Announcement

Collapse
No announcement yet.

Ca-si board vs vermiculite board.

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Ca-si board vs vermiculite board.

    Hello guys, I have two options for hearth insulation:

    1. ca-si board - 40 mm thick
    2. vermiculite board - 25 mm thick

    Fairly similar prices. Would single layer of 40 mm ca-si boards under firebrick floor be enough?

  • #2
    Vermiculite board is not suitable as it is very prone to cracking in larger pieces, the overall product is very brittle and it will suck up water like a sponge.
    Not to say it is a bad product and it has many uses but it has very little structural integrity especially as a base supporting such a heavy weight.
    The board is made from compressed vermiculite and water glass although the actual formular seem to be a secrete!
    What many folk use is a mix of loose vermiculite mixed with cement as that forms a more stable and stronger result .
    However the Ca si board is a popular choice as is ceramic fibre board .
    Last edited by fox; 09-20-2021, 12:37 AM.

    Comment


    • #3
      Originally posted by fox View Post
      Vermiculite board is not suitable as it is very prone to cracking in larger pieces, the overall product is very brittle and it will suck up water like a sponge.
      Not to say it is a bad product and it has many uses but it has very little structural integrity especially as a base supporting such a heavy weight.
      I see, that is the exact information I need. So CaSi boards are de-facto standard material for this? Or should I look into some alternative insulating boards which can sustain such a weight laying on it?

      Comment


      • #4
        Also, I found premade Keramzit/concrete (Liapor - perlite-like insulant) boards.

        Comment


        • #5
          calcium silicate is a popular choice it is strong enough at around 100 tons per square meter and can withstand 1000 °C .

          foam glass is also becoming very popular, I have never used it but it is so not prone to water damage.

          Ceramic fibre has the best thermal properties and is what I use.

          The most important aspect is to make sure you base insulation does not absorb water.
          Last edited by fox; 09-20-2021, 01:02 AM.

          Comment


          • #6
            Thanks! Will got with CaSi board or ceramic/foamglass board if CaSi will not be available.

            Comment


            • #7
              A couple other options, AiSi board will work as well, similar to CaSi. Here are a couple key components in addition to a high temp rating, 70-75 psia compression at 5% compression and a K value of about 0.55 Btu-in/(hr*ft2*F) at 500 F. If budget is a factor, a 5 to 1 p/vcrete is an option you just need twice the thickness of CaSi or AiSi. Min recommended floor thickness for CaSi or AiSi is 50mm. FoamGlas is a good first layer since it will not absorb water but it is hard to find. There are new perlite based boards with good thermal/structural properties and water resistance but I have not used them.

              Click image for larger version  Name:	Vcrete K values.JPG Views:	0 Size:	159.3 KB ID:	441763
              Russell
              Google Photo Album [https://photos.google.com/share/AF1Q...JneXVXc3hVNHd3/]

              Comment

              Working...
              X