Roof cleaning. Idle curiosity

[Truckcab79]

This isn’t a bit of preemptive research as I have zero intention of getting into roof cleaning. Don’t have the time, inclination or equipment.

However I see quite a few tiled roofs that have been cleaned and the red clay roof tiles look rather yellow, faded and worn. If they were mine I’d be wishing I’d left it well alone. Think they look awful.

Out of interest, is this poor cleaning technique? Wrong chemicals or something, or just how they look when old but clean? As a client I’d expect them to look fairly ‘as new’ but they look dreadful (but clean), in my opinion.

Sorry. Appreciate pictures would help but don’t have any at this time.

 

[Deleted member 5762]

@Truckcab79 They've been bleached / sodium hypochlorite. A couple of cleaning company's near me have done it and they look awful in my opinion. It will kill algae quickly and is quick and cheap, but I don't know if it's better than an algeacide or whatever they call it. I don't pretend to know the first thing about roof cleaning, however a roofer I know told me he would never recommend using bleach on a roof.

 

[Truckcab79]

@Truckcab79 They've been bleached / sodium hypochlorite. A couple of cleaning company's near me have done it and they look awful in my opinion. It will kill algae quickly and is quick and cheap, but I don't know if it's better than an algeacide or whatever they call it. I don't pretend to know the first thing about roof cleaning, however a roofer I know told me he would never recommend using bleach on a roof.

Cheers. So does hypo bleach fired clay? I did wonder. I use it on all sorts including clay brick and never seen that issue. Maybe I’m just more cautious with dilution and dwell time.

 

[ched999uk]

From what I have seen some tiles have a coloured coating on them from new. This coating wears away due to wind and rain erosion etc but due to the dirt, moss etc that builds up this hides the discolouration. When they are cleaned by scraping or pressure washing & biocide/hypo the dirt is removed and you can see the discolouration.
I would be very surprised if hypo actually changed the colour of roof tiles.
I do agree that the tiles that are weathered looked better before cleaning but sometimes the build up of moss creates other issues that are resolved by a good roof clean.
I did half my roof last Feb as we had solar panels fitted and they are flat concrete tiles probably from 80's and they came up nice solid colour no weathering at all which I was surprised at as we are close to the sea we get a fair bit of blown sand to blast the house. I must get round to doing the other 2 sides this year

 

[Truckcab79]

From what I have seen some tiles have a coloured coating on them from new. This coating wears away due to wind and rain erosion etc but due to the dirt, moss etc that builds up this hides the discolouration. When they are cleaned by scraping or pressure washing & biocide/hypo the dirt is removed and you can see the discolouration.
I would be very surprised if hypo actually changed the colour of roof tiles.
I do agree that the tiles that are weathered looked better before cleaning but sometimes the build up of moss creates other issues that are resolved by a good roof clean.
I did half my roof last Feb as we had solar panels fitted and they are flat concrete tiles probably from 80's and they came up nice solid colour no weathering at all which I was surprised at as we are close to the sea we get a fair bit of blown sand to blast the house. I must get round to doing the other 2 sides this year

Good point. It might just be wear. There’s another near me that was done recently by some chaps clambering around and scraping it by hand. Not sure if they also treated it but judging by the way they were working I’d doubt it. Looks just as bad.

What made me think to ask was passing one each night on the way back from current job. It’s got a section about 3m square cleaned. Reckon the client saw it after they’d started and put a stop to the rest. ?

 

[THL4KEL]

Good point. It might just be wear. There’s another near me that was done recently by some chaps clambering around and scraping it by hand. Not sure if they also treated it but judging by the way they were working I’d doubt it. Looks just as bad.

What made me think to ask was passing one each night on the way back from current job. It’s got a section about 3m square cleaned. Reckon the client saw it after they’d started and put a stop to the rest. ?

Roof cleaners sometimes do a sample patch so potential customer can see what to expect. It's not a cheap service so not for everyone.

 

[Deleted member 5762]

Cheers. So does hypo bleach fired clay? I did wonder. I use it on all sorts including clay brick and never seen that issue. Maybe I’m just more cautious with dilution and dwell time.

