Cracking glass blocks - Contractor Talk - Professional Construction and Remodeling Forum

CLYDE · 12-23-2008, 09:46 PM

A friend of mine has glass block wall for his shower, and he has about a half dozen that are cracked. Also his metal tabs are rusting also. what causes this?

MALCO.New.York · 12-23-2008, 10:33 PM

A Noob who starts out with "A friend of mine....."

And YES ! I stolded this image!!!

SLSTech · 12-23-2008, 11:26 PM

Quote:

Originally Posted by MALCO.New.York

A Noob who starts out with "A friend of mine....."

And YES ! I stolded this image!!!

That image is to good to not use in a situation like this...

Home inspector who doesn't understand that rust is caused by water & metal interacting - I think you may be in the wrong forum

CLYDE · 01-02-2009, 01:57 PM

Quote:

Originally Posted by SLSTech

That image is to good to not use in a situation like this...

Home inspector who doesn't understand that rust is caused by water & metal interacting - I think you may be in the wrong forum

Wow, you guys are intelligent

I guess I should have asked what are "contractors or other S.A's are using to keep the water from infiltrating the mortor. Is there some kind of water repellent being applied or is it just a diff type being used to protect the metal from the moisture?

But the basic and first question was not answered. Has anybody seen cracked glass and what could be the problem. temp,loads..etc?

NOOB is spelled newby, by the way

MALCO.New.York · 01-02-2009, 02:01 PM

Quote:

Originally Posted by CLYDE

?

NOOB is spelled newby, by the way

http://dictionary.reference.com/browse/noob

Care to try again?

Tscarborough · 01-02-2009, 02:08 PM

In a non structural wall, cracked glass block mean physical abuse, i.e. some beat on them with something. Glass block mortar has integral waterproofing.

concretemasonry · 01-02-2009, 03:01 PM

Mortor is actually spelled MORTAR.

There are specific types of mortar that you friend should have used. Also, glass blocks need the proper mortar and cushioning to prevent the concentrated loads that can cause cracks, since they have been brittle for the last 70-80 years of use.

The blocks or mortar does not rust. It is the attachments and any embedded materials.

gallerytungsten · 01-02-2009, 03:03 PM

Perhaps the surfaces the blocks are set against wasn't prepared correctly, letting water in.

But I suspect the house settled, the mortar cracked open, water penetrated, etc.

SelfContract · 01-02-2009, 03:13 PM

Expansion in joints caused cracks. When water get in join, and temperature make it frozen/iced, the forzen water pockets/volumes will expande, forcing adjacent blocks of joint to crack. Rusty metal also expands joint.

Burby · 01-02-2009, 03:49 PM

Quote:

Originally Posted by CLYDE

A friend of mine has glass block wall for his shower, and he has about a half dozen that are cracked. Also his metal tabs are rusting also. what causes this?

This is just a "test", yeah I bet that is what he is doing, to see if we know this can happen when improperly built..

And for just 3 easy payments of just $49.99 I can offer a free "fix" for "YOUR" freind..

Ms. Fix-It · 05-25-2009, 01:20 PM

Cracked blocks sounds like settling, which would also explain the mortar being compromised, allowing rust...

strathd · 05-25-2009, 01:25 PM

BB guns

skyhook · 05-25-2009, 03:29 PM

Quote:

Originally Posted by Ms. Fix-It

Cracked blocks sounds like settling, which would also explain the mortar being compromised, allowing rust...

I agree, settling could be the culprit since double framing members are required to support glass block. The rest about water in the cracks too. Still don't see how the blocks cracked since they are literally bullet proof.

WarriorWithWood · 05-25-2009, 04:26 PM

Quote:

Originally Posted by MALCO.New.York

And YES ! I stolded this image!!!

Where have I seen that before.....Hmmm.

EIDOL · 05-25-2009, 04:43 PM

someone used sand with iron in it then put way two much portland that made the mortar harder than the glass a home owner i would guess
here in annapolis with lot of old homes the bricks are soft so if you put to much cement it will blow the face off or cause cracking

Darwin · 05-25-2009, 05:24 PM

Quote:

Originally Posted by CLYDE

A friend of mine has glass block wall for his shower, and he has about a half dozen that are cracked. Also his metal tabs are rusting also. what causes this?

Maybe wackin' off too wildly in the shower caused this, I dunno..

glassman · 05-25-2009, 07:08 PM

glass block is installed either with mortar or silicone,older installs used metal strips that acted as spacers that also locked each block to the next.
newer installs,mostly shower enclosures use silicone with mildew inhibitors,and the metal strips were replaced with plastic chairs.
silicone provides a cleaner joint,is easier and less time consuming,provides a more water resistant seal.
as other posters have stated water infiltration has caused the rust problems,also as a metal corrodes or rusts,it will also swell somewhat,causing breakage. settling of the home will also cause breakage as abuse or impacts will too. using mortar or silicone for sealing is fine,the main thing is to leave a specified gap at the top,hidden by molding or trim,thus eliminating stresses from compression,most install prohibit the glass block wall from being a load bearing wall. you can go to the pc glass block website for install instructions.
on a side note glass block has been reduced in depth allowing installs into vinyl window frames,allowing reduced weight for new construction windows for exterior wall applications for privacy in bath locations.

jarvis design · 05-25-2009, 09:16 PM

Quote:

Originally Posted by Tscarborough

In a non structural wall, cracked glass block mean physical abuse, i.e. some beat on them with something. Glass block mortar has integral waterproofing.

Not to be a b*tch, but, Glass Block mortar is modified (ie. polymers), but is no where near being waterproof.

skyhook · 05-25-2009, 11:06 PM

Quote:

Originally Posted by glassman

silicone provides a cleaner joint,is easier and less time consuming,provides a more water resistant seal.

BS

naptown CR · 05-26-2009, 12:55 AM

Quote:

Originally Posted by Darwin

Maybe wackin' off too wildly in the shower caused this, I dunno..

That depends on the height of the crack

Quote:

Originally Posted by glassman

glass block is installed either with mortar or silicone,older installs used metal strips that acted as spacers that also locked each block to the next.
newer installs,mostly shower enclosures use silicone with mildew inhibitors,and the metal strips were replaced with plastic chairs.
silicone provides a cleaner joint,is easier and less time consuming,provides a more water resistant seal.
as other posters have stated water infiltration has caused the rust problems,also as a metal corrodes or rusts,it will also swell somewhat,causing breakage. settling of the home will also cause breakage as abuse or impacts will too. using mortar or silicone for sealing is fine,the main thing is to leave a specified gap at the top,hidden by molding or trim,thus eliminating stresses from compression,most install prohibit the glass block wall from being a load bearing wall. you can go to the pc glass block website for install instructions.
on a side note glass block has been reduced in depth allowing installs into vinyl window frames,allowing reduced weight for new construction windows for exterior wall applications for privacy in bath locations.

I agree with this

Quote:

Originally Posted by skyhook

BS

I do not agree with this mortar is not waterproof silicone may not be also but is markedly more moisture resistant than mortar.

Quote:

Originally Posted by EIDOL

someone used sand with iron in it then put way two much portland that made the mortar harder than the glass a home owner i would guess
here in annapolis with lot of old homes the bricks are soft so if you put to much cement it will blow the face off or cause cracking

We are talking about glass block not brick.

I recently had a glass block window I took out and replaced with an acrylic block awnng window because several of the blocks were cracked. This also happened to be in a shower. There was double framing at the base and 1/2" of space between the header and the block. the cracked block were in the center of the unit. I know that it takes a lot to crack these things I wonder if it was thermal shock as they are not tempered.