Finally, in July of 2018, I'm getting at the project originally done by contractors in the spring of 2015, but needing repair since the summer of 2015 because the grout/caulk around the tub cracked and started washing out. They fixed it once and it needed repair again 3 months later. I decided they were taking the wrong approach with a grout/caulk mixture (on the surface, it seemed like grout), and merely asked them to remove the caulk, at which they did an even more mediocre job. Afterwards, over at least a half dozen or so late evenings, using a variety of heavy duty methods, mostly involving small exacto style knives and more force than they were intended for, I removed all the old grout/caulk, vacuumed, cleaned, then removed more, so that the result is visibly ALMOST like brand new.* In places picking out the old grout/caulk was very hard to do because of the small grooves. But I persisted in many different months over almost 3 years of elapsed time.
(*With a bright light, you can see some mineralization on the tub porcelain surfaces, especially near the downspout. Even after many treatments with chemical cleaners like Lime Away, some, barely visible except in bright light, remains, and it feels slightly rough over these areas.)
Then last year, I started putting in backing rod in every place it would fit. And cleaning the tub and tile surfaces meticulously, ultimately with endless wipes of alcohol--it is cleaner than mint to the eye. And wondering how to deal with the spot where I chipped away an excess 1/8 inch of the vinyl flooring under the 5 inch molding that leads to the tub. (I have complicated thoughts about this now. But no previous idea was correct. Actually, I can just caulk right over it, using a 16mm tool. The problem I know sort-of understand is the 3 point contact with the floor underneath. I may need to use more backing material to *prevent* the caulk from contacting the subfloor, instead having it ONLY contact the flooring material. If it contacts the subfloor it will eventually break the important seal on top of the vinyl flooring.
Now, I really plan to do it in a special summer stay-cation. I've been doing more reading and thinking first. This had turned out to be more revolutionary than I would have believed, after watching this video I realize all the shade tree mechanic "professional" trick methods of installing caulk are wrong. Rarely do you get the correct story, and this may be the first time for me:
How To Apply Silicone
But I'll get to that later.
Back when I first started having trouble with the original tile company installation, I discovered Floor Elf has an illuminating discussion about whether grout or caulk should be used in a shower at changes of plane. If there really is no movement, which there shouldn't be anyway, then grout would work. But more realistically, caulk is the safer approach. There is almost always movement, and grout CANNOT handle that.
In my view, this means the most permanently flexible caulk available--Silicone. Apparently around my bath there is a lot of motion, from seasonal warming differences I believe. The back wall of the tub shower is the west side, which gets the brunt of afternoon sunchine.
I had previously decided that I would try different caulks, but I was leaning toward GE Silicone I Tub and Tile. After all, it has Tub and Tile right in the name. I had been thinking that since the Silicone II caulks are useable quicker, they would give longer tooling time, which someone like me needs, and the Silicone I's might be stronger.
Apparently this is not the case, both I and II allow 30 minutes tooling time. It's true that II becomes water resistant quicker, but that is because of a different hardening chemistry which is non-acidic. They are in the same stiffness category once cured. And, what many people confuse, they are both available in versions with a mold resistant chemical or not. (The ones with a mold resisting additive are called "tub and tile" or "kitchen and bath". The ones without a mold resisting additive are called "door and window" where mold is less a problem.
The only real difference is the curing chemistry, and that means that II is compatible with more materials. Silicone I is bonds to fewer materials, it does not bond to porous alkaline materials such as concrete or masonry, and it stains unprotected metals like copper.
(Unlike my first draft, I see now that both I and II bond to plastic.)
My Italian Porcelain tile is certainly non-porous. Which would mean, I might think, that it's alkalinity is a non issue...it is as non-ionic as glass. Nearly.
I am a bit worried about adhesion to the cut edges of the tile. This may have surface alkalinity, since it is not glazed.
I think experimentation is called for, applying I and II to cut edges (!) if of my tile, or at least the edges, if I have any spares left.
And also, though less important, to the flooring material.
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Even the post which cleared the air about whether I or II have mildewcide (the ones marked "Tub and Tile" and "Kitchen and Bath" do have mildewcide, the ones called "Door and Window" do not, it has nothing to do with whether I or II as many aquarium builders have come to believe) said that II has about 20% less "strength" than I.
