What Kind of Grout to Use!

This post has some gritty grout advice for saving money and trouble on your next tile project. This post also describes what kind of grouts to use for fantastic results.

The bottom line? “Mapei Ultracolor Plus FA” is my favorite all-purpose grout. Read on to find out why!

First, let’s correct some MYTHS

Grout is NOT waterproof! Neither is tile, actually, but the grout joints between tiles are where most moisture wicks through in wet areas like shower floors or tub surround walls. Tile and grout obviously blocks most of the water that sprays onto it. Grout will however absorb some moisture and transfer this moisture to whatever substrate the tile is laid on.

If you have a shower or tub surround that has a proper waterproofing layer behind the tile, then this isn’t a problem. But if your shower wall or tub surround tile was installed on the cheap with the tile set directly on drywall, then this will definitely be a problem. Same thing for shower floors and curbs. If the underlying waterproofing isn’t done correctly then there is no tile or grout combination that will prevent eventual water damage.

There is no magic fix that can make grout waterproof. There is no sealant that will make it completely impermeable to moisture. Sealants can make grout a bit more water resistant, but not waterproof. Waterproofing is done behind the tiles, not between them.

More expensive is NOT always better! The adage “you get what you pay for” does not really apply to grout. While some types are more expensive than others, you should choose grout based on the application and not the price tag.

NO grout is “goof proof”! Installing grout correctly is pretty straightforward and simple-seeming in theory. But in reality, it takes quite a bit of practice and skill to get pro results. There are lots of subtle ways to really screw up any grouting job. Professional installers have lots of learned tricks and techniques to prevent all of these potential problems.

And finally, TRUST YOUR INSTALLER! If you’ve hired a competent pro for your reno project, then presumably you trust their experience and skill. If some designer or rando salesperson at a tile shop or hardware store suggests a particular type of grout for your project, ask ’em if they’ve ever actually installed it themselves. Here’s an analogy. Would you take advice from a ticket agent on how to fly a plane, just because they work at the airport?

Have a talk with your installer if you have questions about what kind of grout should be used for your particular project. It’s the equivalent of talking straight to the plane’s pilot. Ask ’em what grout they plan to use, and why. They should be able to answer with a clear explanation for why a particular grout is best for your job. If not, then get a different installer.

Second, what are the BASIC grout types?

There are only two major grout manufacturers — Mapei and PolyBlend. They’re like the Apple and Android of grouts. So far, seems simple. But each of these manufacturers produce dozens of different formulations. So, grout talk can get pretty confusing pretty quick. Here’s a quick rundown on the basics:

UNSANDED grout is the simplest. It’s just superfine portland cement with added pigments for color. It comes boxed or bagged as a powder ready to be mixed with water just before use.


Unsanded grout is great for skinny lines. It can be mixed to a buttery smooth consistency and squeezed into gaps as small as 1/32-in. It can also be mixed to lots of other different consistencies and tends to be quite sticky. This makes unsanded grout easy to install on walls or even tiled ceilings since it doesn’t slide off the float. It’s also a great choice for delicate glass or clay tiles that can scratch easily. Finally, it’s pretty easy to remove even dried unsanded grout from most tile surfaces, so it’s quite forgiving. Permanent grout haze problems usually aren’t an issue with unsanded grout.

Unsanded grout does have limitations. For example, it can only be used for joints up to 1/8-in wide. It will crack and fall out of gaps any larger than this. Also, unsanded grout is quite porous. No grout is completely waterproof, but unsanded grout is especially not waterproof. Therefore it is prone to staining unless installed with a good sealant.

In summary, unsanded is a great choice for backsplashes or other essentially decorative light duty tile applications where staining won’t be much of an issue. It’s not a good choice for wet area applications (showers or tub surrounds), backsplashes requiring stain resistance (behind a stove or sink for example), or floors.

SANDED grout is also pretty simple. It’s just superfine portland cement with pigmented color and added silica sand for density and strength. It comes boxed or bagged as a powder ready to be mixed with water before use.

Mapei Keracolor S 10lb Bag Sanded Grout - Charcoal #47 - - Amazon.com

Sanded grout is used for thicker grout lines, or for high use surfaces like floors. It can fill tile joints up to 1/2-in wide and is naturally more stain resistant than unsanded.

The main limitation for sanded grout come from the fact that it contains sand. So, it’s too abrasive to be used with polished glass or delicate porcelain, clay, or painted tiles. Sanded grout (especially darker colors) is also more prone to efflorescence (whitish scale that gives a blotchy look) or color shade variations. These problems can happen when minerals or pigments leach out of the cement and sand aggregate mix at different rates as it dries and cures.

In summary, sanded is a great choice for tile floors, shower walls, backsplashes for kitchens used by serious (or just kinda messy) cooks, or other high-use or frequently cleaned tile surfaces. You need to be careful to avoid efflorescence when using dark sanded grout colors, and a good sealant will add extra stain resistance.

PRE-MIXED grout is just what it sounds like. Usually advertised as “a no-mess alternative to traditional grout“, it’s simply regular unsanded or sanded grout that’s already mixed with water and sold in a sealed bucket.

In theory, pre-mixed grout takes the guesswork out of how much water to use when mixing up batches of traditional dry powdered mix. It also eliminates the actual mixing work. Finally, you can get pre-mixed grouts with sealants or other additives that advertise added water and stain resistance.

