Tiled Roof v's Colorbond Roof

White Colorbond Roof Sheeting

Dark Clay Roof Tiles

I am often asked the question, “If I was building a new house in Perth, what type of roofing material would I choose and what are the advantages and disadvantages of each”? Lets start with aesthetics. I personally like the look of clay roof tiles on a classic Hamptons style house and Colorbond on a more modern or even federation style house, but that’s just my opinion. So it really depends on the style of house you choose and your personal preference in color. White roof tiles in my opinion don’t look great, but white Colorbond does and visa versa, black tiles look great but black colorbond doesn’t, which again is my personal opinion. When it comes to the advantages and disadvantages of each roofing material, I think the best way is to just list them in a generalized manner as I have below:

Tiles – Clay

Advantages

• Roof asthetically looks good
• Tiles last longer 50-100 years
• Tile colour doesn’t fade
• Easier than metal roof to access roof space for electrical/plumbing work
• Fire resistant
• Don’t rust
• Quiet when it rains

Disadvantages

• Tiles break. Some tiles can break in places that are concealed by tiles next to or above the broken tile making it difficult to find.
  o  Solution - Tiles can be replaced and broken tiles that are concealed can take some investigation, but usually can be found by lifting all the tiles in the leaking area and inspecting each tile.
  
• Fretting. Clay breaks down when in contact with salts.
  o  Mainly a problem by the coast or when solar hot water systems, evaporative air conditioners or pool heating leaks onto the roof.
• Dust and leaves enter roof space.
  o  Solution - Use Sarking under tiles and valley/gutter mesh to prevent leaves entering roof space.
• More prone to leaking compared to a metal roof.
  o  Usually tiled roofs leak due to neglect and lack of maintenance. A well maintained tiled roof should not leak.
• Lichen and moss grow on clay tiles and can affect the appearance of the roof, the longevity of the tiles and also contribute to leak issues when the drainage channels / pans are blocked up with this growth.
  o   Solution – Pressure cleaning the roof at 3500psi every 5-10 years should keep the roof looking great. There are also other products that can be sprayed onto the roof every 5 years or so to kill the growth of moss and lichen so the roof continues to look great.
• Ridge caps need repointing every 15-20 years.
  o   Solution - An unavoidable issue with tiled roofs, but ridge caps can be pressure cleaned and repointed with a flexible acrylic cement to seal up any cracks that have formed and keep moisture from entering the roof space.
• Sarking. Sarking is the weather proof film that is installed under the tiles to help prevent leaks should there be an issue with the tiles. However, over time the sarking breaks down or gets holes in it from trades accessing the roof space or from vermin chewing holes through it. This then leads to areas where water can enter the roof space onto the ceilings.  When tiled roofs with sarking leak, the cause of the leak may be difficult to pinpoint as the source of the leak may be higher up the roof.
  o   No real solution for this apart from keeping vermin out of the roof by covering valleys and gutters with mesh, and avoiding trades accessing the roof space from the roof, which can be almost impractical when electrical or plumbing work requires access to confined spaces.
• Heavy. Tiled roofs can weigh a lot, perhaps 10–15 tons for a standard-large 4 x 2 house. The problem arises when the roof carpentry is not done to standard, which then leads to sagging roof timbers and in some cases, in danger of collapse.
  o   Solution – When the roof is being constructed, the roof frame needs to be inspected by the building supervisor to confirm that it meets the building codes for tiled roof frames. It would also be a good opportunity to request additional struts be installed where possible to add support and strength to the roof frame.
• Tiles cannot be used on low pitch roofs. Tiled roofs should be no less than 15 degrees, below which they are at greater risk of leaking. A good pitch for a tiled roof is around 25 degrees, above which looks great, but becomes more expensive to construct and is also risker to work on.
  o   Solution – ensure roof frame is 20-25 degrees to reduce risk of roof leaks commonly observed in lower pitch roofs. If a lower pitch roof is required a metal roof is recommended.
• Tiles generally look better in a darker colour. This means they will be hotter in summer, but also warmer in winter.
  o   Solution – All roofs should have some form of insulation, so my recommendation for any tiled roof would be heavy duty sarking, as well as heavy duty ceiling insulation (eg batts). This will help insulate from the heat in summer and help keep the house from losing heat in winter. Also, to help evacuate hot air from the roof space in summer, I would recommend installing some solar exhaust fans or whirly birds.

Tiles - Cement

Advantages

• Cheaper than clay tiles and can look just as good.
• Can last just as long (50-100years) if maintained and restored at 20 year intervals.
• Easier than metal roof to access roof space for electrical/plumbing work.
• Fire resistant.
• Don’t rust.
• Quiet when rains.
• Don’t fret like clay tiles.
• Lichen generally doesn’t grow on cement tiles.

Disadvantages

• Cement tiles generally break and chip easier than clay tiles.
  o  Solution – Broken tiles can be replaced, be careful when walking on the roof to minimise the risk of the weak corners from breaking.
  
• Colour on most cement tiles is applied as a painted coating during manufacture and so the colour fades over time, eventually requiring a roof restoration. Some tiles are coloured with oxides in the actual cement, so should keep their colour / appearance over time.
  o  Solution – Cement tiles can be pressure cleaned, sealed and painted to restore their colour and prevent moisture penetration. This is generally required every 20 years and is an opportunity to change the colour of the roof is desired.
  
