Chicago Masonry Parapet Wall Repair and Rebuilding Services
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If you own a building in Chicago, IL., especially one with masonry walls and a flat roof, you may be familiar with a term “Parapet Wall Repair”. If you’re not, this article will answer following questions:
- What is the masonry parapet wall?
- What purpose it served in the past?
- Parapet wall structure
- How do we repair damaged masonry parapet walls in Chicago?
- How often and when the Parapet Wall should be evaluated?
What is a Parapet Wall? What purpose parapet walls serve?
Masonry parapet wall is a vertical extension of the building’s wall structure above its roofline, usually enclosing it. It can be also erected around the balconies and terraces as a protective barrier or serve as a firewall dividing two adjoining buildings or apartments. Sometimes used on buildings for purely aesthetic reasons. The main purpose of having parapet walls around your low slope roof is to prevent the roof’s edges from being uplifted by heavy winds. Parapet walls significantly reduce air pressure differences along the roof edges minimizing up-lifting force of the wind.
What purpose parapet walls served in the past?
In history, parapet walls played an important role in defending buildings and soldiers during military battles.
Parapet wall repair – structure
- Masonry parapet wall vulnerability
Because of a masonry parapet wall design, its top and both of vertical surfaces are exposed to elements. This makes the parapet wall vulnerable to deterioration accelerated by constant temperature changes, rain, and snow. If you’ve been in Chicago for a while, you already know how harsh our weather can be, and how much damage it can inflict on your building’s masonry parapet wall.
- Cracking sections of brick
- Spalling bricks
- Displaced bricks
- Displaced coping…
all those problems can be abated with preventive maintenance and Chicago masonry parapet wall repairs.
Masonry parapet wall repair – coping
Masonry parapet wall terminates with copings or caps and there are a few materials used for that purpose. The most common ones in Chicago are limestone, precast concrete, hard-fired clay, terra-cotta, and metal.
Although any of them will serve their purpose, if properly installed, it is highly recommended to use coping made from a material with thermal properties similar to the masonry parapet wall material.
On some older Chicago buildings, we can also find brick rowlock cap, however, using this type of a parapet wall cap in our climate, where freeze-thaw cycles occur for a few months every year, is not recommended. Exposed mortar joints on horizontal surfaces retain moisture which results in cracking and leads to frequent maintenance and repairs.
Why is the parapet wall cap/coping material choice so important?
Limestone, precast concrete, hard-fired clay, and terra-cotta have thermal properties almost the same as the brick or concrete block. This means that the cap/coping will be contracting and expanding as much as the brick wall underneath. This significantly extends lifespan of a parapet wall and minimizes its maintenance requirement.
With a variety of masonry parapet wall metal copings currently available on the market, installation of some of them in Chicago climate can be initially less expensive. However, due to the metal’s thermal expansion which is 3-4 times greater than brick or masonry block, water seepage through their joints may occur. If metal coping installation on a masonry parapet wall is what you’re considering, check with the product’s manufacture if such installation is recommended in our climate.
All types of masonry parapet wall copings must have adequate pitch and overhang to provide sufficient water drainage and to prevent staining of the wall beneath it.
The problem with “MUST have” is that sometimes proper water / moisture management of the parapet wall just doesn’t work with the architectural style / design of the parapet wall detail. In such cases we just have to compromise.
Masonry parapet wall repair – flashing
Top of the parapet wall flashing
- To minimize possibility of moisture and water penetration through the coping section joints, a continuous through-wall flashing membrane is required within the mortar bed immediately beneath the coping.
Roof to parapet wall flashing
- Often, when you look at the exterior portion of a parapet wall, the damage appears to be concentrated at the level of a roof behind the parapet wall. Wondering why? Could be a few reasons, one of them being a compromised roof to parapet wall flashing. Just like the flashing installed beneath the coping material, this one plays also an extremely important role in preventing the parapet wall from deteriorating, and the building’s interior from water damage.
When joining different materials on exterior, we have to take their thermal properties seriously. With constant exposure to elements, especially freeze-thaw cycles during the cold season, their contraction and expansion often leads to serious problems.
How do we repair damaged masonry parapet walls in Chicago?
A typical masonry parapet wall repair procedure:
- We remove existing coping (usually limestone or Terracotta tiles) – the copping is cleaned, stored, and then re-installed over the new parapet wall and new flashings. We replace damaged / unsalvageable copping.
- Existing roof flashing along the parapet wall is removed and new flashing installed once we rebuild the parapet wall.
- Inside layers of the parapet wall are dismantled to the flat roof level (in most cases), and rebuilding is performed using cleaned existing bricks in good condition / unsalvageable bricks are replaced with reclaimed Chicago Common Brick.
Chicago Common brick is recommended over the new bricks due to the properties of strength and durability it possesses.
- Face brick of the parapet wall is dismantled to the sound level, bricks are cleaned and reused in rebuilding process. Unsalvageable bricks are replaced with new matching ones.
How often and when the Parapet Wall should be evaluated?
We tend to forget about various things that exist around us and don’t require our everyday attention. We just don’t have time in our busy life for things like maintenance, and sometimes, it costs us dearly. So, open your phone calendar for the next year Mark “Check Parapet Wall” in your calendar for the next year:
- In the spring time to make sure there’s no damage resulting from the cold winter.
- In the fall, to prepare masonry parapet wall for the cold season if needed.
For more details about the masonry parapet wall and parapet wall repairs you may want to check this PDF – https://www.masonrytech.com/detailingmasonryparapets.pdf
Correcting small problems as early as possible can prevent extensive and expensive repairs in the future. Give us a call at 1-847-724-5600 for evaluation and a quote on a parapet wall repair. Always FREE for the property owners.