Working with SpectraLOCK Pro Premium Grout

by Roger

Spectralock Pro PremiumAnyone who reads my blog (and lets be honest – who doesn’t?) knows that I am a diehard SpectraLOCK junkie. For those who don’t know what that is, SpectraLOCK is an epoxy grout made by Laticrete. It is stain-proof, pet-proof, and bullet-proof! (Don’t try that, it’ll really piss off the wife…) If you don’t know any of that – you need to read my blog more! :guedo: So just like everything I love – it changed.

Laticrete has recently come out with SpectraLOCK Pro Premium grout. A little birdie told me that this will replace the SpectraLOCK pro grout in the near future. Given that, I need to figure out how to use it – because it works differently than the stuff I’m used to. The difference in the workability may very well be due to the temperature, humidity, hangover flu bug, or any number of factors on the particular days I was working with it.

But it just doesn’t feel ‘normal’ to me – you know? It seems like it tightens up (gets stiff) and starts to roll out of the grout joints more quickly than the other stuff did. So, as with any installation product, if it begins to cure faster than you can use it you should just mix up smaller batches. And being the awesome DIY crowd you are – it’s probably a good idea for you to know how to do that anyway. So this is the best way I’ve found to do it.

A few basics first: SpectraLOCK is sold in different unit sizes. The base unit is called … wait for it … a FULL unit! Wait, where you goin’? This isn’t complicated like the metric system or anything, stick around. There is also the COMMERCIAL unit, which is what I buy (and you likely will not need) and it contains four full units. There is also the MINI unit – this is 1/4 of a full unit.

So: 1 commercial unit = 4 full units and 1 full unit = 4 mini units. Now, you can split up whatever you feel comfortable with, I split the full units into mini units. And this is what I’m about to show you. However, if you feel the need to split them into smaller units, or split the mini units into smaller units you can do that as well, you’ll just need to change the measurements.

When you break down the components into smaller units you need to do it by weight. I don’t see why splitting the liquids down by volume would be significantly different – but I was always told to break them down by weight. So do that. Really.

SpectraLOCK has three components, the part A and part B liquids and the part C powder. The part A is the yellow stuff in the foil bag, part B is the white stuff. Part C powder is in the carton. For this I’ll be splitting up one full unit so the bags and carton may look larger than what you have – mine’s bigger! :dance:

You want to have a scale (scrape off the *ahem* ‘illegal substances’) and some one-quart ziploc baggies (the unused ones). For a full unit you’ll want to split each liquid into four baggies. Each liquid baggie weighs a different amount! So don’t just go puttin’ the same amount of everything in all the bags, it won’t work, you’ll have 1/2lb. of the white liquid left – then whaddya gonna do?

  • Part A (foil bag) has 5 ounces of liquid in each baggie (4 baggies)
  • Part B (white liquid) has 5.2 ounces in each baggie (4 baggies)
  • Part C (powder) has 2.25 pounds in each baggie – or whatever you choose to dump it into (4 of ’em)

Just measure out all those components and zip them up. Once you’re done with that you’re ready to mix smaller batches in workable sizes. I just measure out the powder as I go along – I’m a rebel like that. 8)

AGAIN! If you have smaller units or want smaller batches you’ll have smaller measurements. You just need to weigh out what you have and split them into equal parts.

The photo above shows one full unit in the back, the two large bags and the carton, and one of the smaller units after I’ve measured them out, the two small baggies and the cup of powder. The amounts in the baggies and the cup is what you’ll be working with at one time.

To mix them just get yourself a nice clean container (scrub the beer coffee rings out of it) and add the two liquids together. Just roll up the baggie from the zipper side down until you have no room left to roll (like toothpaste) and snip off the corner of it with scissors. You can then squeeze all the liquid out of it with a minimum of mess.

Snip off the end of the bagSqueeze it out like toothpasteSnip off the tipSqueeze it out like toothpaste


Once you get those in there YOU NEED TO MIX THE LIQUID TOGETHER! Do that before adding the powder, or it’s gonna be one big mess you don’t wanna deal with – take my word on that. :D

MIx the liquids together before adding powder!MIx the liquids together before adding powder!


