Over 20 years of repairing leaking roofs in Sydney

This has given us at The Roofing Professionals Westside, plenty of data about why and how a roof will leak – and most importantly, how to repair those leaks.

Learning about roof leaks and how to repair them is a gradual process and over the years, all the information that I uploaded and lumped into categories, became a mess and hard to find.

If you want to learn all about leaking roofs, the Roof repair Table of Contents below makes it simple for you to scroll down, find what you are interested in and then dive into the ‘Rabbit Hole’.

Hope you find what you are looking for…

We have not stopped learning about roofs and how they leak


Table of Contents for this Website


Roof leaks in heavy rain only

Sydney gets the occasional bout of real WET. The two most recent ones were in February 2020 and March 2021.

Why do the heavy rain events bring on roof leaks that the normal light rains don’t?

There are some interesting reasons why roof leaks can be temperamental.

Check out our video page on why some roofs only leak in heavy rain.

What are the most common causes of roof leaks?

With over two decades of roof repair data, we have found that there are some causes of roof leaks that occur a lot more often than others.

The common causes are a lot easier to identify and do a repair on. The not-so-common ones present a real challenge for us – and these are the ones that we relish.

If your roof is leaking because of one of the common reasons, then most good roofers will be able to perform a proper roof repair. So, what are the most common causes of roof leaks?

Find out on our roof leaks post here.

What to do when the roof leaks?

When your ceiling starts to drip after the rains hit, there are certain things that you should do.

Firstly, check out my video on how to save the ceiling and direct the drip into a container.

Then follow the tips on the leaking ceiling webpage

How do roofers do roof repairs in Sydney?

As with every other game in town, (where there are good players and pretty bad amateurs) the abilities of roofers vary greatly.

And in the roof repair segment of the game, choosing the right roof repairer can be quite daunting.

We think that repairing leaking roofs need a systemic approach and we have developed our own roof repair checklists to help us gather data, diagnose and come up with permanent repair solutions.

Much of the other roofers out there have no such systems.

We have a story of how some Sydney roofers think that roofer’s silicone is the magic pill that will fix any roof leak.

And at the bottom of the heap has to be the scammers who pose as roof repairers and have no guilt about extorting money from unsuspecting homeowners.

What is the average cost of a roof repair in Sydney?

There is a severe shortage of good roofers in Sydney.

Our average repair prices have spiked in the last several years because of this shortage and the last time I looked at my average job costs, it was almost $3000.00.

Statistics can be a bit misleading and people will quote mean and average figures. There is a bit of variance between the two.

The truth is that hardly anyone is ‘average’. We are either below or above.

To find out more about roof repair pricing, go to our dedicated pricing page.

Who does the best roof repairs in Sydney?

If you Google “best roof repairs in Sydney”, the first page will start off with a bunch of ads, followed by the ‘Google My Business” section, and the organic listings.

You will notice that Google has filled most of this important section with ‘directory’ pages.

Click on any of them and you will have the opportunity to get the three best roof repairers contacting you and giving you the best service ever….

This is a fairy tale.

The best roofers do not need to resort to getting their leads from directory pages. You will not find them bothering to look at your request. Instead, you will get roofers who are from the ‘desperate’ camp. Imagine how your poor roof will survive their workmanship…

The best roof repairers in Sydney are found via word-of-mouth. Social media plays a large part in spreading the good word.

We have not embraced social media yet and so all of our client feedback is predominantly on our roof repair review page.

Are roof repair inspections and quotes free?

In Sydney, there is nothing special about free roof repair inspections and quotes. It has become part of the services culture to offer free inspections and quotes in return for the possibility of doing business.

Like most roofers, The Roofing Professionals Westside provide free roof inspections and quotes.

But everything that is free comes with a catch.

So, when a roofer produces a hastily prepared quote and tells you that there are a lot of things wrong with your roof, it is just a reflection of how he has valued his effort in providing this service.

