You can see from the dirt, this isn’t a fresh break, it’s just a typical tile failure.
You’d be silly to build a house with a tiled roof.
I can’t make it any simpler, but as we explore more subjects in the series of how to talk to builders, hopefully I can explain the many reasons why tiles make a poor choice for solar roofing.
As we’ve written previously, if you’re considering solar panels on a tile roof then you must get some spares to have on hand for install day.
Being Expensive Isn’t a Virtue
One of my more eccentric workmates was a native of Ireland, and his prejudice was that “only poor people had tin roofs”, but he didn’t seem to notice he was living in Australia now, where tile roof restoration can make you poor instead.
Unlike a Gucci handbag, tiles are outrageously heavy. You need twice as much structural timber to frame the house, and harvested koala habitat to make tile battens. The sheer weight of all that broken concrete causes roofs to sag, eaves to droop, and water to pool – thereby rusting the gutters.
It sounds ludicrous but believe me, when a house shrugs off the burden of 16 tons of tiles, I’ve seen first hand the ceiling has lifted off the kitchen cupboards. It had been groaning under the weight and now sighed “thank you”.
Here we see a house with new blanket insulation and roof tiles placed properly – in the bin.
Electricians Love Tiles
Sparkies frequently say that when it comes to installing new wiring, you just have to lift a few tiles and run the cable underneath. However, some shonky tradies will cut corners by placing the cables right on top of the rafters, blatantly disregarding the cardinal rule requiring a 50mm clearance rule from any finished surface.
To be honest, on a cruddy old 1970s brick veneer house, dropping cables down the wall is easy when there’s no wall insulation or vapour wrap. It’s a glorified cardboard box, so the air conditioning and heating bills are incredible, too.
Looking down from the top, this is a typically poor Australian brick veneer house wall.
The sarking shown below is where this “easy” line of reasoning falls over. Putting new wiring through the roof means cutting this woven, foil-faced membrane, which compromises the insulation and waterproofing function it’s supposed to serve. While it can be stuck back together with tape, many won’t bother because it’s time-consuming and invariably a band-aid solution.
Thieves Love Tiles Too
After going through a break-in myself, I can tell you it makes your blood boil. What’s even worse is that no matter how many locks and bolts you have, a tiled roof is like an open door for crooks. They can climb up, make hardly any noise, and get in without needing any tools. It’s that easy for them, and that’s what makes it so infuriating.
This tile cracked when it was stepped on, but it shows how the tiles should be lapped over the bracket to make the install mechanically waterproof, and the dirt that soon works it’s way through the gaps.
Solar Electricians Hate Tiled Roofs
Not least because everywhere you install a bracket, the tiles must be ground out or the edges attacked with a scutch hammer. While the hammer approach is fast, it’s not neat. However, when you grind with a diamond wheel, OH&S laws now demand its done wet to control silica dust. So the tiles have to be marked, taken down, seen to with an angle grinder and a hose, before being taken back and fitted to the right hole in the roof.
Note this tile bracket displaces two tiles, but they’re so thin there’s little material to grind.
Dust everywhere
Terror-cotta
Clay tiles are even worse because they are invariably more brittle and more difficult to find spares. Many people don’t realise glazed tiles aren’t sealed on the underside, so they effectively rot without you noticing. That is, until you step off the ladder and find they crumble underfoot.
Glazed tiles aren’t forever.
If you have a slate roof or flat clay shingles, then the best solution is to budget for both a tiler and a solar installer on the same day. Organise the tile expert to put the hangar bolts through the roof and give you a warranty on how water-tight the dozens of holes are. Then ensure they oversee the solar installers, fixing any breaks as the job progresses. It’ll be expensive, but think of it as cheaper than a sodden ceiling collapsed on your furniture.
The gun installer’s answer to flat shingles is a hangar bolt screwed into the rafter.
Tiles Limit The Size Of Your Solar Power System
Every part of your tiled roof is effectively 600mm shorter because hips and ridges can’t be disturbed; or will need repointing afterwards. As panel frames get thinner and rules more stringent, turning to landscape solar panel orientation doesn’t help because tile roof framing doesn’t offer as many increments to install solar racking.
