Around my bathtub I have tile, and the old latex caulk where the tub and tile meet is cracked so I've removed all the caulk and am ready to put new silicone caulk down. However, I would also like to seal the all of tile using the 511 Impregnator sealant.

My question; Should I caulk around the tub first and let cure, and then do the sealant? Or the other way around?

Tub meets tile Tub

Tile meets floor. Ok to caulk over stuck grout? Should I re-grout this area instead? Floor

4 Answers 4


Those answers are all wrong, I've been a general contractor for thirty years and have had to repair other "experts" work on a regular basis.

  1. seal tile first.
  2. clean very well with acetone or lacquer thinner and let dry
  3. tape off both tub and sealed tile with blue tape so your completed job looks nice.
  4. fill the entire void with polyurethane such as sidewinder to completely fill void(do not grout there the movement of the tub WILL crack the grout).
  5. wipe it down with your finger dipped in paint thinner then pull tape and discard and wipe one more time with your finger to lay edges flat.

I haven't used the 511, but I would caulk first. Please actually forcibly fill the gap & don't "cover" the gap with a big caulk ramp or bead. Just the pin-strip of caulk should be left behind & mostly flush with the tile. Use a tub & tile caulk with or without silicone, don't use a straight silicone.

With the caulk applied first, the 511 can then seal everything & you won't have any chance of caulk adhesion problems. Sealers ruining or weakening caulk's seal is common. This also will help to extend the life & color of the caulk, possibly even boost the caulks mold & mildew resistance.

  • Thanks. The gap is somewhat large I'd say, about 1/4". I suppose I could just fill it with plenty of caulk and that should be fine I suppose?
    – v15
    Mar 26, 2016 at 5:15
  • Oh yeah, that's perfectly fine. If you can find a caulk color that's similar to the grout, that gap size should blend in to the rest of the floor very well. Either chisel out or chisel down any old grout in the gap. It doesn't have to be totally gone, it'll just look better if caulk can cover it for a uniform look.
    – Iggy
    Mar 26, 2016 at 11:44

To directly answer your question, I agree with Iggy, caulk first, then seal.

My long response is going to be different however:

Steps: 1) Clean excess caulk 2) Clean edges to be caulked with acetone (or if you have natural stone, methyl hydrate, or even weaker, alcohol if you have sensitive materials) 3) Allow a few moments for the cleaner to evaporate (prep for caulking) 4) Caulk using type 2 silicon, do not fill the gaps (more on this later) 5) Allow to caulking to cure and you're done

Why you use type 2 silicon: It has an additive to kill off mold and mildew, should the cleaning not have been amply thorough it will kill it off (avoiding one reason for caulking failure.

Why you caulk only two edges: If your house is constructed with wood (like most) there will be expansion and contraction, a major reason for caulking failure (the major reason is the surface is unfit for caulking) is because the caulking is attached to more than two surfaces, causing it to be pulled away from the perpendicular surfaces.

Why you don't use sealants: Unless you have natural stone, the grout is extremely resistant to staining (and has been for about eight years now) while tile doesn't stain (again, unless it's natural stone).


I disagree with the current answers. I have answered this for the bottom of the tile on the top of the tub and I find my answer to be the same here.

You grout to have a base. If your grout cracks then your caulk. If your grout never cracks (it happens) you don't need to worry about caulking. If your grout does crack your caulk will have a base, will last longer, and it will appear more uniformly. Takes literally 10 mins to grout that area including mixing in a throw away cup.

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