We take a slightly different view of providing free roof repair quotes. Since we are playing the infinite game we are here for the long haul), every bit of data that we can collect about why roofs leak and how we can effectively repair these leaks is very valuable to us.

Like Facebook, Google and the other free services out there, we are harvesting data. This data is the key to the future of our roof repair business. We are hoping that when we provide you with our quality roof inspection and quote, we will both benefit.

How long do roofers guarantee their roof repair work?

The strength of a roof repair guarantee depends on confidence levels.

There are roofers out there who are so confident that the homeowner will never be able to track him down for a refund. There roofers will guarantee anything for any amount of time.

Most decent roofers will off guarantees varying from 3 months to 7 years.

The reason that we offer a 7 year warranty on our roof repairs is because our confidence level (that we can fix the roof leak for good) is quite high.

Does home insurance cover water damage from rain?

You have a far better chance of getting insurance to repair (or replace) your roof due to hail than due to rain.

Although rainwater can enter your roof, raindrops do not usually damage the roof. This is where insurance companies rest their case.

Insurance companies can be flexible and pay for part of the damage repairs – even though their assessment that lack of roof maintenance was a major contributing factor to the storm damage event.

Find out more about roof maintenance and home insurance cover here.

Are mouldy ceilings caused by roof leaks?

It is all about the colour.

Brown staining on the ceiling (with or without black mould) usually means a leaking roof. The water leak carries the dust stain through the ceiling and this makes it brown.

If it is just black/grey mould (and usually lots of it). then it is quite likely just a damp ceiling and nothing that can be blamed on a roof leak.

Check out my post For more on why ceilings go mouldy

why do roof valleys leak?

Roof valleys do a surprising amount of work. This means that any ‘small’ thing that is not right at a valley will cause it to leak.

Leaves can block the flow of water.

Roof tiles at valleys can slip out.

Sarking at the edge of the valley can draw water into the roof.

The valley can be installed on a roof that is too flat..

…We do a lot of valley repair work.

Is my roof leaking or is it condensation?

I love metal roofs because of its impermeability. But it is a ‘double-edged sword’.

Moisture under the roof sheets cannot escape and under certain conditions, condensation will form and drip back onto the ceiling…making it appear like a roof leak.

So metal roofs need to be insulated correctly.

how to find a leak in a tile roof?

There are more sources of roof leaks on tile roofs than on metal roofs.

We give a few tips on tracking down tile roof leaks on this website.

But we are continuously finding out more ways that a tile roof can leak – so the more difficult ones should be left to roofers who are more knowledgeable…

Is a roof restoration better than a roof repair?

Roof restorations are very common.

Especially out in western Sydney, there are numerous street pole and fence mounted advertisements for Roof Restoration Services. Some starting from as low as $1400 for a full 3 coat system.

There is no national standard for a roof restoration. A restoration can mean many things and a $1400 roof restoration will not get you much.

It often means a quick high pressure water wash followed by a certain number of quick, thinly applied coats of paint.

A roof restoration is usually sold as a necessity to maintain the roof properly. But the only thing it does is to make the roof look new from a distance. If your roof is leaking, it is unlikely that a roof restoration is an effective way of repairing the roof.

If I wanted to make my roof look good from a distance for a short period, then a $1400 roof restoration is a good deal. I usually tell clients that the only time I would consider a cheap roof restoration is just before I sell my house. Even then, I have no guarantee that I would add $1400 to the final sale value of my house.

If you intend to live in your home for a long time, then $1400 spent on a bathroom or kitchen will add more usable value to your home. Don’t throw money at restoring a roof.

If you have a roof leak or want your roof maintained properly, then you want a decent roof repair and NOT a problematic ROOF RESTORATION.


What is the difference between Zincalume and colorbond?

Both ‘Zincalume’ and ‘Colorbond’ is uniquely Australian because it is made only by Bluescope.