The image below shows what we call diving boards. The installer hasn’t been brave enough to disturb the ridge tiles, so with brackets too close together these panels will flap and rattle in the wind.
The top half of both of these panels is unsupported
This job pictured below needs to either:
- lose three panels by turning the bottom row to landscape and moving everything down 300mm
- or the top row of brackets could be installed 300mm further up. This almost never happens because after fitting brackets, the ridges would then need repointing, preferably before the panels go on.
An otherwise excellent job rendered dubious because the brackets are just one tile apart.
Tile bracket hanging in mid-air on the left. Time-consuming spreader fabricated to support it on the right. Sarking foil would make this even more difficult.
Believe it or not, back in the dark ages when solar power was a cottage industry, I used to hand-make tile brackets from 40 x 5mm steel flatbar. Cutting full-lengths into stacks of 5, drilling 4 holes, then pressing two bends in each piece and making two 90° twists. Once you were into a rhythm doing the process they effectively took about 56 seconds each from memory. No good for the job pictured below though.
Deep spanish tiles with no less than a 50mm spacer bracket and bonus compromised insulation on a raked ceiling.
Tiles Are All They’re Cracked Up To Be
So many times, I’ve just walked across a roof and found cracked and broken tiles even before we’ve started work. I genuinely think if it wasn’t for tradition and the comfortable visual familiarity of archaic materials, people would laugh at the very idea of slate or timber shingles.
Where else on your house do you find parts of it are broken and leaky, and simply accept that as normal ?
Tin-framed tile roofs would have to be the worst. It desperately needs a thermal break, yet there’s no way you can properly insulate it.
Even without inevitable cracks, tiles are porous and they soak up water, making the roof even heavier when it rains. They’re a roof prone to water leaks. Without sarking they’re a sieve for dust, daylight and worst of all they invite ember attack in a bushfire.
Don’t be worried about “what will the neighbours think!” Either they can chip in to pay for the roof they want to look at, or they can take a running jump off it.
Iron Roofing Is So Much Better
We’ll finish here with some hard truths:
- Iron reinforces the house – literally a brace over the roof.
- It’s trafficable – walk without fear.
- It’s lighter – less material is required.
- It’s cheaper and more efficient – see above.
- It’s maintenance-free – needs no regular washing, painting or repointing.
- It’s more secure – screwed in place, not just sitting there.
- It’s fundamentally better – excluding dirt, wind and rain.
- It’s outright more durable – suitable for the extremes of tropical weather
- And it’s rated for fire – with far fewer gaps subject to ember attack.
About Anthony Bennett
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I agree that a tin roof may be preferred by the solar installers, cheaper to install and repair, too. Personally I prefer tiles though, because they look better, last longer, insulate better, and are less noisy in wind and rain. Tin is just hot in summer and freezing in winter, as good insulation is still the exception and not the norm in this country.
The real problem in Australia is not the type of roof structure or covering, it is the abysmally low building standards, and the even poorer quality of materials and most workmanship (despite the astronomical costs for labour).
It’s time to look around, how for example Europeans build houses that last hundreds of years, tiles or not. In this day and age it should be possible to make a roof that combines all advantages for the benefit of home owners and builders alike.
A few myths and generalisations in these comments. Also, tin roofs’ and e.g. Colourbond when light coloured (especially white) can reduce internal temperatures within dwelling by 5 degrees celsius or more. In turn this can reduce air conditioning usage and therefore save $$ and enable occupants to feel more comfortable. Energy efficiency needs to be looked at more broadly. We need to be adaptive as well as reduce carbon emissions.
Great article – colorbond really is a no-muss, no-fuss roofing material
(for us in the tropics it’s a life saviour – and easy to install. Stick to white!
hint – holes and cracks made by fallen branches (joys of rainforest living)
can easily be repaired using woven fiberglass and resin (but make sure
the area is clean and dry first!)
It’s all of those screw holes, with the metal expanding and contracting regularly over so many years, that is the thing that concerns me about metal roofs. In our case the tiled roof was pre-existing and in great condition, so we didn’t want to spend the $20K+ to have it replaced before the panels went up. But would go with iron/steel if we were building new.
