Parapet Problems & Solutions

Question: What is a Parapet?

Answer: A wall extending above a roof.

Parapet Walls w Block Caps

Custom home with different heights of parapet walls

Santa Fe Home - Parapets

One of the most common styles of parapet wall

Santa Fe - With Tall Parapet Walls

Santa Fe again, but with much taller parapet walls.

2 Kinds of Typical Parapet Problems

Most parapet wall or parapet tops problems fall into one of two catagories. 1) Cancer, or 2) Normal Cracking. These two catagories are for descriptive purposes and your not likely to find the same wording used elsewhere.

1) Cancer (also known as bad lath)

Starting with the more dramatic and more expensive to repair. Parapets with "Cancer" are more frequently referred to as having rotted or rusted metal lath. Lath is to stucco what bones are to a human. And when a human has osteoporosis the bones break easily. If the lath was defective, as was common for many years, then the stucco it's supposed to support ends up falling apart. Only instead of the example with a human having osteoporosis, now imagine the bones dissolving completely. When the lath rusts away and vaporizes, stucco falls apart.

The photos below show lath problems. Think of lath as a type of chicken wire, or mesh.

Rotted Lath

In my opinion virtually every home in Barrio Cental, Tucson had defective lath in the parapet tops.

Closer Look - Rotted Metal Lathe in Parapet

A close up picture of the previous picture with a loose piece removed. The rusty diamond patterns are whats left of a piece of stucco lath.

Significant Parapet Top Problems

Typical picture of what rotted "Chinese Metal" lath does to parapet tops stucco.

Typical "Cancer" rotted lath issue

This photo shows the most common of the rotted lath issues we see. Its mainly on the parapet top, and the broken stucco is sitting there.

2) Typical / Normal Parapet Top Cracking

Now that we've seen the dramatic, it's time for the common - and not nearly as expensive regular parapet stucco cracks.

All stucco cracks some, and parapet tops are like your nose and ears in that the sun is harder on them than other parts. An east or west wall on a house might get six hours of sun a day. Parapet tops frequently get most of the suns rays from near sunrise to near sunset. This is frequently double the exposure of other portions of the home out office.

Complicating the natural aging process, water vaor inside the stucco seems espically drawn to the parapet tops. Most likely any water not draining down through the stucco on the wall naturally ends up getting heated, forming vapor and moving upwards. Once at the parapet top it collects. We've broken open stucco on parapet tops months after the last rain, and they were damp

Stucco Parapet Top Repairs

Typical picture of a parapet top stucco repair project, and just into prepping the home for a exterior paint job.

Raw Block

Raw Block is porus and soaks up water. Soak up enough water and it comes out in the house or blisters the roof coating.

Rusting lath in Stucco

Usually the damaged stucco is on the parapet tops, however it can creep down onto the side.

3-of3

Another picture of rotted "Chinese Metal" failing, and the causing the stucco to fail

As the Owner, I've spent quite a bit of time trying to determine the best way to communicate the following information. In the end showing a handful of pictures first, with brief explanations, is the best way to get you as a consumer up to speed on the parapet top functionality and repair.

Below are a several pictures of buildings with parapet walls and tops. As a note, if there is a parapet wall then there is a parapet top. Another note. Since this wasn't learned in school but by figuring it out on jobsites, our termonology is made up. Don't expect even other contractors to immediately know "chinese metal" or "parapet top"

Amazing Home, Rotted Lath

One of the prettiest homes I've ever been to. But, it had alot of parapet problems.

Typical Southern Arizona Parapet Problem

Probably the most representative of an "average" "Chinese Metal" parapet top

Inside a Parapet Wall

The picture to your right or below, depending on your viewing device, shows a drawing I made of a typical parapet wall on a stucco home or office building.

This drawing is made from the perspective of being a bit above the roof and wall and looking slightly forward and down. The various layers are peeled back to show deeper and deeper into the wall / roof.

The first layer is wood. Wood walls and wood roof. then 2) Rolled Roofing. The wall is made of wood, then 2) tar paper (to keep out water). 2) Foam for insulation. 3) Lath or chicken wire to support the stucco. 4) Stucco.

Many people don't realize stucco walls are designed knowing water will get into them. When water gets into the stucco it is supposed to be stopped by the tar paper. After being stopped at the tar paper, it flows downard and comes out through the Z-metal flashing onto the roof. If it's on the other side of the wall, it flows downards and drains out of the stucco through a weep screed. The weep screed is a thin piece of metal which is usually in the stucco and about four inches off the ground.

The absense of a weep screed (drain at the bottom of the wall) is discussed elsewhere in this site.

If a home was constructed with non-defective materials and built correctly, there will still be some cracking on parapet tops. This is most pronounced on parapet tops at corners. (Engineering trivia - cracks like corners and that's why windows in jetliners are now round or oval) But corners on Santa Fe homes and homes in general are hard to avoid.

Typical corner crack

Common, and not a big deal.

Parapet top crack

1-of-2

Need two more pics of corner cracks

2-of-2

Need two more pics of corner cracks.

The absense of a weep screed (drain at the bottom of the wall) is discussed elsewhere in this site.

1-of-2

Neecks

Typical corner crack

Common, and not a big deal.

Parapet top crack

1-of-2

This is a wider card with supporting text below as a natural lead-in to additional content. This content is a little bit longer.

2-of-2

This card has supporting text below as a natural lead-in to additional content.

Card title

This is a wider card with supporting text below as a natural lead-in to additional content. This content is a little bit longer.

Last updated 3 mins ago

Card title

This card has supporting text below as a natural lead-in to additional content.

Last updated 3 mins ago

Card title

This is a wider card with supporting text below as a natural lead-in to additional content. This card has even longer content than the first to show that equal height action.

Last updated 3 mins ago

Card title

This is a wider card with supporting text below as a natural lead-in to additional content. This content is a little bit longer.

Last updated 3 mins ago

Card title

This card has supporting text below as a natural lead-in to additional content.

Last updated 3 mins ago

Card title

This is a wider card with supporting text below as a natural lead-in to additional content. This card has even longer content than the first to show that equal height action.

Last updated 3 mins ago

Typical corner crack

Common, and not a big deal.

Parapet top crack

1-of-2

This is a wider card with supporting text below as a natural lead-in to additional content. This content is a little bit longer.

2-of-2

This card has supporting text below as a natural lead-in to additional content.

Card title

This is a wider card with supporting text below as a natural lead-in to additional content. This content is a little bit longer.

Last updated 3 mins ago

Card title

This card has supporting text below as a natural lead-in to additional content.

Last updated 3 mins ago

Card title

This is a wider card with supporting text below as a natural lead-in to additional content. This card has even longer content than the first to show that equal height action.

Last updated 3 mins ago

Card title

This is a wider card with supporting text below as a natural lead-in to additional content. This content is a little bit longer.

Last updated 3 mins ago

Card title

This card has supporting text below as a natural lead-in to additional content.

Last updated 3 mins ago

Card title

This is a wider card with supporting text below as a natural lead-in to additional content. This card has even longer content than the first to show that equal height action.

Last updated 3 mins ago