Hello Mr. Yasin. I have a question for you. First of all, I made an account as far as I understood from what you told me, but I could not trust this account. I found the weight of 20 pumice briquettes first, then I found how much it goes on 1 m2 area and I found the area load in m2 with these two and turned it. The average weight of 1 Pumice block is 8 kg. There are 12.5 pieces in 1 m2. 12.5*8=100 kg = 100/1000=0.1 tf/m2 classical plaster= 0.036 adhesive mortar=0.01 gypsum plaster=0.01 total= 0.1+0.036+0.01+0.01=0.156 tf/m2 I calculated like this but then for 19 cm brick i did it is not the same?