Insulating a SS liner

[granpajohn]

I want to put SS flex liner in a brick with TC liner fireplace chimney. They say it should be insulated for best draft, but....(showing my lack of experience) Is it really flexible after wrapping it with that hi-temp insulation? Seems like I might as well use rigid pipe liner. Of course, the lower portion has to be flexible to fit in. A local dealer said they don't usually insulate in our (temperate) area. Thanks for reading.

 

[Shane]

The vast majority of liners have to be Insulated in order to meet the UL standard their tested to. The one exception I can think of is Olympic Foreverflex which allows for installation into an operable clay flue-tile lined chimney with no insulation. This is aside from the benefit of warmer liner and better draft. Depending on your flue size the insulation does make life a little more difficult.

 

[hearthtools]

Sorry to be short but there are Several Debate threads on the Forums.
Just do a search for Liner.

 

[begreen]

Is this an interior or exterior chimney? Even in a milder climate a lined chimney will draft better, especially if it's an exterior chimney. What is the flue tile dimension?

Whatever you decide, be sure to have the chimney thoroughly cleaned before lining it.

 

[jjbaer]

I want to put SS flex liner in a brick with TC liner fireplace chimney. They say it should be insulated for best draft, but....(showing my lack of experience) Is it really flexible after wrapping it with that hi-temp insulation? Seems like I might as well use rigid pipe liner. Of course, the lower portion has to be flexible to fit in. A local dealer said they don't usually insulate in our (temperate) area. Thanks for reading.

I just did mine in March so I can pass on some info:

1) If you get the insulation, get the full 1/2" thick stuff and not the 1/4" stuff. I got an insulation kit containing 25 ft of 1/2" thick insulation with wire mesh to hold the insulation to the liner and a can of spray adhesive all for $260 (you spray the ss liner with the adhesive, roll the insulation onto the liner, then use foil tape to seal the seam and finally put on the wire mesh along the entire length of the liner [like putting on a stocking] and pull the ends tight to hold the insulation to the liner) . VERY CHEAP for the peace of mind it gives you!! With a chimney in good condition, there's virtually no way it would burn through the liner, the insulation and then through your tiles. And unless you're 100% sure you have no cracks in the tiles, getting the insulation is a must! Using this I have confidence in doing overnight burns. Also, using the ss liner and the 1/2" insulation gives my liner the UL rating against multiple 1700-2000F chimney fires.......

2) the liner is more rigid with insulation. Before I put the insulation on I dropped the liner down the chimney for dry-run purposes. My liner was 17 ft long and I hauled it up to the roof alone and inserted it. It curls over in a "U" shape as you're feeding it down the chimney however, with the insulation, there was little flex and I had to turn it much more vertical to get it inserted and had to "muscle it around" to get it inserted. The decrease in flexibility was greater than I had expected but was still manageable. That said, my house is only 1 story and I was working against the roof-side of the chimney on a small ladder and I was leaning against the chimney and I had no great distance to fall if things went badly (chimney in front of me and the house roof behind me and only a few feet down) if things went bad.......if you have other circumstances you need a helper and/or let a pro do it. NO WAY I'd try it from a 2-story ladder against the front of the chimney with the ground behind me because a fall would be 15 ft to the ground Even with no insulation, I don't know that I'd attempt it alone from the front of a chimney that might have a large distance to fall......at least not by myself.

3) as for the lower portion, the insulation runs from about 2" below the top of the chimney down to just above the block-off plate so that the liner can pass through the narrow cast-iron damper area where the block-off plate is installed. Most people have to enlarge the damper area a bit to let the liner alone pass through so trying to get insualtion through there is usually not possible and if it were, the block-off plate wouldn't make a good fit against a flexible material. I also elected to put some insualtion on the liner below the block-off plate down to just above the stove collar. Probably not necessary since this is a really hot place anyway and little-to-no cresote forms here in this hotter area and if it does, it's burned off quickly. More forms higher-up the liner where the gases are colder.

 

[granpajohn]

Thanks CastIron, (and everyone); this is very good information. I am in the same boat with a 1 story, working from the roof side. I have ordered the liner with an insulating kit, and expect the total length to be about 14 feet. We talked about using the Thermix style of pour-down insulation, but it didn't save that much, and I compute it to be about 160 pounds of mix to haul and dump. Also, the bottom would have to be shored against the mix, and that may not be easy in my chimney.