Converting an old tiled roof cover to a new metal roof cover (for example a Colorbond roof) is very common throughout WA. There is the right way and the wrong way to undertake this conversion. The wrong way can cause adverse impacts for home owners to the extent that the property can be considered not structurally sound. This can create challenges to property owners trying to sell their property.
1 Why Do People Convert Their Roof Covers?
There can be a range of reasons why a home owner will convert an older tiled roof cover to a new steel roof.
1.1 Roof Leaks
No, building materials will not last forever and eventually all building materials will break down and it becomes more economical to simply replace the item rather than pay for continual repairs. Roof tiles are no exception and continuous leaks may indicate that the tiles are coming to the natural end of their serviceable life.
1.2 Fretting Tiles
Tiles (clay or cement) will not last forever. Eventually the tile will break down and lose their core attributes.
1.3 Loss of Water Proofing Qualities
Eventually the water proofing qualities of tiles (particularly cement tiles) will break down. The tile will need to be recoated or replaced.
1.4 Broken and Cracked Tiles
When there are a large number of broken and or cracked tiles that require replacement, sourcing replacement tiles which are the same colour, size and profile can be difficult. Replacing the entire roof may be an option.
1.5 Delignification of Tile Battens
Wooden tile battens can suffer from a breakdown of the core wood fibres such that the overall wooden batten breaks down. When this occurs the battens will need to be replaced. When a roof requires replacement tiles, ridge caps and or a large number of tile battens replaced, the combination of all of these factors may also contribute to a decision of replacing the tiles in favour of a metal covering.
2 Why Metal Over Tiles?
There can be a couple of key reasons:
2.1 Aesthetic Reasons
Some people choose to convert their tiled roof cover simply for aesthetic reasons in that they prefer the look of metal roofs.
Generally metal roofs are cheaper than retiling a residential property.
3 So What are the Key Issues?
As mentioned there are two key issues that need to be considered.
- Metal roofs are a lot lighter than a tiled roof. A tiled roof will weigh several tonnes while a metal roof will generally be a fraction of this weight.
- Planning approval and a building permit would likely be required from a local authority and the Building Code of Australia is likely to have changed since the property was originally constructed.
The key challenge when converting a property from a tiled roof to a metal roof cover is the dramatic reduction in weight. This significant change in weight conditions, when coupled with high winds, can create enormous uplift on the roof and hence potentially damaging issues.
So the core issues can be not about holding the roof up, but hanging onto the roof in a high wind event. The Building Code of Australia requires the roof frame to be tied down to the house as defined in Australian Standard 1684.
So the key issue associated with getting a Council Building Permit, supported by Engineers Approvals for the conversion is to ensure that the roof tie down requirements for the roof frame to the house have been appropriately considered.
The following video provides an excellent summary of the issue:
4 Your Contractor
It is important that you carefully select your contractor for the roof conversion. The Contractor must:
- Obtain the necessary plans and engineering approvals
- Obtain the necessary Certificate of Design Compliance
- Obtain the Council/Shire Building Permits
- Implement the Engineers tie down requirements
- Complete the conversion in accordance with the approved building permit.
- Adhere to the Housing Contracts Act in WA (this is a core protection for the home owner)
Where the property is in a heritage area or is individually listed as a heritage property, additional approvals may be required.
Where the cost of the conversion exceeds $20,000 then it is critical that the work be undertaken
- by a WA Registered Builder
- that Home Indemnity Insurance is confirmed prior to work commencing
Be very wary of contractors who cut the work down into several small jobs or insist on the home owner organising other contractors to do parts of the work to try and stay under the $20,000 limit!
5 What is the Residual Issue?
Every quarter we identify a number of homes that have had a tile to metal roof cover conversion completed where the tie downs from the roof frame to the external walls have not been installed.
Sadly there are a number of contractors in WA who simply do not comply with the requirements in relation to the tile to metal roof conversions, potentially exposing the property owner.
Where the proper processes have not been followed there can be some key issues:
- The property may be considered not structurally sound
- Insurances may be impacted
- It may be very difficult to claim against a contractor who is not a WA Registered Builder.
- The newly installed roof sheeting and the roof frame may be blown off in a high wind event creating a safety risk for the occupants of the home and or neighbours.
6 Can the Lack of Tie Downs on Roof Conversions Be Remedied?
The short answer is yes. Where appropriate tie downs have not been installed on a tile to metal roof conversion then the required tie downs can be retro fitted to a property.
The complexity and cost of retro fitting is often a factor of:
- Is the property a single or double storey property?
- Properties over single storey can have access issues which may require scaffolding to be installed to enable the remediation work to be undertaken
- Was Council approval ever obtained?
- Retrospective approval may be required
- Is the property double brick, brick veneer or framed and clad
- The type of construction may impact the costs of retrofitting an effective tie down strategy
There are many reasons why people want to convert older style tiled roofs to a new metal roof covering. These conversions happen every day and there are a myriad of firms who provide a good quality service.
The conversion goes beyond the roof cover. The massive reduction of weight between a tiled roof and a metal roof requires the review of the roof ties downs to ensure that the roof remains in place during a significant wind event.
Roof conversions require council approval every time. Council approval requires engineer considerations of the roof tie down requirements. Where the costs exceed $20,000 a WA Registered Builder must undertake the work, although using a Registered Builder makes sense even below $20,000.
If you are selling a home which has had a tile to metal roof conversion, it makes sense to have the property inspected by a Houspect Building prior to going to market. Remediation work may be required.
Build, Buy, Invest in property with confidence.