Feature Project – Impact on the Grand
One stormy day along the banks of the Paris on the Grand River a large mass of ice or a floating log tore into the century old stone wall, knocking loose large stones and leaving the wall in danger of collapse.
This was the situation Heritage Brick and Stone was presented with when they arrived on site on an early Spring morning. It was apparent that during high water levels an area the size of a small vehicle was missing from the face of the original rubble stone wall bordering the river. The challenges were unique with how to properly time and complete this project; working from platforms built right in the river, delivering materials and equipment down to the work platforms, and completing all this with low water levels and while hoping to avoid any storms.
With careful observation of the wall to ensure no new deterioration occurred from the damage, we waited until late summer for stable weather and the lowest water levels. There was also the waiting game of satisfying all the right authorities including the municipal building departments, heritage committees, and even the conservation authority for the river itself. The building we were working on was a century old solid brick structure sitting on a rubble stone wall foundation. Although not designated under the Ontario Heritage Act, we were still obligated to complete the work using heritage best practices; which is our standard level of craftmanship regardless.
We erected custom tube and clamp scaffolding directly along with the river’s edge, and tying into the masonry wall for additional support. We began by stabilizing the loose stone surrounding the damage with temporary timber framing, shimming individual stones to help displace the weight above. With permission from the town, we shut down a turning lane and used a crane to carefully lower material and equipment down to our work platforms. With all material and tools in place, and a careful eye on the weather, we were ready to begin the restoration.
Completing small sections at a time, not to leave any large portion of the wall unstable, we rebuilt the stone rubble wall exterior with stone locally sourced to best match the original stonework. We also used Spira-Lok stainless steel helical ties, provided by Blok-Lok Limited, designed to provide additional anchoring for our new stones laid against the originals, but allow for the movement all rubble stone walls have.
We laid the wall stones in pozzolanic hydraulic lime mortar manufactured by King, a mouthful, but this pre-mixed mortar is of similar mortar characteristics or the original, and the appropriate mortar for use in mass masonry stonework. The pozzolans are an additive to the lime mortar to assist in curing time and reduce damp curing time, as this project was a balance of reinstating the wall in a timely manner while using proper materials that typical require curing by absorption of carbon in the air and without pozzolans, taking weeks to get to desired strength.
We also used a lime mortar blend with Portland cement, specifically a 1:1:6 ratio of lime to Portland to sand, on the outer surface joints of the stonework. This was also a pre-packaged mortar manufactured by King, and custom blended to best match the colour of the surrounding stonework. This use of Portland in this blend was to gain early strength to resist the seasonal water level rising of the river; while the lime still allowed for the required lower strength and other attributes lime mortar gives to stone construction.
With the convenience of already having a scaffold structure in the water, and the professional work we completed on the foundation, the building owner had us repoint and restore the entire rear face of the building above grade, replacing brick and all surface mortar joints. This restored the entire rear of the building and created a blueprint for neighbouring building owners looking to complete future restoration work along the river’s edge.
If you drive over the William Street bridge in Paris, heading towards the downtown, and gaze to your left (South), you’ll notice the third building has a clean new façade facing the river. Our company continues to restore these century buildings back to their original lustre, continuing the story of our heritage buildings in some of our province’s oldest cities.