@Truckcab79 I have no idea how it works. All I can judge is the ones I've seen. The same company did about 6 roofs in the road next to my kid's school. The bleach absolutely stunk when they were doing them and every single roof is a sort of yellow colour now. Most are a were originally a sort of dark grey colour with a grainy texture. One other was a dark terracotta one (apologies I don't know the actual names). All of them stick out like a sore thumb. The best one I've seen was a lady who had it scraped and then an algaecide put on. The roof took a bit longer to look clear completely but it did look good. I think it was quite expensive stuff though so assume roof cleaners use bleach as it's cheaper and quicker.

 

[THL4KEL]

Check out Sid Partridge (You Tube) roof cleaning is mainly what he does. Don't think he uses hypo, mainly biocide either scraping certain tiles or steam or cold water with a pressure washer.

 

[ched999uk]

@Truckcab79 I have no idea how it works. All I can judge is the ones I've seen. The same company did about 6 roofs in the road next to my kid's school. The bleach absolutely stunk when they were doing them and every single roof is a sort of yellow colour now. Most are a were originally a sort of dark grey colour with a grainy texture. One other was a dark terracotta one (apologies I don't know the actual names). All of them stick out like a sore thumb. The best one I've seen was a lady who had it scraped and then an algaecide put on. The roof took a bit longer to look clear completely but it did look good. I think it was quite expensive stuff though so assume roof cleaners use bleach as it's cheaper and quicker.

The biocide seems to be about £100 a tub, so significantly more expensive than hypo. The other issue with scraping and then biocide treatment is the roof will take about 6 months to achieve the full clean - so it could be difficult to convince a customer that they have to wait 6 months to see the final results! A scrape then hypo gives on the day results so a customer can see what they are paying for.

I'm yet to be convinced about biocide actually protecting long term as they say not to apply if there is a likelihood of rain. So what happens if it rains after the application? Does it wash it off or is it fine once soaked in? I can understand it taking a good while to kill the remaining moss, lichen and algae but long lasting effects????

 

[Deleted member 5762]

The biocide seems to be about £100 a tub, so significantly more expensive than hypo. The other issue with scraping and then biocide treatment is the roof will take about 6 months to achieve the full clean - so it could be difficult to convince a customer that they have to wait 6 months to see the final results! A scrape then hypo gives on the day results so a customer can see what they are paying for.

I'm yet to be convinced about biocide actually protecting long term as they say not to apply if there is a likelihood of rain. So what happens if it rains after the application? Does it wash it off or is it fine once soaked in? I can understand it taking a good while to kill the remaining moss, lichen and algae but long lasting effects????

@ched999uk roof cleaning looks absolutely an absolute minefield for me so I've never had an interest in it. My pal is a roofer and I can only go on what he says. The only experience I have of roof cleaning is me and my Grandad used to get the moss off him and my Nan's bungalow roof with a scraper and a broom and that was it. That was years ago and I still drive past their old house and the roof still looks fine to me. Depends alot on what you prefer it to look like I suppose. I agree on alot of people though probably want to seen an instant result. The roofs by my kids school are a faded yellow colour. I tried to take a photo while I was on the school run but the lady house owner was in her porch going absolutely ballistic at someone on the phone so I thought I'd better not lol. I was talking about algaecide earlier but I think I meant biocide (unless they're the same thing).

 

[Pjj]

Cheers. So does hypo bleach fired clay? I did wonder. I use it on all sorts including clay brick and never seen that issue. Maybe I’m just more cautious with dilution and dwell time.

No it doesn’t it won’t bleach any roof tile that I have come accross , it will kill all algae and bacteria lichen etc though .

 

[Pjj]

Roof cleaners sometimes do a sample patch so potential customer can see what to expect. It's not a cheap service so not for everyone.

This is a customer of mine they have just had the roof cleaned by a local firm , it’s an awkward roof to access and it’s 3 storey at the back , they charged her £900 I said that’s a bargain I wouldn’t want to do it for that , she was quite relived as she thought she had been ripped off .

