Oven at Little Stream Bakery - Repair August 7, 2000

This oven was built in December 1997. It has been in continuous use since then, baking around 1500 lbs of bread per day (8 loads) with one firing of 220 lbs of wood.

Recently, a slight drop in the oven vault was noticed.

View of the left sidewall. Notice the bricks in the centre section are kicked in at the top about 1/4".  This was puzzling, as one would expect them to kick out from the vault thrust.

The oven hearth is still in good shape.

View from above. Reinforced refractory concrete cladding wraps around the vault and sidewalls. The cladding was in perfect shape, except for a couple of small thermal expansion cracks - normal in this application.

The sidewall of the cladding, however, had kicked out at the bottom. The oven design did not call for restraint at this location, which, in hindsight, it should have. This also explains why the sidewall firebricks in the photo above were kicked towards the inside of the oven at the top, instead of out.

The repair consists of installing these three giant steel clamps to counteract the vault thrust at the skew course. A piece of 2"x6" steel tubing will run along the skew course on each side. Notice the nuts welded near the top of the (upside down) clamps. These will take bolts that will apply the necessary pressure to the 2x6 rails.

Stuart H. Bell & Sons Ltd. of Perth, Ontario, was contracted to do the steel fabrication and installation. Welder/fitter Ron Ferguson is on the stepladder.

View of the installed clamps. The steel strap running along the top was welded on site to prevent the clamps from twisting as the nuts are torqued.

Steel 2 x 6 tubing runs along the top edge of the vault. The bolt is visible on the centre clamp.

View of the welded nut before installation of the bolt. Access holes had to be cut in the exterior brickwork to access the bolts. This allows for periodic retorquing, if required.

Update: August 2003

We recently returned to do a hearth repair on this oven. Graham Beck, the owner, reports that the arch repair has been a 100% success. After about a month of use the bolts needed to be retorqued, and haven't required anything since.