Let’s Talk about GROUT!

If you’d like to save some money and save yourself (or your installer) some trouble on your next tile project, then read on for some gritty grout advice. This isn’t a post about how to install grout yourself. Instead, this is a post with info and advice for how to have a detailed conversation with a pro installer about exactly what kind of grout to use for your particular tile project to get fantastic results.

This post also describes why “Mapei Ultracolor Plus FA” is my own recommended all-purpose grout. Read on to find out why!

First, let’s pop some grout MYTHS

Grout is NOT waterproof! Neither is tile, actually, but the joints between tiles are where most moisture wicks through in wet areas like shower floors or tub surround walls. Although tile and grout obviously blocks most of the water that sprays onto it, wetted grout will absorb and transfer 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, sure, 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 of grout 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, and 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 someone to install tile and grout for your reno project, then presumably you trust their experience and skill. If some designer or 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 the grout themselves. Think about it — would you take advice from a ticket agent on how to fly a plane, just because they work at the airport? Trust the pilot.

If you have questions about what kind of grout should be used for your particular project, then have a chat with your installer. Ask ’em what grout they plan to use, and why. They should be able to answer with a detailed description of the pros and cons of several different options and a clear explanation for why they recommend a particular grout 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 grout 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 grout lines, since it can be mixed to a buttery smooth consistency and squeezed into gaps as small as 1/16-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. Most importantly, it can only be used for grout joints up to 1/8-in wide. It will crack and fall out of gaps any larger than this. Unsanded grout is also fairly porous — no grout is completely waterproof, but unsanded grout is not waterproof at all. Therefore it is prone to staining unless installed with a good grout sealant.

In summary, unsanded gout is a great choice for backsplashes or other essentially decorative tile applications.

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

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. Also in my experience sanded grout (especially darker colors) can be 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 grout mix at different rates as the grout dries and cures.

In summary, sanded grout 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 grout mix. It also eliminates the actual mixing work. Finally, you can get pre-mixed grout 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, and your installer can’t adjust the moisture level for different install conditions. Also, every premix brand and formulation that I’ve used slides right off the float. So, premixed grouts are actually quite difficult to install on wall tiles without a lot of waste. Premixed grouts also start drying out the moment you crack open the bucket, and so have a 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 grout colors.

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

EPOXY grout is completely different. It’s not made from cement. Instead it’s 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 2021Epoxy grouts have traditionally only be used for industrial and commercial applications, but are now being marketed for residential construction and remodel projects. 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 great 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 Schwarzenegger’s unmodified military Humvee for grocery store errands.

Epoxy grout can also be a real nightmare to work with. Commercial install crews that use epoxy grout every day have tons of experience and tricks for dealing with these potential problems. Just about any residential remodel pro who uses epoxy grout only occasionally generally won’t. 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 Porsche vs Kia expensive.

In summary, please don’t let someone talk you into using 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. But I can 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 grout is very expensive and difficult to work with, and therefore insisting on using it will also 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 grout for the finish simply because I 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 grout is like not allowing a racing team to tune their own car. Any benefits that a specific premixed grout 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 grout 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 grout products 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 for lots and lots of particular uses. They’ll be able to control the consistency of the mix for a trouble-free install, and 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 grout 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 grout 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 added protection against potential efflorescence or color variation problems? There are dozens of 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 grout that uses extra-fine silica and polymer additives. It can be used for tight 1/16-in grout joints or superwide 3/4-in gaps. It doesn’t shrink or crack as it dries and cures. It’s very dense, and it is pre-sealed.

Other highly modified dry-mix grout formulations 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” grout 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.