Thursday, February 18, 2010

How do you prevent paint from peeling off the bathroom ceiling from moisture?

THE BUILDING CODE SAYS YOU MUST HAVE A WINDOW OR A VENTILATOR IN A BATHROOM. WHAT THAT MEANS IS OPEN THE WINDOW IF YOU TAKE A SHOWER AND DON'T VENTILATE. WHY DO YOU SUPPOSE THAT IS? THEY SHOULD MAKE THE BUILDER INSTALL THAT 8 BUCK VENT FAN.How do you prevent paint from peeling off the bathroom ceiling from moisture?
I agree with Tiger, your bathroom needs a good fan. But there's more to the story. You have to ensure that there is no drywall damage to the ceiling from moisture it's absorbed. There may be mold underneath the paint that's causing it to peel. Clean the area really well, then let it dry out for several hours or days. Then use a good base coat and paint that's especially made for bathrooms.





Good luck!How do you prevent paint from peeling off the bathroom ceiling from moisture?
Install a ventilation system.
Try priming the ceiling with an oil primer first. That should work.
Moisture and paint


Outside moisture such as rain and dew can penetrate a


paint coat and result in cracking, peeling, discoloration


and premature paint failure. These problems may be


observed in both heated and unheated buildings, are more


pronounced on edges and ends of boards and are also


observed where water is held on the surface. Porous


paints are particularly vulnerable to moisture


penetration.





Proper construction and maintenance will eliminate


most exterior water problems. Ice dams occur in cold


northern climates when snow on the upper warmer parts of


a roof melts and runs downward. As the melted snow


reaches the roof overhang which is not heated, it freezes


once more. With repeated thawing and freezing on the roof


more water moves to the roof edge and an ice dam begins


to build up. The melted water may penetrate the roof and


drain into the exterior walls, thus causing moisture and


associated paint problems.





Ice dams can be reduced or eliminated by adequate


insulation in attics and by proper attic ventilation.


Inside moisture (water vapor) can destroy paint on the


outside of a building by diffusing through the walls.


Water vapor from cooking, dishwashing, clothes dryers,


bathing and normal respiration by an average family of


four can contribute three gallons of water per day to the


humidity. If the inside of all exterior walls does not


have a vapor barrier or if the vapor barrier is


improperly installed, water vapor passes into the walls


during cold winter weather and condenses to a liquid. The


water eventually soaks into the siding and wets the paint


and is a common cause of blistering and peeling. The


problem may be particularly pronounced around bathrooms,


laundry rooms, kitchens and other areas of high humidity.





Interior water vapor can also move into the attic


space and condense on the gable ends, causing paint


peeling. Moisture may also condense on the attic side of


the roof decking and eventually work its way down the


side walls, causing paint peeling near the tops of these


walls. To prevent condensation problems in the attic, it


should be well ventilated. Gable roofs should have


screened vent areas of at least one square foot per 300


square feet of ceiling area. Hip roofs should have


continuous slotted vents in the eaves to allow air to


enter the attic and ridge vents to allow its exit.


Condensation problems in cold climates are best


prevented by installation of a continuous 6 mil


polyethylene vapor barrier on the warm side of all


exterior walls and ceilings. The vapor barrier should fit


tightly around electrical outlets, doors, windows and


other openings. A vapor barrier, sometimes called a soil


cover, should be installed directly over the soil in all


houses with crawl spaces. This will keep moisture from


moving out of the soil and up into the living space and


then through the walls and ceilings. If a vapor barrier


is absent, it can be installed under new paneling or dry


wall.





To reduce water vapor in the house, vent high


humidity areas such as kitchens and bath areas to the


outside. Clothes dryers should be vented directly to the


outside and not to the attic, basement or crawl space.


Mechanical humidifiers add large quantities of moisture


to the air and should not be used if paint peeling is a


problem.





