Moldy vinyl siding

[Phil_Stein]

OK, so I've got white vinyl siding on my house - about 10 years old. On the side of the house that's in the shade most of the day, the siding has gotten moldy and nasty.

I searched a bit on the web, and they recommend various solutions that you basically have to hand apply. But because of the way this side of my house is situated, the upper peak is about 30 feet up. Also, I don't have a long ladder and am a bit of a coward about that sort of stuff anyways.

So, I want some stuff that I can attach to a hose or power washer and spray to kill the mold, then, I guess come back and power wash everything off, right? What, precisely, can I do/should I use?

I don't have my own power washer, but a couple different neighbors of mine have them, so I can borrow one for the day. I read a bit on the web and they say don't angle the power washer up when spraying, or you'll get water under the siding, causing more probs. So do power washers have 12-18 foot attachments allowing me to angle it horizontally even at the upper parts of my house siding?

[Toddy]

I'm not sure there really is a solution for this. I've got the same problem with white siding under a covered porch at my house, and nothing got rid of the discoloration. It seems to seep right in and ruin the siding over time. The only thing that worked for me was white paint, and that only because I was in an somewhat isolated place and beams separate the under-porch siding from the rest of the siding on the main part of my house.

I'm replacing all my siding this summer (it's 30 years old, and due for it), and plan to make sure I hand-clean the known trouble spots every summer from now on, so I don't have this problem again. Also dumping the white siding for gray. White siding sucks. Shows every single mark from wet leaves, spiders, this moldy crap...

BTW, how much siding is causing a problem? You could probably replace the trouble stuff for a few hundred bucks to around a grand, if it's just the one side of the house. Siding isn't that tough to install yourself, especially if you're just replacing some, and the old stuff isn't hard and brittle (mine is, but yours shouldn't be, due to the age and time of installation -- a lot of mid-70s siding was pure crap, as the UV turns it brittle and then it cracks) but even if you hired somebody local to do it, you probably wouldn't be getting into too much expense.

[Phil_Stein]

I've got a bit of mold on a lot of my siding, but the bad side is totally moldy - the whole side. It's ~40 feet deep and ~25 feet high - there's a lot of it and replacing it myself is not attractive - I don't like doing high ladder work.

[Sarkus]

I thought that as long as you annually pressure cleaned vinyl siding you were supposed to be safe from that kind of problem? Or is that just vinyl siding industry hype?

[Phil_Stein]

Well, annually pressure cleaning vinyl siding is pretty hard, especially when you're not supposed to spray 'up', and your house is a 2 story...

[wisefool]

Would diluted bleach work? It pretty much kills anything. Problem would be if it drips down to your lawn.

[Robert Sharp]

Bleach does work, actually, but is very hard to apply in the situation being discussed. You don't want to spray bleach all over the place. There are cleaning solutions you can buy at places like Lowes that work pretty well, but you really need to pressure it by going up a ladder. I don't know of anything that works just on contact, without some agitation.

[Toddy]

Tried bleach on mine, along with every other household cleanser known to mankind. Didn't work.

[Robert Sharp]

Tried bleach on mine, along with every other household cleanser known to mankind. Didn't work.

Really? It worked on mine, which was white. Maybe it was the type of mold you had. Or the type of siding.

[Rob Beschizza]

Paint over it and pretend it isn't there.

[Phil_Stein]

Just to be a bit more clear - my house is a two story, but the side in question is elevated by 2-8 feet (i.e. the foundation shows), because there's a fairly serious slope from the front to the back. So you've got ~9 feet per floor, plus the extra ~7 feet from the top of the 2nd floor to the peak of the roof, plus the exposed foundation (i.e. basement), equals a total height off the ground to the peak of 25-30 feet. And stabilizing a ladder is very hard because the ground is angling significantly from right to left.

When I was a teenager, I was painting my dad's house, which was pretty much the same, with a hill and all, but only a one story, and I had the ladder standing on a sort of 'foundation' I had built to create a flat surface. But when I was up the ladder maybe 15 feet, the foundation gave, and the ladder slipped about 3 feet down the house, but fortunately caught something, saving me from a probably broken leg or worse. I don't think I've been up on a tall ladder since, and in a similar, but worse situation (taller to the house peak), I'm especially leery.

