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What is Tuckpointing

What is tuckpointing? We’ve all heard the term “tuckpointing“. In Chicago, it’s the standard designation for any method of smearing cement on masonry walls. But,…

Fake Stone Veneer and Avoiding Failures with Manufactured Stone

Fake stone veneer, often referred to as Adhered Concrete Masonry Veneer, the material for fake stones barely existed 10 years ago. Now, it’s on…

No Kickout Flashing | Design Problem Detail

Here’s one that’s kinda sneaky. When an eave dead ends into a wall along with a gutter, guess what happens? Water rushes past the…

What is tuckpointing? We’ve all heard the term “tuckpointing“. In Chicago, it’s the standard designation for any method of smearing cement on masonry walls. But, almost no one knows what this word really means. Real tuckpointing is a method for striking mortar joints between bricks of different sizes and shapes to make them appear uniform. There…

Fake Stone Veneer and Avoiding Failures with Manufactured Stone

Fake stone veneer, often referred to as Adhered Concrete Masonry Veneer, the material for fake stones barely existed 10 years ago. Now, it’s on millions of homes. The material is in the class of claddings called “Rain Screens”. Rain screens allow water to pass through the surface; that water is collected in a drainage plane…

Masonry And Water Management, Part I

f one is going to divide wall systems into two basic types, they would be barrier and water managed. Barrier systems, as the name implies, are wall assemblies that are prophylactically impervious to water entry. Water managed walls, as you’re probably already guessing, take on some amount of moisture and through the magic of well…

Masonry And Water Management, Part II

In some areas of Europe, they make it 6″. In Chicago, due to developers proclivity for increasing all available square footage in their projects, this space has been smashed down to an inch or less. A 1″ cavity is not large enough for the mason to clear out excess mortar, and that excess mortar can…

The Early Years of Home Inspection

It’s sure different now than it was 30 years ago. Back then, home inspections were brand new, standards of practice and reports were marginal to lousy, and only an approximate 15% of houses were inspected as part of the purchase procedure. Home inspections, as a standard operating procedure, were not a component of real estate sales….

No Kickout Flashing | Design Problem Detail

Here’s one that’s kinda sneaky. When an eave dead ends into a wall along with a gutter, guess what happens? Water rushes past the gutter and soaks the wall. If one includes a nice “hole” in the wall in the form of a light fixture, we’ve now got a sluice gate into the wall. The…

Mold Testing Facts and Fallacies

Mold is not good. It can cause substantial problems, both health and building related. That said, let’s get to facts. There are over 100,000 mold types with probably another 100,000 that we haven’t identified yet. Mold is everywhere. There are millions, or hundreds of millions of mold spores, on every surface on the face of the Earth….

Aluminum Wrap on Steel Lintels / Big Mistake

I see it everywhere. Otherwise nice and well maintained buildings that have had their windows replaced, and the window installer wraps the structural steel lintel with aluminum. Ouch. When you wrap lintels in aluminum, they remain saturated. Lintels are supposed to drain and not sealed up with aluminum or caulk. It dramatically accelerates the deterioration…

How Bad can Lintels Get?

This is how bad lintels can get. And these pictures show why it’s a really bad idea to wrap lintels with aluminum.

A Brief History of What Happened and Why

This is a companion piece to the “This Is Not My Beautiful House” post. Both are talking about the same thing only coming at it from a couple different directions. uilding stuff was pretty much the same for a few thousand years. Old growth timber, skin fired bricks and lime mortar, maybe adobe in warm…

What is Tuckpointing

Kurt

January 20, 2018

Tuckpointing is an old method of finishing mortar joints between bricks.

Real tuckpointing is a method for striking mortar joints between bricks of different sizes and shapes to make them appear uniform. There was also a method of applying a decorative “tuck” of different color mortar between bricks (or stone, block, whatever). Go to Instagram and find “@tuckpointer”. That’s tuckpointing.

The term tuckpointing, as used in Chicago, is completely bastardized. It describes any alteration to any masonry whether it’s smearing cement on walls, rebuilding walls, or otherwise fiddling with old masonry in any manner one can imagine. Those things are not tuckpointing.

Not Tuckpointing!

: Smearing cement on a parapet wall is not tuckpointing!

: Mounding up cement in a convex bulge is not tuckpointing!