The original corrugated roof sheets were imports from England. They used a zinc coating to protect the base steel (iron) from rust. These were the original ‘Corrugated Galvanised Iron’ roofing material and can still be seen on old buildings throughout Australia.

Bluescope developed a more durable coating made of zinc and aluminium – to replace the galvanised coating. They called it ‘Zincalume’.

Then in 2013, they made ‘Zincalume’ even better. And it is now called ZINCALUME® steel AM125

Colorbond is simply ‘Zincalume’ steel that Bluescope puts through their special paint coatings factory.

What colours do colorbond come in?

Bluescope keep coming up with new COLORBOND colours and finishes.

New colours were introduced and unpopular colours were discontinued. It got so confusing that Bluescope had to finally break their colours down to 5 different ranges.

There are currently 14 ‘pale’ colours they have put in the ‘Contemporary’ range.

There are only 8 surviving traditional colours – and these live in the ‘Classic’ range.

Recently, they released 5 colours in a matt finish. These matt colours are more suitable for walls than roofs.

Fences have their own colour range, and there are only 14 colours.

Then finally the ‘Ultra’ range (suitable for severe environments) contain only 6 colours. It seems like people who live by the seaside deserve only a few colours.

Go here for more on colorbond colours

How do I know that you have genuine colorbond?

Bluescope is not the only company who manufacture painted roofing material in Australia.

ACE gutters have traditionally manufactured their own roofing and guttering material. It is of a similar product to the Bluescope products and ACE call their painted steel ‘Duracote’.

There is an easy way to find out if your roofing and guttering is made from genuine Colorbond.

What is Colorbond Ultra?

Sea water is very corrosive. Steel and salt water do not mix well. Steel loses the fight in the early rounds. So Bluescope came up with a roofing material that can withstand salt spray for decades. They call it Colorbond Ultra.

From my research, it is not a secret type of steel that is used. It is the same steel – but the zincalume coating is a bit thicker. The paint system appears to be the same.

The official Bluescope information is : The distances are less (you can use ‘ordinary’ colorbond within 100m) if the marine environment is like the Sydney harbour or Parramatta River…

Colorbond “STAINLESS” is just stainless steel with a colorbond finish – so the corrosion resistance is provided by the stainless steel. It is the most expensive of the colorbond steels.

Colorbond “ULTRA” has the same steel base as standard colorbond. The main difference is the grade of the zincalume coating used. “ULTRA” uses the higher grade (thicker) AZ200 zincalume – and this gives it the higher corrosion resistance, and a premium price (but still cheaper than “STAINLESS”).

Is Colorbond better than Zincalume?

The emperor with no clothes is just like Zincalume. Dress him up and he becomes Colorbond. So, who do you think is better?

What thickness Colorbond roofing to use?

The majority of colorbond roofing materials comes in 3 thicknesses.

Roof sheeting is either 0.42mm thick or 0.48mm thick. Roof flashings are usually 0.55mm thick.

The choice between the two roof sheeting thicknesses is not a function of how long they last. It is based on their strength to span between the support purlins. reason I prefer to use the thicker 0.48BMT version. CLICK to find out more…

What is the minimum pitch for corrugated iron roofing?

5 degrees.

Traditional corrugated iron roofs are quite steep. Then most people thought they could use a corrugated roof sheet on flat roofs. This does not work.

Find out more about why roof pitch is important when choosing the correct metal roof profile to use.

Why are the ends of roof sheeting important?

A sheet of roofing material is watertight. When a series of roof sheets are locked together by a side lap, an area of roof is created to be waterproof. Besides any faulty side laps, the only way water can enter the roof is at the perimeters.

The two most important edges of the metal roof are the upstream end and the downstream end.

The upstream ends of the roof sheets must be able to stop water from climbing over the end (due to heavy rain and wind). And the downstream end must be able to stop water dribbling under the sheet and climbing up the roof sheet.

