How do I get rid of moss on my sidewalk and the top of my garage?

try wet and forget

If you would care to share what you have tried we may be able to recommend something else. As it is you are telling us that nothing works. Spray and Forget has worked well for me.

Bleach is harsh but it will kill almost anything, use a spray bottle

Possibly Tilex...It worked for me on mold.

Professional advice: check this: https://www.bobvila.com/articles/how-to-remove-moss-from-roof/#.WmoFGainGUk.

Personal advice: If you can up on the roof safely to spray, Wet n Forget will work to kill the moss and it will gradually wash away. Simple to apply on sidewalks. If you prefer more fun, look up a baking soda solution and get some big water guns and apply from the ground. Bleach solution will kill the moss, but can be hard on the plantings below. All of these methods will require reapplication, depending on your climate and sun exposure.

Scrape off the moss, then nail zinc coated metal strip along roof peak. You should be able to get this material at any home improvement centre. Rain water on zinc will kill moss.

Back in Arkansas, I eliminated moss with direct application of baking soda. Dust in on like powdered sugar on a donut! It may be difficult to get to the roof, though. A longer term solution is figure out why the roof and sidewalk are staying wet in those areas. You can buy baking soda in large 4 pound boxes for a couple of dollars. You may well have to have some shingles replaced, which can be expensive and beyond many DIY types. Moss will hold water in, so you'll need to check the wood under those areas to make sure you haven't got serious damage. We are doing a roof repair now (hail and wind, not moss) and we have so far got about $250 into about 200 square feet of repair. Good luck.