[Bill Dungsroman]

Try applying the bleach with a large guage hypodermic needle on a 100ml or larger syringe receptacle and injecting it into the mold bed.

[beecubed]

plant some kind of ivy. it will grow up over the siding and cover the mold.

[Robert Sharp]

plant some kind of ivy. it will grow up over the siding and cover the mold.

No! Never do this. Ivy creeps me out! I hate it. Here in the south (and probably all over now) we have kudzu and now I am terrified of ivy. It will take over your life in a matter of days. In a week, you will be no more.

[Toddy]

Really? It worked on mine, which was white. Maybe it was the type of mold you had. Or the type of siding.

My siding does truly suck. It's the crap that was apparently made in the 70s either on the cheap, or before people knew what UV rays could do to vinyl. Or so a few different contractors have told me. It's been all hard and brittle for years. Really, really looking forward to getting the siding replaced this fall.

[Toddy]

Just to be a bit more clear - my house is a two story, but the side in question is elevated by 2-8 feet (i.e. the foundation shows), because there's a fairly serious slope from the front to the back. So you've got ~9 feet per floor, plus the extra ~7 feet from the top of the 2nd floor to the peak of the roof, plus the exposed foundation (i.e. basement), equals a total height off the ground to the peak of 25-30 feet. And stabilizing a ladder is very hard because the ground is angling significantly from right to left.

When I was a teenager, I was painting my dad's house, which was pretty much the same, with a hill and all, but only a one story, and I had the ladder standing on a sort of 'foundation' I had built to create a flat surface. But when I was up the ladder maybe 15 feet, the foundation gave, and the ladder slipped about 3 feet down the house, but fortunately caught something, saving me from a probably broken leg or worse. I don't think I've been up on a tall ladder since, and in a similar, but worse situation (taller to the house peak), I'm especially leery.

I hear ya. Never had an incident like that, but I'm just not keen on heights, either. I've no real problem going up on a ladder at my place (I've got a two-story, too, with a pretty high roofline), but I could never do a roof or anything like that. Broken one ankle something like three times as a kid playing hockey and, oddly enough, tennis, so my sense of balance sucks at times. That alone keeps me on a ladder.

[Toddy]

One other suggestion -- Mr. Clean Magic Erasers. Those things work great on all sorts of household stains, removing paint, etc. Cheap, too. Probably not feasible for the whole side of a house, I know, but Magic Erasers seem to clean just about anything.

[Phil_Stein]

One more deterring factor from me and high places with my house:

The back side of my house is effectively 3 stories high - the 2 stories of the 2 story, plus the basement level (the basement floor is flush with the ground outside). The dirt behind the house is non-existent - it's bulldozed clay and rock from the builder, with a thin layer of sod laid on it.

When they were building my house, a roofer fell off the back of the roof ~25 feet to the ground, and again, the ground was (and is) nasty stuff.

Amazingly (and thankfully), the guy lived, and I believe was back on the job after a few months.

Needless to say, I have NEVER been on that side of the roof. (Only a bit on the front side, where part of the roof comes out of the top of the first story at an elevation over ground of ~8-10 feet).

Fortunately, there are no tall trees nearby dropping leaves in the gutters. If there were, well then, I guess I'd just let my gutters overflow...

[Sharpe]

Phil, is there some reason that hiring a professional is out of the question? I am not a home owner yet so perhaps there is territorial manliness vibe that I am stepping on here, but Phil, you are a gifted game programmer, not a construction worker. We have this stone age concept called "specialization of labor". There are agile sun-wisened types who can scale an 18' extension ladder with a high pressure gun in one hand and a Budweiser in the other, and clean your siding off with no worries.

My dad was a painting contractor and I spent 10 teenage summers doing painting grunt jobs. Given my youthful agility and lack of painting skill, I ended up doing a ton of high pressure cleaning and ladder work. Its actually fairly straightforward if you can handle the heights. And I was relatively crappy at it compared to a veteran painter or laborer.

There are handyman guys with high pressure cleaners who can do the work fairly cheaply. If you are willing to spend a bit more (in the range of $20 to $30 per hour for labor plus some kind of equipment fee) most painting crews and general contracting crews will have a guy who is an experienced high pressure man. An experienced guy could probably take care of your entire problem area in a half day's work (for the cleaning). Dunno your area but I would guesstimate you could get a pro to do the cleaning job in the neigborhood of $200 to 250. If you want the siding scraped, patched, sealed, and painted, that would probably run into the low 4 digits, depending on the size of the exterior. If its just one side, you might get it done professionally under a grand.