If you doubt that water can climb against gravity, find out about capillary action.

There are special tools made by the roofing manufacturers to help roofers turn the upstream ends UP and also turn the downstream ends DOWN.

This is not ‘rocket science’ – but we often see new roofs that look like the ends have been mistreated by a hammer to distort the ends. And that is apart from those roofs that have NOT had the blessing of any tool at all.

What is the correct way to lay a roof with end laps?

In the old days, all corrugated roofing iron came in ‘8 foot’ lengths. End laps were very common to get the length of roof sheeting needed for most roofs.

Then, we had long trucks. With them came long sheets. And the end of end lapping. It was a huge blessing.

But every now and then we are forced to end lap two sheets to get the length that we need.

So, what is the correct way to do this?

Why the side laps on roof sheets are critical to the function of a roof?

Engineers try to make their products as fool proof as possible.

Every style of roof sheet has some engineering detail on the side edge to stop the enemy of capillary action. Unfortunately, most roofers do not appreciate this engineering effort – and they try to install roof sheets that would have the roof engineer turn in his grave.

Is a colorbond metal roof better than a tile roof?

It depends.

Tile roofs are more common – so people must like them.

There are differences. Just like some people love Holdens and others love Fords, It can be a personal thing…

But there are times when a colorbond metal roof is the only viable option. See my blog post on problems with flat tile roofs to see why this is so.

Generally, the differences are: <p)• Weight: A colorbond roof is much lighter that a tiled roof. This will mean less weight stress on the roof structure and the walls – leading to less movement induced cracking.

• Insulation: A higher rated insulation can be laid under a colorbond roof to enhance the insulation rating of the roof cavity. Tiled roofs only get a layer of aluminium sarking.

• Noise: The sound of raindrops is more pronounced on a colorbond roof. Tiled roofs are relatively quieter.

• Cosmetic appearance: Colorbond roofs can provide a more ‘modern’ look whilst tiled roofs give that ‘traditional’ look. This is very much a personal choice.

• Life of roof: Roof tiles have a longer warranty (50 years) because they do not rust. They generally do not get any weaker as they age – although terracotta roof tiles can ‘fret’ over time or if they are close to a marine environment. So, roof tiles will generally outlast a colorbond roof which generally lasts about 40 to 60 years…

• Maintenance requirements: The ridge capping on tiled roofs require repair/maintenance every 15 to 20 years. This is because the bedding and pointing will crack over time due to roof movements. This cracking can lead to water leaks.

Roof tiles at the valleys do not get very firm anchoring and these can slip over time and leave a hole in the roof – causing a leak.

Leaves gathering on a tiled roof will choke the drainage laps on the tiles and cause water leakage – so a tiled roof is better off without overhanging branches (dropping branches will also usually crack roof tiles). Colorbond roofs in comparison do not need the same maintenance as tiled roofs – they are virtually ‘maintenance free’.

• Design and construction versatility: Designers can bend and curve colorbond roofs as well as making them steep or flat. Tiled roofs are limited to certain slopes to work. It is also very difficult to curve or bend a tiled roof. You can do more with a colorbond roof.

• Hail protection: I have seen huge hailstones put holes in colorbond metal roofs – although this is very rare. Hailstones usually just leave dents and the roof stays water tight during hailstorms. Dents on colorbond roofs do not usually affect the life or performance of the roof.

Large denting on flat roofs may cause a problem with ponding – and in this case, local replacement od roof sheets are recommended by Bluescope.

Roof tiles simply crack when there is a decent hailstorm – causing large amounts of water damage to the house. Tiles offer little protection against large hail stones.

• Spare parts: There are numerous shapes and sizes of roof tiles and as manufacturers go out of business or decide on a new marketing campaign, tiles are phased out. So, over time, some types of roof tiles will only be available if it is taken off an existing roof. Replacing a few roof tiles can sometimes prove very difficult.

