How should I fix the joint between my glass blocks?

[fioler&kaffe]

Hello!

I have a wall with glass blocks and the grout on the outside is starting to look quite depressing. What product should I use to repair the grout? Is it enough to remove the loose areas and fill in where it's missing, or should I try to knock out all the grout first?

Attaching photos.

Thanks!

 

[jonaserik]

The joint is loose against the glass, almost hanging in the air, it was created when the panes were set, through the joint that goes all the way between the panes. You must scrape out the joint at least 20 - 25 mm in between the panes and fill up with new joint all the way in against what remains between. So you can't just scrape out a little, then the new joint will come loose, nothing to hold it in place.

 

[fioler&kaffe]

The sealant is loose against the glass, kind of hanging in the air, it was formed when the panes were set, through the seal that goes all the way between the panes.
You need to scrape out the sealant at least 20-25 mm in between the panes and fill up with new sealant all the way to what remains in between. So you can't just scrape out a little, then the new sealant will come off, nothing to hold it in place.

Ok, I think I understand. What should I use for sealant?

 

[jonaserik]

Cement mortar A is used and also functions as grout. It is also important to dry/clean the glass, tidy up the joints a bit, before the mortar has fully set. The mortar should be pressed all the way to the bottom of the joint.

Maybe you can get a few kilos from a builder, they are only sold in 25 kg and that might be too much for you.
But read about cement mortar A, maybe you have another place where it can be used.
A difference in shade may occur between new and old, but you need to consider whether you should do everything at once and get the same shade on all joints.