Water, in large quantities, can be devastating. From Noah’s Ark in biblical times, to the Johnstown (Pa.) Flood in 1889, to the 2004 tsunami in the Indian Ocean, water can be as much of a troublesome element as fire.

But in smaller quantities, water can be good. You swallow a couple of glasses of it every day to stay healthy. You wash your car with a bucket full of it, or a load of clothes with a bit more.

In even smaller quantities-when it is condensed and diffused, and generally called moisture, it can cause as much heartache as a flood or other act of nature, especially in the construction industry.

Dampness can be a villain that everyone faces at some point or other.

In a nation such as the United States, with many different climates and weather-zones, fighting moisture intrusion and subsequent damage calls for different products and tactics depending on where in the country the war is being waged.

Part of this article surveys many of AWCI’s contractors to establish widespread use of tactics and products in various areas, but first, let’s review some basics.

Three Water Flavors
Moisture, which is to say water, comes in three different flavors: solid (ice), liquid (water) and gas (vapor).

Most contractors have a respectable handle on the solid variety, and-especially in the South-have little or no trouble keeping it out of buildings. Many also have a fairly good handle on the liquid form. If anything is causing headaches nowadays, it is vapor.

Maria Spinu, Ph.D., of DuPont Building Innovation, has made a brilliant occupation of studying and combating vapors especially, and has this to share about it-and the dew point temperature-in an announcement for one of her 2005 lectures:

“Water exists on earth in three physical states that can undergo reversible phase transformations. Dew point temperature is the onset of the vapor-to-liquid alteration known as condensation.

“Moisture problems in buildings are the result of liquid water accumulation within the building enclosure. The sources of liquid water within a building enclosure include liquid water intrusion or condensation of excess water vapor transported by air currents or through diffusion.

“Dew point temperature is the temperature at which the concentration of water vapor reaches its saturation and will condense on cold surfaces to form droplets of water. We often see condensation on windows or further cool building surfaces. This so-called surface condensation is not much of a problem. However, when condensation occurs within a building assembly (interstitial condensation) it can lead to moisture problems, which range from building durability and performance, to indoor environmental quality (IEQ).”

Envelope Penetration
The purpose of a building’s envelope is to keep the internal environment separate-and protected-from external conditions. This includes keeping the cold (or the heat) out and the heat (or the cold) in. Another purpose of the envelope is to keep moisture out.

According to the McGraw-Hill Construction’s Continuing Education Center’s course on air barriers (January 2006), “Moisture, when it does enter the building, moves through the envelope as liquid water or as water vapors. The difference between the two physical states of water is the size of the molecular aggregates: liquid water exists as large molecular aggregates (up to 100 molecules at room temperature), while water vapors exist as free molecules. Consequently, the transport mechanisms are different for liquid water and water vapors.”

Liquid Water. The main source of liquid water for above-grade walls is rain, which can find its way behind the exterior cladding and so be driven into the building enclosure by four main forces:

• Gravity, which can draw water up through openings and cracks, and into the construction assembly.

• Capillary forces, which act like a sponge sucking water through small cracks and pores. Smaller cracks result in greater capillary forces.

• Rain droplets can pass through openings in the exterior cladding, driven by the thrust of the falling rain.

• The pressure differential can push or suck water through openings and cracks, into the construction assemblage.

Water Vapor. When moisture enters the building as water vapor, it penetrates the envelope either by air currents or by vapor diffusion.

For vapor diffusion to occur there has to be both a driving force and a pathway. In this case, the driving force is the difference in water vapor concentration (or difference in vapor pressure) across an assembly: Water vapors flow from an area of higher concentration (higher vapor pressure) to an area of lower concentration (lower vapor pressure).

However, looking at the practical side of things, experts estimate that the amount of moisture vapor shifted by air currents can be 100 to 200 times higher than the amount shifted by diffusion, and can account for more than 98 percent of all water vapor movement through the constructing envelope.

The air current rule of thumb: Vapor flows from warm (high pressure) to cold (low pressure).

The Vapor Barrier
Keeping the moisture out (and away from insulation, where it can do major damage) is the purpose of the vapor barrier. The main design decision is where, exactly, to place it, especially since vapor, reaching a vapor barrier and with nowhere else to go, will eventually accumulate, reach a dew point and turn into liquid water.

Heating or Cooling Climate. In a heating climate-where a building is heated more days of the year than cooled-the vapor (by the warm-to-cold principle) will prevalently travel toward the outside. In the cooling climate the opposite it true: Vapor will predominantly travel from out the envelope toward the inside of the building.

