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MASONRY & WALLS

Chicago bungalows were built with high quality brick and limestone that, unlike new building materials, can easily last another hundred years if properly cared for.

Brick & Limestone

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Common problems affecting your masonry:

 
Efflorescence
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  • A white powdery substance found on the face of your brick. This is actually salt that has migrated to the surface, usually due to repointing a wall with mortar that is too hard for soft historic brick. Water must be allowed to evaporate through mortar. If the mortar is too hard, water is forced into the brick and salts from the clay are brought to the surface as it evaporates.

 
Spalling
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  • If you notice efflorescence, the salts can be dangerous if they remain on the masonry and crystallize beneath the surface as subflorescence. Subflorescence may eventually cause the surface of the masonry to spall (particularly if a water-repellent coating has been applied, which reduces the flow of moisture out from the masonry's subsurface). The front enamel of your brick will fall off, exposing a softer center that will continue to
    quickly deteriorate.

 

Both of these conditions are typically caused by improper repointing of brick.

 

Old brick is softer than new brick, and the mortar used for repointing should also be softer, meaning it should have a higher lime content. If a hard mortar made with Portland cement is used, water can't evaporate and instead will be forced into the brick. Unfortunately, most masons default to a Portland mortar because it is commonly used on new construction.

 

Be sure to ask your mason or mortar supplier for a lime-based mortar.

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  • Sealing your historic masonry is NOT recommended. Although many of the newer water-repellent products are more breathable than their predecessors, they can still damage masonry that contains salts because they limit the flow of moisture and expedite deterioration.​

 

Deteriorated Mortar & Repointing Your Walls

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Your original mortar has lasted a century but is meant to be the sacrificial element of your masonry wall. If there are gaps in your mortar (especially common on the brick wing walls flanking your front stairs), it may be time to repoint.

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  • Remove mortar carefully and keep in mind that you only need to chip out your joints 3/4” in from the edge of the brick.

  • Only use a power saw on horizontal joints. Vertical joints are too short and the blade will cut into the brick. Use a chisel to chip out the vertical joints.

  • Collect your dust while you remove the mortar. The city requires it and it really does make a huge mess.

  • Use an appropriate lime-based mortar

  • Match the color of your mortar

 

Cracks at Lintel

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  • Cause: Your steel lintel has rusted after decades of taking on moisture. When steel rusts,it expands, causing cracks to form.

  • Remedy: Replace your lintel.

 

A typical indicator that it’s time to replace your lintel is a zigzag pattern at the corners of your windows.

 

To replace:

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  • Carefully remove brick above window

  • Prime new steel lintel with rust inhibitor and paint

  • Install continuous flashing with drip edge and end dams

Cleaning Your Brick & Limestone

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Inappropriate cleaning and coating treatments are a major cause of damage to historic masonry buildings. While the treatments may be appropriate in some cases, they can be very destructive if they are not selected carefully.

 

Masonry cleaning methods are divided into three major groups:

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  1. Water methods soften the soiling material and rinse the deposits from the surface.

  2. Chemical cleaners react with and soften soiling material or paint, then are rinsed off
    with water.

  3. Abrasive methods, such as blasting with grit or the use of grinders and sanding discs,
    mechanically remove the soiling material or paint (and usually some of the masonry
    surface, causing damage down the road).

 

It is always best to go with the gentlest cleaning process available.

 

Once the enamel of your brick or limestone is compromised, the masonry unit cannot be saved.

 

Protecting Your Masonry

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  • Clean your gutters and make sure water is carried away from your house

  • Make sure the top of your foundation is never near the soil line or grade
    to avoid pulling water up through your masonry

  • Make sure your sidewalk, gangway, and the soil around your home pitch
    away from your foundation and keep in mind that over time, soil will erode
    and need to be built back up

  • Remove ivy and vines, as they will hook into your mortar and pump water into your wall

  • Never ever sandblast your brick or limestone

  • Clean your masonry with a gentle power washer set to 200 to 600 psi

  • Do not seal brick

  • Use proper mortar (higher lime content)

  • Do not paint your masonry

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