Once you get your liquids mixed together you can add the powder. Add about 75% of the powder first and mix it all up. Get a nice, smooth consistency, then you can add the rest of the powder. This helps get everything mixed evenly whereas if you dump it all in there and mix it you’ll spend more time getting an even mixture.

(Jesus, did I just type ‘whereas’??? I need a beer nap…)

Add about 75 percent of the powderMIx it up well

Then add the rest of the powder and MIx it up well

Here's your grout - get to it! Quickly, damnit!

And that’s it. It’s all ready to go. When you grout, fill your grout lines and begin washing the tile in about 10-15 minutes. In another 40 minutes or so you can begin the second wash. I’ve noticed with the new stuff that you’ll only have about 35-45 minutes of what I consider ‘workable’ time. It’s not like it turns into a rock after 40 minutes, but it does become considerably more difficult to work with.

If you keep your batches small enough to install in that time frame it won’t be a problem – it’s when you go past the viable working time that it starts becoming difficult.

While I have voiced my displeasure with the new mix in a place or two, after I calmed down and sobered up thought about it I realized that SpectraLOCK is still the easiest epoxy grout on the market to work with. That, coupled with the rock solid (pun intended) color match you get from it, SpectraLOCK will still be my epoxy grout of choice.

I just need to quit being such a hard-headed bastard and learn to work with it a bit differently. One of the key factors in doing that is to keep the mixes in manageable batches. Just take your time, a little extra now will go a long way toward the long-term durability of your tile installation. And it WILL be stain-proof!

Here’s some basic information about the new stuff from Laticrete: Laticrete SpectraLOCK Pro Premium

And here’s a chart for coverage to see exactly how much you’ll need: Laticrete Grout Coverage Calculator

As always if you have any questions at all feel free to post them below. I’ll answer them once I sober up get home from work.

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After I split the full unit into quarters, how long will the little baggies keep?




Thanks again for your forum and advice.

Today my questions is about Spectralock Pro Premium Grout. I’m curious if there is a difference between the Pro and Pro Premium? I used the Pro Premium for my bathroom floor grout. Yup a little tough to work with for a slow DYIer, but I’m satisfied with results (except color was not as dark as sample). :-|

Now the questions. In the instructions it says Pro Premium is a sanded grout. Use in joints less than 1/8″ will result in a coarser texture. Is the Pro Grout still available? Is it unsanded? Shoud I use it instead in my shower joints, which will be 1/16″?

Thanks for everything.



They are both sanded grout, the color is from the colored sand. It will be a bit coarser, but not really noticeably so – unless you’re looking for it.



Hey Roger,
I used the spectra loc pro premium on my subway tile wall 1/16″ white on white grout joints… the rollout seemed to never stop throughout the install and was real hard to pack the joints full. When I cleaned everything thoroughly and came back later, I realized that the joints don’t look as full as they should creating weird shadowing from my down lighting..

Can I go over the existing grout with more grout to build it up and fill the joint a little more or am I kind of stuck with what I have? It’s been less than 24 hrs since the time of this post.




Hi Robert,

With spectralock you can go over it anytime you want. Try mixing it with a little less of the powder, it doesn’t roll so badly. If you decide to go over it you can have it a bit runnier, it’ll actually be easier.


Brandon Latsha

Has anyone ever used anything in place of the wash packets? I subdivided my full unit into 4 mini units but forgot to do the same with the wash packets. Now I have 3 mini units with no wash packets. Another professional flooring guy told me Spic and Span powder works better than the wash packets. Thoughts?



Hi Brandon,

Any powdered dish soap will work. Spic and span works well, as does cascade.



Hi Roger – love the site. We used epoxy grout (Stainmaster) in our shower stall floor. How long should we wait before using the shower? No recommendation on the Stainmaster tub…



Hi Mike,

24 hours will be fine.