Since barrier membranes are usually placed adjacent to wall insulation, the issue of where, exactly, you place it is determined by the prevalent vapor direction. If you happen to place it incorrectly-i.e., at the far side of insulation-as the vapor travels, condensation is likely to occur inside the insulation and degrade it considerably over time. Fiberglass can lose as much as 70 percent of its insulating properties when wet.

It is therefore crucial to place the barrier at the near side of insulation-as the vapor travels-so that vapor hits the barrier before entering insulation.

In a heating climate, that means placing the barrier between the inside of the building and the insulation; in a cooling climate, between the outside of the building and the insulation.

Who Determines Placement?

When it comes to determining not only the risk for moisture intrusion, but the products-and their specific placement-to guard against it, the engineer calls the shots.

As Bill McPherson of Central Ceilings in Massachusetts succinctly put it: “We don’t devise, or recommend, solutions. We implement them.”

This sentiment is echoed throughout the country, where it is always up to the designer or the architect to detect and solve potential moisture issues.

But there is one interesting caveat: According to Pat Arrington of Commercial Enterprises in New Mexico, the contractor license in his state lays the ultimate responsibility for any building problems at the contractor’s feet, whether he followed incorrect design advice or not. So, New Mexico contractors, think twice.

Gregg Conrad, president of CSW, Inc. in North Carolina, adds to that that if he notices something wrong as far as fighting moisture goes, he would “raise a flag. Even though the engineer specifies the system, and we’re only responsible for applying it properly, if there’s an inconsistency in the design we have to make them aware of it.”

An Engineering Vision
Jim Stump is a Portland, Maine-based engineer with Criterium Engineers, a company of consulting engineers with more than 70 offices in North America. His view on moisture problems/solutions is well worth sharing: “Of course, moisture intrusion is always through the building envelope. How that occurs here in Portland, Maine, nonetheless, is different from how it occurs in North Carolina, and certainly different from, say, Phoenix, Ariz.

“The vapor barrier needs to be on the warm side of the insulation. That is the basic criteria. So, in the South, where the warm side of the insulation is usually the outside, and you are attempting to cool the indoors, the vapor barrier would be toward the outside of the building.

“In northern climates like here, it’s the reverse. The warm side of the building in the wintertime is the inside; the cool side is on the outside, so the vapor barrier should be toward the inside.

“The difficulty with design comes in climates that are in-between, states akin to New Mexico or the mid-Atlantic states like Virginia or North Carolina, where you get both.

“The vapor moves from hot to cold, and when it reaches the dew point it will condense, and if that happens to be in the insulation, then you have a problem.

“A critical issue when evaluating a construction for moisture solutions is to view the building as an organic whole, and take all aspects into consideration.

“The climate is just one factor. You also have to evaluate airflow, blueprint, specific location-a building on top of a hill will behave quite differently from one down in a valley-the type of heating deployed, the type of cooling used. How much sun does it get? Is it a solar building? All of these things relate to the organic whole that you should to consider.”

Fiberglass Insulation. As mentioned earlier, fiberglass degrades greatly when wet. Why precisely is that?

“Fiberglass insulation,” explains Stump, “relies on air pockets, and while it gets wet it loses those air pockets and, therefore, loses its insulation value.”

As much as 70 or 80 percent?

“It’s certainly possible. And I, unhappily, see that phenomenon quite often.”

Wood Framing. Stump has this to offer: “Some designers suggest that when it comes to wood-framed walls, you should put a vapor barrier on both the inside and the outside to try to seal the wall.

“My experience is that, although this may look good on paper, in practice-because no barrier is ever 100 percent effective-you’re going to wind up trapping moisture inside that wall.

“You have to consider that the wood frame has quite a bit of moisture in it already, even if it is a kiln-dried piece of lumber. Over time, it will lose some of that moisture, and this has to go wherever. If sealed in, it will eventually reach dew point and condense inside the wall.”

Taking the Country’s Moisture Fighting Pulse
What products are used where? Keeping in mind that the contractor as a rule does not choose, nor recommend, the moisture fighting weapons he deploys, the question becomes instead: Which products does he normally install (as specified by the architect)?

The brand names you would expect to hear are the names that popped out of the mouths of contractors from all over the country; it is their preferences in manufactured goods type that vary.

Gabriel Castillo of Pillar Construction in Virginia likes liquid-applied membranes, which become part of the substrate. “When the liquid spread on membrane dries, it hardens to a rubber-like, waterproof membrane, so you know that it will cover and seal well. There are no pores, no holes, no way for moisture to penetrate. … You just roll it on. It’s as if you were to apply a very thick paint.”

Stephen Angell, president of Cape Cod Plastering in Rhode Island, uses “a self-healing, peel-and-stick product, for exterior cladding.”

