Chimney repair: repoint, rebuild, or remove (and replace [boiler])
October 24, 2013 10:22 AM Subscribe
The flashing around my chimney isn't doing its job, and I'm getting a little bit of water in my attic during very heavy rains. I'm in the process of getting bids to fix this. Both guys I've had out so far have noticed that the brick is deteriorating - one guy proposed repointing and the other guy thought that the chimney needed to be rebuilt from the roof up. But since the chimney only vents the boiler and the water heater, I got to thinking - should I seize this opportunity to replace these aging appliances with a combi boiler and do away with the chimney for good?
The boiler and water heater have both worked fine since we moved into the house about a year ago, but they're old (about 30 years and 10 years, respectively), and I expect we'll be in the house long enough to have to replace one or both of them. The house is heated with cast-iron radiators that I love (and cooled with Spacepak). I saw an episode of "This Old House" in which they replaced a boiler very similar to mine with a fancy tankless hangs-on-the-wall-and-vents-outside combination boiler/water heater. I have no personal experience with these (they seem to be more common in the UK), but Google suggests that they cost between $2k and $4k for the appliance before any tax credits (which sound like they could be substantial). If it's going to be a question of paying $4k to rebuild the chimney (one of the bids) or $6k to remove the chimney, fix the hole in the roof, and have a new energy-efficient hot water system, I'd probably go for the latter. (The two bids to rebuild the chimney were $2,800 and $4,000).
Alternatively, the bid to repoint and reflash the chimney was $1700. I guess the argument against that is that it wouldn't be as permanent a fix as rebuilding the chimney, but they guarantee the materials for 10 years, and there may very well be another decade left in the boiler if not the water heater. I haven't priced any modern boilers that could/would need to vent through a chimney. If they're significantly cheaper than the ones that vent directly outside, that might compel me to invest in the future of the chimney.
I'm interested in any and all thoughts about any part of this question: chimney repair, boiler replacement, boiler installation, expenses, and credits. Thanks!
The boiler and water heater have both worked fine since we moved into the house about a year ago, but they're old (about 30 years and 10 years, respectively), and I expect we'll be in the house long enough to have to replace one or both of them. The house is heated with cast-iron radiators that I love (and cooled with Spacepak). I saw an episode of "This Old House" in which they replaced a boiler very similar to mine with a fancy tankless hangs-on-the-wall-and-vents-outside combination boiler/water heater. I have no personal experience with these (they seem to be more common in the UK), but Google suggests that they cost between $2k and $4k for the appliance before any tax credits (which sound like they could be substantial). If it's going to be a question of paying $4k to rebuild the chimney (one of the bids) or $6k to remove the chimney, fix the hole in the roof, and have a new energy-efficient hot water system, I'd probably go for the latter. (The two bids to rebuild the chimney were $2,800 and $4,000).
Alternatively, the bid to repoint and reflash the chimney was $1700. I guess the argument against that is that it wouldn't be as permanent a fix as rebuilding the chimney, but they guarantee the materials for 10 years, and there may very well be another decade left in the boiler if not the water heater. I haven't priced any modern boilers that could/would need to vent through a chimney. If they're significantly cheaper than the ones that vent directly outside, that might compel me to invest in the future of the chimney.
I'm interested in any and all thoughts about any part of this question: chimney repair, boiler replacement, boiler installation, expenses, and credits. Thanks!
Try to get 3 bids for any particular job. It gives you a better sense of suspiciously low or suspiciously high bids.
"brick is deteriorating"
This is the crux of the issue regarding rebuild or repoint. If you are in a frequently-freezing climate, and someone has previously repointed your chimney with concrete instead of mortar, your bricks are doomed, eventually.
The repointing goes along with the reflashing of the chimney, as the step flashing is embedded in the mortar for a good exterior seal.
"new energy-efficient hot water system"
Here you have to decide how long you're going to be in the house. As the cost of energy goes up, having enough years of fuel savings when you upgrade from a 65 percent efficient furnace to a 92 percent efficient condensing furnace, in a freezing climate, make it a no-brainer.
The question is how long can you wait for break-even? The longer you stay in the house, the stronger the argument is for removing the chimney.
You can probably tilt the deal toward replacement if you demolish the chimney yourself. It's pretty easy, unless your roof is high/steep/slippery. If you want to make your chimney demo cheaper, you can get them to just take it down below the roofline, and get the hole in the roof closed, and then demolish it yourself at your leisure after your new system is installed.
One nice thing about direct-vent high efficiency boilers is that they can often use cheap ABS plastic pipe as the flue, and you don't have to punch through your roof for their exit from the house. You would almost certainly not use the old brick flue for any new heater installation.
I've demolished a brick chimney and installed a direct venting high efficiency propane boiler for a hydronic heating system. I've contracted the repair of the chimney on my childhood home in a freezing climate. I'm not a pro.
posted by the Real Dan at 10:52 AM on October 24, 2013
"brick is deteriorating"
This is the crux of the issue regarding rebuild or repoint. If you are in a frequently-freezing climate, and someone has previously repointed your chimney with concrete instead of mortar, your bricks are doomed, eventually.
