Saturday, July 17, 2010

The Fireplace: Round 2

Some of you may remember our fireplace dilemma. There were two issues with our existing fireplace:

- You lose out on 2 LEED points for having a traditional wood burning fireplace

- We need to ensure that the wall between the fireplace is properly insulated and sealed

In the end we decided to keep the fireplace but we will upgrade to an EnerChoice certified natural gas insert. We viewed it as a good compromise between the charm and appeal of a fire while reducing the air pollution caused by a wood burning fireplace. Montreal city and some of the surrounding towns have banned the installation of wood burning fireplaces and stoves based on studies that show 50% of the city's winter smog is generated by residential wood burning. It didn't feel right to build a green home that contributed to that stat.

That decision though didn't help us with challenge two: the insulation. And that was the one that had the potential to derail the project. A couple of exploratory holes revealed both good and bad news:

The bad news:
  • no insulation
  • no air barrier
  • no vapour barrier
  • and the wall cavity was filled with bricks.

The good news:

  • The wall cavity behind the fireplace was framed like a door with a header beam so we were dealing with one large space instead of three or four little ones.
  • The fireplace was not physically connected to the outside wall
  • the bricks within were not structural (no overhead load). The space actually seemed like there dumping ground for excess bricks and mortar.
So we decided to start removing bricks. This started off fairly simply with the top layer installed with little to no mortar. It is probably a good thing this started off well otherwise it may have ended there. I was able to easily create an opening 8" wide and began working my way down.
It went pretty well until I got about half way down the wall and ran in to a section that was well mortared. If you have never taken anything brick apart it is fairly straight forward. I just had a cold chisel, 3lb sledge and a crowbar. You find the brick you want to remove, you put the chisel between it and the neighbouring brick give it a couple knocks with the mini-sledge and pry it off. No problem.
Where it becomes a problem is when you are trying to remove bricks in a space that is 40" deep and only 8" wide. As reference my arms are only 30" long.

When I had to remove the far bricks I couldn't use the chisel but had to have the crow bar take over chiseling duties. This worked well when it was loose but was a nightmare when the bricks were well set. To further complicate things the wall is to my left while I was working which meant after the half way mark I could only use my left hand for swinging the hammer.

It was a challenge but several hours and two blood blisters later, the wall was empty and I had a giant pile of bricks.

Just like the rest of our Kitchen Deconstruction, I wanted to ensure that as much of that material wasn't ending up in a landfill. So after seveal more hours of work we had:

  • 120 re-usable bricks
  • 242lbs of mortar (re-usable as in-fill)
  • 98lbs of partial or damaged brick (to be re-used as decorative mulch)

But we also still had a large empty wall cavity. Because of the shape and size, we would be challenged to get both traditional insulation and vapour barrier installed and properly sealed. So we opted for spray foam.

There will be times during the renovations that we bring in professionals to apply spray foam. But we weren't calling in the pros for 30 square feet. Instead I picked up the Touch n' Foam professional series kit at Rona. I will admit that I felt very hypocritical buying this one-use-wonder after my "Great Stuff" post.

But it worked. It needed to be applied in two inch layers and allowed 20 minutes to set. But it actually worked really smoothly. It didn't take long to have a well insulated wall with built in vapour and air barrier.

So was all that work worth it? Actually it probably was. As much as I was cursing LEED throughout the process, they were right. Brick is a horrible insulator and had we gone and insulated our whole house and not bothered to fix the problem behind the fireplace 10% of our total heating bill would have been attributed to that 3 and a half feet of wall.

I stated early on that one of the reasons for doing LEED certification was to keep us honest and I think this is a prime example.

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