We listed bathroom ceiling leaks here specifically because these rooms have additional possible causes of water stains that other rooms do not. First and foremost make sure your bath fan duct work exits out side your home. We have witnessed many homes with missing or poorly routed bath fan duct work. Missing or disconnected ducts push warm moist air directly into your attic – A Huge Problem! I have actually been in attics with this problem that looked like ice castles. Every framing member and nail had water or ice on it or dripping from it.
Do not run your bath fan duct work into your homes soffits or eaves as the bathrooms warm moist air ends up in your attic cavity. Soffits and eaves on your home are for air intake Not air exhaust. Make sure your bath fan duct work is well insulated. Many bathroom ceiling water stains are caused by condensation that forms in and around bath fan duct work when that bathrooms warm moist air is traveling through un-insulated duct work. Take a frozen mug out of your freezer and set it in your bathroom when the shower is running and you will see how important insulating that bath fan duct work really is.
Keep your bath fan on long enough to vent all that humidity out of your bathroom. Leaving high humidity in your bathroom can lead to pealing paint, pealing stipple, mold and mildew on your ceilings and walls. Plus all that extra humidity can be absorbed by your ceiling and walls and end up once again in your attic. Some homes do not have bath fans only windows. This is our opinion is a very poor choice that invites the above mentioned problems. Many older homes were built like this with homeowners being told if you have windows you don’t need a bath fan (how many homeowners are going to open that window during the colder months). Bathrooms with tubs and showers need good bath fans in our opinion.
Skylights in bathrooms add another component to possible leak causes. If your roofer has ruled out faulty skylight flashing let me suggest one other possible issue with skylights in bathrooms. Condensation forms on the inside of skylights during high humidity and sharp temperature variation conditions. This condition can occur as the bathroom humidity rises or during a rain storm. You would be surprised how much condensation forms on skylights when cold rain hits them on the outside. Normally this condensation is captured by the skylights condensation channel. This hidden channel runs around the perimeter of the skylights glass inside your home. A skylight condensation channel is designed to capture condensation that occurs on the inside of the skylight glass and then allow that water to evaporate back into the air instead of running into your home. When to much condensation fills this channel it can overflow into your living area. If you are experiencing a leak on the lower end of the skylight have your roofer check and make sure your condensation channel is not over flowing. A skylight tunnel can exacerbate the situation since this causes less air movement and that means more condensation on the skylight (moving air absorbs moisture). It also has the effect of increasing the humidity in the tunnel since condensation that does occur and can not make it out of the tunnel is evaporating in the tunnel area where air is quite stagnate. If this is a problem you may have to better circulate the air up in your skylight tunnel along with measures to reduce the overall humidity in that area.
One last comment on bathroom ceiling water stains. If you see a water stain on your ceiling (not just bathroom ceilings) you may want to go outside and look up on your roof standing in your yard. Take note of any plumbing pipes that penetrate through the roof and line up with approximately where you are seeing the leak inside. This could be a indication of a bad plumbing vent pipe collar on your roof. This could be causing the water stain you see (see plumbing vent pipe collar leaks) . We hope you found this information helpful. Please feel free to contact Maryland Shingle if we can be of any assistance.
Return to Leak Diagnosis Page Click Here