... the trend of saving the earth.UV-protected, anti-mildew, anti-freezing and cracking, anti-slip ,flame retardant ,Easy to assemble, low maintenance ... 12” to 14”, the joist can be wpc or real timber.b, Screw the wpc decking boards onto the joists one by ... certified, passed ROHS, SGS, CTI test Project example UV-protected Anti-freezing Anti-slip outdoor wpc decking