Corrugated metal roofing have stayed the same since inception – so you can find a piece of corrugated roofing quite easily.

The debate on Why replace a tile roof with a colorbond roof? continues…


What is the difference between terracotta and concrete roof tiles?

Terracotta roof tiles are baked from clay. The colour is either baked on or blended into the clay and baked.

Concrete roof tiles are manufactured from sand and cement and the colour is painted on.

Because of the manufacturing process and the raw material characteristics, terracotta roof tiles come in in more intricate designs and shapes – whilst concrete roof tiles are of simpler shapes.

The paint on concrete roof tiles will fade and weather away over time – whilst terracotta roof tiles will keep their colour. Both concrete and terracotta roof tiles have limitations on how flat they can be laid. These limitations are more on the tile design rather than the tile material.

Concrete roof tiles tend to be more resistant to breakage than terracotta roof tiles – although concrete roof tiles will generally chip more easily. Terracotta roof tiles generally have a more intricate interlocking lap and will not slide off even if they move off the roof batten. Concrete roof tiles can and slide off the roof if the holding hook moves off the roof batten.

Salt water can cause terracotta roof tiles to ‘turn into powder’ (fret) whilst concrete roof tiles are generally immune. So water front homes fair better with concrete roof tiles.

For those into roof repainting… concrete roof tiles can be repainted quite successfully to produce that new look – whilst terracotta roof tiles will resist the paint and cause paint peeling.

For those into costs… concrete roof tiles are slightly cheaper to manufacture and to lay. So a concrete tiled roof will be found on most budget homes.

How long does a tile roof last?

Terracotta roofs have been around longer than concrete tiled roofs – so there are more terracotta roofs that are too old to repair than concrete tiled roofs. Generally, concrete gets stronger with age and even though the tile manufacturers give a 50 year warranty, you should expect a lot more.

The older terracotta roof tiles tend to get brittle with age and these will break readily. The newer terracotta roof tiles do not have this tendency. Fretting (exact reasons not very clear) will shorten the life of terracotta roof tiles.

As a general rule, you can safely say that a tile roof will last a life time….

What are fretting roof tiles?

In the roofing game, “Fretting” is a term describing a roof tile (mainly terracotta) decaying into powder.

It is a problem that seems confined to terracotta roof tiles. I have not seen a fretting concrete roof tile yet…

For some reason, the terracotta does not like salt (and some other corrosive chemicals) – and the tiles turn into powder. So, terracotta roofs near the sea coast tend to have more fretting problems – although I have seen fretting terracotta roofs in the western suburbs of Sydney.

This means that there are other factors besides just salt that causes fretting.

Besides salt spray near the coast, swimming pool heating elements on roofs can produce a salty environment that promotes fretting. Home owners with pool heating on their roofs (especially salt water pools) should check for leaks on a regular basis. I have seen very bad fretting under leaking pool heating.

…Also, for more information and a video on fretting, go to my blog article about Fretting terracotta roof tiles in Sydney.

What is bedding and pointing on a tile roof?

The bedding is the mortar bed that is used to hold up the ridge capping and provide support to maintain the ridge capping in a straight line. Once the bedding hardens and the ridging is held firmly in place, a flexible pointing compound is applied over the bedding to provide a binding layer.

The pointing provides the waterproofing element and also binds the ridge to the tiles – providing security against dislodgement by winds and other forces…

There is a specific page on this website that goes to more detail about bedding and pointing. Take a look at this if you want more information.

…Also, for a video on why leaks happen at the bedding, go to my “roofing repair western suburbs sydney – how to repair a leak at the ridge capping” blog.

What is roof sarking?

Sarking is generally used under roof tiles. It is a reflective and water resistant membrane that is installed under the timber tile battens.

Sarking has reflective properties and this provides some insulation to the roof cavity.

The other reason sarking is used is because tiled roofs let in some water during heavy rain. During these occasions, moisture is then caught on top of the sarking and it dribbles down and finds its way into the gutter.

