Mold-Free Interiors

A lot of essential oils are effective fungicides. It’s no surprise since the plants need to protect themselves from fungi all around them.

You could mix up the oils yourself, but having a calculated mix of oils in a blend can help it kill a wider variety of molds.

You can mix the oil blends into a liquid cleaner or use the products that come pre-mixed in a surfactant to kill mold on hard and porous surfaces in the home. You can also fog to kill mold spores in the air.

We will go over all of these methods in detail.

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Essential Oils That Kill Mold

1. Fir Oil

Essential oil from Pinus sibirica (Siberian pine) and Аbies sibirica (Siberian fir) are effective against Candida albicans(source). 

2. Lemon Oil

Citrus limon (lemon) essential oil showed inhibitory anti-fungal activity against Aspergillus flavus, Fusarium spp., Aspergillus niger (source), Aspergillus parasiticus, Cladosporium cladosporioides, Eurotium herbariorum, Penicillium chrysogenum, Aspergillus carbonarius (source) and Penicillium verrucosum(source).

Similar: Other citrus oils like mandarin (Citrus reticulata L.), grapefruit (Citrus paradisi L.) and orange (Citrus sinensis L.) showed anti-fungal activity against the molds Aspergillus niger, Aspergillus flavus, Penicillium chrysogenum and Penicillium verrucosum (source).

3. Cinnamon Oil

Cinnamon oil proved to be a potent fungitoxicant against: Aspergillus niger, Aspergillus fumigatus, Aspergillus nidulans, Aspergillus flavus, Candida albicans, Candida tropicalis, Candida pseudotropicalis (Candida kefyr), Histoplasma capsulatum (source), Coriolus versicolor, Laetiporus sulphureus (Source), Eurotium spp., Aspergillus spp., Penicillium spp. (source), and Botrytis cinerea (source).

4. Rosemary Oil

Rosemary essential oil exhibited anti-fungal activity against Eurotium spp., Aspergillus spp. and Penicillium spp. (source). Other studies show Rosemary’s anti-fungal activity (source).

5. Clove Oil

Clove essential oil exhibited anti-fungal activity against Eurotium spp., Aspergillus spp., Penicillium spp  (Source), and Botrytis cinerea (source).

6. Copaiba Oil

Copaiba oil displays anti-microbial action against fungi, such as Candida spp (source and source), Candida parapsilosis, Aspergillus flavus, and A tamarii (source). 

7. Tea Tree Oil

Tea Tree Oil is effective against Candida albicans, as well as a range of yeasts, dermatophytes, and other filamentous fungi (source).

8. Eucalyptus

Eucalyptus is a potent antifungal agent against C. albicans and its biofilm (source) and Penicillium funiculosum, Aspergillus niger and Aspergillus flavus (source).

9. Thyme

Thyme oil exhibited antifungal properties against Aspergillus spp, such as A. flavus, A. ochraceus and Fusarium spp, for example F. oxysporum, Candida spp, for example Candida albicans and Candida tropicalis, Penicillium spp and Cladosporium spp, Botrytis cinerea, Alternaria brassicae, and Dermatophytes (source and source).

*Please note that spp means multiple species.

Essential Oil Blends That are Anti-Fungal

Germ Fighter by Plant Therapy – Cinnamon Cassia, Lemon, Eucalyptus, Clove, Rosemary. This is a well-priced non-MLM brand that is high-quality and legit (they produce GC-MS testing by several third-party laboratories).

On Guard by doTerra – Wild Orange Peel, Clove Bud, Cinnamon Leaf, Cinnamon Bark, Eucalyptus Leaf, and Rosemary Leaf/Flower.

Thieves Oil by Young Living – Clove bud oil, Lemon peel oil, Cinnamon bark oil, Eucalyptus leaf oil, Rosemary leaf oil.

Diffusing/Fogging Essential Oils to Kill Mold in The Air

Diffusing/nebulizing essential oils is the best way to deploy them to kill mold spores in a building. I would do this when people and pets are out of the room because diffusing creates high levels of VOCs and PM_2.5 particulates. 