An old 1950’s corrugated iron roof of ours only had those “tin hat” roofing nails, and they worked loose over 3/4 century. Replacing them with gasketted roofing screws took two people a day, but it’s now weather tight for another half century or more.
But time does bring advances. Over thirty years ago, I used Rolldeck roofing on my first OB, as there are no roof penetrations for fixing – it simply clips into place with a firm heel stamp at each fixing.
On the second OB, a year or two back, KlipLok decking is the same deal, but with a profile better suited to PV racking clamps – so in addition, no roof penetrations for array mounting. In over 200 square metres of roof, there is _one_ hole – for the wood heater flue. The site was only BAL19, but I would never contemplate a concrete colander roof – a blatant invitation to house incineration already at the ember attack stage. (My brother has just had the tiles ripped off his existing house, to extend the fire protection of the new extension’s decking to the old part. He’s admittedly in BAL FZ, so also adding steel shutters to doors and windows.)
Putting any holes at all in a “tin” roof for fixing is unnecessary, unless it just has to be old-fashioned corrugated for aesthetic reasons.
Preaching to the converted.
I honestly wish I could get a class action lawsuit started against the manufacturers of Terracotta tiles such as the ones my builder “upgraded” my house to. They’re just not fit for purpose… they can’t even manufacture them to be “flat” or “straight”, making the cracking of them even worse. It’s honestly disgraceful that they’re still allowed to be sold in Australia.
Just sold my parents house- dad helped build it in 1954- it still has the same terracotta tiles on the roof and has never leaked ever ! He had the roof cleaned & pointing touched up about 20 years ago and that’s it ! I think it passes the test of time.
Anthony,
A small point: on ONE aspect at least you are unwittingly singing from the hymn book of the roof restoration companies with regard to concrete tiled roofs.
In fact, concrete roof tiles, like all concrete products. become stronger and less porous with time, unless subjected to extreme frosts and air pollution. Also, in practice the absorption of water by capillary action during periods of heavy rain would only increase their weight by only 5%. Contrary to the claims of some sales people, this weight increase is extremely unlikely to cause structural roof or stump failure.
At least that is the opinion of the CSIRO – above is direct quote from their Information Sheet for Concrete Roof Tiles.
Hi Greg,
Thanks for the information. It would be nice to know if “stronger” translates into more brittle when dealing with tiles?
Cheers
Well I guess as a home owner with a tiled roof I can attest to having cracked tiles after a minor upgrade of a couple of panels back when there was a 60 cents per kw ie the golden days. I told the boss when I required more upgrading that I didn’t want that fat oaf again he had on my roof before and was told he wasn’t with the company any longer.
While I appreciate the points in your article about the advantages of colour bond roofing. I observed that there is an enormous deficiency in skill today; unlike yourself making from scratch the brackets for example.
However I wonder how many of us tiled roofed house owners would be inclined to fork out extra tens of thousands of dollars to slap on pvc worth 4K to 5K systems.
Peter, if you’re referring to the Victorian solar PFIT of 60 cents per kWh, those golden days are still with us. Yep. Till November 2024. Happy days till then.
If solar roof is the future?
There are few videos from the UK floating about. From what I’ve seen it’s not impossible, but it’s a lot more work to make the roof water-tight as you are not overlapping the panels the way do with sheeting and tiles.
AND not only that but if the roof is made white it will reflect a lot of light and encourage the use of bidirectional solar panels that harvest the incoming energy from the sun and then the reflected energy from the roof. This might not be common now but panel manufacturers are increasing the practicality.
White will also stay cooler so the air around the panels will be cooler and hence their efficiency will be higher.
Graham
Yes IF your local council allows it!
One advantage of concrete roof tiles is their resistance to hail.
After a recent hail storm, in Port Macquarie, there were dozens of homes being re-roofed because of the low standard of corrugated roofing on modern homes.
There was no visual effect on our recently sealed concrete roofing tiles, and we have had no cracks at all from three separate solar installations.
We have a 1970s house which had concrete tiles.