• Dust and leaves enter the roof space.
  o  Solution – Use sarking under tiles and valley / gutter mesh to prevent leaves entering roof space.
• More prone to leaking compared to a metal roof.
  o  Usually tiled roofs leak due to neglect and lack of maintenance. A well maintained tiled roof should not leak.
• Moss (but not lichen) grows on cement tiles and can affect the appearance of the roof, the longevity of the tiles and also contribute to leak issues when the drainage channels/pans are blocked up with moss.
  o  Solution – Pressure cleaning the roof at 3500psi will clear away moss and debris, but this is generally only done on cement tiles in preparation for painting. There are products that can be sprayed onto the roof every 5 years or so to kill the moss but pressure cleaning is generally the best way to clean out the drainage channels between tiles. Also, when a cement roof is pressure cleaned, any oxidized paint will also be removed, so unlike a clay tile which doesn’t lose its colour, a painted roof will lose its coating over time and eventually require recoating.
• Ridge caps need repointing every 15-20 years.
  o  Solution – An unavoidable issue with all tiled roofs, but ridge caps can be pressure cleaned and repointed with a flexible acrylic cement to seal up any cracks that have formed and keep moisture from entering the roof space.
• Sarking – Sarking is the weather proof film that is installed under the tiles to help prevent leaks should there be an issue with the tiles, however over time the sarking breaks down or gets holes in it from trades accessing the roof space or from vermin chewing holes through it. This leads to areas where water can enter the roof space onto the ceilings.  When tiled roofs with sarking leak, the cause of the leak may be difficult to pinpoint as the source of the leak may be higher up the roof.
  o  No real solution for this apart from keeping vermin out of the roof by covering valleys and gutters with mesh, and avoiding trades accessing the roof space from the roof, which can be almost impractical when electrical or plumbing work requires access to confined spaces.
• Heavy – Tiled roofs can weigh a lot, perhaps 10 – 15 tons for a standard-large 4 x 2 house. The problem arises when the roof carpentry is not done to standard, which then leads to sagging roof timbers and in some cases, in danger of collapse.
  o  Solution – When the roof is being constructed, the frame needs to be inspected by the building supervisor to confirm that it meets the building codes for tiled roof frames. It would also be a good opportunity to request additional struts be installed where possible to add support strength to the roof frame.
• Tiles cannot be used on low pitch roofs. Tiled roofs should be no less than 15 degrees, below which they are at greater risk of leaking and cement tiles are more prone to leaking at lower pitch compared to clay tiles. A good pitch for a tiled roof is around 25 degrees, above which looks great, but becomes more expensive and also risker to work on.
  o  Solution – ensure roof frame is 20-25 degrees to reduce risk of roof leaks commonly observed in lower pitch roofs. If a lower pitch roof is required a metal roof is recommended.
• Tiles generally look better in a darker colour. This means they will be hotter in summer, but also warmer in winter.
  o  Solution – All roofs should have some form of insulation, so my recommendation for a tiled roof would be heavy duty sarking, as well as heavy duty ceiling insulation (eg batts). This will help insulate from the heat in summer and help keep the house from losing heat in winter. Also, to help evacuate hot air from the roof space in summer, I would recommend installing some solar exhaust fans or whirly birds.

Metal roof – Colorbond or Zincalume

Advantages

• Modern / archituctural look but can be used on older colonial / federation buildings.
  
• Fire resistant.
  
• Require less maintenance and are less likely to leak compared to a tiled roof.
• No risk of broken tiles.
• Anticon is used instead of sarking which adds insulation.
• No need to repoint ridge caps every 15-20 years like a tiled roof.
• Lighter in weight compared to a tiled roof so don’t require as much frame support strengthening.
• Less gaps for leaves and dust to enter roof space.
• Harder for burglars to break and enter through roof (apparently the roof is commonly used by burglars to enter a building.

Disadvantages

• Screws require replacing every 20-30 years as the tend to be the first thing to go rusty.
• Roof sheets corrode on underlap especially in coastal areas.
  o   Solution – This normally takes a long time for this to happen if the correct roof sheeting (eg Colorbond Ultra) is used. Roof sheeting can be replaced fairly easily.
• Colorbond roofs will fade over time, especially the darker colours and require recoating every 20 years to continue looking good and help protect the metal base material from corrosion.
  
• Metal roofs are hard to access the roof space from top (eg for plumbing/electrical work)
  o   Solution – Sheets can be unscrewed and removed for access, it’s just harder than removing a few roof tiles.
• Lighter in weight - Although being lighter is an advantage, metal roofs must be tied down to the house walls/frame to ensure they don’t lift and blow away in strong winds.
• Risk of denting - No risk of broken tiles, but risk of denting when people walk on the roof.
  o   Solution – Install heavier gauge sheeting , closer battens, or simply educate people/trades to tread on the screw lines.
• Gutter guard and valley mesh - Gutter guard and valley mesh require adhesive strip or saddles to secure the mesh – these collect leaves where they join onto the roof.
  
• Metal roofs are more noisy when it rains.
  o   Solution - Anticon and ceiling insulation significantly reduce rain noise.

Which Roof Covering Is The Best?

So overall, each roofing system has advantages and disadvantages and the list above should help give an insight into the pros and cons and help you choose what type of roof is best for you. If you are building a new house, you really have a great opportunity to select a roof that best suits your house from an architectural perspective, as well what’s best for your climate and location (eg proximity to coast, ease of access for maintenance etc). Whatever roof you choose, there is no such thing as maintenance free, so expect to spend some money over time to
keep your roof looking great and free from leaks.

For professional advice and more information about our premium roofing maintenance, roof restorations and roof replacements in Perth, please contact the Kalamunda Roof Restorers team on 0422 469 125 or email [email protected] or fill in our Online Form to request a complimentary quotation.