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While masonry is the best choice for longevity and durability for your home’s exterior, it does require maintenance to keep it looking as good as new. Small cracks if left unaddressed on exterior masonry, over time can spread leading to costly repairs and potential hazards. Kavanagh Masonry provides repointing and crack repair services in Ottawa and based on experience, listed here are some of the most common areas mortar cracks start on your home.
Foundation Settlement
On new construction homes, unless your home was built directly on bedrock, your foundation will inevitably settle as the soil below the foundation load deforms. The structure of your foundation and the quality of its construction should minimise this settlement process. However, this settlement can cause foundations to crack at high stress points and continue up through your brick/stonework typically in a stairway pattern to relieve this stress, meaning the crack runs up the brickwork like a set of stairs.
Below Window Sills
During heavy precipitation, a properly installed window sill with adequate slope will wick water away from your window and direct the water away from the masonry work below the sill if a proper Drip Key has been installed. This area is notorious for cracks for a number of reasons.
Expansion
Some window sills such as concrete sills will have a different expansion rate then the surrounding masonry. This can cause cracks to form over time if your concrete sill has been bonded directly to the masonry work below it. Typically, a waterproofing membrane is required between the sill and the masonry work below to prevent any moisture penetration to the surrounding masonry and it allows for the concrete to shift without cracking any adjacent masonry.
Poor Window Sill Material
Another more common problem for Ottawa window sills is the use of brick installed in a rowlock pattern as a window sill. For home builders, it is the most cost effective option however clay bricks do not respond well to prolonged exposure to moisture especially in the horizontal plane. During the frequent freeze thaw cycles in our harsh climate, brick window sills that have moisture in them will begin to crack and spall. These cracks, if left unaddressed, will spread over time to adjacent masonry work.
Window Sill Mortar Perps
This is another issue that can occur with stone/manufactured stone sills that require one or more vertical mortar joints to join multiple smaller sills together. Over time water can get into these exposed joints and cause cracking. This is a crack that requires maintenance over the life of your home and is a common repoint repair in Ottawa.
Garage Door & Window Lintel Angle Iron Corners
This is one of the most common areas that requires repairs over time. In the absence of a masonry arch, steel angle iron is commonly used to span windows, garage doors, man doors and other openings.
Rust
The use of angle iron for this has been around for several decades and it typically comes with a red coating to prevent rusting. Unfortunately steel will begin to rust over decades of exposure to the elements. Rusting at the corners where the lintel is embedded into the masonry can begin to rust which can cause expansion. This rust heaving can cause surrounding masonry work to crack. The only solution for rusting lintels is replacement.
Thermal Expansion
Another common issue with steel angle lintels is thermal expansion. The steel has a different expansion rate than masonry which can cause the masonry to crack where the angle iron bears its weight on the masonry jambs.
Weight
Masonry work, whether brick or stone, is incredibly heavy. Over longer opening spans, such as garage doors, the weight of the masonry above the opening can cause stress on the steel angle. This can cause the lintel to begin to sag slightly over time in the middle. Under this stress, the central masonry work or where the Keystone is located over a large span opening is where stress cracks can start to form as it is the least supported.
How To Repair
Remove the Cause of Stress
To properly repair common masonry cracks, it is important to first resolve the major issues that caused the cracks to first if at all possible. This means replacing rusted out old steel angle lintels or having new custom window sills installed such as the Sills Installation Service we offer at Kavanagh Masonry. Minor foundation cracks should be cut open and patched with a Sand Mix concrete product to prevent water/moisture penetration.
Repoint
For the cracked masonry itself, it is highly advised to get the work done by a licensed masonry contractor that specializes in restoration.
At Kavanagh Masonry our process is always to grind out cracked mortar joints to a minimum depth of 20mm from the masonry face and repoint with the right prescribed mortar based on the masonry units and function of the masonry structure. Our mortar matching and jointing process will allow the repair work, once fully cured, to blend in to your existing masonry work as best as possible. For more information about crack repair or our Repointing services, please visit our Ottawa Repointing Service page or reach out on our Request a Quote Page to get your free estimate process started.
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