[Pete's Painting]

I'll be renting a pressure washer for my exteriors this year. Have 2 small houses to tackle starting in mid-May. There is only a touch of mildew on each house, Is it wise to pressure wash both at the same time eventhough i might not start the second for 2 weeks?

for that matter, is there a recommended wait period for the mildew to die if you're using an additive to kill it?

 

[PressurePros]

Pete,

The only things that kill mold are sodium hypochlorite (bleach), sodium percarbonate, and qaurtenary ammoniums. The only cost effective and efficient one of those is bleach. You are looking to hit the house with a 2% concentration mixed with some type of soap (car wash works well) and some TSP. With this combination and a dwell time of 10-15 minutes (make sure you keep windows and plants wet) the mold will be dead. Nothing will stick and regrow enuugh to hinder a finish for a couple of months.

 

[slickshift]

Two weeks is fine

 

[plainpainter]

I have suggestion for you - if you don't intend to use the pressure washer as a means to knock off paint - why not go ahead and scrape and sand both homes and save the pressure washing for afterwards as a way to clean off mildew, grime, and clean up the exposed wood of contaminants in a low pressure application and rinse?

 

[Pete's Painting]

I have suggestion for you - if you don't intend to use the pressure washer as a means to knock off paint - why not go ahead and scrape and sand both homes and save the pressure washing for afterwards as a way to clean off mildew, grime, and clean up the exposed wood of contaminants in a low pressure application and rinse?

Good question......both houses are in fine condition, neither is peeling. They're both stained with the same color going ontop. One guy just wants it freshened up with 2 coats, and the other lady got a raw deal a year or 2 ago when some ass simply slapped on one coat of stain and called it a day.

There's only a touch of mildew, and I told them I would rinse the house with something that would kill it.

 

[smalljobs]

Ditto on the sodium hypo, just pickup some pool chlorine in gallon jugs, its cheap. In a fiver mix 1 gal hypo, 4 gal water and 3 cup tsp or I use a oxi-clean alternative. mix well. Pump up spray it. I use a spray unit with a twenty five gal drum for big projects. Wear safety googles and spray up wind. Dwell 15 or keep wet if in sunlight. Wash off with 1000 psi or less w/ atleast 4gal per minute rating on the pwasher. Spray from base of the house up always with chems, its a good habit for no streak. Rinse windows while dwelling. good to go. I always scrape then powerwash. You might have to wait a couple of days to dry in the wood exposed areas. I have a moisture meter to test, 15% moisture level or below is optimal in those areas for adhesion.

 

[Pete's Painting]

What are the dangers of using bleach as far as bushes, roof etc? Can I just use an ordinary mildew/mold killer found at any hardware store

 

[smalljobs]

Pre-rinse the bushes. I've never killed a bush except when I've used a wood stripper. Even then it spotted the leaves and it grew back in a couple of months. I would'nt be concerned about it. You need the sodium hypo to effectively kill the mold and mildew.

 

[Pete's Painting]

Thanks for the input,