Anyone with experience Installing a new chimney liner and chimney cap?

Submitted by Instant_Bacon t3_z8puk2 in DIY

A chimney company quoted me $3300 for a new chimney liner while a kit is $500 to $1000. It vents the furnace and water heater, neither of which is low efficiency and both are about 3 years old. The chimney company calculated that I would need a 5" flue liner which could fit inside the old round clay liner.

The round clay flue is stubbed out about a foot from the square concrete chimney cap. Most of these kits come with a square steel chimney pan that sits flat on the concrete. How are the clay flues supported inside the chimney? My thought was to use a masonry grinder blade to cut the clay flush, but I don't want to cause it to collapse or break apart inside the chimney.

Also, how do you know if the liner need to be insulated?

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CLIMBFIFAMobile t1_iyco3q5 wrote

Weird Al's parents died of carbon monoxide poisoning from a chimney. I would get a reputable professional, this things are no joke.

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aZamaryk t1_iyd2v7u wrote

Pretty sure Clay liners are set in mortar. Saw a chimney company jack hammer one out for about 2 days. I'd definitely hire someone to do this.

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jeffersonairmattress t1_iydj2yi wrote

Clay liners are typically just stacked and laid in place while brick goes up surrounding them. I’ve done a few stainless liners- the upper termination just sits on top of existing chimney. The pain in the ass part is getting into the side of the flue down low- you need a good hammer drill with chisels to slope the flex liner up and to mortar around the liner, setting a termination ring in place, you need your wye fitting to the two appliances to be at a safe height above both appliances and you should not use appliance with powered vent when the other is natural draft- ask a plumber if they will let you snake the liner and have them do everything in the basement.

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Instant_Bacon OP t1_iydv3gi wrote

Replying to aZamaryk (#807,394)

There's a clean out at the bottom and looking up from there, it appears that there's a void between the brick and clay. It's hard to see if there's any supports, but the bottom of the clay is just hanging at the bottom. I'm going to have to get a better look with a camera I think, but it's definitely not encased in mortar.

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Instant_Bacon OP t1_iydvnlx wrote

Replying to jeffersonairmattress (#812,526)

Yeah neither has a powered vent, they are natural draft. The clean out door on bottom seems adequate to fit a 5" liner but I was planning on feeding from the roof and have someone pull the rope from the bottom. Did you pull up from the bottom?

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Instant_Bacon OP t1_iydw8mq wrote

Replying to CLIMBFIFAMobile (#802,633)

I just heard him talk about that the other day, that was from a wood burning fireplace with the flue closed. Unfortunate to happen, but the liner kit is pretty foolproof as far as how to connect things an where to seal them. I'm aware of requirements like sloping the vent upward

Reading around it sounds like it's quite DIY friendly. I have a little tuckpointing experience as well if necessary.

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stinkasaurusrex t1_iye1rgh wrote

I installed a fireplace insert into a masonry fireplace/chimney including a chimney liner and cap. It was not hard to do. The hardest part was getting the liner through the damper 'gap' at the bottom of the chimney and then attaching it to the back of the insert so that made a good seal. I needed a helper to get the liner down the top of the chimney, but the rest I was able to do by myself. 20' of corrugated/insulated metal pipe is very awkward for one person to wrangle and downright dangerous to do so on a roof.

From your post it sounds like you are considering a different kind of cap than I used. I did not need to modify the flue tiles at all because the cap was designed to fit over them and then held in place by screws. The liner attached to the cap with an adjustable clamp. See here:

https://www.rockfordchimneysupply.com/chimney-liners/316ti-flexible-chimney-liners/316ti-liner-components/round-liner-components/terra-cotta-top-plate.php

I bought my kit from this company, and I am happy with the result. Maybe they sell a kit that will work for your furnace/heater?

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theSiegs t1_iyen08n wrote

Couple things here.

  1. I did my own stainless liner install for my wood fireplace insert. My approach was to give it a try and get help if I couldn't get it to work. It worked fine.
  2. You should look up the installation manual for your furnace and water heater; many of the new high-efficiency ones won't work properly with a 5" vertical exhaust. You may be able to vent out the side of the house instead.
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stinkasaurusrex t1_iyeoldt wrote

Replying to Instant_Bacon (#819,397)

On the question of insulation, I recommend it if there is room in the chimney for the liner + insulation. Insulation keeps the gas hot as it exits the house which is a good thing. Hotter gasses rise faster, therefore the insulation will improve drafting. The gasses staying hot also reduces the build up of deposits from gas condensation. Maybe this is less an issue with natural gas exhaust, but with a wood burning stove you will get more rapid creosote build-up on the liner and therefore must clean it more often if you skip on insulation. You don't want a chimney fire.

Edit: I should make it clear that I am not a professional, just a DIY guy with a degree in physics. My opinions are worth what they cost you. :)

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