Sarking gets more important as the tile roof gets flatter Or if there is a downpipe discharge on the roof. Tile manufacturers mandate the use of sarking on lower pitched roofs.

Where do I get a replacement roof tile in Sydney?

Roof tiles get upgraded quite often and also manufacturers come and go.

In Sydney, CSR Monier is the major tile manufacturer, followed by Boral tiles. So if you have a new roof and the roof tiler has not left you some spare roof tiles for your roof – then you should grab a tile off your roof one sunny day and head off to these companies to get some. Before they phase them out.

If you have an old roof, then the above companies will not have your tiles in stock. The handiest place in Sydney to get some replacement roof tiles is in Prospect. See Grant and his team at Roof tile recyclers… Best place in Sydney for that hard to get spare roof tile.

For emergencies or if you can’t find a spare roof tile to fit, most roof tiles with simple cracks can be repaired using roofing silicone quite successfully.

You just need to know how. See my “how to repair a roof tile = when you don’t have a spare” post

What are roof valleys?

As soon as the shape of a roof gets more complicated than a rectangle, the roof has a change in angle. And the only practical way to build a roof with change in angles is to install valleys.

Most people don’t know that they have roof valleys – until a leak starts happening and a roofer tells them that the valley has a hole in it or it is blocked up with debris – or it has overflowed.

Roof valleys are one of the simplest flashings on a roof – but they can cause all sorts of problems.

Go to this page to learn all about roof valleys and their problems.

Do I need weep holes under my ridge capping?

In a lot of situations, the pointing and the bedding will crack under the ridge capping and this allows water to seep through the cracks and pond on the top edge of the roof tile that is upstream of the bedding.

If this pool of water is not allowed to escape (via weep holes), it slowly builds up and will eventually overflow the top edge of the roof tile. This is usually why a tile roof will develop a leak only after prolonged rain.

There are numerous ways to fix this roof leakage problem caused by the lack of weep holes.

Also, the need for weep holes is not universal under every ridge cap. We have a lot more information about needing weep holes for roofs on this website.


How effective is a whirlybird at cooling my roof?

For some apparent reason, if you had Googled “How effective is a whirlybird”, this website ranks number 1 or 2. And we do not want to install whirlybirds – because I think that they are rather ineffective (especially how they are generally installed – without eaves vents).

A whirly bird (if installed correctly) can be used to ventilate a roof attic – but NEVER think that a whirlybird can cool a roof!

Check out our webpage For more on the effectiveness of whirlybirds and user’s comments

My ceiling is mouldy, Is my roof leaking?

If there is no water dripping through the ceiling (or a light fitting), and/or there is no brown staining, then there is a good chance that your roof is not leaking.

My website has been targeted by Google for mouldy ceilings! If you had searched for “why is my ceiling mouldy” – you will find me on the first listing. I don’t fix mouldy ceilings!

So unfortunately, we are only of any good to you if your roof is leaking…

But I have the best information about mouldy ceilings on this webpage

Why is it important to stop condensation under your roof?

Most bathroom exhaust fans pump damp moist air into the ceiling cavity. If the the underside of the roof is cold, condensation occurs and water start dripping back onto the ceilings. This is not good.

All roofs should have sarking or anti-condensation blankets installed under the main roof element to stop internal condensation. Even patio ceilings should have anti-condensation. We will have a lot more information on the importance of the anti-condensation layer coming soon…


What is a box gutter?

Wiki has excellent pictures and details about box gutters. In Sydney, most box gutters are constructed from sheet metal. And the main problem with metal is rust.

Box gutters made have to survive the most severe corrosive environment on any roof – so they should be made of colorbond metal as a minimum. Unfortunately, the cheaper Zincalume finish is often used instead because of perceived cost savings.

There are numerous problems associated with box gutters. For more information about how we deal with box gutter problems – go to our page “What is a box gutter”.