Bathroom Mold and Mildew

Bathroom Mold and Maintenance

It’s time to chat about bathrooms again.

One of the easiest rooms to grow mold and one of the easiest rooms to prevent mold.

Typical areas in the bathroom for mold growth.

    • On the grout between ceramic tiles.
    • On the caulking around the tub, shower and sink
    • Toilet tank bowels
    • On the ceiling and wall paint
    • Behind the pictures
    • On the frame of a bathroom window
    • On or behind the wallpaper (bad idea for a bathroom)

This list doesn’t account for leaks and mold growth behind bathroom walls and tubs etc.

Let’s breakdown the list and discuss the prevention of mold growth.

  • Grout between ceramic tiles

Mold doesn’t grow on ceramic tiles or the grout between the tiles as these are not organic substances. However, the soap, dirt and body oils that remain on the ceramic tiles and the porous grout are organic and mold will grow in/on those areas. These are easily cleanable by the homeowner.

Remedy, Use a strong household cleaner/disinfectant to remove the current mold growth. Find a grout sealer to seal the porous aspect of the grout, this will allow for better/easier cleaning and help prevent mold growth. All the big box stores sell grout sealer, my favorite is found online at www.groutshield.com.

  • The caulking around the tub, shower and sink

Caulking must say “Mold and Mildew Resistant” on the packaging or it’s probably not and shouldn’t be used in a bathroom, kitchen or laundry room. Mold and Mildew resistant caulking has a 5–10yr life span against mold growth, if mold has started growing on the caulking it was either the wrong type or it’s expired, either way it needs replacing.

Remedy, Remove all the affected caulking with knives or caulking scrapers, do not try caulking over the bad caulking this will not last. Once the caulking has been removed and the areas cleaned leave the areas un-caulked for about 24hrs to allow drying behind the old caulking. Caulk with the proper type caulking, practise makes perfect or hire a handyman. Do not forget to caulk the tub and shower faucet, they are usually loose and allow water behind the wall if not caulked. Only caulk 75% of the faucet the bottom stays open to allow moisture out.

  • Toilet tank bowels

Often a neglected area which can be a source of mold growth. The tank bowel will sweat if the toilets water tank is unlined. This can be the source of moisture which allows mold growth on the underside of the toilet water tank and the wall behind this tank. The mold will not grow on a porcelain toilet but it will grow on any organic matter that is left there such as dust and dirt.

Remedy, Check the underside of the toilet water tank for dirt, dust and mold growth occasionally and clean with a strong household cleaner/disinfectant if necessary. The wall behind the tank is typically painted or worse…wallpapered. If mold growth is detected or suspected it’s time to repaint with the proper mold and mildew resistant paint types and please avoid wallpaper, mold really enjoys the wallpaper paste.

  • On the ceiling and wall paint

This is the most typical areas to grow mold in the bathroom. Paint in the bathroom, kitchen and laundry room should always be mold and mildew resistant to prevent mold growth. When water comes through drywall ceilings it will leave a distinctive yellow stain from the drywall materials and this is how you know it’s from a leak above. If the ceiling just has blackish spotting without the distinctive yellow stain you know it’s from high humidity and mold is growing on the paint. Nine out of ten times it’s mold growing on the paint from high humidity. Mold and mildew resistant paints and caulkings have a life span, when it’s expired you will grow mold.

Remedy, Clean the visible mold growth with a strong household cleaner several times. You may need to give a light sanding and make some minor repairs depending on how long the mold growth was eating the paint. Prime with a good mold and mildew resistant primer then paint with a mold and mildew resistant paint, at least 3 coats.

  • Behind the pictures

The steam from a shower or even just a decent humidity spike can get trapped behind a picture on a wall. There is little to no air flow behind the picture so it will stay wet or humid longer than the rest of the room and mold growth will start. The picture can be cardboard, paper, wood and canvas to mention a few organic substances that mold will grow on, did I mention the wall paint. View the back of the painting as a gap for moisture to get trapped, now look around your bathroom for other gaps and seal them if possible.

Remedy, Bathroom pictures rarely have value or sentimental value, this allows us to shellac the back of the picture sealing it from moisture penetration and future mold growth. Mold won’t grow on shellac based products. If not, check behind the painting every month to ensure there is no mold growth.

  • The frame of a bathroom window

The bathroom window will easily condensate during a shower and the water will pool on the window sill. The condensation will drag the dust and debris off the glass and deposit it on the window sill, this is organic mold food. The worst area to have a window is the shower itself. The frame is typically wood and susceptible to water damage and eventually mold growth. On the upper floors of the house never open the bathroom window during a shower. Typically the soffit vents (the fresh air intake for the attic) are directly above the window and the steam will enter the attic. You can safely open the windows after the shower but not during.

NEVER open the bathroom window during a shower

Remedy, This is the area that needs the most care and diligence keeping them dry. Paint with mold and mildew resistant paint. Make sure all cracks or openings are properly caulked to prevent water getting in behind the sill or trim work. Window in the shower can benefit from a clear shower curtain on a spring rod, still allows light but doesn’t allow the water directly at the window. Ceiling fans (don’t cheap out here) on a 60min timer will reduce the humidity quickly and help prevent bathroom mold growth.

  • On or behind the wallpaper (bad idea for a bathroom)

Wallpaper paste is a food source for mold growth. The wallpaper gets wet every time you have a shower and as such the wallpaper paste gets wet/damp too. You wont see the mold growth until it has firmly taken hold and started eating it’s way to the front of the wallpaper.

Remember: If it’s not mold and mildew resistant it doesn’t belong in the bathroom