To comfortably smooth a deck, a force washer with a PSI wide variety of 2500 to 3000 is good
https://wiki-dale.win/index.php/Understanding_Pressure_Washer_Efficiency:_How_Many_Gallons_Per_Minute_Do_You_Really_Need%3F_70101
To safely refreshing a deck, a drive washing machine with a PSI range of 2500 to 3000 is right. This tension degree effectively eliminates dirt, grime, and mildew without destructive the picket