Blistering


Temperature blisters are bubble-like swellings that


occur on the surface of the paint film as early as a few


hours or as long as one to two days after painting. They


occur only in the last coat of paint. They are caused


when a thin dry skin has formed on the outer surface of


the fresh paint and the liquid thinner in the wet paint


under the dry skin changes to vapor and cannot escape. A


rapid rise in temperature, as when the direct rays of the


sun fall directly on freshly painted wood, will cause the


vapors to expand and produce blisters. Usually only oil-


based paint blisters in this way. Dark colors which


absorb heat and thick paint coats are more likely to


blister than white paints or thin coats.





To prevent temperature blisters, avoid painting


surfaces that will soon be heated.';Follow the sun around


the house'; for the best procedure. Thus, the north side


of the building should be painted early in the morning,


the east side late in the morning, the south side well


into the afternoon, and the west side late in the


afternoon. However, at least two hours should elapse


before the fresh paint film cools to the point where


condensation will occur.





If blistering does occur, allow the paint to dry for


a few days. Scrape off the blisters, smooth the edges


with sandpaper and spot paint the area. Moisture blisters


are also bubble-like swellings on the surface of the


paint film. As the name implies, they usually contain


moisture when they are formed. They may occur where


outside moisture such as rain enters the wood through


joints and other end grain areas of boards and siding.


Paint blisters caused by outside water are usually


concentrated around joints and the end grain of wood.


Paint failure is most severe on the sides of buildings


facing the prevailing winds and rain. Blisters may occur


in both heated and unheated buildings.





Moisture blisters may also result from inside liquid


water moving to the outside. Plumbing leaks, overflow of


sinks, bathtubs or shower spray and improperly sealed


walls are sources of inside water. Moisture blisters


usually include all paint coats down to the wood surface.


After the blisters appear, they dry out and collapse.


Small blisters may disappear completely, fairly large


ones may leave a rough spot and in severe cases the paint


will peel. Thin coatings of new, oil-based paint are the


most likely to blister. Old, thick coats are usually too


rigid to swell and form blisters. Therefore, cracking


and peeling will usually result.





Elimination of the moisture problem is the only


practical way to prevent moisture blisters in paint. The


moisture source should be identified and eliminated to


avoid more serious problems such as wood decay or rot and


loss of insulating value.





Peeling and Cracking


Intercoat peeling is the separation of the new pain


film from the old paint coat, indicating a weak bond


between the two. Intercoat peeling usually results from


inadequate cleaning of the weathered paint and usually


occurs within one year of repainting. This type of


intercoat paint peeling can be prevented by following


good painting practices.





Intercoat peeling can also result from allowing too


much time between the primer coat and top coat in a new


paint job. If you wait longer than two weeks before


applying a top coat to an oil-base primer, soap-like


materials may form on the surface and interfere with the


bonding of the next coat of paint. When the period


between applications exceeds two weeks, scrub the surface


before applying the second coat. Do not apply a primer


coat in the fall and wait until spring to finish with the


top coat.





A simple test can be conducted to determine if the


new paint coat is likely to peel. First, clean the old


paint surface. Then, repaint a small area with the new


paint and allow it to dry for at least two days. Then,


firmly press one end of a';band-aid'; type adhesive bandage


onto the painted area. Jerk it off with a snapping


action. If the tape is free of paint,the new paint is


well bonded to the old surface. If the new paint adheres


to the tape, the old surface is too chalky and needs more


cleaning or the use of an oil-based primer.





Cross-grain cracking occurs when paint coatings


become too thick. This problem often occurs on older


homes that have been painted several times. Paint usually


cracks in the direction it was brushed onto the wood.


Once cross-grain cracking has occurred the only solution


is to completely remove the old paint and apply a new


finishing system. To prevent cross-grain cracking, follow


the paint manufacturer's recommendations for spreading


rates. Do not repaint unweathered, protected areas such


as porch ceilings and roof overhangs as often as the rest


of the house. If possible, repaint these areas only as


they weather and require new paint. However, if


repainting is required, be sure to scrub the areas with a


sponge or bristle brush and detergent in water to remove


any water-soluble materials that will interfere with


adhesion of the new paint.





