Brick and Mortar vs Caulk?

[Ben H]

I watched my first episode of Holmes Inspection yesterday. While I don't want to start a conversation about how the show again, they did something that I just don't quite understand.

Five year old brick home. Looked to be (from what I could tell from the .0001 sec camera shot) small cracks in the mortar around some windows of the home. The "brick guy" pulls his grinder out and grinds all the mortar out, tapes the seams and begins to fill the freshly ground joint with caulk.

My question is, why caulk? Why not tuck that joint back with properly mixed mortar?

Maybe it's a regional thing, eh?[] Perhaps my Canadian friends could ring in and give some insight on how things are done up north.

I suppose the repair would in fact keep the water out, but it looked like crap.

[kurt]

I and the guy I work with on occasion, have gone over this many times with the MIA and the BIA. Neither of them condones the method.

Having seen hundreds of jobs like this, I can say with absolute certainty that it does not work.

Also, almost no one knows what the right mortar mix is. The guy probably stuffed previous jobs with crappy bag mortar, found it didn't work, and now decides caulk is better.

[randynavarro]

At face value, caulk would do a better job at keeping water out than mortar, no?

Ultimately, I understand that there needs to be appropriate detailing under the masonry that would shed/divert/repel the water, but obviously that wasn't determined in that episode.

So would it be accurate to say that caulking is the quick fix?

Then, in a perfect world, that masonry work would have been peeled away completely and re-installed incorporating proper flashing, membrames, weeps, etc. Would that be accurate also?

[hausdok]

At face value, caulk would do a better job at keeping water out than mortar, no?

Ultimately, I understand that there needs to be appropriate detailing under the masonry that would shed/divert/repel the water, but obviously that wasn't determined in that episode.

So would it be accurate to say that caulking is the quick fix?

Then, in a perfect world, that masonry work would have been peeled away completely and re-installed incorporating proper flashing, membrames, weeps, etc. Would that be accurate also?

Hi Randy,

No, it won't do a better job unless they use backer rod in that joint before they use the sealant. It also won't help much if there are through-wall flashings over the windows and they haven't used end dams on the flashings.

Was it a home with vinyl windows? Vinyl expands at about twice the rate of aluminum, wood or fiberglass, so any mortar placed right up against the side of a vinyl window isn't likely to maintain any sort of seal very long.

ONE TEAM - ONE FIGHT!!!

Mike

[hausdok]

At face value, caulk would do a better job at keeping water out than mortar, no?

Ultimately, I understand that there needs to be appropriate detailing under the masonry that would shed/divert/repel the water, but obviously that wasn't determined in that episode.

So would it be accurate to say that caulking is the quick fix?

Then, in a perfect world, that masonry work would have been peeled away completely and re-installed incorporating proper flashing, membrames, weeps, etc. Would that be accurate also?

Hi Randy,

No, it won't do a better job unless they use backer rod in that joint before they use the sealant. It also won't help much if there are through-wall flashings over the windows and they haven't used end dams on the flashings.

Was it a home with vinyl windows? Vinyl expands at about twice the rate of aluminum, wood or fiberglass, so any mortar placed right up against the side of a vinyl window isn't likely to maintain any sort of seal very long.

ONE TEAM - ONE FIGHT!!!

Mike

[Ben H]

Was it a home with vinyl windows? Vinyl expands at about twice the rate of aluminum, wood or fiberglass, so any mortar placed right up against the side of a vinyl window isn't likely to maintain any sort of seal very long.

I can't say for sure, but I think so.

It wasn't the seal against the window on the show. There was some precast limestone arch in place around the window itself, the crack was between the actual brick of the home and that precast piece.

[kurt]

Well, caulk laid on masonry without a pre-treat of acetone or primer, and lacking backer rod to provide a bond breaker, the caulk will not work. Will not.

I've got a few thousand pictures to show it doesn't.

[Ben H]

Kurt, what does a "bond breaker" mean"?

[Marc]

Sealant that is properly applied to a crevice has an 'hourglass' cross section. The 2 flat sides of the hourglass make contact with the two opposing sides of the crevice. The other surfaces of the hourglass should not bond to anything. The backer rod is installed within the crevice before the sealant is applied to accomplish the hourglass cross section and to deny the sealant any chance to bond on the back side. This way, when the crevice widens or narrows with temperature/humidity or whatever, the waist section of the sealant will stretch or compress without breaking the bonds. If the waist section is too large, it becomes strong enough to break one or both of the bonds and the seal is lost.

Marc

[kurt]

Thanks Marc. That's basically it.

I also describe caulk as being "engineered" to bond to two surfaces; if you introduce a 3rd surface, it will pull to one side or the other, opening up a seam.

The bond breaker action of backer rod keeps the caulk off the "3rd surface", i.e., the bottom of the crack.

[Ben H]

I understand, thanks a bunch guys.

[randynavarro]

Maybe another way to ask the question: Is there a situation where good quality sealant (properly installed) is more water repellant than mortar?

[kurt]

Sure. We put Vulkem in stone coping joints, always with prep, backer rod, and tooled joints.

That's only in new construction. The old stuff does better with a soft lime mortar.