Of course, what is available now may have changed since then. II is now actually "II+" and the "Supreme" series seems to be unavailable anywhere. II+, at least in the Door and Window or "All Purpose" versions, is said to have be especially tolerant of movement (what I need). But the "Kitchen and Bath" version of II+ doesn't make that claim.
Anyway, it has always stood to reason to me, that the original stinky version is still popular because for what it does, it does the best. It was a revolution when it was introduced. II was an attempt to achieve most of the same quality, but in a more consumer friendly, and possibly higher applicability version. But something had to be compromised to achieve those ends.
Aquarium builders have gotten more and more cynical about II. Not only do they fear (often falsely) the mildewcide, they think it isn't very strong or adhesive.
With all such videos one can see now, one doesn't know not only if they were rigged, but were the surfaces properly cleaned, etc. ? I've found some of them quite unbelievable. But they showed a very bad cred now existing for II (is that why GE had to change to II+ ?). I, on the other hand, seems to have *some* cred still. This is the reverse of what you read in magazine and online reports generally, where II was King at least not long ago.
I think some of these videos, and a lot of people's experiences, may have been clouded by improper application techniques, including lack of surface cleanliness, and improper tooling (and see below, the "professional" use of soapy water may be the worst thing of all...especially for quickly water insoluble GE Silicone II).
From the beginning, GE Silicone I, silicone caulks were known as unusually flexible and movement tolerant, as well and never cracking fading etc. But...they were never known for universal adhesion.
I only rediscovered this I above II line after I had decided to go with II+ after buying 3 tubes of II+. However, from years ago, I had wondered if I might be better.
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So, which caulk is actually best is ever and always and unknown.
But my big discovery, yesterday, was caulking technique.
After having seen two videos on silicone caulking, where they both used some sort of alcohol spray solution (it happens, for my intended go at this project last year I got a little can of spray alcohol, which I was all set to use) to make the finger tooling go easier.
But then I saw the best caulking video I've ever seen. And it fully made sense.
Using a no-stick solution is the very worst thing you can do. In means your "tooling" cannot possibly fill any gaps that were left in application, as they would normally be expected to do. Instead, your finger tooling is now pressing the alcohol solution (or worse, far worse, a soap solution) behind the caulk and in some cases and in very tiny particles within the caulk itself. If this is soap, or if it is alcohol with finger debris, it will now be ready to host mold (which the actual siilcon itself cannot do).
It's not even a very good idea to use your finger at all, both for that reason, and for the reason that the finger itself doesn't really have the correct shape.
The correct shape, as I had long thought, is not convex. Nor is it concave. It is diagonal, the caulk should have a straight 45 degree edge from top to bottom, perfect for anything to run off, and as strong as possible.
The usual convex "bead" made with a finger is essentially nothing at all--weak edges bound to immediately start wearing way connected to a fat center which may have different stress on it and pull apart from the sides, creating a crack and then a tear.
I tried using GE I and Loctite (Polyseamseal) sealant with a 14mm (large!) edge in an experimental mockup yesterday (though not actually using MY tile but just a plain ceramic). Both caulks came out strong and non-saggy, did a perfect 14mm bead using an inexpensive silicone tool I bought last year. Well actually I had some problems sometimes in keeping a smooth bead. Which I chaulked off to having limited space (inside a small box) to work with. But I liked the Silicone most--it was smoothest and easiest to work. The Loctite was thicker and tended to lump more. But I thought both were quite workable and much better than I had expected. Having always seen super thin silicone beads, I thought Silicone was watery (even if not actual water) and wouldn't hold in a large bead.
This is doable, however there might be better tools. This is a complete reversal of my previous thinking on this topic. Previously I never liked "tools" except my finger.
I'm now also thinking that one can be too obsessed with cleanness beyond the edge. Way beyond the edge, if there is some silicone residue, I believe it can be rubbed off with alcohol. After all, that's how you do the preparation also. That can be done any time after the caulk is installed.
The important thing is to get the caulk itself smooth, and with a secure edge, in the allotted 30 minutes.
There also may be some limited ability to caulk over caulk. It may actually stick to itself in many cases.
Going from horizontals first, wrapping toward the uplines, then coming down from above may be the best overall plan. That way all the merges are in the uplines which are less critical, and could even be slightly skinned-over when one gets there. This is another reversal of my thinking.
So by this thinking I would literally start at the bottom, around the floor, and work into half the upline . Then I'd do the main horizontal around the tub itself, wrapping into the two uplines. Then I come down from the top, into the uplines I just started.