Fogging to Kill Mold Spores

Dr. Edward R. Close, PhD in Environmental Engineering, diffused Thieves Oil blend (a blend of Clove (Syzygium aromaticum) bud oil, Lemon (Citrus limon) peel oil, Cinnamon (Cinnamomum verum) bark oil, Eucalyptus (Eucalyptus radiata) leaf oil, and Rosemary (Rosmarinus officinalis) leaf oil) in the Aroma-Ace Atomizing Diffuser in homes for a 24-hour period. 

(You could also use the mix by Plant Therapy, which is made with the same plants but is less expensive). 

Dr. Close and his wife, Jacquelyn Close, discovered that diffusing essential oils with a waterless cold air nebulizer was the best solution to address mold spores in buildings. The results of their case studies showed a huge reduction in mold spores and it had residual effect (i.e. the spores did not come back quickly). 

His research showed that the essential oils digest the mold spores that they come in contact with and don’t leave dead mold spores behind.

NOTE! If you have mold growing in the wall this does not address that underlying problem and the mycotoxins and mold VOCs being produced. Putting a bandaid on the situation could cause a false sense of security. 

They recommend that you place one diffuser in each room (one for every 1000 sq ft) and diffuse continuously for a minimum of 24 hours. How long you have to diffuse (24-48 hours or longer) is determined by air sampling or tape-lift sampling. Use a glass plate under the diffuser to protect surfaces from the oil. 

This book by Dr Close and his wife goes into more detail. 

If you prefer to watch a seminar about Dr Close’s methods, this masterclass will be helpful. He is talking with mold-preventative architect Cheryl Ciecko. The other classes in the series will also be helpful in making sure you properly identify the source of the mold and safely clean mold (as you could do a lot of harm cleaning it yourself). Don’t just put a bandaid over it!

Cleaning Surface Mold With Essential Oils

“The surface mold is usually being caused by moisture and mold spores somewhere else that is causing the ‘surface mold’ to appear in the first place. If the surface is porous (wood, drywall, grout, brick, concrete or other materials) then cleaning the surface mold can be like cutting down a plant while leaving the roots below the surface. The plant and the mold will grow back.” says Cheryl Ciecko, mold preventative architect.

Make sure you have identified the source of the problem, corrected the problem, dried out the area. Many moldy materials need to be totally removed – like moldy drywall and most moldy wood. But if you truly have a superficial mold problem you can clean it with essential oil based cleaners then dry out the area again with dehumifdifiers, says Cheryl Ciecko.

Cleaners for mold on surfaces:

Thieves Cleaner – is made with Clove bud oil, Lemon peel oil, Cinnamon bark oil, Eucalyptus leaf oil, Rosemary leaf oil and surfactants.

Benefect Decon 30 is an EPA approved fungicide. The product’s active ingredient is natural Thymol (from Thyme) which kills Trichophyton Mentagrophytes which is the representative organism over the entire category of mold/fungi/yeast; ie, the hardest to kill as per the EPA. It is also effective against Candida Albicans and Aspergillus Niger.

Cleaning Mold Off Concrete With Essential Oils

Make sure you diagnose the cause, and correct the problem first says Cheryl. Next up make sure to dry out the concrete before cleaning (if it’s interior concrete, like basement walls).

To clean use diluted Thieves Cleaner with a scrub brush. You can see Dr Close show his experiment with a moldy patio in Cheryl’s recorded webinar with him (I do consider this webinar series essential if you want to learn how to safely clean mold yourself).

You can also use Benefect Decon 30. Wet the surface by sprayer (high or low pressure, hand or power operated), cloth, sponge or mop. Leave for 10 minutes. Allow to air-dry. No rinsing or wiping is required.

Make sure you’re using PPE (respirator, goggles, Tyvek suites). You may want to use a HEPA vacuum as well first to pick up spores.

Dry again after cleaning using dehumidifiers (for indoor concrete).

Cleaning Mold Off Wood With Essential Oils

Make sure you have identified the source of the problem and corrected it. Moldy wood usually needs to be wet sanded or removed. Test it with a moisture meter to make sure the problem is resolved. Remember that structural wood needs to be evaluated by an engineer before removing it (that includes small areas of subfloors).

