Caulking advice needed for flooring [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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07-11-2002, 03:28 PM
I've just finished tiling and grouting about a 100 square feet kitchen and laundry room area. I left a minimum 1/4 inch of expansion where the tile meets the walls, doorways, and counters. Here's my question: although I have caulk to match my grout (Polyblend Ceramic Tile Caulk from Custom Building Products), what else can I use to form an effective expansion joint while still maintaining maximal protection in these areas? I am intending to put bullnose tile as a kind of baseboard along the walls and toekick.

Can I also use another kind of caulk (silicone) as a kind of flexible sealant and then use the grout color-matched caulk over it? This would be a cheaper way of ensuring that the joints are sealed up tight while not using up gobs of the expensive stuff.

Any ideas, feedback, comments, or anecdotes would be appreciated.



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Bud Cline
07-11-2002, 03:36 PM
Have you ever seen a caulking product in your area called "Big Stretch"?

It's pretty good stuff and could be used to fill the perimeter gap. You can then set your tile baseboard over it then caulk THAT joint with the colormatched product.

Any caulk that has elastomeric properties will work though. If it is elastomeric it will say so on the label.

I wouldn't try to caulk over silicone because nothing sticks to silicone. Silicone ain't that cheap either.

John Bridge
07-11-2002, 03:40 PM
Howdy, Muskadine, Welcome.

There is such a thing as "backer rod." it's a styrofoam cord-like material that comes in various diameters. It is stuffed down in the joint prior to caulking. It is usually purchased from builder's supplies. Probably not Home D. type places.

An alternative is using cotton clothesline rope which is available at H. D. Pack it into the joint and caulk over the top of it.

Now watch someone come along and shoot me down over the clothesline rope. ;)

Under the base you need nothing.

07-11-2002, 03:48 PM
I like the clothes line deal. Reminds me of when we used to build solid masonry walls, you know rocks and bricks. I saw some old timers use a cotton or hemp cord between the bricks to funnel water and moisture down and out the walls. They would run them vertically and cut them off. They would presumably rot away and leave a nice hole.

That clothes line is probably cheaper than backer rod!

07-11-2002, 03:55 PM
The problem I see is that, around the joints from tile to wall, cabinet, etc., I've got 1/4 inch width PLUS about 1/2 inch depth to seal. That's a lot of real estate once I get to caulking around the perimeter of these two rooms, even though they don't seem so big. I want to do the job right, but at the same time, I'm cognizant of the fact that I'm paying extra to get a special caulk that costs more because it aesthetically matches my grout color. I'm going to be doing layers of expensive caulk that nobody is gonna see!

The clothesline/"Big Stretch"/Sill Seal/foam expansion joint idea is appealing, but I haven't seen it in my area. I certainly don't mind looking, however.

I'd rather just do two layers of caulk. One layer that offers moisture and expansion protection up to about the level of the tile. I can do that one with a caulk gun and get better coverage at a better price than using my thumbs to squeeze my pretty brown caulk a half inch down behind where my refrigerator is going to go. The next layer would be the color matched caulk to make things look peachy-keen.

So here's another question: what kind of bulk caulk (NOT silicone, now I know) should I use. GE, for example, has lots of different, non-silicone caulks available. So does a brand called DAP. Any ideas?

Thanks, John and Bud, so far, for replying. Everybody else, thanks for reading and don't hesitate to post any thoughts you may have.


John Bridge
07-11-2002, 03:56 PM

You probably go back to the days before wall tiles had spacer lugs. They used cotton storage string to space the courses. Lay up a course of tiles and run the string across the top of it. Install more courses, and so on. When the tiles had set, the helpers would go back and pull on the end of the string and strip it out. A little washing and the walls were ready for grout.

Those days were before mastic. :)

Bud Cline
07-11-2002, 04:40 PM
I've rode in that foam backer rod rodeo more times than I care to remember. It's available in various sizes as John says but the trouble is, if your going to get it to stay in your joint and remain low enough to caulk over it then the rod must be purchased in a size bigger than the joint.

You stuff it in the joint usually with a putty knife. You can only hope it stays. A lot of times it doesn't. A lot of times it doesn't raise its ugly head until the next day pushing your fresh caulk out with it. Now the only thing to do is to remove the pricy stuff along with the caulk you just installed.

If you've got a full 1/2" depth then you might get the rod to stay that deep.

It's an expensive gamble which is why I didn't mention it.

Actually the clothesline rope sounds like a better deal to me but I've never done it. But I'm not as old as John is either.

07-11-2002, 05:23 PM
Is the two-layer caulk idea do-able? One layer of elasometric, non-silicone caulk to get me up to tile level and a second layer of the color-matched stuff to make even Martha Stewart happy.

The foam strip makes sense, but I see two problems: One, I'd have to go on a treasure hunt to find it. Second, if the two-layer caulk method works, and it's cheaper, to boot, it may be easier to apply because I won't have to play rodeo clown and yell "Yee-Haw!" while I lasoo it in. My wife thinks that I'm crazy enough. The other day, she said,"You look at this floor more than you look at me."

And she was right. That's why I have to finish this job quick, but finish it right.


07-11-2002, 06:37 PM
Why fill that joint at all?...once the baseboard is will cover the joint? Did I miss something?:)

John Bridge
07-11-2002, 06:43 PM
Yeah, Bri, there are also the gaps against the toe boards, etc., that will show.


