North Side

[D_Tagr 14]

I'm having a reasonable time with this job here except for the north side which looks like this. I used a regular house mix which Hotsy makes and then a mild caustic degreaser which Hotsy also makes with a 15 deg tip and I went up to 120 Fahernheit. I don't want to go higher in temp for fear of stripping but I want those streaks gone. These are great clients who are selling their building, the lower portion used to be covered in graffiti.

My only thought is to try some combinations of 12% + TSP and/or Borax + Dawn.

Any comments or suggestions are appreciated.

I'm also trying not to get electrocuted!! For obvious reasons.

[chris francis 15]

Chris I would have used 12% TSP first. I though caustic does not kill mold but I could be wrong.

[814jeffw 71]

It looks to me like for the most part, sodium hypochlorite should get rid of that problem. Being it's so heavy on there you may want to go to 4%-6% product hitting the building, because it's gonna want to run off fast, even with some added cling added to the mix.. At least I would. I personally use a little hydroxide mixed in with the the bleach and water for a good basic house wash mix., you may want to try a little of that if the bleach and water doesn't do the trick on it's own. But don't use alot, it can cause the paint to possibly bubble. So be careful and go with small amounts.Very easy to dissolve also, unlike TSP.Could possibly need painted anyhow, because that heavy of growth can lift the paint on it's own. Good luck!!

Jeff

[PressurePros 249]

Jeff nailed it. Mold migrates into masonry and gets a foothold. I am guessing there is not much to worry about in the way of grass or landscaping. Presoak the windows and X-Jet straight 12%. That building will look brand new and all of those streaks will most likely be history. I doubt you will need up close and personal washing.

If the top is painted, you won't even need a mix that strong. Another caveat if it is painted.. you may have some shadows left if the mold has compromised the finish.

[D_Tagr 14]

Thanks for the info guys.

Does 1 gallon of 12% + some Dawn in a 5 gallon pail sound about right?

[chris francis 15]

Are you down strreaming or xjeting it. if you are ds 2 12% to 3 gallon wash. xjet 1 & half 12% to 4 gallon will work.

[D_Tagr 14]

Are you down strreaming or xjeting it. if you are ds 2 12% to 3 gallon wash. xjet 1 & half 12% to 4 gallon will work.

Thanks.

[Chris S 14]

That mix will work for houses, but you probably need something stronger, like straight 12%.

[D_Tagr 14]

That mix will work for houses, but you probably need something stronger, like straight 12%.

Won't that eat the paint?

I'll try it diluted first and work my way up the concentration ladder.

[Beth n Rod 1,279]

You might try a truck washing brush on an extension pole too....sometimes a little agitation helps.

Beth

[John Orr 206]

If this were my customer, I would downstream 12.5 @ 120 degrees. Let it dwell for a few minutes and re-apply. Without knowing what is around this wall, I would not want to apply too strong a mix. 1% on the wall is plenty - especially with heat. (You'll want a "shooter" tip for downstreaming.)