In 2012 we upgraded to white colorbond with a thermal blanket underneath- soooo much better and dramatically cooler in our hot summers.
I’d never dream of going for tiles if building new, and it would be a very major disincentive if buying second hand.
The article is biased. Installers do their job and leave. Try periodically cleaning corrugated colorbond roofing with a fair pitch.
Hi Greg,
As an installer I assure you that after fitting a solar system, the next time the tile roof leaks, my phone would ring and I would have to go back. Whether is was my fault or not, being the last person on the roof meant I couldn’t just leave.
The point is that you don’t have to periodically clean, paint, repoint and replace random parts of a corrugated roof.
And if you do want to paint an iron roof, it won’t break underfoot while you’re doing the work.
Cheers
The process could take “30 SECONDS” !! and a hose off after a short soaking time.
Removes mould, lichen and dirt well.
Good on panels also.
I had to agree with the Irish colleague re iron roofs. They were used to cover barns and outhouses for livestock. Now after living in Australia for 30 years I love Colorbond – don’t split this word it is a brand name and it really irritates me to see colour bond. I am building a new house which will have a shale grey Colorbond roof and it looks great. Also, the builder is first generation Italian and quality and workmanship is guaranteed. I agree Aussie house builders/workmanship needs to be investigated. That’s from my Irish craftsman son.
I’m a regular reader of solarquates.
Out of interest, would anyone be able to suggest a solar installer specializing in unique roofings (potentially unique bracket need for the type of tin roof).
I have a 45degree roof, and unique tin material. Can share photo if needed.
Hi Mert,
Have a look at the Clenergy catalogue or perhaps S5! products from the US. Otherwise send us an email.
Last time I looked at the datasheet, Sunlock SLRC700 clamps were only rated to 40 deg. slope, so it’s advisable to check whatever you’re contemplating using. If roof penetrations are acceptable, then I guess the problem goes away.
Would you mind if i send a photo of the roof ? How can i send a direct message with a photo attachement?
“harvested koala habitat to make tile battens” lol I didn’t know koalas ate pine needles!
I’ve never seen a pine tile batten… unless it’s an oversized oregon timber (imported douglas fir) Conventional 20 x 35mm battens are either hardwood or lightweight cold rolled steel.
When you have high winds which roofs are the ones that go flying off like a guillotine frisbee letting in wind and rain immediately. I certainly ain’t a tiled roof that’s for sure.
This article is all about making life easier for the solar installer and not about the strength of a properly-tiled roof. Yes you need some spares because installers use clumsy subbies and inevitable they’ll crack and damage your tiles. But they are an easy fix – old one out- lift and new one slides straight in.
Hi Reg,
If you’d like to consult AS1170.2 you’ll find the tropic of Capricorn is about where the wind map changes building requirements. Anywhere north of there it’s illegal to install a tile roof because high winds make tiles into concrete missiles.
This article is all about making buildings cheaper, more durable, more efficient and generally better for people to live in.
Cheers
Yes, galvanised roofing is shiny and modern and easier for the solar installer.
But for some (i.e. me), replacing my 40-year-old, perfectly watertight tiled roof with galvanised iron would have turned my $14,000 solar installation job into a $45,000+ job. Probably would have stopped me installing solar given the overall low cost:benefit.
Plus there would have been the environmental impact of changing my roof largely for change/convenience sake. Also my cement tile roof was in great condition despite its age, and my house shape/position is such that you can’t see most of the roof.
I had the roof repointed and ‘serviced’ immediately before the solar panels were installed. As it turned out, my solar installer broke all of one tile in installing my 11kW system. I was happy with the outcome.
In the end, each situation will be unique. Maybe some roofs are in atrocious condition and need replacing. But this doesn’t hold true in every situation and shouldn’t be a deterrent for those contemplating a solar installation!
Hi Jan,
There certainly are reasons to keep an existing tile roof. I’ve seen a bloke make a small crane and haul them off the roof 5 at a time for hand painting. He would work through 20 or so each weekend changing them over as he went. Not something you could do with tin really but not time I would invest personally.
I’m glad you’ve got solar though, everyone should have some.
I have sold my house which has solar panels and bought a small old house which is being renovated.
