Roof Moss Removal

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tdgeek

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#293822 15-Feb-2022 18:30

The Management Team has decreed that on my weeks annual leave, I take care of roof moss.

Two level house, concrete roof, the moss isnt the flat green stuff, its the 3D yellow stuff

The obvious option is Wet and Forget on a hose. I can stand on a step thing or a fold over trestle.

Whats the best option? More about effectiveness than cost. White Vinegar works great but i dont have an applicator, but if I got WnF, I can use that after a week or two as a boost? As I will then have a hose applicator.

Any thoughts appreciated.

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#2869037 15-Feb-2022 18:58

Wet and forget, the super power one that you leave on, is worth a shot first. I used it on my guttering and it did ok, in that I can't see it any more. I also used the version you brush in and hose off which worked well on paint. The leave on one takes some time to work, from memory 1-3 months, if it's not helped in a few months get a professional in.

Wear a mask (ideally a proper one not a cheapie), eye protection, old clothes as they may end up bleached, gloves, and ideally wet weather gear.

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#2869041 15-Feb-2022 19:10

Found bioshield is quite good same active ingredient as wet and forget but more concentrated

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#2869042 15-Feb-2022 19:11

timmmay:

Wet and forget, the super power one that you leave on, is worth a shot first. I used it on my guttering and it did ok, in that I can't see it any more. I also used the version you brush in and hose off which worked well on paint. The leave on one takes some time to work, from memory 1-3 months, if it's not helped in a few months get a professional in.

Wear a mask (ideally a proper one not a cheapie), eye protection, old clothes as they may end up bleached, gloves, and ideally wet weather gear.

Thanks

On the last house we sold, white vinegar was great. It kills all the moss, unlike bleach that kills what's on top. Fences and here and there. The two level house is more problematic.The house next to house is plastic tiles. (Plastic over steel?) The other one is Coloursteel, both no issues. But I will get Wet and Forget tomorrow and give that a try. Its not everywhere on the roof, but I guess that concrete tiles gives it a foothold

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#2869109 15-Feb-2022 20:03

A solution of iron or copper sulphate will kill moss on contact...

pluses , it’s cheaper than the others

minuses.. the moss will turn black on contact and you still have to get it off the roof

timmmay

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#2869118 15-Feb-2022 20:37

I think I something sulphate in the greenhouse and it REEKS for days. From memory copper sulphate is very strongly colored as well and can stain. Be a bit careful.

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#2869185 15-Feb-2022 21:33

I used wet and forget with a hose to spray the yellow lichen on a clay tiled roof.
Took about 3 months and more as @Timmmay said for it to flake off and wash away by rain.

Got a professional to treat certain areas of the tin roof in our current dwelling.
He claimed that his stuff is better and more potent than the stuff from stores. Even that took a while to kill the lichen off.

Suggest that you apply when you have a few days clear of rain. Spray and walkaway!

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#2869190 15-Feb-2022 21:44

I didn't use wet and forget, I used something from Miter Ten with the same active ingredient.

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#2869193 15-Feb-2022 21:55

Benzalkonium Chloride is the active ingredient in the slow acting spray and walk away type moss and lichen removers.

Different brands just seem to have different concentrations of it and may have their own spray systems for application.

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#2869229 15-Feb-2022 22:16

I used the 30 seconds spray and walk away hose end before lockdown in august, the moss was very thick on my roof, particularly under the aerials.

The spray could reach over half the roof so I did not have to walk on wet tiles.

I then used the rest on my driveway.

I have to admidt the drive looks a lot better, there is still a fair bit of moss on the roof but not as bad, the thin patches are gone and the this patches are getting thinner, every day or two I see a clump of moss off the roof and on the lawn, could be birds it could be wind, I dont know.

I should do it again soon so when the winter rains come they will hopefully take some more away.

https://www.mitre10.co.nz/shop/30-seconds-spray-and-walk-away-hose-end-2-litre/p/201833

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#2869313 16-Feb-2022 05:43

Moss will work it's 'roots' into concrete tiles so it will take some time for it to fully go away - could be a few months and it will slowly discolour in that time. You really need to be spraying preventively (but I've been in your shoes before).

I recommend the number 8 branded stuff from mitre10 (with the 30 seconds hose applicator). Apply it now and again in a month, then do 3 monthly applications.

If you must get rid of the '3D' bits tomorrow then it would need a careful waterblast

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#2869326 16-Feb-2022 07:31

Unless it's a light infestation I wouldn't bother with the retail products. I have found them next to useless. After 2 years of trying different products (these things can take months to show effectiveness) I got the professionals in which probably cost less than I spent trying to do it myself. It came with a guarantee and took 2 applications to fully get my roof clean and free. Application was done without standing on the roof (so no fear of damage) and was worth every cent to stand there and watch someone else do it.

Lazy is such an ugly word, I prefer to call it selective participation

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#2869412 16-Feb-2022 09:58

Ive found that Wet & Forget is not that good in areas that get a lot of water when it rains . ( They say it needs to be wet to re-activate )
My sloped Driveway , meh .
Side of the house & the fence, it was really good.

I also found the Wet & Forget you plug the hose onto the container worked better than the old style W&F I mixed & used a manual sprayer .

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#2869506 16-Feb-2022 11:13

Thanks all, I'll get a hose end version today, see how it goes. The hose end might be quite handy for lawn/garden foliar spray of seaweed emulsion, exterior house spray with dish detergent or turtle wax etc

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#2869542 16-Feb-2022 11:45

timmmay:

I think I something sulphate in the greenhouse and it REEKS for days. From memory copper sulphate is very strongly coloured as well and can stain. Be a bit careful.

Copper sulfate is blue, no discernible odour that I remember. Lime sulphur stinks likes the hounds of hades. Copper hydrochloride, is powder blue, with minimal odour.

Mike

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#2869544 16-Feb-2022 11:47

I would say seeing as you are on leave and it's been designated your job, do the slow acting spray-and-walk away product. You'll be done in a few hours and then you can have an actual holiday.

Mike

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