Bathroom mold (C) Daniel FriedmanHow to Remove Bathroom Mold & How to Prevent Future Mold Growth in Bathrooms

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How to clean up or remove mold in bathrooms:

this document explains how to best to remove & prevent future mold contamination in bathrooms, including bathroom renovation tips - easy details that will help mold-proof your bathroom.

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How to Remove and Prevent Bathroom Mold

Bathroom mold cleaner (C) Daniel FriedmanHow to Clean off mold on tile, grout, or caulk

Small amounts of mold can be removed simply by cleaning or removing infected materials, something most homeowners can handle. Use any household cleaner or bathroom cleaner to clean off mold from tile, grout, or other hard surfaces.

You can use a fungicidal cleaner such as the product shown at left if you like, but any household cleaner, even plain soap and water will do fine. It's the cleaning that is important, not surface infection, when we're removing mold.

Preventing future mold growth can be assured more reliably by fixing the conditions that invited it in the first place, rather than by relying on mold killing sprays.

Bleach solution to clean off mold is not necessary - the object is to remove mold, not kill it.

But since cleaning off surface mold may leave stains in the tile grout, you might prefer to bleach that surface anyway. If you are going to use bleach to clean mold anyway, perhaps for cosmetic reasons,
see MOLD CLEANUP with BLEACH for more advice.

Handling Hard-to-Remove Brown or Black Mold Stains in Tile Grout or Caulk

Before giving up on mold-stained grout or caulk in a bath, kitchen or other area, try first drying the stained area, then spraying it with a bleach-based tile cleaner. Let the cleaner sit on the surface for 24 hours before washing off the surface. As long as you are dealing with a ceramic surface, the spray won't damage the tile or marble and you will probably find that the stain diminishes or disappears completely. Two or three such treatments will usually remove just about all dark stains on grout or caulk in a bathroom or other area.

Watch out: don't over-do it with straight bleach. The straight-bleach solution may be strong enough to damage building surfaces, and it's not normally necessary.

You may find that moldy caulk just won't clean up - you'll need to cut and remove the old moldy caulk, clean the tile or tub surfaces thoroughly (we use alcohol), and re-caulk with a mold-resistant bath caulk.

You may read that your bathroom caulk is "mildew resistant" which is funny since there is no mildew in buildings - mildew (a sub group of the larger group of molds) grows on living plants - unless you are growing grapes in the bathroom, it's mold, not mildew.

But forgive the sloppy language and buy mildew-resistant caulk anyway.

Cleaning mold or other stains from paper or other delicate surfaces

Even when removing brown rust and water stains from japanese Shoji screens I never use straight bleach. The risk of damaging the material is just too great. For those delicate surfaces, copying the work of art conservators, I work with a the most gentle, dilute solution possible, with patience, even with a cotton swab in some situations.

For paper and other delicate surfaces I use a dilute cleaner on a cotton swab and I watch for the stain to fade. Quickly I clean the treated area with clean water and gently pat it dry. For more expert advice on this topic see BOOK MOLD, CLEANING

Guide to Renovating & Improving Bathrooms to Avoid Future Mold Growth

At Bathroom Vanity Cabinet Mold we explained how water running under or behind a bathroom vanity or sink base can cause hidden mold growth on the vanity back, under-side, and on the wall behind the unit. Our two photographs just below show mold that was found on the chipboard vanity base back surface and on the drywall behind the vanity.

Bath vanity mold (C) Daniel Friedman Bath vanity mold (C) Daniel Friedman

The drywall behind the vanity looked bad enough that we explored the wall cavity to be sure that additional demolition above the moldy drywall itself was not needed.

Bath vanity mold (C) Daniel Friedman Here we show the underside of the bathroom vanity cabinet. At the top of the photo, in particular, you can see that the chipboard vanity side was swollen and damaged by water that had passed along the bathroom floor.

We decided to toss out this vanity base rather than try to clean and repair it.

Placing our new bath sink vanity base upside down, we sealed the bottom edges as well as all other un-coated surfaces on the vanity back (and front kickboard) before the new unit was installed.

We continued mold-proofing this bathroom with the details listed just below.

How to Prevent Mold Growth in Bathrooms, Kitchens, Laundry Rooms

After cleaning up a moldy bathroom, or when renovating or when constructing a new bathroom, we take these steps to reduce future mold growth:

  • Install a high capacity low sone (quiet) bath vent fan, making sure that the fan is properly vented to outdoors and that fan duct condensation will drain outside and not into the ceiling space.
  • Install sliding glass tub doors in baths where users are careless with shower curtains (that also grow mold, especially cloth shower curtains) and for people who splash water onto the bath floor
  • Seal the un-coated hidden sides of new vanity cabinets, such as the vanity bottom edges, back and under-side before installing the new vanity. We use a spray shellac but any water resistant coating will do. Coating these surfaces reduces their moisture uptake and thus increases mold resistance.
  • Seal exposed drywall: in a laundry room or other area subject to water splashing you might want to paint the drywall with a semi-gloss or even a glossy paint that is more water and splash resistant than flat latex wall paints. If renovation in such areas is needed, use cement board or greenboard. I'm not sure that DRYWALL MOLD RESISTANT is necessary or worth the cost.
  • Select bathroom caulks & sealants that include a mold-resistant chemical additive. (Most modern bath caulks include this feature - which is a good reason to use caulks designed for use in the bath. You may read on the caulk label that the sealant is "mildew resistant" - which is ok, if technically nonsense (mildew, a subset of the huge mold family, grows only on living plants - see MILDEW in buildings ?).
  • Caulk the sink vanity to the floor to be sure that spilled water from a shower or tub does not run below the vanity as we explained at Photo Guide to Mold Under Vanity Cabinets. We used clear caulk at the exposed vanity edges where they contacted the floor, extending caulk up the vanity sides as well. Against a white drywall bathroom wall use white polyurethane caulk for better appearance and easy cleanup.
  • Caulk the floor trim at floor level - if installing new trim, run a small bead of caulk along the bottom edge of the trim boards before they are nailed in place - you won't see the caulk but you'll keep water out of the wall cavities when it spills onto the floor.
  • Clean the tile surfaces after showering - use a squeegee to clean water and soap scum off of tile walls and shower doors - they will look better and you'll be reducing the organic debris on those surfaces, thus reducing mold growth.
  • Do not leave very wet towels hung from hooks anywhere; spread them out on towel racks to dry, or put wet towels into the laundry. One of the moldiest closets we found in a home without other leaks was caused by an owner who daily hung his very wet towel on the back of the door to a tiny, clothes-filled closet, closing the door trapping moisture there.
  • See CONSTRUCTION DETAILS TO AVOID MOLD for additional details about mold-resistant construction.

Watch out: in most circumstances it is not necessary to test mold to identify the genera species. That information will not change how mold should be removed or prevented in buildings. But on occasion, such as for medical reasons or for control of a larger, costly mold remediation project, there are reasons (MOLD TEST REASONS) to identify mold on surfaces or in building air or dust.


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