In the early years of the restorative drying industry we were mostly concerned about drying carpet and carpet cushion.

In the early to mid-1980s, our industry underwent a significant paradigm shift. We began to recognize there was much more to be concerned about when a building suffers a traumatic intrusion of unwanted water. We must be sure that the building is dry—the whole building.

This is why we must think about drying the structure. Water can wick up more than six inches into porous materials (like drywall) in as little as eight hours. The bottom sill plate can hold water. Often, there are several layers of materials that are wet.

Airflow, airflow, airflow
The number one thing that increases the rate of evaporation from wet materials is airflow on wet materials, the more rapid the better. It's difficult to imagine a water damage situation where we could use too many air movers!

Of course, we also need to be able to handle the humidity created from this rapid rate of evaporation with a dehumidification system. Heat always helps, but there are practical considerations.

Dry from the outside
Air movement blowing directly on a wall with the base trim intact will dry a wall amazingly fast. Of course, if you are dealing with a large quantity of walls, this may be impractical. As long as the conditions are right, many materials and layers of materials can be dried with air movement. If we have the ability to run more air movers, this should always be our first consideration because it is less destructive to the building.

Remove the base trim
Removing the base trim to enhance evaporation has been used (sometimes overused) by our industry for several years. When we remove the base trim, we could damage the wall and it may need some repairs and painting. If we paint one wall in a room we will likely find it necessary to paint the other walls. We will also have to refinish the base trim. If we refinish the base trim, we will likely have to refinish the door and window trim. This can result in an expensive restoration invoice. Remember the purpose of restoration is to reduce repair costs.

Some restorers wait a day or so before removing the base so that the drywall will firm up and won't be as likely to be damaged. Make sure you use a wide putty knife as a backsupport for your prybar. If you make the decision to remove baseboard, make sure it's the right decision. It is very possible repair bills will soar.

Dry from the inside
Over the years, various methods and systems have been developed to dry wall assemblies. They all work if used properly and can speed up drying in many cases.

Cut holes and set airmover
In the early years before any wall drying systems were developed, we would remove the baseboards and set air movers so that some of the airflow would enter the holes. The bigger the holes, the better this system worked. There were some drawbacks though. We had to be very meticulous about cleaning up the dust, and we still would blow drywall dust into the environment. The holes also had to be patched to meet fire codes. Additionally, the issues concerning repair costs discussed above were an issue.

Carpet dryer manifolds
Carpet dryer manifolds attach to the snout of a carpet dryer, increasing its versatility. We can broaden the path of air up to four feet and increase the area of the wall surface getting air movement or drill holes below the top of the baseboard line to increase airflow inside of the wall. The holes could be a little smaller, but bigger holes work better.

Again, the issue of repair costs was an issue with this method because the base trim has to be removed with this system. This system works best if used with an airmover capable of high static pressure.

Air manipulation devices
There are also devices that attach to a carpet dryer snout that will direct air through hoses that will get air where you need it. Then mini manifolds attachments or hoses would be attached to the end of the hoses to direct the air where you want it.

This method generally requires smaller holes than with the manifolds, but it is still somewhat destructive and some limited repairs would be necessary. With these air manipulation devices, an airmover with high static pressure is also recommended.

High-pressure inter-air drying systems
High-pressure inter-air drying systems were introduced to our industry a few years ago and are very popular. They use high-pressure blowers to either push air into a wall cavity or pull air out of a wall cavity. This creates a positive or negative air pressure inside the wall cavity. The energy from pressure generates air movement. However, it is important to remember: Pressure doesn't dry, air movement dries.

The primary advantage of this type of system is the small holes that are necessary to insert the nozzles into the wall. You might consider not removing the base trim and actually inserting the nozzles in the wall above the baseboard. Your total repair may be less than if you removed the base trim.

Strategic considerations
There are a number of factors to consider when developing your drying strategy. Determining whether the wall is an interior or exterior wall and the construction method or design are important. Further, consider what is covering the wall and how drying will be affected.

Wall design
There are several wall systems in use in North America. A discussion of the particulars is beyond the scope of this article. However, most walls have common characteristics: Exterior walls should usually be insulated and may have a vapor diffusion barrier. Interior walls usually do not have insulation or vapor diffusion barriers.

Exterior walls
Things to consider when you encounter exterior walls are:

• Cellulose insulation
• Fiberglass insulation
• Vapor diffusion barriers
• Low-permeance exterior finishes
• Extreme outdoor weather conditions
• Failed building wrap and components
• Exterior facings, including brick and stucco

Interior walls
Since interior walls are usually hollow and don't have vapor diffusion barriers, they are usually easier to dry. However, some areas of concern are:

• Headers (2x and 3x layers of construction lumber)
• Door and window casings
• Plaster, double-thick drywall
• Metal studs (trough-bottom plate)

Wall decoration
The ease or simplicity of drying a wall assembly is largely determined on how it is decorated. Any type of decoration or fixture can impair drying effectiveness.

Finishes
The type and amount of paint on a wall will affect drying. Drying a drywall wall with one or two coats of paint is much easier than a wall with 8-10 coats of paint.

Many homes and businesses will use latex enamel on walls because the finish is washable. Latex enamel wall paint has a very low permeance factor and acts as a vapor barrier.

Coverings
Items that cover walls that are important considerations. Some examples of challenges we face are:

• Laminates
• Ceramic tile
• Paneling and wainscoting
• Wall paper, particularly, vinyl and foil
• Behind built-ins (tubs, vanities, cabinets, bookcases, etc.)

Trim
All buildings have decorative trim and all can impact drying by acting as a vapor barrier.

• The base trim
• Chair rail and crown molding
• Door-jambs
• Door and window-casings

Understand the wall design
It is important to understand the construction method used in your geographic area. Visit some construction sites and inspect a building as it is being built to determine what types of materials being used in construction. However, not all buildings are alike because:

1. construction methods and materials change with time
2. workmanship standards vary
3. building codes change
4. trades people move around the country and bring exported construction methods, etc.

Measure your success
Professional restorers use instruments to determine and measure their drying effectiveness. There simply is no other way to do this. Restorers who don't use moisture meters shouldn't call themselves professionals! Restorers typically use two types of moisture meters: penetrating moisture meters and non-penetrating moisture meters. Each has its appropriate use and usefulness.

The non-penetrating moisture meter is a useful inspection device and can be used as a reliable moisture meter. These meters do, however, have functional limitations. It is important to clearly understand how your meter reacts to different situations and different materials.

The penetrating moisture meter is the most reliable meter for determining the moisture level at a precise location. Most meters have short pins for checking moisture levels at or near the surface as well as extended insulated pins for checking moisture levels deeper within materials and layers of materials.

Every restorer should have both types of moisture meters and both should be used on every job.

Thorough inspection
Checking the moisture levels of materials is absolutely critical in restorative drying. Inspect any material that was in the water's path; you will find that water and porous materials behave predictably. However, assuming that something is dry or will dry is risky business.

Results
There are a number of factors to consider when drying walls and the structure. Not only should we consider the content and extent of the water migration, but also we must deal with building components and decorations that can dramatically slow the rate of evaporation. Restorers have numerous tools and devices at their disposal, as well as their own ingenuity and creativity. Buildings are not dry until the restoration professional has made the determination that all materials are returned to a pre-loss moisture level. The only way to make that determination is by using appropriate moisture measuring devices.

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