Whether you need a grout sealer depends very much on the situation. A grout sealer could actually do more harm than good.
For that reason, I will list out the non-toxic sealer options by application and then by type of sealer.
The siliconates and silicates (densifiers) are the most tolerable least toxic options, they are both very benign products.
Topcoats of acrylic or polyurethane do have some odor and off-gassing at first, but the off-gassing comes to completion in a short time.
There is also the possibility of going with a natural product, some natural penetrating oils can be used on concrete grout.
I recommend all of the products here, some products have affiliate programs and some do not. Upon purchase, I earn a small commission through affiliate links at no extra cost to you.
1. To Seal Grout in Tiled Showers
In wet areas, you generally want to use a breathable sealer if one at all.
Both Mike Holmes and Cheryl Ciecko recommend not sealing the grout so that it is breathable and allows water to dry out to the inside. Your waterproofing is done behind the tile.
You can keep the grout unsealed. If you must seal it, use a breathable (vapor-open) sealer.
Breathable Sealer
AFM Grout Sealer is one option, It’s zero-VOC and is one of AFM’s most tolerated products.
It has almost no odor at all even when wet.
This is a potassium siliconate product that provides water repellency while still allowing the water vapor to pass through.
It does not change the look of the grout at all.
This sealer makes it easier to clean and less likely for dirt, grime, and mold to get embedded. It’s not intended to be waterproof.
You could also use a DIY/homemade option by buying a silicate “liquid glass” product which is similar to this in function. However, I would caution against that because it’s easy to end up with a white film with densifiers.
I would buy AFM Grout Sealer, or another brand made for grout, and follow their instructions so you get an even (and invisible) finish.
This does work on Custom Building Products grout but it may not work on all polymer modified grout.
2. To Seal Grout on Tiled Floors
If your tiled floor is on a concrete slab (on grade or below grade) then Cheryl Ciecko and Mike Holmes also recommend keeping that breathable so that the concrete can dry to the inside. It’s best not to seal it.
Breathable Option
You can use AFM Grout Sealer which is breathable and a no-VOC product that does not change the look of concrete-based grout at all.
If your tiled floor is on an upper level of a house or apartment building and the floor below is the same temperature (more or less) as your space then it’s less risky to use tile sealer that blocks moisture. (If your tiled floor is a bathroom floor then it should be left without a sealer for maximum breathability).
You can also use:
ECOS Stone Sealer
ECOS, a well-liked brand, has a stone sealer that is used on grout. They do not disclose any of the ingredients in this product so it’s not possible to know how breathable it is exactly or if it contains PFAS. It is zero VOC.
Integral Sealer
AFM Safeseal is an acrylic coating that can be mixed into a dry mix concrete grout (with the water) instead of adding a topical grout sealer.
Polyurethane Sealer
For a strong topcoat sealer, you can also use a water-based polyurethane like Earthpaint Nanotech.
All-Natural Sealer
You can also use a natural oil on concrete-based grout. I have been experimenting with 100% natural tung oil and have so far have liked the effect. It certainly darkens the concrete by quite a bit.
3. To Seal Tile on a Backsplash
You don’t necessarily need to seal grout on a backsplash since it doesn’t usually get that damaged. But if you do want to seal it that can provide some stain proofing.
If your tiled wall is on an exterior wall and you use AC inside the wall should be kept breathable, and don’t seal it.
Breathable Siliconate
Use AFM Grout Sealer.
Acrylic and Polyurethane Sealers
If your tiled wall is not on an exterior wall, or you don’t use AC inside, you could use something that blocks more moisture like ECOS Stone Sealer, Safeseal mixed into the dry powder at the time of application, or Earthpaint Nanotech.
All Natural Sealer
You can also use a natural oil on concrete-based grout. 100% natural tung oil leaves the grout partially breathable (similar to silicates and siliconates) but darkens the look quite a bit. It takes some time to fully cure but provides good protection against stains, especially oil stains.