: Smearing cement on completely damaged brick is not tuckpointing!

In addition to using the wrong terms, everyone uses the wrong cement. Everyone. And that’s where some real problems come in. If you are anticipating repairing the masonry on your old Chicago building, you need to know a couple very basic things most masons won’t tell you.

Mortar technology is a more than two millennia old, dating back to ancient Greece and Rome.

Old mortar uses hydraulic lime as the primary binder. Specific types of lime, upon exposure to atmosphere (specifically carbon dioxide), create calcium carbonate in a process called carbonatation. (Not carbonation; that’s how fizzy drinks are made.) The calcium carbonate created by carbonatation binds the material together. Lime based mortar is soft, “flexible”, and allows moisture to breath in and out of the masonry. Lime mortars are soft and expand and contract at similar rates as the older soft brick. Cracks that naturally occur in any masonry are minimized by the similar rates of movement. Carbonatation also heals any micro cracks in a process called autogenous healing, Latin for “self healing”.

New mortar uses Portland cement as the binder. Portland cement is hard, brittle, and water resistant. It doesn’t breath, there’s no carbonatation, and it’s not self healing; cracks in modern mortar let lots of water into the wall. Water management in new masonry is accomplished by installing flashing that collects water and diverts it back to the exterior thru weep holes.

Here’s the problem…..

When new hard Portland cement is laid over old soft lime mortar, it holds moisture in the wall.

Water retained in the wall causes damage from freeze and thaw cycles. In addition to damage from freezing and thawing, using the wrong mortar can damage masonry in other ways.

Old brick expands and contracts at different rates than the new mortar, so much so that the new hard mortar causes the face of the old brick to cleave off in a process called “spalling”. Spalling exposes the soft inner core of the brick, creating more moisture absorption, resulting in more spalling. The end result is accelerated deterioration of the masonry.

: Massive damage caused by smearing the wrong mortar on soft brick.

: The original mortar is still there, but the brick is so damaged it doesn’t matter.

: This area fell apart, and the mason though smearing even more cement on it would somehow make it better again. Nope.

Why don’t masons use the right mortar?

Modern masonry trade practice in Chicago, with the exception of a small number of specialty practitioners, completely eschews using traditional lime mortar like that used in all our houses. The defacto material for every job is modern Type N mortar.

There are many reasons, some obvious and other’s not so much. The obvious stuff is, there’s no useful education. The trades shot themselves in the foot years ago with short sighted objectives in their trade schools (see “A Brief History of What Happened and Why”). And, the old guys that knew this stuff died off years ago without any tenable pathway for sharing their knowledge.

The less obvious stuff isn’t actually all that surprising. Lime mortar is more expensive. It takes more time to apply correctly. Lime mortar requires a much higher skill set; it requires training and experience to use effectively (again with the Brief History of What Happened…..).

Masonry is a tough gig, maybe the toughest. It’s not unnatural to want to go with materials that are easier to work with and lend themselves to higher production volume. Unfortunately, using the wrong material leads to conditions the opposite of what the repair is supposed to accomplish.

Finally, for all those buildings that have been smeared with the wrong mortar and still seem to be working OK……..well, OK. Sometimes smearing cement on old masonry “works” to the extent it doesn’t flake off. That’s a large indication that the wall didn’t need repointing in the first place. Take a look at the featured image for this post; it shows hard Type N mortar laid over beautiful lime putty. See what it does? It flakes off.

Here is a great article describing lime mortar and old masonry. Go here, here, and here for additional info about lime mortar. Here, here , and here is where you can find products and technical support.

After you’ve read the articles and have a solid background in lime based masonry products, come over the House Talk to ask questions about your particular building.

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Featured posts

What is Tuckpointing

Fake Stone Veneer and Avoiding Failures with Manufactured Stone

No Kickout Flashing | Design Problem Detail

What is Tuckpointing

Fake Stone Veneer and Avoiding Failures with Manufactured Stone

Masonry And Water Management, Part I

Masonry And Water Management, Part II

The Early Years of Home Inspection

No Kickout Flashing | Design Problem Detail

Mold Testing Facts and Fallacies

Aluminum Wrap on Steel Lintels / Big Mistake

How Bad can Lintels Get?

A Brief History of What Happened and Why

Resources