loss, it is necessary to utilize proper drying equipment sized and placed to allow for optimum drying. Follow local and industry guidelines in determining salvageable materials and the best drying process for each water loss.

Be sure to follow the EPA’s lead RRP procedures when doing demolition in a building built before 1978. Older buildings may have lead paint or asbestos, and it is imperative that safe abatement procedures are followed. 

Posted on Leave a comment

Techniques for Effective Wall Cavity Drying

General Guidelines for Wall Cavity Drying

by Jocelyn Hare; e-published in R&R Magazine

Wall cavity drying. It’s a simple concept, but what does it do for the drying process and why is it so important?

We know the drying process consists of three stages:

  1. Removal of surface water through evaporation – using airflow of warmer drier air to evaporate moisture as it wicks from the material pores.
  2. Removal of free water through capillary action – as long as surface tension is decreased and the material pores are still wet, water will continue to be pulled from the affected materials and then evaporate. Baseboard is a common inhibitor to the capillary action, so it is commonly detached.
  3. Removal of bound water through vapor diffusion – capillary action can no longer continue, forcing the moisture to turn into vapor and evaporates from inside the pores. The third stage of the drying process is the most difficult to achieve in materials that do not have full airflow on all sides of the affected materials.

Wall cavity drying is especially useful for the second and third stages (drying through capillary action and vapor diffusion). Let’s take wet walls of drywall as an example. After removing the baseboard, which blocks air flow, technicians may create ⅝” holes along the perimeter of the affected walls. Through a combination of the pressure exerted, the volume of the space, and the latent energy, water is taken from its physical state and turned into a gas, or vapor. This process can also take place in ceiling and cabinet cavities.

So when should you use wall cavity drying methods? Here are some general guidelines:

  • to help achieve the standard drying time of 3-5 days
  • decrease demolition, such as “flood-cutting”. While gypsum board loses structural integrity when wet, the strength returns as it dries, allowing for salvageability.
  • Category 1 and Category 2 losses – be sure to consider all potential contaminants during inspection for proper safety and health of customers and technicians.
  • to dry rooms without direct air circulation (such as server/computer rooms)
  • to dry hard to reach spaces through the backside of an adjoining room
  • to dry under cabinets and vanities
  • in conjunction with specialty cavity drying systems and equipment

There isn’t a “one size fits all” method for water restoration, as each job and customer is unique. It is important to assess each situation so you can use the best tool for the job. After removing the baseboard, being sure to score it so as to not cause secondary damage, the most common method of creating holes for wall cavity drying is with a drill and vacuum. Did you know you can typically add this as a line item in your estimates? A fact of the restoration industry is the high margin profitability of equipment rental, and conversely, the low margins associated with labor intensive tasks.  When you remove affected materials that could have been dried, you decrease the amount of drying equipment needed. Drying wall cavities allows you to minimize your labor costs while maximizing the amount of drying equipment on a job.

A new tool has emerged in the market, called the Aerator, that speeds this process by 15 times. This innovative tool is designed and produced by Restoration Tools. The team has over 40 years of combined experience in the disaster restoration industry and is improving restoration one tool at a time. To learn more about the Aerator and Restoration Tools, visit restorationtools.com.

Be sure to follow the EPA’s Lead RRP procedures when doing demolition in a building built before 1978. Older buildings may have lead paint or asbestos, and it is imperative that safe abatement procedures are followed.