4. To Seal Tiles on a Countertop
In this scenario, use a dark-colored group. Mike Holmes recommends not sealing even on a countertop. However, this is the least risky place to seal.
Synthetic Options
If you can, mix an integral sealer like AFM Safeseal into the dry mix grout and follow that with a topical coating like Earthpaint Nanotech. If that is not possible use AFM Grout Sealer first, followed by Nanotech.
The Natural Option
You can also go all-natural with pure tung oil. This darkens the look of the concrete-based grout and will certainly give you particularly good protection from oil-based stains. Tung oil is really quite durable for a natural choice. You cannot use a synthetic sealer over this, and it likely won’t work over a synthetic sealer since it needs to soak in to work.
Related Posts:
Choosing non-toxic grout and mortar
Non-toxic waterproofing in bathrooms
Non-toxic countertops
Corinne Segura is an InterNACHI-certified Healthy Homes Inspector with certifications in Building Biology, Healthier Materials and Sustainable Buildings, and more. She has 10 years of experience helping others create healthy homes. You can book a consult here.
Paty Arias
Hi Corinne! Wondering if you know of any “less toxic” grout enhancers that would darken (not paint) grout? We just got our kitchen tile installed and the grout color we selected is very different from the end product. Our options are to enhance/darken it using what is probably a pretty toxic sealer (Laticrete Stonetech Enhancer Pro Sealer) or take it all out and start over (costly and time intensive). We considered using linseed or tung oil, but I am worried it will create a sticky grout that attracts dust and grime. Any thoughts would be greatly appreciated!
Corinne Segura, Building Biologist
the oils are only sticky briefly, once the drying oils polymerise it’s a good finish
Paty Arias
Thank you! Unfortunately, our problem has worsened and the ceramic tiles are now stained. We are now being asked to choose between applying: 1) linseed/tung oil or 2) Laticrete Stonetech Enhancer Pro Sealer on the ENTIRE floor (not just the grout). I am nervous to apply oil directly to semi-porous ceramic tile……do you know if the Laticrete product is something that offgasses relatively quickly? Thanks for your help with this headache!
Kaelynn
Hi Corinne,
So it seems I have some effervescence or limescale on a few places in my grout on my tile shower floor. But we literally just ripped out the shower and put in the Schluter Kerdi board system, so I struggle to think there’s standing water underneath it like there was before we ripped it out. Is it possible that I just have minerals in my water and it’s evaporating from the surface and I can use some vinegar to clean it? I’d hate to seal it because I know it needs to breathe?
Brooke
Hi Corrine!
I am considering the breathable AMF Grout Sealer, but my shower contractor mentioned adding caulking to all the edges and corners to the showers. Is this something that is recommend? If so, do you have a product recommendation?
Thank you!
Corinne Segura, Building Biologist
see the article on caulking
Whitney
Hi! Thank you for all your work; your site is very helpful. I like your rational for not sealing grout. I am wondering, though, if unsealed grout will breakdown a little through the years causing the dust to be airborne. If one needs to wear a mask when mixing grout due its harmful nature, is this a concern for the product with product wear and tear?
Corinne Segura, Building Biologist
that could be a problem if you use the wrong cleaning products
Laura
Hi Corinne. They just put down some toxic grout in my home. I can smell it off gassing. If I seal this grout with the AMF Safecoat Grout sealer, will this reduce the off gassing? Or does this product simply seal it from water penetration? Thank you!
Corinne Segura, Building Biologist
no, safecoat grout does not seal in offgassing. also the toxic grouts are usually urethane or epoxy and likely wont take a sealer at all. especially if this is in the shower or tub area. if it’s a bathroom, heat the bathroom up and use the exhaust fan continuously.
