VHT1500 - Spray on insulation or inside side sill?

[Frank 03SRT]

Do I have to take the insulation off before spraying the VHT1500, or will it work just spraying on inside of insulation?

Thanks.

 

[Ulysses]

The whole idea is to reduce the heat on the interior metal. Remove the insulation on the inside of the sill. Not the insulation behind the pipes, that can stay on. Insulation on the sills should just slip right out.