If you have superficial mold on wood, or after you have sanded it, Cheryl Ciecko recommends scrubbing with a stiff scrub brush using Thieves cleaner only slightly diluted or undiluted to not add much water. Then dry the area well.

The Thieves cleaner will result in some color changes to the wood (as do all essential oils in my experience).

You can also use Benefect Decon 30. Wet the surface by sprayer (high or low pressure, hand or power operated), cloth, sponge or mop. Leave for 10 minutes. Allow to air-dry. No rinsing or wiping is required.

Use protection for yourself (respirator, goggles, Tyvek suites) and a HEPA vacuum as well to clean up spores.

Cleaning Mold Off Drywall Walls With Essential Oils

Cheryl Ciecko cautions cleaning mold off drywall. Mold on drywall is often a sign of water damage behind it and if mold is in the paper layers or the gypsum layer it must be removed she says.

It is possible that you have superficial mold growing only on top of the paint. You still need to correct the source of this problem which is high humidity.

But you can clean mold off the paint with a gentle all purpose cleaner, Thieves Oil cleaner or Benefect Decon 30 (Benefect needs a dwell time of 10 minutes).

Cleaning Mold Off Shower Walls and Grout With Essential Oils

Two things to note first about mold in showers/grout. Mold is grout is very common but not “normal”. Cheryl says about her well built shower that she never has mold in the shower area. Mold in grout is often a sign that there is mold behind the grout/tiles.

Keep in mind that the grout is not the water protection layer, there is a layer behind the mortar for water control (which is so often done wrong). Use a moisture meter to test your tiles/grout for possible water damage behind. Grout doesn’t need to be sealed to prevent mold and you don’t need this to be your water control area. You can use a breathable grout sealer, outlined here, which makes it a little easier to clean.

Make sure to keep soap scum off the grout by regularly cleaning it and make sure your exhaust fan is adequate to dry out the room during and after each shower and bath.

You can clean your grout with Thieves oil cleaner, or Benefect Decon 30 (with a dwell time of 10 minutes). You can use hydrogen peroxide with baking soda (mixed together) to remove the leftover mold stains. (Don’t mix essential oils with hydrogen peroxide).

Cleaning Mold Off Soft Items

Using Essential Oils in Laundry to Kill Mold

Those who are extremely sensitive to mold that gets on clothing from the home or workplace use a variety of methods to clean laundry. There isn’t one solution that works best on all molds.

The most popular non essential oil products are borax, ammonia and TSP (separate, not all together!)

Essential oil based cleaning products for laundry that folks like include:

• EC3 laundry Additive – is made from Citrus Seed extracts, Tea Tree oil, and natural surfactants.
• Thieves Oil Laundry Soap – contains Clove bud oil, Lemon peel oil, Cinnamon bark oil, Eucalyptus leaf oil, Rosemary leaf oil, Jade Lemon, and Bergamot essential oils, enzyme cleaners, and surfactants.
• On Guard Laundry Detergent -contains Wild Orange Peel, Clove Bud, Cinnamon Leaf, Cinnamon Bark, Eucalyptus Leaf, and Rosemary Leaf/Flower essential oils, surfactants, and enzymes.
• Or add essential oils of your choice to your unscented liquid laundry detergent and mix together before adding it to the wash.

Using Essential Oils to Kill Mold on Carpet

For carpet in a car Cheryl Ciecko recommends using diluted Thieves cleaner to clean and scrub, then blot out moisture with towels moving on to using paper towels until no more moisture comes out.

It terms of carpet in a house that is a different story. It depends on where the mold is and how it got there. If you have moisture rising from below then you need to remove the carpet. If a flood caused major mold then I would remove it as well.

If the problem is smaller or more superficial, then you can first HEPA vacuum and then fog essential oils as described in the above section on fogging. You may need to do this every 3 months says Dr Close.

Cheryl Ciecko believes that shampooing is not a good ideas as it adds water which will feed mold spores.

If you do want to shampoo your carpet Benefect Decon 30 is an EPA approved carpet sanitizer. Apply to the pre-cleaned carpet area by wand, sprayer, extractor, spin bonnet or immersion processes until saturated (spot test fibers for colorfastness before use). Scrub or agitate the carpet as needed to ensure the test substance is delivered throughout the carpet pile and backing. Allow the product to remain on the carpet undisturbed for a minimum of 60 minutes. Extract & allow to air-dry. (Use a dehumidifier after if your humidity is not low).

