Browse Forums Heating, Cooling & Insulation 1 May 16, 2010 7:48 pm Hi all, This is my first time posting on this forum and I was hoping that someone might be able to help me out with an interesting problem. We have a 1920s-30s era old stone house with a masonry fireplace in the main living room. We recently got a freestanding wood heater installed in this fireplace (with the mandatory stainless steel chimney liner inside the chimney) which we are extremely happy with, however in order to get it to fit we have also had to knock out some of the back smoke shelf which has left a fairly large hole in the inner wall of the chimney. There is also no air barrier in the throat of the chimney. I suspect that all of this means we are losing a fair bit of heat from the top of the heater up the chimney. I was wondering if anyone had any ideas for how best to block off the chimney? My current plan is something like the following: -Use a piece of fibre-cement to fill most of the gap at the throat of the chimney. Use muffler putty (this is what the heater manufacturer recommended) to make an airtight seal to stop heat loss through convection currents. -Use a couple of fibreglass batts on top of the fibre cement sheet to reduce heat loss through conduction (this is what the heater installer recommended). -Attach some alfoil to the bottom side of the fibre cement to reduce heat loss through radiation. Not quite sure what kind of adhesive to use to glue the alfoil in-place. Other options I had considered: 1. Using fire-resistant polyurethane foam to do the seal & insulation instead of the muffler putty. I saw at my local hardware megastore that Fuller do a fire-resistant foam, but it is pretty vague on the detail as to where it can be used and simply tells you to contact your local Fuller (which I might do anyway). I thought that using foam would make a better seal & better insulation than muffler putty. 2. Using chimney insulation mix (like this one: http://www.chimneylinerinc.com/insulation_kits.htm) to pour down the chimney on top of the fibre cement (if I can find a local supplier in Adelaide). This would insulate the flue, which apparently makes it burn hotter & more effectively, reduces buildup inside the flue & protects the masonry itself too, but I thought that this might also prevent heat from the flue from actually getting into the house? What are people's thoughts on this? One other thing I'm concerned about with my "batts" solution is required clearances (if any) for the batts from the stainless steel flue. I know that in regular ceiling installations a clearance of about 5cm (forget the exact number) is recommended, but as I understand it this is not because the batts themselves are flammable (being made of glass) but because it can cause a hotspot where the flue passes through the ceiling & cause the ceiling itself to ignite. If I am using fibre cement around the flue this shouldn't be an issue, right? Obviously if I went for the chimney insulation solution this would be a moot point because the batts would be unnecessary, but I'm curious nonetheless. I had a couple of other questions but I have to head off so this will do for now. Any help, suggestions or ideas would be greatly appreciated! Cheers, -Jeremy Re: Chimney insulation? 2May 25, 2010 10:35 pm Sorry I'm very little help other than to suggest that you have a chimney repair person come and look at it. People make one happy, not houses? I do not think so. Houses are more to be trusted than people. Elizabeth Aston, Mr. Darcy's Daughters http://www.youtube.com/watch?v=pmDX0tgONFs http://lightndreamy.blogspot.com/ Hey guys building a new place through a volume builder and just wondering if i should complain to the site supervisor as we just had plasterboard installed. Looks like… 0 11273 1000000% definitely add insulation. I have in my home and it makes a big difference minimising sound transfer. Insulation is pretty cheap and definitely worth it 2 6191 |