Preventing Moisture Damage

Preventing Moisture Damage

The next time you take a shower, consider the damage you may be causing to your home. Actually, one shower won't cause moisture damage in itself, but together with washing clothes, steam from cooking, and dishwashing, a good deal of moisture is added to the atmosphere of your home each day. And on the outside, rain and snow regularly drop a good deal of moisture on your house. All these factors can cause extensive damage both to your home's appearance and structure. Moisture can cause ugly rusting or decay of building materials, and blistering or peeling of painted surfaces. It can warp wood, and promote mildew and other fungi growth on our home.

But moisture need not be a menace, if you are aware of its threat and take the proper steps to prevent its accumulation in unwanted areas of your home. You should understand how moisture damage occurs, learn how to prevent future damage, and know how to repair present damage.

Moisture Damage From Outside
Each year rain, ice and snow can expose the outside of your home to great quantities of moisture. Moisture has historically been the cause of damage to building structures, but because of recent energy-saving measures, environmental factors can cause more havoc to homes than they used to.

Construction methods and building standards have changed to accommodate the increased interest in conserving energy. Houses built prior to the 1930s generally had no effective insulation in either ceilings or walls. Roofs were usually steeply pitched and constructed with shingles that had gaps between them which ventilated attics and cooled the roof deck.

These homes were, of course, heat-wasters -- heat escaped into the attics and natural ventilation kept the attic air moving. As a result, roof-snow melted rapidly and did not accumulate. Ice and icicles formed on the eaves and in the gutters rather than remaining on the roofs. Snow-water penetrations into the house were insignificant and gone before they could cause damage.

But in these days of high fuel costs and the need for energy conservation, new houses and modernized older homes must meet new standards. Often, the new standards represent only minimum requirements and serious moisture damage results.

Because of increased insulation, millions of homes now have warm attics instead of the hot attics in the old heat waster houses. The snow accumulation on roofs of houses with warm attics melts slowly along roof edges causing water pools to back up behind ice dams.

The water often remains in this area for weeks, penetrating roof shingles and finding its way into ceilings and wall cavities. This, of course, can create severe damage, such as soaked insulation, stained, swollen and cracked plaster and drywall panels, dampness and rotting in wall cativities and, eventually, stained, blistered and peeling paint. Interior paint damage may show up fairly soon. The blistering and peeling of exterior painted surfaces, however, may not become apparent until summer weather arrives. Water trapped in insulation and wall cavities may then penetrate the wood siding and emerge as blisters under the exterior paint film.

Rooftop ice dams aren't the only exterior moisture culprits. Water from moisture-soaked ground can seep into a home's basement through the foundation. Once water has penetrated into the home, it may continue to do so whenever a heavy rainfall occurs. Obviously the water will eventually cause damage to interior and exterior building materials.

Exterior Prevention Measures
There is little point in repairing damage done to the structure of your home unless you first take all the necessary steps to prevent future moisture problems. You should first eliminate the cause of problems before tackling the result of them.

First, thoroughly inspect your home for clues of moisture damage.

The first days of spring are a good time to check these spots:

Near gutters and downspouts, windows and doors, and the ground level row of boards or masonry.
Old caulking materials, where gaps may have occurred.
Masonry and roofing where hotels or seams may have appeared.
Gutters and downspouts where there may be backups or leaks.

Once you have sized up the damage, follow these steps to overcome future problems:

To prevent future damage from ice dams, remove snow from the roof, wherever possible.
Electric heating cables are available to melt ice in gutters— but be sure to melt and clear downspouts first.
The best safeguard is a well-insulated, but well-ventilated attic.
If the attic can be kept near the outside temperature, ice dams aren't likely to form.
Remember, proper insulation must be done in conjunction with adequate ventilation.
Repair any damage to your roof as soon as possible and apply a roof coating if needed.
Clear dirt and debris out of gutters and downspouts and repair them with a patching compound and a coat of the proper paint.
Make sure that flashing under shingles is secure, does not leak and covers proper areas.
Caulk around problem areas such as wall joints or cracks, pipes through walls, window and door frames, flashing, leaky gutters and downspouts.
Keep heavily used decks and porches in good repair, recoating or repainting every two or three years.
Trim shrubbery away from buildings to allow air circulation in ground-level areas.

Repairing Exteriors
Once you are sure the moisture has been dried out of the wall cavities and an adequate ventilation system has been installed, you should begin repairing exterior paint damage. Where the paint is blistered, loose, or peeling, it will have to be removed. Paint damage caused by moisture usually results in the paint coming loose right down to the bare wood.

All exposed wood surfaces should be sanded and spot primed with a suitable exterior primer. Many paint manufacturers recommend a solvent-thinned alkyd type for this purpose. When the primer is dry, apply a topcoat of either an alkyd or a latex exterior paint following label directions carefully. Your paint retailer can help you choose a paint that's right for your home.

Moisture Damage From Inside
Trapped water and moisture, escaping toward an area of less vapor pressure is technically the cause for moisture damage. When excessive moisture is retained in such areas as ceilings and walls that are not properly ventilated, it will begin to work its way out through these surfaces, causing a variety of ills to the materials with which your home is built.

Inside your home, you contribute to this build-up of moisture in many ways -- bathing, cooking, washing, and even breathing. Of course you can't call a halt to these basic activities. But you can make sure the moisture they create is routed safely to the outside instead of into your walls and ceilings.

Interior Prevention Measures
As with exterior damage, it doesn't help much to repair the surface of the interior of your home before you have corrected the problems that caused the damage in the first place. Check for interior surface damage in such moisture-prone areas as kitchens, bathrooms, laundry rooms, attics and basements. Be sure to look past cosmetic damage and check insulation to see if it is wet.