Of course, I'm bad about hiring people to work for me too. But you know, this whole specialization of labor concept, it works pretty well :0.

[Phil_Stein]

I'm already hiring somebody to cut my grass - it leaves me feeling so emasculated...

My wife had a quote on it and I think it was $600. As a once every 10 years thing, that's no big deal, but if I have to do this every year or two, and could do it myself in 2-3 hours, I'd prefer that.

Actually been doing lots of outside things this spring and really enjoying most of them. It's nice to work on something tangible when you spend so many hours manipulating code on a computer screen.

[Sharpe]

$600 for what type of service? I don't know your region or the size of the wall involved but for pure cleaning service $600 sounds high. If the $600 includes cleaning, prep and sealing then that might be right. But keep in mind if you are getting prep and sealing (or even painting) then that's a lot more service than just a simple cleaning.

Have you tried to get an estimate for just a simple high pressure cleaning?

[Euri]

Get rid of that crap and get wood! It never molds, only mosses up, and moss can be sprayed off if you don't want it there.

[Toddy]

Yeah, because nothing says "low maintenance" quite like wood.

[Phil_Stein]

Borrowed a neighbor's power washer - 1650 PSI electric.

I didn't get over to the siding yet, just working on some guttering on the front of the house that was moldy. Overall, I wasn't impressed. The pressure washer didn't really work unless you get the nozzle about 6 inches from the target surface, and even then, it only takes off about 60% of the mold (i.e. there's still some residue left that really doesn't want to come off).

Then I got up on a ladder and rubbed it with a brush, and it loosened right up, and the loose stuff was easy to spray off for pretty much 100% cleanliness (or maybe ~95%).

I'm gonna scout out the hardware store for a scrub brush that I can attach to a 6+ foot handle...

[mouselock]

Borrowed a neighbor's power washer - 1650 PSI electric.

I didn't get over to the siding yet, just working on some guttering on the front of the house that was moldy. Overall, I wasn't impressed. The pressure washer didn't really work unless you get the nozzle about 6 inches from the target surface, and even then, it only takes off about 60% of the mold (i.e. there's still some residue left that really doesn't want to come off).


You should be aware that depending on the type of vinyl (mainly related to age) you may never get the mold completely "off" because the mold can infiltrate the siding. If there's mold growing a few mm into the siding, it will never come clean, and will always show.

If you can find some of the siding that's low enough to address, try there and see if having the nozzle right up there is sufficient to truly clean it. If, despite your best efforts and cleaning solutions, you can't clear it up there, chances are the mold's been growing long enough to have infiltrated the siding. (That's not a particularly hard thing for organics to do to plastics like vinyl, though it depends on the type of vinyl, preparation, etc..)

[Phil_Stein]

So I went to the hardware store and bought a brush on a 6 foot handle, and a second on a handle that telescopes to 16 feet (pretty cool). The 6 footer is more convenient to the extent that I'm working on low areas, as it's lighter and a bit more rigid (i.e. easier to put pressure on and really scrub), but being able to alternate to the long one was nice.

With these, I was able to get most of the stuff off. Basically - rinse the siding to get it wet. Make one pass over it with the brush to scrub it, then rinse again. For the rinsing, I was using my regular hose on 'jet'. This process got about 70-95% of the mold off (a few areas withstood scrubbing)

I also bought some anti-mold cleaning liquid that can feed into a pressure washer. I did a last pass with this, and it pretty much cleaned off the remaining 5-20% of the mold. I don't think 'pressure washing' was the key here - I was spraying it on and washing it off on the low pressure setting most of the time.

So after I return the pressure washer to my neighbor, I think if I have to do this again, I'll see if I can find something that I can attach to my hose to feed liquid into it - I think there is such a thing - and use that in conjunction with brushes. Excluding the visits to the hardware store, I spent 3-4 hours and got all the parts of the house that I cared about (the accessible/visible parts of the exterior).

[Aleck]

Phil,

Lessons for the rest of us...

(Lesson seems to be: avoid vinyl siding, stick with the brick if I can...) :)