Repainting Procedures





If a new paint coat is to be successful over a


problem area, any moisture problems must be eliminated.


Good surface preparation is also essential.





If the wood has been completely stripped or is being


painted for the first time, it should be brush treated


with a paintable water-repellent preservative or water


repellent. This treatment will reduce the uptake of


moisture by the wood. After the water-repellent


preservative or water repellent has dried for at least


two warm days, apply an oil-base primer or a stain-


blocking latex primer, followed by at least one top coat


of high quality acrylic latex paint. One top coat of


paint should last four to five years, but two top coats


can last up to 10 years.





If only isolated areas of the paint coat have failed


by peeling to the bare wood, spot painting may be the


best alternative. First, scrape away all loose paint.


Sandpaper or ';feather'; the edges of any remaining paint


smooth with the bare wood. Then clean the old painted


surface by scrubbing with a sponge or bristle brush.


Rinse the scrubbed surface with clean water. Wipe the


surface with your hand. If the surface is still dirty or


chalky, scrub it again using a detergent, and rinse with


clean water. After the surface has been thoroughly dried,


apply one coat of a paintable water-repellent


preservative or water repellent to the bare wood, being


careful to liberally treat end and lap joints. Any water-


repellent preservative or water repellent on the painted


surface should be wiped dry with rags. At least two warm


days should be allowed for the water-repellent


preservative or water repellent to dry before painting.





An oil-base primer or stain-blocking latex primer


should be applied to the bare wood. At least one top coat


to match the rest of the house should follow. Caulk large


cracks and openings after treating and priming. If


intercoat peeling is a problem, clean and prepare the


entire surface. Then apply the desired top coat. Where


intercoat peeling has been a problem, it is particularly


important to clean areas protected from sun and rain


such as porches, eaves and side walls protected by


overhangs. It is probably adequate to repaint these


protected areas every other time the house is painted.


If paint fails because of penetration of rain and dew


through porous paint, clean and prepare the paint


surface.





Then apply one coat of an oil-base primer and top


coat with acrylic latex house paint The oil-base primer


will prevent penetration of the wood by rain or dew. To


insure good adhesion, apply the top coat within two weeks


of priming. Always use a high quality paint, and apply it


as recommended by the manufacturer. Do not skimp on the


amount of paint. On the other hand, cross-grain cracking


will result with excessively thick paint coats.


Therefore, it is important that the paint weathers


normally before repainting. Protected areas may be


painted every other time. Research has shown that an


entire paint film (consisting of a primer and one or two


top coats) thickness of 4-6 mils, or about the thickness


of a single sheet of newspaper, will result in the


maximum service life.
open a window when you take a shower...





or stop bathing.
i agree with intensefirejr.


when you repaint, be sure and scrap off the old paint and prime the surface with a latex primer. I also think you should use exterior latex to go over the primer. I wouldnt use oil, b/c if you have poor ventilation in the first place, you'll be waiting a mighty long time for the ceiling to dry...dont shower in that restroom UNTIL the paint is completely dry. There is an additive you can get put in your paint called mildewcide, to prevent against mildew, however, some exterior paints are mildew resistant anyway.
use a primer as a base coat and then paint
there's a bathroom paint you can get with a sealant in it...it also controls mold
We had the same problem.





Make sure you have the fan always on when showering. Also, we keep the window open. Also when nto using the bathroom keep the door open at all times.





Above is what we did and it worked.





Good Luck
first off, if you have a window open it. if not install a ceiling fan.if that's not possible. after your done with the bathroom leave the door open.
Once the paint starts peeling, you must remove and repaint. There are special bathroom paints out there. Alos be sure to install a vent syetem and or just open the window.
Some of you have good answers. There's another idea. Remove all the paint, dehumidify the room to remove all the moisture (with a ventilator), and use plastic wallpaper instead of paint. Use sealant as your adhesive (apply as thin as possible) and allow 24 hours before using the bathroom again. Make sure the wallpaper you use is weatherproof. :)

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