Robert Aird of Robert A. Aird, Inc. in Maryland does of lot of exterior insulation and finish systems and sees the gamut when it comes to product names, but he cautions about maintaining the integrity of the entire system: “Some [barriers] can be used with other products, but normally they are only tested and approved to work with their own EIF system.

He goes on to say, “In the last 10 years or so, though most actively over the last three or four years, we tape all sheeting joints, we spot the screw heads, we seal all penetrations and connections to other materials, and then apply a liquid-applied barrier over the complete face of the building to create an air- and water-barrier-or a WRB, a weather resistant barrier.”

But in Florida, Eric Boulanger of Boulanger Drywall Corporation does not frequently see liquid applied membranes being applied.

Gerald Roach of Forks Lath & Plaster in North Dakota mostly sees the big brand names, but adds that “it’s also getting more common to do a sprayed-on or trowelled-on moisture barrier over the sheeting, particularly on bigger jobs like the Wal-Marts and motels.”

Glenn Sieber of Easley & Rivers, Inc. in Pennsylvania says, “What we now see more and more of is studs, sheeting, then a spray-on or a trowel-on or a place-and-press membrane for waterproofing-afterward a rigid insulation.”

Richard Riley of Simpson Commercial Contracting, Inc. in Alabama: “On the exterior partition substrate we like to use a roller applied barrier, because they’re seamless. On the exterior wall-if we’re worried about moisture-we normally use an elastomeric finish.” Riley adds that all the major brands work.

The moral of this story is that if you can smell it, you missed a turn way back there, and you’re now facing damage control, literally … which usually means several pounds of cure.

The ounce of prevention is to understand how moisture travels, and how to channel its movement.

Coeur d’Alene, Idaho-based Ulf Wolf writes for the construction trade as Words & Images.

Moisture in the Crawl Space

Moisture ruins houses by providing a hospitable environment for mold, fungi, and insects that destroy wood framing. Our moisture transfer solutions include sealing all air leaks from vents, windows, doors, duct work and eliminating any puddles of water. The problem with a vented concrete crawlspace is that as warm air rises in your home, it brings up with it the air that was previously in your crawl space, including moisture and mold spores, as well as anything else that may be airborne down there. Sealing the crawl space from the earth and outside air is the solution to moisture and dampness in the home. Properly sealing the crawlspace and removing the moisture from the ground and air is part of the solution that helps provide a mold-free, radon-free, and insect-free environment, which leads to a more energy-efficient and healthier home. The moisture generated in the crawlspace will lead to structural damage and higher energy costs. To avoid moisture’s negative affects, a crawlspace should be completely sealed and isolated from the ground and the humid outside air. An important part of a crawl space moisture control strategy is the installation of a vapor barrier.

Crawl Space Moisture Control

Homes that feature crawl spaces often suffer from moisture damage related to the crawl space environment. If you have standing water in your crawl space or if the insulation in your crawl space falling down or wet and moldy or if there so much junk in your crawl space that you can’t even get inside or if your crawl space is humid and is your plumbing and heat ducts are sweating or if you are you concerned about mold and fungus in your crawl space then it is time to give us a call. The polyethylene sheeting should be laid over the crawl space soil with a minimum of joints. We always install sealing tape over the joints as well. Over time contractors and inspectors realized the vents that were installed to remove humidity in fact helped to increase the humidity level in most crawl spaces.

Oakbridge Construction Takes Over

Oakbridge Construction can seal your crawl space, lower relative humidity levels, eliminate odors, lower energy costs, and gain you storage space. Lower energy bills translate into savings year after year. Oakbridge Construction provides two main product systems to seal your crawlspace and protect your family’s health. That would include the drainage and pump system and the encapsulate system. In most geographic areas, fresh outside air is not dry and tends to worsen the humidity problems when it enters the home. Mold spores, odors, humidity, and critters create a very unhealthy environment for people.

Oakbridge Construction encapsulation system includes products that prevent crawl space moisture by encapsulating the crawl space with a vapor barrier and closing off the crawl space vents, and, to make a healthier crawl space and home. The real issue in crawl space encapsulation is its power to make your home free from any moisture problems. After installation of the encapsulation system, along with the optional dehumidifier, the humidity levels dropped from 80% to 45% within a 2-week period. In the summer this lower humidity (sweatiness) can feel pretty good.

There are crawl space encapsulation products such as crawl space vapor barrier liner to get your crawl spaces free of insects and other organisms. To avoid moisture’s negative effects, install a crawl space vapor barrier to isolate your home from the ground and the humid outside air, and then optionally, condition or dehumidify the crawl space air. Call Oakbridge Construction at 586 703 0112