# Forum Home Renovation Painting  Cleaning Terracotta Roof Tiles

## John99

Hi all  
Does anyone know how to clean terracotta roof tiles they have about 45 yrs of build up on them? 
What type of chemical would I apply then water blast off ?  
What are some of the things I should look out for while I'm doing it ? 
The tiles are unglazed terracotta, are there any coatings that I could apply to them to give them a gloss look ?  
I did get a quote to clean the roof but the bloke carried on so much and gave a quote of $5000 just to clean the tiles !  
I can replace the whole roof for $7000  
All I what to do is clean the tiles does someone have some advice on what the go is ?

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## echnidna

A hand held wire brush takes it off easily but is very slow.
I reckon a high pressure water washer would do it very well

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## rsser

A gurney will do a lot to remove grunge.  Just beware of where you point the jet - it won't do wonders for weak ridge cap pointing for example. 
And try to prevent too much of the muck going down your drain pipes - perhaps block them and scoop the muck into a bucket.  It tends just to sit in storm water drains where the drop is only modest.

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## blt

We did the following on our roof, not sure if it's right or wrong! 
Brushed the whole roof with an old broom and diluted bleach (about half bucket bleach, half water)
Waterblasted it with a cheap high pressure water sprayer (avoiding the ridge capping, which in our case does need repair)
Admired the results (looked almost brand new, after 20yrs of crud buildup) 
Unfortunately we didn't seal it afterwards... like you we weren't sure what to use, and just didn't get around to it. So now (about 6mths later) it looks pretty grungy again. Would like to find out the best product to seal it with....

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## Ian007

roof repairs/ painters only use high pressure water. 
terracotta tiles are lovely to look at but are a major pain as far as working on them. so use extra care, terrecotta tiles when wet can be very dangerous if not lethal.  :mad: 
what sort of pitch is your roof? any thing over 25-27 starts to get a bit steep for working on all day. ( kills the ankles by the end of the day)  :Shock:  
one of the other draw backs is you will more likely than not get some water ingression into your house from pressure cleaning them :eek: . so use extra care as stated in the other posts. 
I hope that you are not that big a person as they usally break rather easily if you stand in the wrong spot on your roof. :eek: 
I work on air conditioners all day so am always on someone's roof. I personaly hate terracotta roof tiles  :mad: because they always seem to break(read have plenty of spare tiles) that my 2 cents worth 
hope that helps 
Cheers Ian  :Smilie:

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## journeyman Mick

John,
why do you want to clean them? I reckon "if it ain't broke, don't fix it". As Ian has pointed out, just walking on a tile roof can do a lot of damage, and there's always the possibility of water ingress and damage to the pointing. If the only thing left on my around the house "to do" list was cleaning the roof tiles I reckon I'd go and put my feet up and have a beer instead!  :Cool:   
Mick

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## bitingmidge

In the good old days when all sorts of things were safe to use, James Hardie  :mad:  used to recommend treating Fibro  :mad: roofing with a Copper Sulphate solution. 
We used it a few times on new sheet and old, and it certainly killed the mould.... I guess it's too dangerous to use now  :confused: . 
If it won't kill you and half the fish in the Pacific Ocean, mix a brew and slop it on the roof...leave it for a week or so then pressure blast.  If you are careful with the blasting you won't get any more water in than in a normal heavy storm, and if you blow any pointing away it needed replacing anyway. 
Oh... and tread lightly!! 
Perhaps you should have an accident first involving a chemical lab and a spider bite.  
Cheers, 
P   :Biggrin:   :Biggrin:   :Biggrin:

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## echnidna

Copper sulphate will corrode metal gutters so dont let it sit in the gutters and flush them out properly.

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## John99

thanks for the suggestions about cleaning the roof and if I use high pressure water to clean it I wont have to worry to much about the ridge cap pointing as most of it is gone long ago, well sometime in the last 45 yrs and needs re-doing anyway 
But I have to clean it because i`m putting on a extension and would like to match what is up there as close as possible any way, the pitch of the roof is 26% and it seems the more time I spend up there the more I like being up there  
Does anyone know what product I can use to seal it with after it is clean? I`d like it to stay clean for more then 6 months if possible ? 
thanks for any help or advice you can give

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## scooter

John, don't know exactly what product but I'd look at concrete & masonry sealers (in the indoor timber section at Bunnings among other places) and possibly talk to the manuafacturers of same - there are products there that can be used for sealing terracotta pots, etc so should be something. 
The stuff used by roof renovating rogues is pretty thick, coloured,  and has some sort of flexible base. You may be able to do some research through roofing product suppliers to source it. 
Good luck.......cheers.........Sean the roofless  :Smilie:

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## jimc

A tip from someone who spent 5 months cleaning over 7000 bl@#dy terracotta 100 year old Marsielle tiles. Removal and replacement with colorbond was to cost approx $12000 and in Victoria you must have a roofing plumber do the work.  
If your roof does not have sarking then DO NOT high pressure clean tiles in place. The 4000PSI water jet WILL get into your roof space and being pumped at 9 litres per minute that is lots of water inside your roof space. 
To start with I was striping 100 tiles at a time and relaying, but then changed to a trusty hand garden trowel and very stiff nylon scrubbing brush. Went through 2 brushes in total and the trowel became nice and sharp and very quickly removed all lichen and moss. 
And after two bouts of 2nd degree sunburn the roof is clean and does not leak! 
Thats my experience, yours may be differrent

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## TassieKiwi

I successfully pressure cleaned a 32deg concrete tile roof before painting it.  Hardly any water got into the roof space - you just have to be careful where you spray.  I used a 3000psi job, which allowed a wide jet - about 6".  Laborious, bt just like new when done.  You will break some too - I found white soled tennis shoes stuck the best.  Make sure you have fall protection:eek:   
There is a product out there apparently that you can spray on - kills the lichen etc and all washes off in the next rainfall.  Sounds like a fairy story to me.

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## blt

We didn't get any water in our roof after hi pressure cleaning either - you just have to make sure you always spray DOWN towards the guttering  :Smilie:  
To help prevent slips when on the roof, buy some inexpensive boat shoes. They're made of a neoprene type material and have grippy rubber soles. We picked some up before our cleaning spree and found them very good on the wet tiles.

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## Jacksin

I guess blt, spraying 'downwards' to avoid water entry to the roof, would explain why these companies who spray and then paint tiled roofs always have a problem with moss soon growing back on the tile ends, which looks bl**dy awful. 
Jack   :Wink:

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