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Soft washing a roof

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41
Location
Lochgilphead
What’s the best way to tackle roof cleaning? Scraping the moss off then treatment or can this be done with just treating the roof. Roof is a big area and will take days scraping the moss off. The roof has a fair bit of moss on it  

 
What’s the best way to tackle roof cleaning? Scraping the moss off then treatment or can this be done with just treating the roof. Roof is a big area and will take days scraping the moss off. The roof has a fair bit of moss on it  




Scrape the worst off first then softwash 

 
Scottish hope it all works out for you but you only need a loose/cracked tile and your custy gets a complimentary shower in the loft ? Marely the tile manufacturer website https://www.marley.co.uk/blog/how-do-i-remove-moss-or-lichen-from-my-roof

"It is not recommended to remove moss by pressure washing as this can force water into the roof space, particularly if sprayed upward from ground level.


I sit on the ridge like a little gnome with my 90 degree lance which is 1.5m long. I use a roof ladder as I move down. Any broken tiles then I just replace them. Roofers and tile Merchants don't want you to do it because they lose business and want you to replace the whole roof. ? 

 
Conspiracy theorist hey...if you go to the link Marley do talk about how to clean their roofs...they don't exclude it, just sensible observations.  

 
Conspiracy theorist hey...if you go to the link Marley do talk about how to clean their roofs...they don't exclude it, just sensible observations.  


Guy on utube powerwashes a roof tile and there's no difference in thickness. I use a Falch nozzle so its 4 jets and doesn't tear into the tiles. I use it on decking also, I did a short video of it on my Checkatrade page if you want to look at it. You will soon realise that big business will do and say anything to protect their business, Boeing is a fine example. fwiw

 
Scottish - Different folk, different strokes, in my personal experience, almost without exception every roof I've ever cleaned (or got up close to) has defects and or shows signs of wear and tear (most are 30-40-60-100's years old).

To name a few...

Major cracks in tiles

Slipped tiles revealing 'black holes'/battons/felt...

Loose/ill-fitting tiles 

Large gaps in tiles/slate (fit your hand in them)  

Holes the size of a tennis ball (that one was weird, the roof had about 3-4 of these holes in different places - all covered by moss so not visible until moss was removed). 

Mortar fillets at edges/valleys, missing, slipped or visibly corroding.

Signs of past dogey repairs, mastic/sealants in cracks etc...

With the roof covered in moss it would be too late once I'd blasted off the moss exposing the 'issue' to prevent water ingress... Water travels and water under force will travel further 'seeking' out any vulnerabilities already present on the roof.

So if I had gone in with my pressure washer I'm 100% convinced I would have caused considerable water damage or further damage to the roof,  some visible at the time, some only apparent weeks or months later...it would simply be a factor of the number of jobs carried out sooner or later I'd come a cropper (or rather my customer would), do this to the 'wrong' custy and I'd fancy I'd end up being sued/pursued for repairs/damage costs (which I suspect would be significant).

So for me, being risk adverse, I prefer the more time consuming but more 'gentle' approach of scraping... (if someone can convince me otherwise I would bite his hand off as my productivity would go thru the roof (pun intended ?)

 
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Seriously...you raise an excellent point, when I'm quoting for moss jobs, I always explain the process and I'd say 50-70% people say - 'ah yes good, so you don't use a pressure washer, great' or similar and this is after most of them coming to me via my website which details my approach so they are/should already be aware. I've noticed this has changed over time so I suspect most google it and soon form an opinion 'gentle' is best 

 
So for me, being risk adverse, I prefer the more time consuming but more 'gentle' approach of scraping... (if someone can convince me otherwise I would bite his hand off as my productivity would go thru the roof


I am a joiner to trade so i know how old the building is. I'm looking to do houses that are not more than 20yrs old or have been re-roofed. If I ever get one that i uncover a nightmare then I will stop and inform the customer that it is not worth doing because new tiles are order of the day. The folk that I seem to get are only wanting all the moss removed. Cleaning a roof on Monday where I will take a few photos to see what everyone thinks.

Seriously...you raise an excellent point, when I'm quoting for moss jobs, I always explain the process and I'd say 50-70% people say - 'ah yes good, so you don't use a pressure washer, great' or similar and this is after most of them coming to me via my website which details my approach so they are/should already be aware. I've noticed this has changed over time so I suspect most google it and soon form an opinion 'gentle' is best 


My Checkatrade site shows me using a Pressurewasher so they all know my method. Will probably take a before and after photo for my website on Monday.

 
Just my luck,the first softwashing job I have offerd to an existing window cleaning client,says he dosent want the roof scraped in case I damage some tiles. I don't know weather just applying benz bioside would work.i could just walk away but hes a nice bloke,an I would like to help him out.Theres a medium coverage of moss I would say. What shall I do please?Thanks

 
Just my luck,the first softwashing job I have offerd to an existing window cleaning client,says he dosent want the roof scraped in case I damage some tiles. I don't know weather just applying benz bioside would work.i could just walk away but hes a nice bloke,an I would like to help him out.Theres a medium coverage of moss I would say. What shall I do please?Thanks
Coat it with Bio soap powder and it will die off, Then you could brush it off.

 
Just my luck,the first softwashing job I have offerd to an existing window cleaning client,says he dosent want the roof scraped in case I damage some tiles. I don't know weather just applying benz bioside would work.i could just walk away but hes a nice bloke,an I would like to help him out.Theres a medium coverage of moss I would say. What shall I do please?Thanks
You can spray it with a strong mix of bio and it will kill it over time provided there is no rain within the first 6 hours or so !,,, the problem will be over a period of months it will gradually come down the roof filling the gutters up , and you will need to keep going back to empty them so allow for that when pricing , also you might find that it will need a further spray at a later date @kevinc250 is the expert in this field and Ime sure he could offer some useful advice .

 
roof scraped in case I damage some tiles.
Diamond - you can 'scrape' with a nylon or plastic (or wooden etc) blade would just need to knock something up - doesn't need to be metallic - this will mitigate risk of damage somewhat - but the risk is still there. Charge for multiple sprays and regular gutter cleans to keep the roof free draining once the moss dies it will clog the valleys/gutters etc or you could spray, let it die off, and brush it off (brush head with an acme thread where the handle attaches and get an acme screw adapter from say..(insert your fav WFP supplier) and fit to your WFP - you can then brush from the ground/gutterline...there's a smaller risk of damage brushing down the tile/than scraping along/down them (Coincidently I spoke to a biocide supplier earlier this week about if their product would be effective for light moss covering and the no scrape but spray and leave approach - they basically said it probably wouldn't be effective)

 
Diamond - you can 'scrape' with a nylon or plastic (or wooden etc) blade would just need to knock something up - doesn't need to be metallic - this will mitigate risk of damage somewhat - but the risk is still there. Charge for multiple sprays and regular gutter cleans to keep the roof free draining once the moss dies it will clog the valleys/gutters etc or you could spray, let it die off, and brush it off (brush head with an acme thread where the handle attaches and get an acme screw adapter from say..(insert your fav WFP supplier) and fit to your WFP - you can then brush from the ground/gutterline...there's a smaller risk of damage brushing down the tile/than scraping along/down them (Coincidently I spoke to a biocide supplier earlier this week about if their product would be effective for light moss covering and the no scrape but spray and leave approach - they basically said it probably wouldn't be effective)
Bio will kill it with out scraping but it might need a couple of applications, I agree it’s best to scrape first I made this out of plastic works a treat and doesn’t cause any damage 

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