Perlite Dome insulation quantity

[Djeffrey]

Hi All, i'm looking to purchase some perlite just to be used for the dome insulation (over a fibre blanket). Ive read 50mm is a good thickness. Does anyone have any idea how much perlite this will require for a 1meter outside dome and 50mm thick? I have found somewhere that sell 100 litre bags.

On a separate question how is best to waterproof, I have heard aluminium flashing between fire blanket and perlite but can only find it in strip form?

Dave J

[UtahBeehiver]

On the dome 8-10 to 1 by volume is the appropriate ratio for insulation plus about 20%. You can calculate the volume of the OD diameter of a sphere and subtract the ID diameter of the sphere and divide by 2. Sphere volume calculators you can find on Google.

[Djeffrey]

Thanks Utah, only just got access to this post.