Rectangular cast-in-place liner for old chimney?

[Forthup]

We have a square chimney for a wood burning fireplace which no longer meets code. We want to keep the fireplace. It needs a new liner which will allow 0" clearance to combustibles (i.e. wood surrounding it), and which will not cut down the flue area too much.

I've been investigating cast-in-place liners. The names I've seen are Supaflu, Golden Flue, Guardian, and HeatShield with CeCure Shield. The web pages for Supaflu are "not safe", and there is no web site I can find for Golden Flue. Images I've found for both show a round liner. The Guardian system also apparently uses a round liner. A round tube will cut down the cross section too much to allow use of the open fireplace.

However, the HeatShield/CeCure system apparently can be done in a rectangular shape. Example here:
https://www.georgethechimneyguy.com/heatshield-system/sleeve-relining-system-cecure/

Info on the HeatShield/CeCure system:
https://saversystems.com/products/heatshield-cerfractory-flue-sealant

HeatShield’s hybrid “Cerfractory” technology combines the strength of a high-fired ceramic with the heat resistance of high temperature refractory cements. HeatShield Cerfractory Flue Sealant when used with CeCure Sleeve is certified to UL 1777- Standard for Chimney Liners by Intertek. HeatShield has been tested to ASTM C199 Standard Pier Test for Refractory Mortars and is rated “Super-Duty”. It exceeds both IRC and NFPA code requirements, which specify medium-duty.

It can be used to reline masonry chimneys with the addition of the CeCure Sleeve, provided the HeatShield Cerfractory Flue Sealant mix plus the CeCure Sleeve achieve a total minimum of ½ inch lining material thickness.

Does anyone have experience with these?
Any suggestions on finding an installer in west Michigan (the Mitten)?

Note that the fireplace is not primarily for heat, although we have a Grate Heater. It's in a mostly unheated 1901 summer cottage.
If we can figure this out there are probably a few dozen other cottages in the area which need the same solution.

Thanks.

 

[begreen]

Has a fireplace insert woodstove connected to an insulated 6" liner been considered?

 

[Forthup]

Yes, but not what we want. We want the fireplace primarily for aesthetic reasons.

We have also been told that a woodstove would put out too much heat for our purposes.

It's a bit like cooking on a charcoal grill. You could get pretty much the same results from a propane grill, with less mess to clean up. But people still like to cook with charcoal. Or having a wood fire at a campsite when you could cook on a bottled gas or white gas stove.

 

[begreen]

Could be right. How large is the cabin? Is it insulated?

 

[Forthup]

It’s a fairly small cabin. I dont have square footage. Maybe 300-400 sq ft in the main room (which now combines four very small original rooms).

The problem I’m running into is that no one I can find installs the HeatShield-CeCure system.

Michigan is peppered with summer communities with 100+ year old cottages which have narrow out-of-code chimneys. There’s a big market if someone figured that out.

 

[brenndatomu]

The Guardian system also apparently uses a round liner. A round tube will cut down the cross section too much to allow use of the open fireplace

But in reality, round ends up flowing almost as much as, or more than a larger square flue, just due to all the turbulence that a square flue has...the corners really don't help add much capacity, and actually causes problems (creosote likes to build up there too)
"Square or rectangular flues have corners that create flow restrictions, so they require a larger cross-sectional area to achieve the same draft performance"
^^^ From https://www.toolgrit.com/guides/chimney-flue-sizing-guide

 

[bholler]

It’s a fairly small cabin. I dont have square footage. Maybe 300-400 sq ft in the main room (which now combines four very small original rooms).

The problem I’m running into is that no one I can find installs the HeatShield-CeCure system.

Michigan is peppered with summer communities with 100+ year old cottages which have narrow out-of-code chimneys. There’s a big market if someone figured that out.

They arent very available because they simply arent a very good liner. They dont hold up well at all. Btw how will you have room for a pour inplace liner with the proper thickness but not for an insulated stainless liner?

 

[begreen]

I'm wondering if breaking out the old clay liner, then installing an insulated stainless liner may be the best route. However, if the place is 400 sq ft and not all that well insulated, then I would consider a small insert too. It won't overheat the place unless you want it to.

 

[Forthup]

The chimney does not have a clay liner. I’m not sure it is lined at all. Built in 1901 for a summer cottage. Cottage then used maybe three weeks in July. It was for aesthetics and occasional heat.

Thanks for all the suggestions on inserts, but as I said, we want an open hearth fireplace. If we can’t do that our alternative is propane gas fireplace, but we don’t have a propane tank.

in theory a cast-in-place liner can be thinner than an insulated stainless liner. That’s why I’m looking at them. See the first link in my original post. Cast-in place liners are also smoother than other retrofits.

Part of the solution could be to reduce the fireplace opening.

If we can’t fix it, we will probably leave it as is and not use it.

 

[begreen]

Whatever is done, the chimney needs to be cleaned first. What are the dimensions of the fireplace opening? What is the size (ID) of the flue throat?

 

[bholler]

The chimney does not have a clay liner. I’m not sure it is lined at all. Built in 1901 for a summer cottage. Cottage then used maybe three weeks in July. It was for aesthetics and occasional heat.

Thanks for all the suggestions on inserts, but as I said, we want an open hearth fireplace. If we can’t do that our alternative is propane gas fireplace, but we don’t have a propane tank.

in theory a cast-in-place liner can be thinner than an insulated stainless liner. That’s why I’m looking at them. See the first link in my original post. Cast-in place liners are also smoother than other retrofits.

Part of the solution could be to reduce the fireplace opening.

If we can’t fix it, we will probably leave it as is and not use it.

View attachment 348103 View attachment 348104

A cast in place liner can not be thinner than an insulated stainless liner no. It needs to be a minimum of 1" thick. Some require 1.5" to meet zero clearance. Stainless is thinner and holds up and performs better

 

[Forthup]