 

[THL4KEL]

Doubt you will ever find a roofer who will recommend getting someone to the clean a roof, they would be putting themselves out of business... Their answer is always - you need a new roof.

 

[Cleanco]

More like they’ve changed the tiles back to the original colour and they were that mingin prior, same as their neighbours so they would have no reference. The newer tiles do have a coating on them but once that wears away it’s anyone’s guess as to what the manufacture used to bulk up the mix to create the main body of the tile. I tend to not listen to roofers on this subject as they are always gonna be biased cos they want the job of retiling as opposed to cleaning. That said they once the coating wears off whether from natural erosion or from any cleaning is that they are a lot more porous but still shouldn’t let any water soak through but I’m not exactly sure. I would be looking at the shoddy use of cheaply manufactured tiles as the problem and the cleaning process merely highlights this rather than causing it.

 

[Pjj]

When I went on a softwashing course by AC Lockier the yank he was very suppprised that roof cleaning in this country is on a very small scale he said you wouldn’t clean your car and not clean the roof so why clean a house but not the roof , I do think he had a point he showed the temperature difference between a clean and dirty roof with thermal imaging pictures it was very interesting, the clean roofs the temperature was considerably lower stopping the felt from being cooked and drying out causing premature cracking in it then it all needs replacing, what he said made sense . Roof cleaning in this country is starting to take off slowly I think but still not on the scale of a lot of countries

 

[ched999uk]

@ched999uk roof cleaning looks absolutely an absolute minefield for me so I've never had an interest in it. My pal is a roofer and I can only go on what he says. The only experience I have of roof cleaning is me and my Grandad used to get the moss off him and my Nan's bungalow roof with a scraper and a broom and that was it. That was years ago and I still drive past their old house and the roof still looks fine to me. Depends alot on what you prefer it to look like I suppose. I agree on alot of people though probably want to seen an instant result. The roofs by my kids school are a faded yellow colour. I tried to take a photo while I was on the school run but the lady house owner was in her porch going absolutely ballistic at someone on the phone so I thought I'd better not lol. I was talking about algaecide earlier but I think I meant biocide (unless they're the same thing).

I think it's very very hard work and I am surprised that there as many people as there are getting it done. If you watch Sid you will see he does have to travel quite a way to maintain a busy week.
My roof had a bit of moss on, not much and was quite a dark red colour flat concrete tiles. I won scrapers from Sid a long time ago plus I have a diy scaffold tower, so I thought I would give it a go especially as we where having solar panels fitted so last opportunity. The small amounts of moss scraped off quite easy and I use hypo to 'clean' the tiles, they did come up brighter which was nice plus I'm guessing that them not being as dark will stop a little heat absorption which was heating the room in the roof. It was quite hard work, I would much prefer to clean windows all day than do a roof job, so the money would have to be good

 

[THL4KEL]

Roof cleaning is more lucrative than pressure washing, but more equipment needed and takes longer to set up.

 

[Pjj]

I think it's very very hard work and I am surprised that there as many people as there are getting it done. If you watch Sid you will see he does have to travel quite a way to maintain a busy week.
My roof had a bit of moss on, not much and was quite a dark red colour flat concrete tiles. I won scrapers from Sid a long time ago plus I have a diy scaffold tower, so I thought I would give it a go especially as we where having solar panels fitted so last opportunity. The small amounts of moss scraped off quite easy and I use hypo to 'clean' the tiles, they did come up brighter which was nice plus I'm guessing that them not being as dark will stop a little heat absorption which was heating the room in the roof. It was quite hard work, I would much prefer to clean windows all day than do a roof job, so the money would have to be good

Yes it will reduce the heat in the loft but that’s not a bad thing as it stope the felt from being cooked and drying out and cracking up

 

[Cleanco]

Yes it will reduce the heat in the loft but that’s not a bad thing as it stope the felt from being cooked and drying out and cracking up

Give me some moss then cos my office is in my attic and come summertime I’ll be 2 stone lighter?

 

[Deleted member 5762]

I'm not saying a roofer would recommend getting a new roof over cleaning it. Far from it and certainly not the one I know. Only that he didn't recommend bleaching it.

 

[THL4KEL]

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