Roof pressure washing?

Hi All,
Has anybody any experience of having their roofs pressure washed?
Ours is a 70's house with concrete tiles and is covered in moss etc.
I was keen to get it cleaned this spring as the moss fall out around
the house is getting worse. However Im not sure how damaging
this process can be, and if a good stiff brush is better? Although I
have
a pressure washer I would have somebody else do this as Im not keen
on climbing over a roof. Any idea of cost?
Matthew
Reply to
m_d_allen
I can't help but also have the same problem. It's worst on my north facing garage roof. I had contemplated fitting a copper strip under the ridge tiles, which is supposed to do the trick and inhibit moss growth, but the price of copper has gone rather astronomical lately.
Has anybody tried this and is there an alternative to copper?
Andrew.
Reply to
andyv
So long as the pressure wash is used down towards the eaves of the roof no damage will result,however be prepared to clean up a lot of sh*te afterwards. :-)
This will not get rid of the build up of moss permanently but will take a while to build up again in the future.
Reply to
George
This issue came up here a couple of weeks ago and professional advice was *not* to pressure wash, others disagreed and said it was OK...
The message from gerry contains these words:
have
Marley certainly advise against pressure washing. We use Armillatox and elbow grease. Three courses shouldn't take that long to clean, with a deck scubber.
-- AnneJ
formatting link
Reply to
Dave Osborne
tiles.
I can ust see the headlines now....
Man takes hours scrubbing his roof tiles clean with a scrubbing brush and Armillatex.
Reply to
George
There is a fine line between pressure washing, and eroding tiles and or breaking them
As there is when getting lichen off car bodywork: sometimes the paint come's too..
I think that if you prioeed with intelligence and care, pressure washing is a huge boon. Used by the average gibbon, great damage can be caused.
Hence the advice, which has to be for the average Gibbon:
Rules are for the obedience of fools, and the guidance of wise men.
Reply to
The Natural Philosopher
LOL, I appreciate what you're saying, but the priciple apparently applies to whole roofs (including large commercial roof and churches) as well. Have a look at the copperidge website.
Reply to
Dave Osborne
I find it hard to believe that an ordinary pressure washer can do "great damage" to concrete roof tiles, unless they're in bad condition already. Probably the biggest risk of damage is that of gaining access.
Reply to
adder1969
"The Natural Philosopher" wrote in message
Urban myth,the guy two doors up is always using a Karcher 2kwatt jobby on his every month.
Reply to
George
I suppose it all depends upon how close tyou hold the nozzle. Too close and you could do a lot of damage.
Re: copper. It doesn't need to be a heavy section so cost shouldn't be an issue. Some old electrical cable stripped down would do the trick.
Reply to
John
I have stripped paint from an old car. Get a bit of loose grit in there and you have what amounts to a sandblaster.
You can cut stone with a high pressure waster jet and sand.
If you want to try it, get some sand, lay it ona concrete slab, and get pressuring.
You can probably etch your name in it in a few minutes. Once the concrete starts breaking up, it generates its own 'sand'
Reply to
The Natural Philosopher
Sorry, no myth. I have actually done it. Twice. If there is a tiny rust bubble, the jet gets behind the paint and it comes off. If there is any flaw in the clear lacquer, that flakes off as well. If there is any grit in the jet, it scores the paint as well.
If the car is bran new and in good condition, and you hose it down to remove grit first, then it will likely be fine. If its is old, and there are any suspect areas, pressure washing will scrub down to bare metal faster than you can say 'bloody HELL'
Reply to
The Natural Philosopher
Hah! now we're getting somewhere ie blistered paint,raised laquer film...of course it will damage these areas more so but generally ti won't daage the cars paint wor providing there's no flaw in it to begin with.
I jet wash my upstairs/downstairs windows and it makes em gleam...realy takes all the weathered sh*te of. ;)
Reply to
George
Wha are you on? In 30 years I've only ever seen paint damage once - that was a hand painted Lada. If the paint is basically sound not pressuer washer on the planet will remove it. If not properly bonded, its gonna come off one day anyway.
I should say 'hand held' pressure washer here. They use 5000 bar machines to remove paint & rust with water alone.
Reply to
The Medway Handyman
No it isn't, I managed to lift a section of paint. All it needs is a weak edge to the paint to start it and once started it is eaaasy to take the paint off.
Reply to
Harry Bloomfield
There ya go...weak paint area,like I said its urban myth to lift paint of any sound suface ie I can't even take the paint of the walls of the house and thats emulsionised paint.
Reply to
George

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