Laura Rusick

Hi. Great site! This is our first time using Spectralock Pro Premium. We’ve used epoxy grouts before, as well as traditional.

We finished tiling (combo of 8×32 and mosaics) and wanted to get the grouting done today. We know everything has to be exact. The contractor pack we bought has everything already divided into nice 4 part packages except part C. So we weighted out 2.25 pounds of that. Mixed the liquids together first then added in the part C.

Here’s the thing – it came out nothing like any grout I’ve ever worked with. It was downright runny. Nowhere near the PB-like consistency we were expecting. We did try to use it on our wall in case set up time was quick. As you might imagine, big mistake. The stuff just oozed out and own. We were able to clean it up reasonably well thereby staving off my heart attack, but it definitely isn’t right and many spaces between tiles are empty or low.

Any idea what happened? Really disappointed! Thanks in advance.



Hi Laura,

Just last year laticrete changed the mixture ratio and chemicals in spectralock (I’ve been told). During this transition there were many people selling the new parts a and b with the old part c. It sounds like that’s what happened in your case. The part c should be divided evenly for the packaging of the a and b.


The ‘four pack’ of parts a and b you received was a ‘contractor’ pack, this is not divided into the four parts I describe, Each bag is four parts. So your a and b packs would actually have made 16 mini-units. You had 1/4 the amount of part c you should have had. Each of those bags (1 bag a, 1 bag b) should receive a full carton (9lbs. or whatever it is) of part c.

My guess would be the second issue. Try splitting one part a bag and one part b bag into fourths, then add 2.25lbs. of part c to it – I think you’ll find it much more like grout than pudding. :D



Thanks so much. Will give that a try. Worst directions EVER! :)


Karen Hare

we are a Habitat restore and have gobs of the part C SpectraLock color powder, could this be used to color other grout?



Hi Karen,

Unfortunately not. It is a colorant for an epoxy grout which is formulated to mix with the color of their components once mixed. Every manufacturer is different, so they have a different color grout base once mixed. The A and B parts will form a specific color when mixed, part C is formulated to achieve that color grout once mixed with that color of base.



Thanks much for the extra details and tips. Been very nervous about using this stuff but finally took the plunge. We bought the Spectralock Pro Premium.

As you suggested we subdivided a full pack into quarters, really glad I got my feet wet with the smaller portions. I decided to verify your measurements, because that’s what I do.

I first weighed part A and B in their respective bags and they were almost the same, i.e. 615g (20.64oz)(I used grams for better resolution). Not sure if they’ve “tweaked” their formula since you wrote this article as the weights were the same. Since the bags weighed the same I decided to verify the liquids too (all measurements are +/- a few grams). They each measured about 585g without the bags. The bags weigh ~25g – 30g. Anyway, I subdivided to approximately 146g per baggie (5.15oz).

After mixing up my first quarter batch with a margin trowel (took about 10 minutes from pouring parts A/B in the cup to starting to grout), I noticed the texture was similar to your picture, more like thick peanut butter; whereas, the Laticrete videos show a much creamier, easier to spread grout. I worked as quickly as possible. The grout starts to thicken pretty quickly and I had to use A LOT of muscle to apply it…forearms burning and hands cramping (I thought I was in better shape, and not the round kind).

We followed your shorter timing suggestions on cleaning…the Laticrete directions have a bit longer timing, i.e. 1 hour before first wash and 1 hour before second wash. We weren’t sure if the timings start as soon as one begins to mix the grout or when one starts applying it. We started the clock as soon as part A/B were being mixed as the chemical reaction starts ♦from that point.

A few observations.
-Epoxy grout “haze” is shiny not dull like normal grout. We kinda liked the “wet” look but we removed anyway as we had no idea how it would wear and frankly it wasn’t even, but anyway.
-For 24″ by 6″ planks, a quarter pack covered ~34sf, close to the Laticrete calculator. I think I remove too much thinset from between the tiles, i.e. down to the Ditra.
-We had to do a third cleaning with vinegar / water solution, scrubbie and sponge after which the “shinyness” disappeared off the tile. We did the cleaning about 1 hour after the second.
-We couldn’t find white scrub pads so we used blue, non-scratch, Scotchbrite pads for wood-looking Porcelain plank tiles.



