Chimney liner confusion

[Brian Andrews]

We've been in our house for 3 years and have never used our fireplace because a chimney cleaner told us that we need a new liner. We didn't do the repair because it was low on our to-do list.

Now we are converting from an oil furnance to gas and a new chimney cleaner has told us that we need to do the new liner.

First chimney guy quoted $2600 to install a stainless steel liner.

Second guy quoted $1275 to install an aluminum liner. He said this was all we needed for our new gas burner.

So, I went with the aluminum. I wasn't pressured or rushed but when speaking to the guy on the phone he assurred me that this was the correct liner for the oil furnance, but I forgot to ask him about burning wood in my fireplace.

I've now read that aluminum is fine for gas and stainless is required for woodburning stoves or oil. Is SS also requried for having a small fire in the fireplace? Does this liner even matter for using the fireplace?

I know this is a dumb question because you all have never seen my chimney, but is it possible that I have 2 flues and that one for the furnance just needs the alumnium liner and the other for the fireplace does not?

The house is a 1945 Cape Cod in northern NJ.

Thanks.

[Bob]

It is most likely the case. Where I live, sharing a chimney for these two things would not be legal. Aluminum liners are not appropriate for wood fires.

Bob

[IHateSpam]

Have you condider upgrading your furnace to high-efficiency, then you do not need chimney. You will pay probably the same or less if you go from mid-efficiency furnace to high efficiency furnace as price of linear.

Regards

[Art]

Excellent advice. HE furnace uses PVC for exhaust.

[Doug Kanter]

I just bought a house with a HE furnace. Two home inspectors and the realtor both explained that when I had the chimney cleaned, the contractor would probably suggest a liner, and that this was NOT just a sales pitch, but a good idea. Reason: The water heater still vents out the chimney, but with not enough volume to carry out all the moisture contained in the exhaust. Therefore, there'd be moisture collecting in the chimney. I haven't gotten to that point - just throwing this info into the mix. Apparently, the previous owner never reached this point because he never used the fireplace to begin with.

[John Barry]

I'd sure hope so (that there are two)- never seen any other appliance share a flue with a fireplace. Should be pretty obvious to you if you examine chimney structure, and/or the topology of the liner(s). You could ask the people who did the previous work.

John

[FireBrick]

I can help with this. I was both a Firefighter and a Licensed Chicago Mason Contractor. (these comments pertain to Chicago metro area construction norms) In most home built since the 50's, there are two types of chimneys. The size of the pipe is determined by the size of the furnace or the fireplace and the total height from the furnace/fireplace to free air.

A service chimney handles heaters such as furnace or water heater. This type of chimney uses a round clay pipe flue. this pipe is hard fired clay and has a shiny ceramic type surface. This pipe is interlocking and resembles sewer pipe, usually 8" diameter for average home. Acids resulting from gas fired furnace/heaters would dissolve chimneys or pipes without this protection.

A fireplace chimney is different and requires a different type of pipe. The average fireplace only requires a rectangular pipe, also a clay product but not hard fired. This pipe is usually a soft orange/buff color and can break quite easily. These pipe have no interlocking bells and is usually laid in a small bed of mortar between units. No acids result from wood burning fires hence a less sturdy pipe is required.

While a chimney may contain both types of pipes, they must be separated by masonry as to form multiple chimneys in one large unit. In no way can heating and wood burning share the same pipe or the gases, smoke, from one pipe be allowed to escape to the any other pipe.

And as for chimney cleaners. Pro construction people know that this is RARELY NEEDED in today's modern era homes with the exception of possible debris accumulation.

In older homes, and I mean old, where the clay liners were not used and the chimneys were brick only, then a stainless steel liner is used for the gas fired heating chimneys. Some older homes that were coal or oil heated may not have the proper liner and also require a stainless steel liner if conversion to gas fired takes place.

So now I've given you far more than you need or probably wanted to know about chimneys..... Many many many questions on the masonry license exam are dedicated to chimney construction codes. Which explains why 'chimney shakers' can offer such low bids compared to honest reputable contractors.

Carbon Monoxide leaking chimneys kill people in their sleep. Improperly built or maintained fireplace chimneys result in severe damage..

[FireBrick]

"> A fireplace chimney is different and requires a different type of pipe.

I should have said very little destructive acids result from wood burning fires

proof read, proof read, and then get someone else to read it. :-(((

[John Galbreath Jr.]

Aluminum cannot be used on a wood fire.