ok, so im new to smoking. built a smokehouse on 2 layers of block. with 2x4 framing and pine boards on the sides. question is i put small fire in bottom. how hot is to hot for the walls? had it close to 250 for a little while Sunday. boy did the sap seep out then! but since its brand new, as am i to this. i would rather not burn it down. any good ideas? was thinking about adding cement board to lower sections of the walls.