Carl
Do you know of any options to seal concrete on the exterior of a home? The end result must be absolute zero odor. I’m designing and planning to build my own concrete block home, and this is the part that worries me since it’s possible that any odor from the exterior coat could pass through to the interior. If it were just headaches or a sore throat that I’d have to deal with for a while then I’d be less concerned, but I’ve been dealing with this formaldehyde exposure illness for less than a year and I’m on course to developing dementia before age 40 with the minor daily exposures I deal with, despite how far I’ve come from stuttering, shaking, and stumbling on day one.
Anyway, I’ll be glad to test any recommendations you have, and I’ll test a number of other promising products or mixtures as well. I’ll also be sure to comment again with my findings if or when I find something that works for me.
Corinne Segura, Building Biologist
You can check out the post on concrete sealers, as some of those can be used on the exterior, but I would definitely recommend doing a consult with Andy Pace and also testing options. Normally that would be painted so it would not be a common place to just seal. I would do a paint but the first thing you ned to know if if you need it to be vapor open or more vapor closed. Check out the article on exterior paints. I would also consult with Cheryl Ciecko for mold prevention. What you are describing is coming from mold.
Amy
Thanks Corinne for all you do. I don’t remember what kind of grout or caulk we ended up using in the bath/shower, but both are moldy and I’m planning to replace soon. Im wondering if you have anything to recommend that is less likely to end up moldy. I can air out the room until it off gasses but am hoping for something that will hold up longer. I think the problem with the grout is that I was scrubbing with a toothbrush and it was wearing away, leaving bigger pockets where water could hang around. So maybe something that can stand up to scrubbing better? Thanks!!!
Corinne Segura
i would use one of the breathable grout sealers here as that will help a bit. for grout types see the post on thinset and grout and choose one with antimicorbials and for caulking see the article on caulking and choose one with antimicrobials (and avoid polyether as that molds faster). You might also have mold behind the tiles.
Sarah
HELP! In the past, I used the AFM sealer on our grout and it worked beautifully. It was time to re-seal and, unbeknownst to me, my husband just used Aqua Mix Gold Choice. Why, I do not know. I walked in the door from running errands and the house stunk, my eyes started burning, and my mouth tastes toxic. I am livid! I need some input as to whether this product will continue to off-gas horrid chemicals long-term, or just while it’s curing. I fear the former, but hope I’m wrong. Thank you, Corrine, for your help with this.
Corinne Segura
https://www.mychemicalfreehouse.net/2021/06/non-toxic-low-voc-sealants-for-marble-granite-limestone.html
Sarah
Thank you so much, Corinne. Sorry to have bothered you. I didn’t find that on your site which is an incredible database and public service!!!
Sarah
Just read your write up on the product and I’d already checked out the manufacturer SDS. What I want to know is if the product continues to off-gas once it’s cured.
Corinne Segura
the information i have on it is in that article i linked to
Aaron
Hi Corinne
As always I appreciate all of this information that you’ve brought together. I think your website is one of the few that doesn’t just tell people to seal any and all grout they can find.
I have been interested in concrete densifiers so I appreciated your recommendation of the AFM Safecoat grout sealer. However, I’d like to clarify something: As far as I can tell, their product is a potassium siliconate, not a silicate. https://www.greenbuildingsupply.com/core/media/media.nl?id=42833&c=772072&h=cgoFGp-pr1LPj_Fmusnv1p2N6K0C_VWrEJvggAuHc5EOSMLJ&_xt=.pdf
And as far as I can tell, siliconates are sealers, not densifiers. [https://www.euclidchemical.com/fileshare/Literature/Technical_Bulletins/CP-20-Silicates_siliconates_and_Fluorosilicates_explained.pdf] Which would explain why greenbuildingsupply.com says that AFM Grout Sealer should last for five years if applied correctly rather than the life of the grout (which is what I would expect would be the case for a silicate).
Of course I’m always a bit hesitant with these things and you are the expert but…if I am right, is there a densifier you would suggest? And (for bonus points) do you know if people ever mix the densifier with the grout before it is applied?
