Bumps on VCT

[Darol Wester]

OK. I didn't see a VCT catagory so it gets thrown in with vinyl. While working at a school, I was shown this by the janitor. The tile is around 6 years old. He strips and finishes it yearly and the bumps are there after stripping also. I scraped some of the bumps and it appears to be tile material. It's kinda randomly scattered throughout the halls. What would be the culprit here? I was thinking that someone may have gotten something on it before one of his earlier finishes.

 

[Floorist]

I've seen this Darol. I always assumed something was leeching thru the concrete into the tile.

 

[Darol Wester]

In the past, some have explained it as efflorescence, but it's usually a different type of lump than these. I've suggested that he pull one up and see if there's anything obvious from the back. If not, it's gotta be an issue with the surface of the tile or contamination. Wouldn't ya think?

 

[Floorist]

I think you are right. Only way to be sure is to pull one. Hope they have replacements.

 

[DarisMulkin]

Have you tried scraping any of it off to see if it is topical?

Daris

 

[Twomly]

That looks to me to be surface blistering. Usually atributed to manufacturing fault. I have seen new tiles with this in and cast them to one side to not be used. They may not have spotted it during installation or they may have been so small at that time and not as in your face obvious as they are now.

 

[Incognito]

That's "blistering" alright and it's the result of some caustic chemical. Other than peeling up a tile and ruling out alkali (usually the culprit) I don't know how else you could determine if the caustic chemical is attacking from below, within or something that was dripped from above.

 

[Ernesto]

looks like fisheyes.

 

[Darol Wester]

Have you tried scraping any of it off to see if it is topical?

Daris

Sorry Daris, somehow I missed this. As mentioned in my first post, I did scrape some of it off and it seemed as though it was the tile material I was scraping off.

I was down there again today and the janitor said that all the tile was installed at the same time. Both in the multi-purpose room and the halls. The tiles are different in both of these areas and the ones in the MP room never produced the bumps, which brings me to believe that the tiles in the hall are probably the culprit. Both are Mannington but different colors. The guy said that these bumps started out as just a few in a year or 2 and has progressed to almost everywhere in 6 years.