Good old fashion barn... washing?


Ok guys, need some help on this. My parents just put up this barn and need to wash it inside and out before staining it. I, being the son with the 8gpm 3500 psi hot water pressure washing rig, decided that I am going to give them a hand so that it doesn’t take them a week to do it with their residental sized machine.

The barn is ponderosa (yellow) and white pine that has not been sealed, stained or treated. Some of the beams have mold/mildew on them, some just dirt and others are clean.

The “barn raising guide” that came with the building calls for mix of water, SH and TSP, wet the wood, apply mix, wait 15-20 minutes then rinse with 600-800 psi, scrubbing where needed.

The inside has fresh concrete that I really don’t want to mess up so I’m leaning towards tarping it and directing everything out the door where I can recover it.

What chemical/s do you recommend or is the process in the guide the way to go? I have searched around but nothing seems to match what I need to do.

Thanks in advance!


Bleach it and rinse. No need for tap or covering the concrete


What he said^ You can just downstream it with a weak mix since it’s new. Presoak everything including concrete first. Real TSP is tough to find here and the synthetic stuff is as benign as baby shampoo.


Awesome barn!


Before cleaning, after cleaning and then stained. Like IBS said wet, Downstreamed 50% 12.5% 50% H2O, Rinse. Wood Defender Semi-Transparent Sable Brown Stain.


Wow that looks great.


Thanks guys. I figured there had to be a better way than hand scrubbing the entire thing. Time to place an order for SH!