Pouring the Walls

Last week the foundations  and ground level of the fist two units were poured at the Parkdale site.  The forms were more than 10 feet tall so a lot of care was taken to reinforce and brace the walls before placing the concrete. The greatest fear with this operation is a blow out due to the weight of the wet concrete.  A 90 degree pipe was put on the pumper hose to slow the rate of  concrete being delivered, so that there would not be a sudden load which might break a weak point in the formwork.  The walls were poured to the 5 foot mark and allowed to set up before topping up the remainder. Accelerator in the concrete mix allowed the first lift to stiffen in just an hour, so that the remainder would not put undue pressure on the formwork.

Winter Construction

Construction in cold weather can be slow, or some days impossible. Temperatures have been too cold for the guys to possibly work this week, until Friday.  It was a balmy -15C and more pieces of the ICF (insulated concrete form) product arrived for the foundation walls.  Luckily this work can be done with gloves on. These foundations are complicated.  There are different wall widths on each side of the same building and the reinforcing bar size and spacing changes with height.  There also are several heights of ICF panels and a step for the masonry ledge, so sorting out the pieces is a task in its own right.  By afternoon, the crew was into a rhythm and progressing well.

The wood form in the foreground is a shear wall which will support the rear of the buildings over the carport.  This form is made of differing thicknesses of horizontal plywood 'boards' so as to leave a textured pattern on the exposed walls, rather than flat planes of concrete, like a bridge or civil structure.

Pumping Concrete

While the thaw has delayed opening of the canal skateway and kept me off the ski trails, it was a real break for forming and pouring the footings at Stirling Avenue.   It took four truck loads of concrete but with the help of a concrete pump the footings were cast, complete with rebar and tarped over by noon on Friday.

The pumper is a large truck with mechanical arm and hose that has a long reach.  It would have taken several men all day and probably several spilled loads to wheelbarrow the concrete down a ramp and into the forms.  A great way to finish the week.

Next stage will be forming the foundation walls.

Stirling Ave Footings

When I moved to Ottawa in the early 80's construction went on hold until March or April.  Between the milder winters and construction techniques intermittent work right through the winter has become the standard practice.

Last week we had minus 20 C for several days and about 60 cm of snow.  I was thinking, maybe we should hold off till spring.  Brad knew better.  The weather broke this week.  It has been just at the freezing point for several days allowing the guys to form the footings on clean bedrock.  They drilled lag bolts into the rock to brace the forms which are level on top, but slope, or step,with the slope of the slab rock.  Today the forms were about done and the guys were starting to assemble the steel reinforcing bar grids and dowels that will go into the footings.

Looks like they are in good shape for placing concrete on Friday, which is forecast to be mild so we won't have to pay the 10% premium for cold weather admixture to the concrete mix.

Big Day on a Small Site

A surveyor will verify the grades tomorrow, but it seems the breaking-out of rock is complete.  John McRae has been using a large shovel to load the fractured limestone into trucks for two days to empty nearly the whole site to a depth of 1.5 -1.8 m.

The form materials were being delivered ready for forming of the foundation walls directly on the rock. Large packages of the styrofoam modules that will be assembled as insulated concrete forms were lowered into the hole with a special boom truck.  Even on a small project like this as much as possible is done by machine. The next step is is assembly of the forms which will likely take about a week, depending on the weather.