A- Base is 2X4 and plywood/osb
B- Insulate 4 sides and bottom w/polyisocianate
C- Waterproof membrane - 1st coat silicone
D- Fiberglass screen
E- Imbed screen into silicone
F- 2nd coat of silicone
G- 3rd coat of silicone
H- Side walls and trough(right) same steps w/white silicone and install
fill/overflow and outlet tubing.
/const