9.22.2012

removing our brick chimney


Marc and I have spent the past few weeks working to remove a brick chimney. The chimney was used to vent an oil burner for heating the house. We switched the house to natural gas when we bought it, so we didn't need the brick chimney any longer. 

Here is a before and after comparison of the house:


If you are thinking about removing a brick chimney, here are some tips. The story of what we did gives the tips a bit more context.
  • A mechanical chisel is a good moral booster because the labour is hard work, but you can do the entire project with a manual chisel and hammer.
  • Focus on breaking the mortar at the corners/ends of the bricks. If we separated the mortar at both brick ends usually the brick just popped off the mortar line in the middle.
  • Remove material from the inside to the outside. We had a layer of normal bricks surrounding a layer of refractory brick. It was basically impossible to remove the regular brick before taking the refractory brick down first.
  • Try using a spray bottle to wet the mortar if you are finding it difficult to break the bricks from it. You don't want lots of water running down the chimney because of soot and dust, but getting the mortar moist seemed to help us break it up.

And this is the story of us taking our brick chimney down:
Our friend (and possible super human disguised as a Danish electrician) Jørgen started the removal process. I was discussing with him how the chimney needed to come down before any other work is done to the back building, but we didn't have the tools or a ladder so I didn't know when we would be able to do it. I was also telling Jørgen how we were planning to borrow safety harness so whoever is taking the chimney down could be secured to it, since the chimney was so high. He thought that was pretty funny. A few days later Jørgen calls me and asks if we had eaten dinner. He said if he and his wife, Jytte, could eat with us then he could help us start taking down the chimney that night. No problem for us! A little while later, Jørgen walked into the yard, put the ladder up and just started working. He took a 45 minute dinner break and continued to work after that. At almost 10pm, I stuck my head out of the bedroom window (where I was level with Jørgen). I said "It's really dark, can you see?" Jørgen said he could not see, and then proceeded to work for another hour! He took two thirds of the height off the chimney in the four hours working with just a hammer and chisel. The next day, Marc and I worked for 2.5 hours and did not even get down half of what was left. So we decided Jørgen had super powers.

I did a lot of internet research on removing brick before we started this project. Marc and I had it a lot harder then I was expecting. Obviously we were not as skilled as Jørgen, but I think the mortar lower down the chimney was also much stronger. After the first few rows on the first day, breaking apart the chimney got a lot more difficult, even after borrowing a mechanical chisel as well. And, for a good section of the bottom, the mortar would not break before the bricks did. Mortar is supposed to be weaker than brick, so that really puzzled us. We were frustrated at the pace of the project.

We started the project trying to save whole bricks so we would be able to clean them and use them again. We stopped doing that. We were always waiting for good weather, but we gave that up eventually also. The last day we worked on the chimney, it rained the entire previous night and there was more rain planned for the afternoon. Marc and I took turns starting early in the morning, one destroying chimney and the other entertaining E. Suddenly the mortar was much easier to break and we were getting whole bricks off again. I really think it was because the mortar was wet, and there is something from my civil engineering education that says this makes sense... but I can't remember the scientific explanation...Something about water weakening the bond between the cement in the mortar and the brick itself because the brick is a smoother surface? maybe? don't quote that! In any case, it was as easy as the internet had made it sound. I have since tried to find internet sources suggesting that wet mortar is easier to break apart and have come up empty. I really think it was the rain, but when we take the chimney down inside the building (we only removed the exterior section so far) I will be doing a wet vs. dry mortar destruction test.

This chimney removal was pretty simple in terms of logistics. The bottom of the chimney is split between the furnace room and a bathroom. Jørgen put a hole in the chimney on the furnace room side the first day so that all the little rocks and rubble could fall down the chimney and into a wheel barrow (the wheel barrow is not in the picture). We also really did not need to worry about covering the hole or keeping rain out during the weeks it took to get the chimney down because the furnace room is unfinished (but not for long!). Water running down the sooty inside of a chimney is usually a problem, but it wasn't for us. Even though it did take us a few weeks to finish, we only actually worked about 8 hours beyond Jørgen's four. Between the rainy Denmark weather, getting really sick and having lots of end of the summer partying to do, finishing the chimney wasn't a big priority and that's why it took weeks, not days.

We still have work to do within the building. Right now it is split into three rooms, a bathroom, laundry room and furnace room. The plan is to make it all one big bathroom/laundry room with the new natural gas burner tucked nicely in a closet. It will probably take a few years to save up the money to realize that dream though. In any case, we are aesthetically pleased by the lack of the chimney on the back of our house. And, we're pretty proud of ourselves for persevering through the hours of hard labour and frustrations. Next, we teach ourselves how to lay brick because the wooden door on the back of that building is totally going to become part of the wall.

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