Can You Mix Essential Oils With Other Cleaning Products?

You can mix essential oils into vinegar, or a liquid soap. Mixing essential oils and hydrogen peroxide produces a strange oxidized odor in my experience, so I would not mix those myself.

Corinne Segura is a Building Biologist Practitioner with 8 years of experience helping others create healthy homes.

Which type of bathroom flooring is both non-toxic and truly waterproof? There are now tons of flooring options that describe themselves as waterproof that I don’t think are adequate for a bathroom that has a shower or bath. So let’s go through the options that would be safe in a wet room.

This post contains affiliate links. Upon purchase, I make a small commission at no extra cost to you.

1. Tiles

Tile Type & Tile Sealers

Tiles may be stone, ceramic, or concrete.

Stone floors should be sandblasted or naturally textured (like slate tile has a natural texture) so as to not be slippery.

Keep in mind from the start the type of sealer that you will use. If you go with a white or light cool-toned tile, most sealers contain PFAS (per- and polyfluoroalkyl substances aka “forever chemicals”), especially if used as the shower floor.

Aqua Mix Sealer’s Choice Gold, or Granite Gold Sealer are two options that are based on PFAS, though they are extremely low odor and basically odorless when dry. The PFAS may not be much of a health concern if they only touch your feet but we do have to consider the upkeep and resealing and the effect on the environment. 

If your stone tiles are on the floor (outside of the shower) you can use the PFAS-free, and extremely low-VOC AFM Mexeseal.

(If your tiles are not on the floor, you can seal them with the 0-VOC, non-PFAS sealer SimpleCoat which is slippery on floors).

The next tier of tiles would be warm tones or darker tiles that can be sealed with The Real Milk Paint Company’s Soapstone Sealer which is walnut oil and carnauba wax. This can be used inside and outside the shower (though for wet areas like inside the shower it requires a very long cure time).

Then there are stone tiles, just like countertops stones, that are dense enough to not need a sealer, like dark slate. 

Ceramic/porcelain should be textured. Make sure that the tile is rated for floors (some are only rated for the walls). There is no offgassing from ceramic/porcelain tiles. Some do have antimicrobials in the glaze (which will be listed), and they may contain lead in the colorant/glaze.

Lead in ceramic/porcelain tiles is actually a big concern as many brand-new tiles sold in North America still have high or significant levels of lead in the glaze. It is more common in bright colors like reds and blues, but lead can be found in neutral tiles of major American brands as well. I tested 64 tiles in 2021 and 12.5% contained lead. Here are the full lead test results.

Concrete tiles are highly porous though they can be used on bathroom floors. Floor tiles can be sealed with Soapstone Sealer walnut oil sealer (though this does darken them significantly), AFM Mexeseal, Acri-Soy, or GBS Concrete Sealer.

There are also many ceramic tiles that look like concrete tiles, and these don’t need a sealer which makes them much more practical. 

Grout and Thin-Set

Grout and thin-set should be concrete-based in a healthy home. With thin-set, whether you need modified or unmodified depends on your tile type and membrane type. Ethylene-vinyl acetate (EVA) is a common polymer in modified thin-set. For grout use a concrete-based, powdered grout (not premixed). This grout type is zero-VOC and usually contains EVA. EVA is safe for the majority of chemically sensitive folks. Some brands don’t contain antimicrobials, and some do (and it seems that nano-silver is the common type). See brands in the post on thin-set and grout.

The grout should remain breathable and so sealers are not needed or recommended, generally. An optional sealer option that still leaves the grout vapor open is AFM Grout Sealer. Lighter-colored grout darkens with time as it gets dirty, so starting with a darker grout is a good idea. 

Tile Size

While you can use small tiles as the shower floor, which does help with slip resistance, the pebble tiles are not the most ideal tile type for shower floors since there is a lot of grout and the grout lines are often lower than the pebbles, causing water to pool.

Waterproofing

Under tiled flooring you should have a membrane like Schulter Ditra and behind wet areas you should have Schulter Kerdi membranes or Kerdi Board.

