It's moss...not serious, but you want to get it off so that it doesn't increase and start the shingles to start deteriorating. Here is an article on the subject: Moss removal

As for the gutters, you need to get those fixed. If you don't understand what is required, best to call a gutter repair company.

I have had success with applying Wet and Forget on my asphalt shingle roof.

I used pool algaecide on the moss on my roof. Same chemicals as Wet & Forget, only cheaper.

I bought the 50% concentrate. Apply a 2% solution or 5 oz: 1 gallon of water. I used a hose end sprayer to apply it.

Also works to kill mold & mildew on siding and algae on patios & sidewalks. Takes time for it to work so be patient and don't expect instant results.

Hi,

Thanks for the replies. Do you know how urgent this is? Should I get this fixed as soon as possible, or can I wait till till the beginning of next rainy season?

I do not have tree branches that overhang the roof. So not sure why would this happen.

Also the roof is old, and I was told by the realtor that I have a few years. So I want to assess if I want to get the roof & gutters fixed, or do I need to get them replaced. How do I make the call?

I would spray the roof now so the moss doesn't grow more. Your call on the gutters. May be that you can repair the gutters yourself for a few $ with some new gaskets or sealant if you have a single floor home? From what I can see of the shingles, they look to be in decent shape w/ no urgent need to replace them.

Just my opinion, but there's no need to rush to get the moss off the shingles.

It's not an emergency, but moss growing on a roof does ultimately shorten its lifespan. Why do you want to wait until the "next rainy season"?

Ok, I got the gist :)

I will try "Wet & Forget" myself.

I will do some homework on gutters & get them fixed before the next rainy season.

And the roof will be redone after a few years.

If your even just a little bit handy and can get to gutters with a ladder you can get a sealant for seams and connection points, made especially for this. I would imagine there is a bunch of stuff on YouTube for this. Also you need to make sure your gutters and downspouts are clear of debris/clogs so water flows freely.

The reason that I would do it now is because the conditions are right; the chemicals work better when the roof is moist/ the air is humid/ the moss actively growing.

My dH is always looking for excuses to put something off 'til next year. Translation: It never gets done.

So, you have wet conditions now; If you wait a year, you might forget to do it or be tied up in something that prevents you from getting it done.

Oh, that's good to know about checmicals and humidity. Thanks.

As far as gutters go, as I was mentioning, spouts are little loose from gutter. So sealant may not work everywhere. Attaching a photo, I hope it gives an idea.

Par Asm-

Just so you know, you don't normally seal the gutter-spout connection or any of the drainpipe connections below the downspout. They simply fit inside one another with the higher piece always placed inside the piece below it. If any joint is a little loose, you can drill a hole and put a very short sheet metal (preferably stainless steel) screw through the two pieces.

Sometimes you get clogs somewhere in the spouts, and it's much easier to take everything apart if the pieces are just held together with screws rather than being stuck together with some unnecessary sealant. If you are getting leaks when it is raining, it means either that there is a clog and water is backing up, or that the pieces haven't been assembled properly as I explained.

Checked the roof condition after 1+ month of spraying Wet&Forget. Looks like the situation has not changed a bit. Looking at the level of fluid in the Wet&Forget can, I think it is not dispensing properly. Any thoughts?

Wet and Forget is not a fast acting product, so I wouldn't worry about that.

You might need to switch out the liquid to a hand pump sprayer - less than $10 at the big box stores.

Hand pump sprayer

Any idea what is the range of the hand pump sprayer? Would I have to climb up the roof to get all of it covered?

Attaching the garden hose to Wet&Forget is easier, but it does not seem to mix 20% of the solution with water.

Also it is possible to rent a powered pump sprayer from Home Depot?

Since the Wet & Forget isn't dispensing properly, I would return it to the store or contact the company directly.

Wet and Forget

Just use common bleach. You can get copper roof strips to mount at the peak that will prevent anything from growing on your roof for the rest of it's life.

The hand pump is probably good for maybe 4 feet - guessing.

I think Home Depot rents electric pressure washers. If you could practice with one one enough so that you could get the solution to fall as an arc of rain on the roof rather than direct pressure, that might work.

Also remember that if you do spraying of any kind it will atomize the liquid: you want to be wearing respiratory protection so you aren't breathing this stuff into your lungs.

Got a replacement, put it ON position, and it's working :) Applied today, will check the results after a few days.