I would like solar panels and a battery at my new house but don’t know is this is permitted in the area or if the tiled roof is suitable.
It is at 82 Arnold Street Princes Hill Victoria 3054.
Also, is there a government rebate now for solar panels?
I don’t know about the other states , but here in Adelaide there are a lot of houses built in the 60’s and 70’s with asbestos roofs.
“The sheer weight of all that broken concrete causes roofs to sag, eaves to droop, and water to pool – thereby rusting the gutters.”
Absolutely not true. If the builders stuck to construction standards then the sags would not occur. Case in point is my own house. Tiles but no sags.
The roof tile issues and the various comments, usually from installers, nearly stopped me from having my solar system installed at all. I’d been warned in the gravest terms to have spare tiles available on the day of the install. I had 35 glazed terracotta tiles on hand and they ended up using, none at all.
“Nah no problem mate” was the installers comment when I enquired about the added difficulty i thought id put him through. Bottom line, dont let this put you off getting a system installed as there seems to be a bit of a disconnect between the actual blokes that did my install and the experts here.
Indeed Michael,
Solar on a tile roof is no problem, if you have the right installers with the right attitude. Even so having spare tiles is critical, especially as the weight of panels and the weight of Australians carrying the panels generally goes up.
Glad you’ve had a good experience
I was doubly lucky. We have a concrete tile roof, so I had it restored before the panels went on, figuring it’d be stupid not to if I want the panels on there for the next 2 decades or more. (That’s advice I’m not sure if I’ve seen here, but it wasn’t hugely expensive and I’d recommend anybody with tiles do it.) A full clean, re-pointing of the ridges, and re-painting. The restorers were highly professional, and went under the house (I was at work), found the spare tiles and cleaned and painted those too, leaving them in a neat stack, knowing we had solar installers coming. The installers (Penrith Solar, legends) I don’t think needed any of them.
“Many people don’t realise glazed tiles aren’t sealed on the underside, so they effectively rot without you noticing.”
The time when terracotta tiles “rot” (fret) is when exposed to salt, which can be seen in the photos in this article. However a steel roof would “rot” (rust) even quicker in the same salt laced conditions eg near a beach.
There are terracotta tiled roofs in europe centuries old. No steel roof will last that long.
Hoover Rd Hope Valley is 20km from the coast as the crow flies, so I’m not sure you could call that coastal?
https://www.google.com.au/maps/place/Hoover+Rd,+Hope+Valley+SA+5090/@-34.8411348,138.6894266,
Salt water pool heating tubes leaking? I see salt (white residue) in the picture and water coming from somewhere…
I Owner Built in the early 1980s.
Concrete Tiles were the favourite because they were the cheapest. Colorbond was as horrendously expensive as the then upmarket Terra Cotta Tiles.
The only things “Solar” was which came out of the sky. And I did ask about Double Glazing (I was living and building in Canberra) and only 2 of the 5 or so majors knew about it and they didn’t recommend it because it was “so expensive”.
The Tilers (lazy spivs that they were) asked why did I have Sarking under the Roof.
And after talking to an ex RAE chippie who joined War Graves after he left the Army, who told me that during a Posting to Washington where he moonlighted building houses, that they installed as much Insulation into the External Walls (and Roof) between the Studs as possible after running Sarking around the outside of the frames before sheeting, I did the same. Then people (in Canberra) asked “why did I insulate my walls?”
I O/B again in 2012/13 and used ICFs and Double Glazing. Again I was asked a lot of Qs as to why I did that. Go figure.
There is a problem with steel roofing that no one has mentioned. CONDENSATION! Not only that but most installed steel roofing has the insulation directly underneath the steel roofing, apparently a big no overseas. This can cause the insulation to become waterlogged and be a major cause of moisture within the roof cavity and subsequently mould in the ceiling. This is becoming a huge problem in Australia. Apparently there is supposed to be an air gap between the roofing and insulation but I don’t know if this is a standard in Australia.
Love reading your articles by the way.
