Help me with a tricky old tile/grout question
September 4, 2018 1:56 PM   Subscribe

My Dad installed some kitchen counter tiles many years ago, and being an amateur, didn't leave enough space for grout. We'd like to find some way of sealing the spaces between the tiles that doesn't involve a complete demo and redo. Does such a solution exist?

The issue is that the spaces between the tiles are 2mm (and sometimes much less), so if he applied grout (I think he did), it was too thin, didn't bond to the underlayer, and so now the gaps are kind of microbe breeding grounds, because they're often damp after a good counter scrubbing.

If possible, we'd like to avoid a full demo and redo, for both cost and functionality concerns, and because we'd have to take a few days off (at least) to do that.

Do you know of a DIY or handyperson-usable solution that would be workable for a kitchen counter? Some kind of acrylic or plastic seal that would stick around for the long term? Caulk? Anything? If you've encountered this issue and mastered it before, I'd love to hear practical experience over theorizing, if possible, though theorizing may also provide good answers, so whatever you think's best.

Thanks in advance for any answer or pointer you provide!
posted by kalessin to Home & Garden (8 answers total) 2 users marked this as a favorite
I think you're going to want to rake out the old grout as a minimum. There are electric multi-tool things that will do a decent job of this, although you can also do it with an inexpensive hand tool and a lot of elbow-grease. If the grout is loose and full of gaps, it ought to come out easily enough.

Re-grout with a flexible, waterproof, mould-resistant grout, and then seal the whole thing with a purpose-made tile and grout sealant, which you'll want to reapply every few years. A 2mm spacing isn't unreasonable, although 3mm or more is more common. No reason why a good grout wouldn't cope with a smaller spacing.

If the tiles are affixed to wood, then the gaps are likely due to expansion of the wood leading to cracks in an inflexible grout.

Also, don't be tempted by a ready-mixed grout. Powder grout that you mix yourself is what the experts use for good reason - it doesn't shrink nearly as much, and is more durable.
posted by pipeski at 2:18 PM on September 4, 2018 [4 favorites]

Also be sure to select UN-sanded grout.
posted by humboldt32 at 3:48 PM on September 4, 2018 [2 favorites]

Update: I measured the common grout space widths while looking for appropriate removal tools. Unfortunately according to my calipers it's 1.1 or 1.2 mm wide.
posted by kalessin at 5:16 PM on September 4, 2018

There is a product/variation called Grout Refresh. It's available in several colors and is essentially a paint/sealer. Clean the old grout and tile thoroughly and apply the refresh with a toothbrush or other small brush. Use rags to wipe away any excess. They also sell this in a "pen"
posted by emjay at 6:25 PM on September 4, 2018

With spaces that narrow, the tool that comes to mind is a dental pick. It's going to be a miserable job (picking grout out always is), but a big pack of cheap dental picks ought to see you through it. Then, yeah, clean up all the old grout, regrout with unsanded grout, and you're good.
posted by Making You Bored For Science at 6:27 PM on September 4, 2018

Has anyone heard of epoxy grout? Apparently it doesn't need sealing and is good for kitchen and bathroom applications?
posted by kalessin at 6:37 PM on September 4, 2018

I did this - you can do this. I have shower tile that is very close together. I tried all the grout removal tools - grout rakes with carbide grit, grout saws with steel blades, even a fancy 1/16" grout removal multi-tool attachment. None of them worked - they were all to thick and chipped the surface of the tile.

I ended up using a plain old utility knife. I bought a 50-pack of good blades. By angling the knife to the left or right it scraped the edges of the groove very clean. I scraped to a uniform depth about equal to the thickness of the tile - it was pretty easy to see how much blade was disappearing into the crack. I went through a lot of blades as they dull very quickly. I should have started a trial with the knife - I spent more time faffing about with buying expensive tools that didn't work than just scraping away with the utility knife. Thank god I stopped myself before getting a Dremel with grout removal tool . The good news is the very thin grout lines chipped out very quickly.

For grout - I used standard un-sanded grout and really packed it in. I also made sure the cracks were very clean, going over with a dry stiff brush and a shop vac. I think the grout box instructions suggested that the grooves be made wet before applying so maybe I did this. I also "slaked" the grout, allowing it to sit for about five minutes after mixing with water in the bucket and then mixing again before applying. I do not regret buying a good quality grout float with a two-layer rubber base, and grout margin float. Once the grout is mixed and slaked the clock is ticking so good quality floats made a stressful job go smoothly. I used the big damp sponge to clean up and pressed it into the joints a little to smooth them out - that was surprisingly easy and fun.
posted by sol at 8:15 PM on September 4, 2018 [2 favorites]

Epoxy grout is not something I'd go with. Everything I've read suggests that it's complicated and labour-intensive to apply. My most recent grouting exercise (kitchen wall tiles a couple of weeks ago) was done pretty much as sol describes, followed up with a coat of tile protector (which adds a clear barrier over the whole thing - this fills in any roughness in the surface of the grout and tiles, making it easier to keep things clean later). Grout will usually stay workable for half an hour or so, so just make up enough to do a few sq. feet at a time. I just used a finger to smooth the joints and it worked just fine.

One other thing - where the tiled surface meets a wall (or anything else), it's better to use a silicone sealant instead of grout, because these are areas most likely to experience movement. Silicone will flex much more than even the most flexible grout. I just used a white grout and white silicone, so it looks like the same thing, but won't crack in the corners.
posted by pipeski at 4:46 AM on September 5, 2018 [1 favorite]

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