In practice, pre-mixed grouts are an expensive pain in the ass. You’re paying extra for all that premix water that has to be shipped in the bucket. It’s also impossible to adjust the moisture level for different install conditions. Every premix brand and formulation that I’ve used also slides right off the float. So, premixed grouts are actually quite difficult to install on wall tile without a lot of waste. Premixed grouts also start drying out the moment you crack open the bucket. They therefore have a vary short working time before getting too thick to use. This also makes it very difficult to ensure an even drying and curing time for the installed grout, which can result in shade variations for darker colors.

In summary, pre-mixed is usually something to avoid unless you want to pay a lot for iffy results (and really annoy your installer).

EPOXY grout is completely different. It’s not made from cement. It is instead made of epoxy resin mixed with color pigments (kinda like super thick colored glue). It comes in buckets and has to be mixed with a chemical hardener right before use.

Best Mapei Kerapoxy Cq 1-gallon Epoxy Grout for sale in Winter Park,  Florida for 2021

Epoxy grouts have traditionally only been used for industrial and commercial applications. This is because epoxy grout is almost waterproof and therefore is also nearly impossible to stain once fully cured. So, it’s a great option for commercial kitchens, tile floors in schools or restaurants or bars, etc etc.

However, epoxy grout is (in my opinion) not a good option for residential remodel projects. Unless you run a commercial food service business out of your home kitchen, using an epoxy grout for your floor or wall tile is like using a Humvee for grocery store errands.

Epoxy grouts can also be a real nightmare to work with. For example, epoxy grouts have VERY short working times and also have a VERY unforgiving setting time window. And remember that epoxy is essentially super-strong glue, so you’re pretty much screwed if you miss the window for fully wiping it off a tile surface before it sets. Also, epoxy will fill literally any crack or even pinpoint-sized hole, so is very difficult to use with anything other than perfectly smooth glazed ceramic or glass tile. Finally, it is by far the most expensive grout you can buy for a project (like Ferrari vs Kia expensive).

In summary, please don’t let someone talk you into using an epoxy grout for a home project unless they have a really compelling argument and a clear understanding of the material.

Third, what type of grout is best?

Again, it really depends on the specific project. I can however offer some general guidelines for residential bath and kitchen tile projects.

Should you use EPOXY grout? In general, NO. Seriously, please don’t. It’s really not necessary to use an industrial commercial product for your house. Epoxy is very expensive and difficult to work with. Insisting on using it will therefore really shorten your list of potential installers. For example, I won’t even consider a tile job if a residential reno customer is fixated on using epoxy for the finish. I simply wouldn’t be able to guarantee a perfect result for a reasonable price. Also, I’m not a fan of using bazookas to kill flies.

Should you use PRE-MIXED grout? Again, please don’t. Forcing an experienced tile pro to use a premix is like not allowing a racing team to tune their own car. Any benefits that a specific premixed product might advertise (sealant additives, color options, anti-efflorescence guarantees, etc etc) can also be found in a dry grout mix. There is no need to pay extra for a grout mix that simply has the water already added to it.

If you’re working with an install pro who is a big fan of a particular premixed brand/type and who can clearly explain why the benefits would outweigh the added costs and guarantee good results, then sure go ahead. However, I’ve never met such a person. The only folks I have met who are fans of premixed grouts are salespeople and the occasional DIY homeowner who’s also a big fan of “as seen on TV” gadgets.

Should you use dry-mix SANDED or UNSANDED grout? Yes, almost certainly. Any competent pro installer will have lots of experience using straight unsanded or sanded Mapei or PolyBlend mixes. They’ll be able to control the consistency of the mix for a trouble-free install. They will also be able to use well-practiced techniques to help ensure perfect results. And if you need extra stain protection for a backsplash or extra easy cleaning for a shower or kitchen floor, etc, then there are lots of good proven sealants and also many dry-mix options with sealant additives to match these and other needs.

So, what’s the bottom line?

Now we’re down in the weeds of residential remodel recommendation details. Do you need a super-duper stain resistant grout because you want the kitchen backsplash and tile floor to be nigh-impervious to bubbling marinara or red wine spills? Do you want a water resistant grout becuase you’d like your shower floor to dry quickly for minimizing mold and mildew growth? Do you want added protection against potential efflorescence or color variation problems? There are a couple dozen dry-mix additive and formulation combinations for all those needs.

I’ve experimented with lots of ’em, and my favorite by far (so far at least) is Mapei “Ultracolor Plus FA“. It’s a highly modified cement-based formula that uses extra-fine stone dust and polymer additives to achieve the smoothness of unsanded grout with the density and stain resistance of sanded. It can be used for tight 1/16-in joints or superwide 3/4-in gaps. It doesn’t shrink or crack as it dries and cures. And, it is pre-sealed.

Other highly modified dry-mix grouts that I’ve tried have had at least one or more install challenges. For example PolyBlend’s “Prism Performance Grout” has most of the same features in theory, but in practice it has an annoyingly short working time before drying in the bucket. And PolyBlend’s “PolyBlend Plus” formulation tends to stick to tile surfaces, and so needs careful attention to prevent difficult to remove grout haze.

In contrast, Mapei’s “Ultracolor Plus FA” has never given me a problem in any situation. It has a good 40min working time in the bucket whether mixed thin or thick, it holds on a float well so is great for wall or ceiling installs, and it has never resulted in a callback for color mottling or efflorescence. And as a bonus it won’t scratch even polished glass or painted clay tile, and won’t haze or spot even on porous natural stone tile — pics for proof!

Hopefully this has been a helpful guide for understanding some of the key practical differences between different grout types. While you don’t need to be an expert yourself if you’re hiring a pro for your tile project, it certainly still helps to understand the basics.