Day 5 & 6: Mon/Tues - Didn't get very far on these days due to some long hours at work and not very much sleep. In any event, progress was made. Now that the floor modification was complete, I took some time to make sure all of the squeeks were gone by adding screws to a few percarious areas. Just a side note: I HATE SQUEEKS! I want to walk through my house and not hear each step that I take. /End rant.
The next step was to cut and fit the Micore board. Based on some of the threads I read here, I figured that Micore would be very difficult to find. I researched it a bit online before trying for some local sources, just so I had an idea of the price. As luck would have it, the very first place I called had it in stock ready to pick up for $50 per 4'x8' sheet out the door price. For anyone in the Mid Michigan area looking for Micore 300, try Young Brothers and Daley on E Michigan in Lansing. They had it in stock and even cut it in half for me so I could transport it easier. Below is the Micore cut and fit to the opening.
The Micore I purchased was 1/2" thick. The old subfloor was 3/4". So I had a 1/4" gap to fill. Now the stove that I am installing (Englander 30 NC) requires an R 1.5 hearth. I am trying to keep the floor as shallow as possible so that the tile is roughly on the same plane as the carpet. I am not going to go into all the different ways I could acheive the R 1.5 rating. Here's what I chose to do... one 1/2" layer of Micore (R 1.03) and one 1/2" layer of cement board (R 0.26) puts me at R 1.29, 0.21 short of the goal. I decided to fill the 1/4" gap by compressing unfaced fiberglass insulation. Now I can't give you the exact R value of the insulation, but I did find a reference on the Owens Corning website with a chart for compressed fiberglass. (broken link removed)
Note the value in the bottom right corner of the chart. If you take 2.5 inches of fiberglass insulation and compress it to 3/4" you end up with R 3.3. The way I see it, as long as the insulation has at least an R value of 0.21 I have met the requirements of the manufacturer. This is precisely what I did. I took 2.5 inches of fiberglass insulation, but compressed it down to 1/4" to fill the gap underneath the Micore. By my math, it should be right around an R value of 0.70. If anyone knows more about this, I would be happy to know the true R value.
Once compressed, the Micore felt good and solid underneath and is flush with the subfloor. This sets me up nicely so that I can lay the cement board on top and have the floor flush all the way across. I also plan to add a piece of sheet metal as an added bonus between the Micore and the cement board. Had to go a bit screw crazy to keep the Micore from pushing up...
This last picture is just to show the location of the return air duct that I mentioned in an earlier post. It is high on the wall just around the corner from the wood stove location. I am not trying to move the "hot" air with it, but it will help to mix around the air throughout the house when things get too overwhelming.