Shaun
The correct insulation to use directly under ‘tin’ is known as ‘anticon’ – anti condensation. It consists of about 20mm fibreglass ‘pink batt’-like material with reinforced foil sarking on the underside only. The fibreglass component stops the high temperature differential between the roofspace and the Colorbond roof. With the fibreglass squashed between the sarking and the tin there’s little likelyhood of moisture finding its way into the insulation.
Of course one still needs regular insulation directly on top of the ceiling.
Hi Clive,
This kind of blanket/anticon insulation often comes in 55mm and even thicker stuff gets difficult to crush with roofing screws, because that’s how they install it.
The key with any of these things is understanding where condensation forms. ie not many people realise the internal surface of an external brick wall is often wet.
Anticon isn’t ideal in some climates as I understand it, but in other places it’s a required component in bush fire ratings.
13.2 kW of panels were installed on my roof today.
I asked the installers to carefully check the state of the roof before starting work so they would not get blamed for damage that was already there, despite it being a new build at lock up stage.
They found one cracked tile straight away. I handed them a new one to replace that before they started.
The other spares I supplied in case of breakages during the installation were not needed.
Total broken during instal zero.
When quizzed about typical breakages on tile roofs the installers said between 0 and 2 on a new roof, could be upto 5 on an old poorly maintained roof. He mention doing a Terra Cotta roof once and that sounded very ugly.
With the Colourbond roofing method there is a ridge cap on top where the
panels meet from both sides of the roof. Up here in Qld. and the NT it is a
requirement that the edge of the ridge cap must be “scribed”. Scribing refers to cutting the edge of the ridge cap to fit the profile of the corrugations of the colourbond sheets.
A “scribed” ridge cap has only a 0-2mm or so gap between the cap and the sheet it is covering. It is a requirement since a few years after Cyclone Tracy tore Darwin apart. In the southern states most ridge caps are not scribed and the gap is about 25mm as it is not a requirement.
I am of the belief that a “scribed” ridge cap on a colourbond roof makes the house far more resistant to ember attack during a bushfire. It is one of the reasons that I think that forest fires result in more loss of houses in
southern states compared to QLD and the NT. It also makes the roof almost completely waterproof.
I will expect differences of opinion from builders in southern states!
Even 30 years ago, here in Victoria, the ridge capping on my steel decking roof was notched as you describe. The capping would have had to have its wings bent far back if not notched. The upper end of each decking tray was also bent up with a custom tool, to prevent wind driving rain in under the capping. The other end of the tool was used to slightly bend the lower end of each tray, to coax rushing water into the spouting, rather than shooting over.
On the recent owner-build, the roofing plumber did not have to be coaxed to cut the notches, for the capping to fit, but I did have to insist on a fire blanket under the capping, to seal against ember attack, as the site is BAL 19. I then applied a second layer of rockwool blanket from within the roof cavity, to further protect the closest framing parts. You can’t rely on the roofing plumber to maintain the requirement of no aperture in the building envelope bigger than 3mm. Fire rated foam in the outer end of each decking rib should not be forgotten.
I figure that the capping can also be notched to admit conduit for PV wiring, so there are no roof penetrations for anything anywhere, other than the wood heater flue. What chances of no apertures > 3 mm on a tile roof?
Hi Geoff,
You’ll find that better class roofers do scribe ridges and hips in my experience, you just have to ask. However the best way and indeed the method specified in high risk areas is to put mineral fibre (rockwool) blanket insulation under the iron and use it to fill all the gaps at the bottom edge and under the ridges & valleys.
I have tile roof and there is metal plate under the tiles. The solar installer assessed our roof and said they are not able to instal solar panels on our roof as its ‘too thin’ to drill and mount the solar panels. Any solution to this situation?
Hi Dorothy,
It sounds like you might have a “steel framed” house construction. I use the quotes because they’re actually flimsy thin sheetmetal, folded into shape to offer some strength. They’re engineered to be cheap, but end up with nothing like as much redundant capacity as a timber frame.
There are some solutions available I think but like pergola installations I have seen it may involve screwing pieces of custom machined wood to your steel frame, in order to attach brackets for solar. There may also be a specific solution invented for your frame. Best ring up Clenergy and ask them directly, but make sure you have details of who built the house using what system.