A plywood form at the lintel of the fireplace is supported by jacks to contain the hydrostatic pressure caused by filling the chimney with wet mix. The bottom form surrounds the tube and is made of three sections so it can be removed with the tube in place.
There is some extra lining material here that must be removed to expose the new smoke chamber. Just like a sculptor, we'll remove the bits that are not the smoke chamber.
The other side is similarly contoured. It can be difficult to get the two sides exactly the same. We'll correct variations tomorrow when the tube comes out.
The top is firming up, so the bags and bricks are removed. The chimney is beginning to look more like it should.
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Supaflu is a lightweight, insulating concrete material that is designed for relining chimneys. It is listed to UL 1777, the standard for chimney lining systems.
Today, we filled the chimney with this lining material.
To prepare the chimney for the pour, a plywood form was placed at the lintel of the fireplace and supported by floor jacks. The top of the form was covered with plastic sheeting so the mix wouldn’t stick to it.
An inflatable tube was lowered down the chimney and pulled through a hole in the bottom form. This tube was then inflated until it reached the proper size. Today we used an 11″ tube.
Supaflu lining material was pumped into the chimney, filling all open areas. A vibrator was attached to the tube to help the Supaflu flow around it and completely fill the chimney cavity.
The bottom form was removed 3 to 4 hours after the first mix was poured. A smoke chamber was carved while the mix was still relatively soft.
The tube will remain in place overnight, allowing the Supaflu to harden. Tomorrow we’ll pull the tube out and begin the finishing touches to this chimney renovation.