The two-stage caulking job will work just fine. I would buy the 99 cent stuff for the first go-round and not even worry about brand name or use. It's only to take up space.

07-11-2002, 06:48 PM
When I do stick on that ceramic, bullnosed baseboard, what should I stick it with?

I was gonna use thinset, but while we're on the caulk/sealant topic, I thought, why not use LIQUID NAILS? It's strong, relatively cheap, and not too messy.

But I still have a half-opened bag of thinset to use.

What do y'all think about that one.

By the way, thanks for all the help. This is my first tile job, and reading through this forum lately has really helped improve my knowledge and confidence level. Keep up all the supportive feedback.


Bud Cline
07-11-2002, 06:52 PM
I'd use up the thinset, you already have it. Then take your wife to Dairy Queen with the Liquid Nails money.

Rob Z
07-11-2002, 07:36 PM
If you end up using the backer rod, H*** D**** does have it (no one there knows about it, though). It is next to the weather stripping stuff for doors and windows. Putting it next to the caulking products makes too much sense. :)

07-11-2002, 08:56 PM
Real mason yards should have backer rod, they will even know what it is.

I once saw a big box employee trying to stomp a 10' piece of it, thought it was a snake. :D

Rob Z
07-11-2002, 09:53 PM

07-12-2002, 08:09 AM
It's true.. it's true! Would I make something like that up?;)

Sonnie Layne
07-12-2002, 09:09 AM
Rob's right, HD does carry it (backer rod). So does about every hardware store I've been in. Certainly your local paint stores carry it and much cheaper because you can buy it bulk/by the foot from them. Being painters, they can also tell you how to use it.

I'm with Brian... if the base/cove/shoe moulding is wide enough to cover the gap between tile and base it won't be an issue. I try to set my tile up closer along the toe kicks (1/8" and caulk), but a shoe or other trim can be installed there as well. Even if you have a 1/4" gap, trim could be applied and get better results (more labour) to cover the gap. I guess what I'm agreeing with Brian about is there is no technical reason for having to fill the expansion gap with anything, we just need to cover it, or conceal it to please the eye. Ideally, I like to lift the base, install the tile and refix the base down on top. Can't always do that.

Don't go the two step route with the caulk. It's a lot of time waiting between steps and the caulk will shrink 15% IF YOU GET A GOOD ONE. Pure silicones are an exception, but we won't even go there. In the world of painting, only pure amateurs who believe everything they read on a label, or crafty pseudo-professionals would load up a joint that size with caulk. If you must, use backer rod in the areas it's needed, that is an acceptable bridge. no, not JOHN bridge :) But I'll say his idea of braided clothesline roping is fine, so is a smooth hemp (gasp!). Fact is, after the caulk has set, we don't care so much about the undersides in this case.

Big stretch is a good product, colours are limited, but as I remember, it's paintable. So is any siliconized latex/elastomeric on the market and yes, I've painted caulk before as a last resort, but... I'm a painter.

I vote for shoe or other trim that's painted/stained to match the base/toekick. It'll be a good excuse for buying a brad gun. It'll also be faster. But as I said, I'm a painter! :) That's worse than being a Senator!

07-12-2002, 09:31 AM
I think that I'm gonna cover up my joints with my baseboard tile and not stuff anything down there except for the one joint between the floor tile and the baseboard tile. The only exception will be in areas where there won't be any baseboard; there I'll just use a bunch of color-matched caulk and keep a smile on my face while doing it. As far as the backer rod goes, I did see that stuff at HD, but it's very thick (1/2") and I'd have to spend a fair amount of time cutting it to the correct thickness in order to do its job but not be too obtrusive. Is that what you do, you cut it to size or just stick it in around the edges?

Thanks again for everybody's help here.


Sonnie Layne
07-12-2002, 09:53 AM
I think that's best. And it's OK. Now what to adhere the base tile to the base board with? I'd use mastic, it grabs fast and would be fine as we're not talking about "wet" areas here.

The backer rod is available from 3/8" to 3/4" thickness in 1/8" increments. HD won't have all that. Look up your local Benjamin Moore, Kelly Moore or (maybe) Sherwin Williams store and they'll at least not make you feel like an idiot for asking. Likely they'll have it. If not, ask a painter in your neighborhood (they're everywhere! they're everywhere!). She/He can tell you a likely place. waylay all that grief, just use clothesline cording/roping as John suggested. But, no I don't trim it to width. I just use the size about 1/8" larger and press it in lightly, don't cram it in there. As much as I'd like you to know your local retail paint store (vs the boxes), it may be just as simple to get the rope and it'll be fine.

best of luck,

07-13-2002, 10:44 PM
I found the 3/8 inch backer rod at Home Depot. I had to go on a treasure hunt to find it, but there it was in the paint section. I was able to stuff it into most of the joints around my kitchen. The trick was to stretch it out a bit and use a dull-edged screwdriver to get it in each joint. Some of the drywall at the base crumbled, but that made it easier for the backer rod to fit in there.

Next, I took some 3/8 inch spacers (the same ones I used for my tile) and put those at the point where the walls and cabinets met the floor. Using mastic, I butter-backed my tile baseboard and stuck it all around the room. being sure that it was square on those spacers.

Tomorrow I'm gonna caulk up all the spaces and with some luck, I'll be ready to finish up. I just hope I don't scratch up my new floor putting back the refrigerator, washer, dryer, sink, ....