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I do already have a shiny-clean like new surfaces on tub and tile. I do already have gap filled (as much as I could, in many cases it is too narrow) with backer rod. So it's been like I'm almost there, now, for at least one year. (It was about a year ago I finally finished the very thorough cleaning with alcohol, it was probably everclear which I figure is as good and safer than denatured.
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I do NOT have any spare pieces of the Italian Marble-look tile. I will test tiny beadlets on a hidden corner of the moulding (I had the tiler do all around my floor with spare pieces. Now I have tile as my floor moulding, which is super. But I also have no spare tile pieces anymore).
Mainly now I'm testing GE I Tub and Tile against GE 2+ Kitchen and Bath. I worry about the latter. The former is making a very nice and hard bead after 24 hours. It feels like stone across the 14mm bead face. Meanwhile, the Loctite is still mushy, and seems like whipped cream density. I got these tubes last year and maybe it is expired. But I think so far the GE I feels like the superior product, but I haven't tried either the GE 2+ or the AST yet.
Previous, as I said, I thought the GE 1 would be watery, but instead it's nicely firm but magically smooth.
The DAP caulking tool is thicker and more rigid than the generic Chinese one I bought last year. But it does not have a 14mm bead, only 10mm and 16mm (which I think may be just like that famous name tool in the video blog, which I have on order). 10mm doesn't cut it even for the ends of the horizontal (14 would mostly). 16 covers everything, even the extra wide gap on the entry to the bath. With 16 I would not have to worry about tapering from 14 to 17 to make the coverage at that extra wide gap OK. 16mm is a bit of a challenge, but it is the about as strong as it gets. 17mm is a bit too much maybe.
I'm thinking now Almond color would look best, blending better to the tub and bringing some tub coloration into the sides. The white wouldn't really match anything, because the current "white" grout is actually tinted.
But if GE I is the better caulk, white it will be. Or clear??? I understand that is very cloudy, but might still match the tile better than pure white. I'm not thinking the designer choices are Almond in II+ and Clear in I.
It occurs to me that the relatively non-stickiness of Silicone I to concrete and masonry is actually an advantage...it prevents "3 point attachment" to undesired surfaces, such as the subfloor and the tile board.
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I had decided by Tuesday night of my staycation that White was superior to Clear, even if it doesn't entirely match. Clear tries to be clever in blending in. But if you look at it closely, it will look more uneven in color because of substrate and other issues. In the long run, it will be hard to tell the natural variations from dirt and mold. With white, the dirt and mold will stand out so you can clean them easily. Unlike Clear, White is honest.
Rarely do you see pictures of the Clear caulk, and there are many complaints about it not being clear but milky. In my case, with varying gaps behind and some huge, I don't even want perfectly clear, I want to cover up the construction interfaces behind the caulk.
White with my Almond bath and off-white tile will stand out. But it will stand out in a good way, like the whitewalls in a 1929 Packard, given the impression of strength and uncompromised quality.
Almond might have been a better choice, but almond is not available in GE Silicone I, and that is what I had decided to use, because it seems even stronger and thicker (but equally smooth) as Silicone II. Strength is more important than appearance.
The first results of my strength and adhesion test show Silicone I to be at least as good if not better than Silicone II in holding to the unfinished edge of my porcelain tile (tested in an inconspicuous corner of the bathroom floor molding made out of edge pieces). With both silicones, they hold best to the actual finished side of the tile, basically impossible to remove because stronger than the silicone itself. With the edge of the tile, only Silicone I hold that firmly.
This test could have been corrupted slightly because I didn't clean the edge of the tile equally well before performing the test. But since I was so much better than II in holding on to the edge, I feel confident that it is at least equally good to II in that regards, if not better.
Both I and II are quality caulks, dense and firm yet buttery smooth, and harden to a very strong bead. Side by side they are quite similar compared to other caulks, even other silicones. The AST silicone caulk was even less dense (and somewhat less smooth) than GE II, but had the foul smell of GE I--the densest of all.
Actually I think the foul smell is a good thing. It means the stuff is working as it cures. Some have observed that the foul smell (of Vinegar, a highly common natural substance) goes away completely after the caulk has cured, then you have no smell at all. Meanwhile the slightly chemical smell of the "neutral cure" caulks never goes away. That would not surprise me.
My own testing, if it can be believed, also confirms the slightly superior strength of GE I vs GE II.