The key to preventing future moisture problems inside your home is to make sure your house is tight enough to prevent moisture from entering but at the same time adequately ventilated to allow interior-produced moisture to escape. Most importantly, you want moisture to escape through vents, windows and other openings created for that purpose — not through walls and ceilings where it will eventually cause structural damage.

Use ventilating fans or louvers to properly ventilate your home so that moisture can escape to the outside.

Waterproof your basement from the outside. Make sure the basement contains adequate drainage to avoid build-up of standing water.

In homes without basements, rot-proof sub-flooring and joists are necessary, and the ground under floors should be covered with a vapor barrier such as polyethylene plastic.

When insulation gets wet, it conducts cold rather than inhibits it. Insulation should be completely dried out before repairs begin.

Repairing Interiors

If damage to your walls or ceilings is severe enough to require replacement of some of the panels, you may need the help of a professional painting contractor. He can assess the damage and give you an accurate cost estimate for repair. Many painting contractors are qualified to do the whole repair and repainting job for you.

Sagging Drywall
To repair sagging drywall on ceilings, it is recommended that 5/8 inch panels be used. The old damaged panels can be removed and replaced or new drywall can be installed in front of the sagging panels. The thicker, 5/8 inch drywall is recommended today, since greater amounts of insulation are being used.

On the outside, under exterior overhangs, use waterproof sheetrock or exterior grade plywood panels to replace sagging drywall.

Once the structural damage has been repaired and you have determined that wall cavities and areas above ceilings and under floors have been properly dried out, you should repaint. Ask your paint retailer to help you choose the correct paint for your particular purpose and follow manufacturer directions for application.

Stained Walls and Ceilings
Most stains caused by water are likely to be amber or brownish streaks or blotches. If
p laster or gypsum board has not been damaged by water, repainting may be a sufficient remedy for stains. Since water has caused the stain, you can assume that it is at least partially water soluble. Wash the stained surface carefully with water and detergent or a household cleaner intended for cleaning paint. Without soaking the surface, remove as much stain as possible. Allow the washed surface to dry thoroughly — 48 hours or longer.

Before applying the finish coat of paint, use a special stain-blocking or stain-killer type of primer sealer. These primers are solvent-thinned therefore they will prevent further leaching of the water-soluble staining material. Any type of topcoat or enamel may then be used.

If painted woodwork, doors or paneling are discolored or stained by water from inside walls or ceilings, they can usually be refinished with a moderate amount of work. If the painted surface is blistered or the paint is peeling or chipping, it may be necessary to remove the paint down to the wood surface to achieve a smooth attractive finish. Many types of paint and varnish removers are available at your paint dealer. Be sure to follow label directions carefully when using paint removers.

If the painted wood surface has not been badly damaged, but has become dulled, discolored or stained, clean the surface thoroughly, sand lightly and apply an enamel undercoat. Allow the undercoat to dry completely, then sand lightly with a very fine sandpaper. Wipe clean and apply either an alkyd or latex enamel in any color or sheen you like.

If the wood surface has not been painted but is a finished natural wood, minor damage may be repaired with a light sanding, followed by a coat of gloss or semi-gloss clear varnish. When the damage is extensive, remove the finish, sand the wood until it is smooth, and refinish. Most paint stores carry a wide variety of fine wood stains as well as clear varnishes in a choice of sheens.

Repairing Plaster
If water has caused plaster to swell and crumble, or if sections have collapsed, it is likely that new plaster will be needed in some areas. New plaster must be allowed to dry and harden properly before painting.

Professional contractors often use a moisture meter to determine whether an area of plaster is dry, wet or very wet. But if you are doing your own work and cannot readily purchase or rent a moisture meter, be sure to allow adequate time for the plaster to dry. Most plaster can be safely painted in four weeks, if the temperature in the house or building is above 50 degrees F. and the relative humidity is not above 70 percent. If your home does not meet these conditions, or if plaster is applied directly to a solid wall such as brick, tile, etc., a longer drying time is necessary before painting.

If you must paint new plaster before adequate drying time has elapsed, the best procedure is to apply just one coat of a high quality latex wall paint. The latex paint will not be affected by any free alkali coming to the surface and the single coat will allow moisture to continue to evaporate through the paint without causing blisters. Later, another coat or two of either latex or alkyd wall paint may be applied.

Once you have determined that your newly plastered walls are dry enough to paint, you should check them carefully for chalky areas.

These can occur when plaster dries too rapidly at high temperatures. Chalk should be removed by vigorous brushing before painting.

Repairing Drywall
Drywall which has become badly soaked by water from inside the wall will probably need replacement. Once new gypsum board panels have been installed and the joints have been properly taped and sanded, painting is a fairly straightforward procedure.

For the first coat on new gypsum board, a latex primer is recommended. These fast-drying, water-thinned primers prepare the drywall panels for topcoat painting by providing a smooth, sealed surface. Following an evenly applied coat of latex primer, the topcoats can be either latex or alkyd paint in your choice of color and sheen. Latex wall and ceiling paints are usually recommended for this purpose because they clean up easily.

Repainting
Certain types of paint can be excellent vapor barriers — helping to keep moisture from permeating walls and ceilings. Vapor barriers, when used to coat interior ceilings and walls, inhibit inside moisture from penetrating these surfaces and damaging insulation and exterior finishes. Many of the familiar paint products work well as moisture barriers and there are now special vapor barrier paints available as well. A topcoat can be applied over the vapor barrier paint if the latter is not available in the color of your choice.

By ridding your home of moisture traps, promptly repairing any damage, and repainting or recoating properly, your home will be more energy efficient, protected from harsh weather, and more attractive.