How much does it cost to rebuild a chimney?

Inspection on the house was about as expected for a house that is close to 100 years old. There were a few things that jumped out at me as "have to fix that right away" but only one that was expensive--the chimney. Our inspector said that it needs to be at a minimum re-tucked (re-tuckpointed?), and might need to be rebuilt entirely above the roofline. It is fine from below the roof on down.

So, anyone have any clue on how much that would cost, knowing that it varies by area? It is probably about 8-10 feet tall above the roof, and close to square--about 2x2. It is there at this point only for the water heater, so what about just taking it down to the roof level--is that cheaper, knowing you'll have to "re-roof" that small area? (If we did this we'd get a powered-exhaust water heater that doesn't need the chimney)

Other than that the inspection was pretty good. A lot of things that I'd like to get to, but nothing that is stopping me from going through with the deal.

In reply to mtn:

Just had a mason out on Saturday looking at some of the brick work needed on the place we're presumably buying. Chimneys weren't a specific concern of ours, however the mason did mention anyways ours would run something like a few thousand to rebuild above the roof line if it ever needed it.

I paid about $2100 to have the top about 10 feet rebuilt and a stainless steel liner put in.

A little off topic but maybe worth a mention. You said you only have the water heater installed. Rules dictate that a chimney can not be more than 7 times the cross sectional area of the vents connected into it, or it needs to be lined with a smaller flue that falls into the 7 times rule. So if once upon a time there was a boiler and a water heater, then the boiler was removed. You may now have a chimney with too large a flue to draft properly. The flue gasses from the water heater cool inside the flue instead of rising out the top. You end up with flue gasses backing into the area where the water heater is... can you say carbon monoxide. The other thing you get is condensation of corrosive flue gasses that eat away at the mortar and bricks and cause failure of the chimney. Time to measure the water heater flue(probably3" round) and the chimney flue. If the chimney flue is more than 7" square, you will have an issue, especially when its colder.

tr8todd wrote: A little off topic but maybe worth a mention. You said you only have the water heater installed. Rules dictate that a chimney can not be more than 7 times the cross sectional area of the vents connected into it, or it needs to be lined with a smaller flue that falls into the 7 times rule. So if once upon a time there was a boiler and a water heater, then the boiler was removed. You may now have a chimney with too large a flue to draft properly. The flue gasses from the water heater cool inside the flue instead of rising out the top. You end up with flue gasses backing into the area where the water heater is... can you say carbon monoxide. The other thing you get is condensation of corrosive flue gasses that eat away at the mortar and bricks and cause failure of the chimney. Time to measure the water heater flue(probably3" round) and the chimney flue. If the chimney flue is more than 7" square, you will have an issue, especially when its colder.

He mentioned this as well, it is in the report. However, I feel this is a much smaller issue compared to the rest of the chimney--how much could it be to drop a stainless steel (or even aluminium) flue in there? Besides that, the inspector couldn't tell. He thinks that it was done correctly from what he could see, but he also said that he can't see that much and would count on it not being done correctly. The furnace was replaced in 2012; the water heater is from 1994. We're thinking that the correct line of attack is to get a water-heater with a powered exhaust to where the furnace is exhausted, through its own set of PVC. I'm ball-parking that cost+install at around $1.5k to $2k. (50 gallon tank). Note that doesn't account for anything with the Chimney, just a new water heater and PVC for exhaust.

I think the liner itself wasn't that expensive bit the other damage like removing the old disintegrating liner and repairing the chimney added up.

Since it's a 100 year old house, are there any decorative patterns in how the bricks are laid? That will cost more to replicate if it has to be rebuilt. One other concern is the bricks may or may not be the same size as modern bricks, which makes mixing the new and old difficult. I ran into both issues with my house when I had the chimneys rebuilt.

stuart in mn wrote: Since it's a 100 year old house, are there any decorative patterns in how the bricks are laid? That will cost more to replicate if it has to be rebuilt. One other concern is the bricks may or may not be the same size as modern bricks, which makes mixing the new and old difficult. I ran into both issues with my house when I had the chimneys rebuilt.

NO decorative patterns, at least that we care about.

A 3" liner is under $300 for a 35 footer with a cap. You won't get 35 feet, more like 30. Try to stretch it to 35 and it will rip. You rip it, throw it away. They also come in 25 footers in case its a single floor dwelling. Liners for gas fired appliances are similar to flexi dryer vents. Oil fired ones are stainless and more expensive. Have a chimney guy do it, and you can triple that price. Easy to do yourself. I can talk you thru it as long as you promise not to fall off the roof and come after me. A 50 gallon gas fired direct vent water heater will cost you a couple of grand by the time you get a plumber to do it. I gave a quote of $2800 today to replace a wall mounted one that someone installed without a permit and used regular smoke pipe for the vent. Vent rotted out and flooded the house with CO. Priced the correct stainless venting material for the existing water heater and once I hit $1100, I stopped counting. Told the people replace the whole thing with a newer even more high efficiency unit that uses PVC for vent and makeup air. Right now its tagged out and they have no hot water until they make a decision. My guess is they are looking for a better estimate, but they won't get one.

What is direct vent? Is that the chimney, or one that would go through PVC through the wall and out the house?

Direct vent is anything that vents directly to the outside. Chimney vent is obvious. Direct venting requires greater efficiency/ reduced flue gas temps because you can't pass 500 degree flue gases thru a combustable wall and directly outside. Tank type water heaters vent directly with the assistance of a powered fan or power vent. They aren't much more efficient than a regular chimney vented tank type water heater, but the flue gases are combined with non combusted air to dilute them and bring the temperature down enough to direct vent the combustion gases. Sort of like an air pump on an engine. Condensing direct vent units extract so much heat out of the combustion process that the flue gases condense, and acidic water needs to be removed from the venting by means of a condensate pump. In some cases that acidic water needs to be neutralized before its discharged. I've installed condensing units that are 99% efficient. Anything above 92ish can use PVC. 85 to 92 needs stainless. Under 85 goes into a chimney. There are exceptions, but thats the jist of it, except for power vented tank type water heaters. Those are around 63%. No such thing as a high efficiency condensing oil fired system because oil is too dirty.

Thanks Tr8. I'm thinking that it would probably be the best idea to have it rebuilt from the roof up, then a new vent/flue dropped down. Might wait on replacing the water heater (with a "normal" water heater) for a few months at that point.

All of this is assuming that the sellers give us some money back at closing. If they don't, I think the deal is off.