Thanks Geoff!



Hey Roger,

I have 1/16″ grout joints on 3×6 ceramic subway tiles…

The laticrete video suggests that ” it is acceptable to leave out up to 10% of the part c color additive to produce a more fluid mix.”

I’m going to assume you’ve done a job or two with 1/16″ joints and use pro premium before… is thinning it out like that necessary? Even though it’s white will there be a color difference possibly? Is it harder to push into the joints if I use it as is? What’s the advantage if any? I need to mix up 2 minis to do my shower.

I would like to avoid breaking down into smaller units if at all possible and just use it the way it came to avoid any complications.

And… have you used the pro premium on ceramic and found that the grout set up quicker than other various types of tile?

I’ve been in remodeling for over 20 years, my expertise is NOT based in the “tile sector” however I’ve done a few tile jobs here and there mostly for family.

I’ve never been so leery or down right afraid of the potential consequences of any product I’ve ever used…. What’s that noise? Oh, I think that’s me hyperventilating… :-?

Thanks for your input.



Hi Robert,

On vertical installations it is best NOT to leave out 10%. I use all the powder most of the time. No issues with 1/16″ lines or ceramic tile. (Type of tile makes no difference in the set-up time).



Does the full unit come with the cleaning additives they mention in the installation instructions?



Hi Tony,




Roger, how do I clean off the residual film left on the ceramic wall tile in the shower-installer used Spectralock Pro Premium. The installer did the normal clean up and told me not to touch tile for 7 days. Upon subsequently trying to remove the film, it is solid. Instructions say use vinegar within 24 hours. Now too late. What may remove after the 7 day wait?



Hi Tom,

A white scrub pad, barkeeper’s friend (it’s like old-school ajax) and a lot of elbow grease.



Gawd – I wish I saw this article before I started.

I tried to buy six MINI units but my local supplier did not have the mini’s in stock. They convinced me the commercial unit was a better deal so they gave me two commercial units for the price of the six minis. Mistake #1.

First timer using any sort of grout – I mixed the full unit and each time I ended up throwing 1/2 of it away. Grout looks great at the beginning of each batch. Looks terrible/lumpy where I eventually quit trying to shove the hardening epoxy in the grout lines at the end of each batch. I was not even close enough to keeping up with the cure-rate of the Spectralock and I now wish I had hired a pro (or insisted on the mini unit).

Great product – sucks working with it though.



Hi Roger,
I’m having trouble getting Bostik QuartzLock2 grout (pre-mixed urethane – sorry!) residue off my porcelain tile. If I keep wiping the grouted tiles with a damp sponge the grout starts to go away. If I stop, there remains a film of urethane that is extremely difficult to remove. Goof-Off (TM) works but is know to cause cancer somewhere, besides being a pain in… Would sealing the tile before grouting work? By the way, here’s my favorite Physics 101 question. If you heat a plate of steel with a hole in it does the hole grow or shrink?



Thanks for answering my question, Jon. :-D



I an ready to grout my shower stall. I am using 1 inch square polished marbles tile. I am only going up the walls 3 inches with the same tile I’m using on the floor. My question is can I use the spectra lock Premium grout to do the whole thing, or do I need to silicone where the floor meets the wall even though it only goes up the wall 3 inches? Question 2 if I need to use silicone with such small tiles how do you keep the silicone where it needs to be and not going up into the grouting lines. Do I grout first and then dig that bottom grout line out, order a silicone first. Please help thank you Mark



Hi Mark,

Yes, you need to use silicone there. The tile doesn’t care that it only goes up three inches, there is still an eight-foot wall above that. :D If you use color-matched silicone you won’t notice where it goes into the grout lines a bit. I grout first, scrape out that line before the grout cures, let the grout cure then silicone.


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