Corinne
Thank you for that catch. The Safecoat Grout sealer still acts like a silicate in that it provides water repellency while staying vapor open. So that is still what I would go with. But if you want to find a densifier those work well too, there is a risk of a whitest tint when applying them.
Aaron
Thanks Corinne. Why would you go with the siliconate over a silicate? Is it just the tint issue?
Corinne
I would go with AFM, it’s odourless and easy to use.
Aaron
Hmm… Is there reason to think silicates are dangerous? Densifiers work for the life of the grout–they don’t have to be reapplied after five years. And floor grout (as opposed to shower grout) can last…I’m not even sure. My parents’ tiled bathroom floor has the same grout it had 30 years ago as far as I’m aware. But maybe in higher-traffic areas it wouldn’t last as long? Still, not having to reapply the product several times over the life of the grout is appealing to me. Am I just really over-estimating the difficulty of applying sealer or the life of grout in a floor generally?
Corinne
grout doesn’t actually need a sealer. I don’t think there has been any sealer on grout anywhere I’ve lived in the past many years.
Aaron
Thanks Corinne
CAROLE J ROSEN
Thank you so much for all the great work you are doing! SO helpful! Much appreciated.
I am searching with little luck for a bathroom floor tile colorant and sealer in white which is non toxic. The guy cleaning the floors uses Ultra Care Grout Refresh, Universal Grout Colorant and Sealer (WHITE) which is advertised as “eco friendly” on Amazon but if you read their SDS it is full of toxins and carcinogens. Any suggestions ?- He insists on white colorant not clear. I have found non toxic replacements for pretty much everything during this home renovation but this one is stumping me! Carole
Corinne
bathroom tile grout should not be sealed according to mike Holmes, Cheryl ciecko and me. It needs to retain its ability to dry out. As for the SDS I don’t see any real life hazards there, titanium dioxide needs to be inhaled or injested, and silica or quartz need to be inhaled to be a hazard and this is a liquid product. It’s not ultra low VOC and verges on not being low VOC so that will be up to you.
Corinne
if it’s a concrete based grout you can use Earthpaint Nanotech. I would only seal grout if there is no chance of the tiles getting very wet since grout usually needs to stay breathable to let water dry back up.
John Dallmus
Hello,
I used a tile grout that is not agreeing with me. It is in a bedroom. What sealer do you suggest when the intent is to seal the grout from off-gassing?
Thank you,
John
John Dallmus
I should have noted that the tile is ceramic.
Thank you!
John
Mary Torres
You mention that AFM Safe Seal could be added to dry grout along with the water to help make the grout more waterproof and more stain proof. Could you suggest how much seal to add to a 10 pound bag of dry grout?
Rachel Quigley
I think I found another good stone, tile, and grout sealer that you might want to add to the list. Do you know anything about it? No VOCs, solvents, flurochemicals, etc. Small family company. I have not tried it yet. I’m choosing between this and AFM Grout Sealer.
https://www.sealitgreen.com/pages/grout-shield
I see on the TileLab Grout Sealer Safety Data Sheet that there appears to be at least some flurochemicals which are highly toxic.
Corinne
That one doesn’t say what is in it though. Maybe you have to email them for a SDS. In almost all cases AFM is what you want to use to keep it breathable.
Rachel Quigley
They would not send me their SDS until I told them the government requires them to provide it to the public! It’s a little vague, like I wish they named the actual active chemical. They told me it bonds completely to the grout or stone and is food-safe for countertops. I’ll let you decide if it’s worth including it on your list. I give them credit for no odor or flurochemicals. Oh, I don’t see a way to attach a document, but I can email it to you if you are interested.
rachelrquigley@gmail.com
P.S. If you need a payment to answer my question I posted about the kitchen cabinet finish called Gemini, I will be happy to pay you because I need to know the answer. Thanks!
Karen
HI Corrine, Is the Vinyl Legends of Cali Bamboo one of your recommendations? I do not know how to interpret the test results, and I am concerned about the chemicals in this LVP..
Corinne
I have a post on vinyl plank flooring