Replies

1. 
   Bob_Walker | May 11, 2001 03:12pm | #1

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   How about water and bleach (or deck cleaner)? Forget the pressure. You need to kill the mold, not take a chance on driving water behind your siding (and a chance of damaging it to boot.)

1. 
   Jason | May 11, 2001 11:18pm | #2

   *I asked my painter this same question a while ago, and she slapped me. Pressure washing everything including the dog seems to be real popular, and a lot of people do it in prepping to reapint, but it appears that it drives just too much water either into or under the wood. I'd think (but then again, I don't do the painting), that the old tried and true methods are the best; scrape, sand, wash.

1. 
   Louis_Romano | May 12, 2001 02:14pm | #3

   *Bob,Thanks for the reply. Have you had success with any particular recipe and procedure?. I thought the pressure washing would take some of the muscle out of it, but I had heard of the dangers.Louis

1. 
   Louis_Romano | May 12, 2001 02:16pm | #4

   *Jason,Thanks for replying. Does your painter recommend or practice a certain procedure and recipe of cleansers?Louis

1. 
   Mike_Smith | May 13, 2001 11:47am | #5

   *the two that get used the most around here are bleach.. with a clear water rinseor TSP with a clear water rinse..b but hey, whadda i no ?

2. 
   dave_porter | May 16, 2001 06:17am | #6

   *I use 50/50 bleach and water in a spray bottle for small areas, or a pump-up sprayer for larger areas. Wear a respirator, goggles, etc. Then I spray it off with clean water. It works well to get rid of mold. I haven't seen it kill any vegetation yet. I haven't used TSP on exteriors and wonder if the sodium would kill plants.

3. 
   FredB | May 16, 2001 07:02pm | #7

   *Dave - Instead of a 50% solution of bleach try a 10% solution. That will kill just as well, be cheaper and less dangerous to you. And did I say cheaper?

4. 
   James_DuHamel | May 17, 2001 07:01am | #8

   *50/50 mixture of bleach and water. Add 1/4 cup of liquid laundry detergent to each gallon of mixture. Use a garden type sprayer to apply. You can hit the tops of two story houses without ever having to leave the ground. This means no ladders or scaffolds. The bleach evaporates very rapidly. Adding liquid laundry detergent keeps the bleach suspended in the solution, and keeps it on the surface longer before it evaporates. The soap also helps in cleaning.Rinse well with garder hose.Pre-treat plants/vegetation with a liberal dousing of clear water, then rinse off all plants/vegetation when you finish. I have never killed any plant life in over 20 years of using this method.10% solution of bleach is not strong enough in MOST cases. It really depends on how heavy the mildew growth is, and how many times you want to repeat the application before it all comes off.James DuHamel

5. 
   Louis_Romano | May 17, 2001 06:16pm | #9

   *James,good, sound advice.Thanks.When you say a garden sprayer do you mean something hooked to a hose with house pressure? or a pump up sprayer?The siding has some grey and darker grey mold mostly just a visual thing, not anything physically growing on the boards.The discoloration comes from being stickered for a year under tarps before I installed it.other than that somewhat dirty in places.Do you ever have to scrub with this method?Do you discourage the use of a power washer?

6. 
   James_DuHamel | May 18, 2001 04:08am | #10

   *Louis,No scrubbing necessary. If it doesn't come off with the bleach solution, then it isn't mold or mildew. If this turns out to be the case in some spots, then you may need to scrub a little to loosen the dirt. Not much scrubbing should be neceesary either way. Use a garden type pump up sprayer. Rinse with a garden hose. An adjustable nozzle on the end works great.I would NOT power wash wood siding. It is way too easy to damage the wood, and to inject water into places it was never meant to go. You have to be EXTREMELY careful around windows, doors, eaves, seams of siding, etc... These are all places that water can penetrate into the sub-structure very easily with the use of a power washer. Good old garden hose pressure is all that is necessary (along with a good cleaning agent)Too many times people use a pressure washer without any cleaning agents. They figure that the pressure will wash off the mold and mildew. It won't. It will only spread it. The spores get blown and spread all over the wood, and mold will start to grow in places that it was not present at before. James DuHamel

7. 
   Louis_Romano | May 18, 2001 05:40pm | #11

   *James,Thanks again,Hoping to tackle this soon,when warm weather arrives here in WVI'll try to let you know how it works out.Louis

2. 
   Louis_Romano | May 18, 2001 05:40pm | #12

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   Any suggestions on how powerful a Power Washer needs to be to clean a 26-foot tall house sided with rough-cut Hemlock that is beginning to mold. I'm not sure whether to buy a $3-400 dollar washer or rent a more powerful one.