Stevebass4 said:
Thanks again for your help Goose!
i already have a block off plate and i use a "direct connect" for my insert (goes about 6 feet into the terra cotta flue) but the plan is to use the Kaowool on the sides and back of the fireplace and then slide the insert back in
my exterior chimeny is in fine shape but there is a crack that runs to the smoke shelf - so i figure if i insualte the fireplace before i stick the insert back in - i wont lose any heat from the crack and to the outside brick
Well, the blockoff plate is good, but IMHO direct connects are problematic at best. Insulating the fireplace will help keep you from loosing heat out the back for sure, but replacing that direct connect with a full length liner will probably improve your performance, and make future maintainance a LOT easier...
1. With a Direct, you are supposed to remove everything for cleaning in order to get the creosote etc. that falls down between the chimney and the connector pipe - otherwise it can build up and cause a chimney fire. With a liner, you normally don't have to remove anything for cleaning - take the baffle out of the insert, close the doors, brush down the liner, and clean the crud out of the stove, about as easy as it gets...
2. Most chimneys are larger than they should be to service an insert - you probably have a 6" diameter flue exit - codes say that you shouldn't have a flue more than 1.5x the cross sectional area of the flue exit on an outside chimney - anything larger than about an 8x8" square tile flue is way to big (the 8x8 is marginal) - going to the right size liner, especially if it's insulated, will improve your draft significantly. Remember it's the chimney that makes your stove work, so it's important to get that right...
3. A "crack that runs to the smoke shelf" is not consistent with "a chimney in fine shape" - I'd seriously reccomend trying to patch the crack (preferably after consulatation with a mason as to materials and methods) as preferable to just trying to insulate over it... A full liner will also ensure that even with the crack you are still reasonably fire safe.
4. With a direct connect, you don't want to put any sort of insulation above the blockoff plate - it will rapidly soak up any liquid creosote and become a potential fire hazard and a real mess to deal with, especially if you get any rain or snow entering the chimney and adding to the mess. With a full liner there is no creosote exposure, so the insulation will stay clean.
Gooserider