Grout cracking on fireplace


  #1  
Old 06-15-15, 01:53 PM
C
Member
Thread Starter
Join Date: Nov 2013
Location: United States
Posts: 49
Received 0 Votes on 0 Posts
Grout cracking on fireplace

Hi guys,

Long story short, we had our fireplace done about 2 years ago. It was great, however after a year or so one of the tile pieces separated (probably due to the frame inside shifting) and so we had to redo that section of the fireplace.

I am using the same exact grout as was used before, on the same exact spots; however I must be doing something different than 2 years ago. The grout didnt crack before, but now I am getting cracks all along the newly laid grout about 24 hours later. What am I doing wrong? It is the "add water" type grout, am I adding too much or too little? Any tips on what I can add to it to make it more flexible and crack resistant? Can I mix in caulk?

Whats strange is that those vertical joints are using same exact grout from same exact mixing, they are same-ish size and have no issues with cracks.

Here is a picture:

Name:  grout.jpg
Views: 347
Size:  22.4 KB
 
  #2  
Old 06-15-15, 04:02 PM
czizzi's Avatar
Member
Join Date: Jul 2007
Location: USA
Posts: 7,388
Received 15 Votes on 13 Posts
Grout cracking and tiles falling off can be related or totally separate. How was the fireplace prepared for tile? Was cement backer board put over the framing/plywood? Were the seam between the pieces of backer board taped and mudded? Was thinset mixed from a bag used or was a ready mix from a tub used to adhere the tile to the substructure?

Regarding fresh grout cracking, aside from movement or stress - most likely you mixed your grout with too much water.
 
  #3  
Old 06-15-15, 04:06 PM
C
Member
Join Date: May 2015
Location: USA
Posts: 3,138
Received 2 Votes on 2 Posts
The cracking probably indicates movement between the two surfaces. Not sure why it doing it now and not before. May be because the two different types of tiles expand/contract differently. If the structure underneath isn't rock solid you are going to get cracking. I'd treat it like the corner of a shower and caulk it instead of grouting it.

Good luck!
 
  #4  
Old 06-15-15, 04:20 PM
C
Member
Thread Starter
Join Date: Nov 2013
Location: United States
Posts: 49
Received 0 Votes on 0 Posts
The grout is in a bag, and was not pre-mixed. I am not too concerned with tile separation anymore, when we put it on originally we only secured the inside beam on the ends, so over time (perhaps from wood dying more or humidity) the beam warped a few millimeters, which I think is what caused the tile to separate. This time I secured it in 4 places including the center, this should keep the beam from moving.

Going to try and mixing with less water, if that doesnt work then Ill try caulking. Whats weird is that it worked before for 2 years with no cracks or anything, from same mix bag. Wonder if last time I used less water and thats the key.
 
  #5  
Old 06-15-15, 05:38 PM
czizzi's Avatar
Member
Join Date: Jul 2007
Location: USA
Posts: 7,388
Received 15 Votes on 13 Posts
Unsanded grout is funny, the difference between too much water and not enough sometimes is a matter of drops. Then again, if you are not used to using it on a regular basis you know not what you are looking for in texture and consistency. Shoot for thick peanut butter when mixing and you should be fine.
 
  #6  
Old 06-16-15, 12:11 PM
C
Member
Thread Starter
Join Date: Nov 2013
Location: United States
Posts: 49
Received 0 Votes on 0 Posts
Thanks for all the replies guys. Last night I removed the old grout and redid it with as was recommended below "Peanut Butter" consistency mix. This morning (about 16 hours later) no cracks... last time there were cracks by this time... crossing my fingers
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description: