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What are those black spots on the bathroom ceiling?

In Hawaii, because of the excellent trade winds and beautiful weather, many bathrooms are built with only a window to evacuate moist air. This is all that is required by building code, but in many cases, it is not enough. Warm, moist air rises, and condensates on the ceiling above the shower and throughout the bathroom area. Without proper ventilation to evacuate this air, microbial growth can occur.

Is this dangerous?

It can be. Mold is an allergen, and everyone has a different reaction to amplified microbial growth. There are several factors to take into consideration when trying to determine if this growth is a danger to the occupants of a residential structure. Dangerous or not, the original design of the house most certainly did not include the presence of amplified microbial growth on the bathroom ceiling.

What do I do?

The simple answer is, remove it. But there are right and wrong ways of doing this. The proper procedure for removing surface mold growth is to wipe it away with a damp cloth. You can use water and a bit of dish washing soap to accomplish this task. The EPA does not recommend using chemicals. Most importantly, DO NOT spray anything on the growth in an attempt to “kill” it or bleach it. Spraying microbial growth with a mist-type sprayer will only dislodge the spores into the air where you can breathe them. Remember that mold spores are microscopic, so when you can see little colonies of mold growing on your bathroom ceiling, they could already contain millions of spores.

If you are going to clean your ceiling, it would be wise to wear a respirator to protect yourself from accidentally inhaling any mold spores. The proper mask is an N95, which filters particles as small as mold spores. Standard painter’s dust masks are not suitable for this task. N95 masks can be found at your local hardware store. You should also wear some type of rubber gloves, as mold spores can be absorbed into the body through the skin.

Once you wipe the surface of the ceiling clean, you may notice that the black spots haven’t gone away completely. This is probably because the mold has embedded itself in the paint and has stained the ceiling. If this is the case, you may look into repainting the ceiling with a medium or high-gloss paint which has excellent moisture resistance. This will help keep moisture from penetrating into the paint and thus deter future microbial growth. For even better resistance, prime the ceiling with an antimicrobial primer such as Kilz. This can also be found at your local hardware store.

How do I prevent this in the future?

If you are looking for a more long term solution, install a mechanical vent fan. Make sure to run the fan for at least 20 minutes after you have completed your shower and have exited the bathroom. Many people have vent fans but still have mold problems in their bathrooms. This is because they shut off the fan when they leave the room. This does not allow enough time to evacuate all the moist air. If you are concerned with remembering to turn the fan back off, you can always install a timer switch to shut off the fan automatically.

Bathrooms are a perfect environment for microbial growth, and require unique solutions and preventative maintenance that aren’t normally required in other parts of a home. If you have any questions on how to better equip your bathroom to resist microbial growth, give us a call, or post a comment below.  We can definitely help you with mold removal!