The repointing goes along with the reflashing of the chimney, as the step flashing is embedded in the mortar for a good exterior seal.
"new energy-efficient hot water system"
Here you have to decide how long you're going to be in the house. As the cost of energy goes up, having enough years of fuel savings when you upgrade from a 65 percent efficient furnace to a 92 percent efficient condensing furnace, in a freezing climate, make it a no-brainer.
The question is how long can you wait for break-even? The longer you stay in the house, the stronger the argument is for removing the chimney.
You can probably tilt the deal toward replacement if you demolish the chimney yourself. It's pretty easy, unless your roof is high/steep/slippery. If you want to make your chimney demo cheaper, you can get them to just take it down below the roofline, and get the hole in the roof closed, and then demolish it yourself at your leisure after your new system is installed.
One nice thing about direct-vent high efficiency boilers is that they can often use cheap ABS plastic pipe as the flue, and you don't have to punch through your roof for their exit from the house. You would almost certainly not use the old brick flue for any new heater installation.
I've demolished a brick chimney and installed a direct venting high efficiency propane boiler for a hydronic heating system. I've contracted the repair of the chimney on my childhood home in a freezing climate. I'm not a pro.
posted by the Real Dan at 10:52 AM on October 24, 2013
I highly recommend getting a new combi unit. I updated my 35 year old boiler and 12 year old water heater in the summer when the water heater died. My bills have dropped by a lot. The hot water is endless and the heat works great. It did take the contractor some time to install, but it was a great result. It will definitely pay itself back very quickly.
I also have a chimney that is falling apart. I did the repairs to get it through the winter, but I am planning on taking it down next spring. It is the easiest thing to do since it is not used any more and patching the roof is much cheaper and easier than fixing the entire chimney.
posted by Nackt at 11:12 AM on October 24, 2013
I also have a chimney that is falling apart. I did the repairs to get it through the winter, but I am planning on taking it down next spring. It is the easiest thing to do since it is not used any more and patching the roof is much cheaper and easier than fixing the entire chimney.
posted by Nackt at 11:12 AM on October 24, 2013
Another reason to go for a new, efficient, sealed appliance: less risk of backdrafting. Getting rid of the chimney means one less hole in your roof, which reduces the risk of a leak developing.
posted by Monday, stony Monday at 12:06 PM on October 24, 2013
posted by Monday, stony Monday at 12:06 PM on October 24, 2013
I just faced a similar problem in my house, replaced the boilers a couple of years ago, and have just had the chimney taken down. For me, the deciding factor was that my chimney ran smack through my kitchen, and by removing it I would enable a much more sensible room layout. In my case, fixing my chimney would almost certainly have been the cheaper approach. But your mileage may vary:
The house is heated with cast-iron radiators
You need to figure out whether this is a single-pipe steam system or a hot water system - I've had old cast iron radiators with both. If it's hot water, you can quite easily find a high efficiency direct vent boiler. If it's steam, your options are more limited, but I was able to find a power vented boiler. Power venting is more expensive, more complicated, and almost certainly more trouble in the long run.
I also installed on-demand hot water heaters, also direct vented. This required running new gas lines as the BTU demands of the on-demand heaters is considerably higher than for a conventional storage tank.
I live in a 3 story, two family house, so I had to replace 2 water heaters. I replaced one boiler and retrofitted a power vent to the other. The bill for all this was around $13K. The quote for demolishing the chimney and patching up the roof, walls, and floors, was around $6K - again for 3 stories. I think rebuilding the chimney from the roof line up would have been around $5K to $8K. (all of these numbers are from memory, and the chimney demo ended up part of a larger job so is only approximate). This is Boston, where tradesmen are expensive.
I'm very happy with the performance of the new heating systems, and except for an annoying delay when I run the hot water, very happy with the water heaters.
posted by mr vino at 1:46 PM on October 24, 2013
The house is heated with cast-iron radiators
You need to figure out whether this is a single-pipe steam system or a hot water system - I've had old cast iron radiators with both. If it's hot water, you can quite easily find a high efficiency direct vent boiler. If it's steam, your options are more limited, but I was able to find a power vented boiler. Power venting is more expensive, more complicated, and almost certainly more trouble in the long run.
I also installed on-demand hot water heaters, also direct vented. This required running new gas lines as the BTU demands of the on-demand heaters is considerably higher than for a conventional storage tank.
I live in a 3 story, two family house, so I had to replace 2 water heaters. I replaced one boiler and retrofitted a power vent to the other. The bill for all this was around $13K. The quote for demolishing the chimney and patching up the roof, walls, and floors, was around $6K - again for 3 stories. I think rebuilding the chimney from the roof line up would have been around $5K to $8K. (all of these numbers are from memory, and the chimney demo ended up part of a larger job so is only approximate). This is Boston, where tradesmen are expensive.
I'm very happy with the performance of the new heating systems, and except for an annoying delay when I run the hot water, very happy with the water heaters.
posted by mr vino at 1:46 PM on October 24, 2013
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It did take him quite some time (more than a week) to do, so...
posted by KokuRyu at 10:45 AM on October 24, 2013