2. Polished Concrete

Polished concrete can work for a bathroom floor when your bathroom is on a slab. You do need to talk to the contractors about adding (or not removing) all the texture, otherwise it’s very slippery.

Safer stains and topcoats include:

1. SoyCrete – this soy bio-based non-toxic concrete stain is a penetrating semi-transparent non-film-forming decorative concrete stain that integrally bonds and colors porous concrete and masonry surfaces. The company claims this product is breathable. The stain creates natural and variegated effects without the use of acid stains. (Top coat would be AcriSoy penetrating sealer or their Eco Poly).
2. Acri-Soy is a bio-acrylic (an acrylic made from natural soy oils). This is a partial penetrating sealer. 
3. GBS Concrete Sealer – a waterborne polyester polymer and polyurethane sealer that penetrates and becomes part of the concrete.
4. Earth Paint NanoTech Floor Stain/Sealer – an acrylic and polyurethane sealer. No silicones.
5. More conventional topcoats used in polished concrete are often extremely low VOC and could be acceptable in a healthy home. 

If your bathroom is on a slab, polished concrete or tiles are the best choices in order to allow the flooring to dry to the inside.

3. Marmoleum

Marmoleum is a natural linoleum made from flax seed oil, wood flour, pine rosins, jute, limestone, and pigments with a synthetic topcoat.

Marmoleum sheet is the only form of Marmoleum that should be installed on a bathroom floor in my opinion, and it must be professionally installed. The seams should be heat welded.

You should also “flash cove” which means the Marmoleum is installed slightly up the wall, as a sort of molding, which makes the perimeter seam much less prone to water damage. Where it can’t be flash coved, use a silicone caulk or synthetic cove molding. Cheryl Ciecko recommends waterproofing the subfloor (with a product like WEDI) and waterproofing the seam between the subfloor and the tub before installing the Marmoleum. (May 2023 Q&A Dwell Well) And we are talking here about an upper level of a house, as she does not recommend this as an ideal flooring over a slab.

The toilet should be removed for installation and be sure to caulk around the flange so that if the toilet leaks it leaks on top of the flooring and not under the flooring.

The TopShield2, a synthetic topcoat, is fairly new and is less permeable than the original TopShield, so water is less likely to soak through even if you do leave standing water. However this is still a “breathable” material.

The warranty for Marmoleum is 30 years.

This flooring type feels warm to the touch and is not slippery so it is nice in a bathroom.

4. Bio-Based Polyurethane Resilient Flooring

Unlike vinyl sheet flooring which has a very strong off-gassing odor, bio-based polyurethane flooring has virtually no odor and no VOCs. It comes in a solid waterproof sheet flooring, just like vinyl, or glued-down planks.

The polyurethane is sourced from natural oils like castor oil plus minerals. They do not contain plasticizers (which are used in all vinyl/PVC flooring) or any other major chemicals of concern.

One residential (non-commercial) brand is Wineo, their Purline Organic Flooring is pictured.

Another similar “safer plastic” option is TPE flooring. UPO floors are made from minerals and the plastics TPE and polyolefin. Polyolefin in this case almost certainly means PE (polyethylene) and/or PP (polypropylene). They don’t use any plasticizer and there is no PVC.

5. Click Together Flooring

Luxury vinyl plank (LVP) and luxury vinyl tile (LVT) can both be waterproof flooring types if they are thick enough and have a good quality locking mechanism.

Waterproof here means the water won’t make it past the locking mechanism to below the floor.

They are extremely low in offgassing and are often used by highly sensitive folks, though they do contain the plasticizer DOTP which has some big question marks hanging over it in terms of health/safety. Vinyl is also extremely hard on the environment.

I would not use this floor in a bathroom that has a shower or bath because I have seen the planks pull apart. This is likely because there needs to be a space left between the planks and the perimeter wall, so this allows some planks to slide.

The same thing goes for the extremely low-VOC Amorim Wise click-together cork flooring.

However, any click-together water-proof flooring can work just fine in a powder room.

Corinne Segura is a Building Biologist Practitioner with 8 years of experience helping others create healthy homes.