Need advice about cleaning this

[Guest Sopowerclean]

Pleas look at these pictures. It is a wood sided townhouse complex that i cleaned in early spring this year. When i cleaned this it didnt come 100%clean. The house are stained a gray color, not painted. I used a standard 12% bleach house wash mix and xjetted it. I need some advice as to how to get better results on this. Thanks in advance for this.

[Guest Sopowerclean]

another pic. The stains are black and looks like mildew

[John T 744]

If your Chlorine mix didn't clean that did you try a stronger mix of it to see what happens. If you did this and nothing happened then it looks like the stain is failing in that area. Maybe the stain was originally put over the wood that had mildew on it already which is causing the stain to fail in those areas. Another thought is that the wood is getting wet behind it which would mean some kind of structural fault.

[Cat Powerwashing Inc. 17]

Looks like failing stain to me.

[PressurePros 248]

I'm not sure what is going there but I can take a wild guess. Define your "standard 12% bleach housewash". Whats your mix and what other ingredients are in it?

[Tracy Handl 108]

If the wood siding is stained, and it is an oil based stain, then using bleach can actually pull the stain out. You've probably done some damage to those areas and that is why it looks like a failing stain. Bleach is an alkaline just like strippers are. I have bleached maintenance jobs on wood decks and have removed some of the stain with a mix very similar to most house washes. Always be careful with wood sides homes. Latex painted wood siding doesn't present this problem, but oil-based paints or stains will. Use a product made for wood care on oil-based finishes on wood siding, that won't do any stripping at all.

[Celeste 341]

Housewash mix on stained wood siding - instant no-no for us :) That job should have been evaluated as a clean/stain, not just a general housewash. Percarbonate cleaner would have been much more appropriate if you could not determine the state of the finish prior to the actual clean. (Ahh, the test area!)

Celeste

[Tracy Handl 108]

If the wood siding is stained, and it is an oil based stain, then using bleach can actually pull the stain out. You've probably done some damage to those areas and that is why it looks like a failing stain. Bleach is an alkaline just like strippers are. I have bleached maintenance jobs on wood decks and have removed some of the stain with a mix very similar to most house washes. Always be careful with wood sides homes. Latex painted wood siding doesn't present this problem, but oil-based paints or stains will. Use a product made for wood care on oil-based finishes on wood siding, that won't do any stripping at all.