insulating floor

[DrakeRemoray]

Originally Posted by mfiore

How about 4 inches of cal sil? (two boards stacked on top of each other)?

That would be more, but I still say overkill.

I certainly don't think you get any benefit from using two different types of insulation. That is, no need to pour perlcrete AND use insulating board. If you are going to pour perlcrete, just pour as much as you think you need. I have 4" of perlcrete, no problems maintaining floor temps, and a 350 degree oven 18 hours after firing. I stand by my overkill statement.

Drake

[dmun]

I have 2.5 inches of insblock19, which is not as good an insulator as cal-sil, under my brick floor, and my support slab seldom even gets warm. I think either/or is perfectly good.

[thebadger]

I went with 3 1/2 inche of perlcrete mainly to help raise my hearth...

I then got the cal sil that sits on top...

+ cal sil will provide more insulation on top
+much easier to level your bricks on the your hearth
-cost/shipping

I agree - you don't have to use it but it can't hurt if you have a little more money in your budget. I opted for the FB blanket as well.

My 2 cents.

Dick

[SpringJim]

If you do choose to overkill, I believe the hearth is the place to do it!

[DrakeRemoray]

I am ok with overkill, I just say (like dmun) do either/or. 8 inches of FB board? Fine! 12 inches of perlcrete? fine! But unless you have some specific reason (like badger trying to get the hearth at the correct height) choose either perlcrete or FB board.

[peter]

Thank you for the help folks. I will continue on this week and hopefully have the floor ready by Friday.

[mfiore]

Well, I'm short, so I don't think I want the hearth floor too high. I'll wait until I'm at that point, then deterimine if it's high enough or not. Otherwise I'll likely go with just 2 inches of FB board.

[Johnny the oven man]

Go the Cal.Sil board option. Cheers J