Committed to Canterbury
The 6.3 magnitude earthquake on February 22 this year has proven to be far more devastating than the previous big quake in September last year, and tragically, there has been significant loss of life.
At this time, all our efforts at the Fletcher Building Roof Tile Group are focused on helping staff and contractors directly affected by the tragedy and supporting their relatives, friends and neighbours as the true scale of the disaster unfolds.
The information below was prepared following the earthquake in September last year.
Clearly, many things have changed since then and the resources we had previously allocated to the rebuilding programme are now otherwise engaged in dealing with the current crisis.
There will be much to learn from this event and once we are able to mobilise our teams again, we will carefully evaluate what has occurred and update the information below.
In the meantime, our thoughts are with the people of Christchurch at this tragic time and we remain committed to do everything in our power to help in the recovery process.
Gerard Roofs Canterbury 0800 857 857
A. The safety of your family and possessions should be your first priority. With roofing, the key considerations are weight, structure, fixing, and of course, cost.
Weight is important. Because the framing for a house is designed with roof weight in mind it is generally possible (depending on the slope of the roof) to replace a heavy weight roof with a lightweight roof such as steel tiles from Gerard Roofs. Putting a heavyweight roof on framing that has been designed for a lightweight roof normally requires upgrading the framing and structure underneath. Because heavy weight roofing requires a more substantial structure beneath it, this will add to the cost.
Keeping a roof on is important in an earthquake and in wild weather conditions. Every Gerard Roofs’ lightweight steel tile is nailed to the roof structure at 90-degrees to wind up-lift forces, making them highly secure in strong winds and earthquakes.
A. An independent assessment of housing in Canterbury after the 7.1 magnitude earthquake in September 2010 was conducted by University of Canterbury engineering specialists who found “most common type of damage for older buildings (more than 15 years old) was chimney collapse.” This report went on to say:
"Chimney collapse on to corrugated steel roofing often caused no further damage, depending on the height of the chimney, but some fell through the roof or caused rafter failure. Chimneys falling on to tile roofs (concrete or clay tiles, or slate roofs) more often fell through into the house, sometimes causing further structural damage and potential loss of life."
To date we have not received any reports or seen any evidence that shows Gerard lightweight steel tile roofs performed any differently to corrugated steel roofing. Where chimneys needed to be removed the repair generally required only a few tiles to fill the void.
A. From a technical point of view, certainly not.
Replacing your clay tiles with a Gerard lightweight steel tile roof will require no changes to the framing structure. However, new roofing battens and underlay will be required, as can be the case when replacing with other roof types.
In a July 2003 report the New Zealand government recognised that heavyweight roofs on existing school buildings caused extra stresses. As a consequence, many schools had their roofs replaced with lightweight steel tiles. Your house can benefit in the same way. Below are the recommendations from a Ministry of Education commissioned report titled "Technical Guidelines for Structural Mitigation Work":
"As long as they are adequately connected to their foundations and do not contain a heavy roof or ceiling, school buildings are expected to perform adequately during a severe earthquake almost irrespective of configuration. The major reason for this is the lack of seismic mass at roof level generating significant lateral forces. This is not the case if the building has a heavy tile roof. All buildings with heavy tile roofs have been identified.
Recommended Action
All heavy tiled roofs are required to be removed and replaced with a lightweight roof. The only exception to this is if the school wants to retain the tile roof and this would need to be agreed to by the District Property Manager. In the latter circumstances, a detailed analysis of the building would be required and strengthening provided..."
From an insurance point of view, you will need to talk to your insurance company as they may decide it is cheaper to simply replace the damaged area. However, there is a shortage of second-hand clay tiles and the price of these has increased substantially.
A. Gerard lightweight steel tiles are between 6 and 10 times lighter than concrete tiles, and because every tile is nailed to the roof, it is highly unlikely individual tiles will be dislodged by earthquakes or high winds.
Gerard Roofs steel tiles are available in a number of profiles and colours so you should be able to find something that closely matches the look of your current roof.
A. Our certified installers will measure the roof, and once they have the OK to proceed, will remove the old roof and replace it with Gerard lightweight steel tiles.
This usually involves replacing the roof one section at a time to avoid undue exposure to the weather. You can remain in your home while the new roof is being installed. The roof of an average 230sqm house will take around four days to replace.
A. No. Gerard roofs can only be installed by Gerard certified installers. This means that we are able to offer a 50-year pro-rata product warranty and 5 year installation warranty. Our installers have all the equipment necessary to remove your old roof and install a new Gerard roof in a safe and professional manner.
A Ideally you should have an idea of roofing type before you start, although colour and profile can often be left until later. Because Gerard Roofs steel tiles weigh less than concrete or clay tiles, the framing of the home can be designed differently, often resulting in significant savings.
If your house is already designed for a heavy roofing material such as concrete or clay tiles and it meets the minimum slope requirements of 12 degrees, substituting Gerard lightweight steel tiles is easy.
A. The cost of a roof varies significantly based on the complexity of the roof, but typically the cost of Gerard lightweight steel tiles is competitive with longrun corrugated iron and clay or concrete tiles. Check that all costs have been included, such as roofing battens and paper underlay, when pricing your new roof. Remember also that heavyweight roofs such as clay or concrete tiles can also require more extensive supporting structure which can add to the final cost.
A. This is a little hard to quantify in the absence of data for all roofing types. What we can say is that Gerard lightweight steel tiles are manufactured from recyclable steel and we have ISO 14001 certification, an international standard. This means we have procedures in place to constantly measure and reduce our environmental impact.
A. Gerard Roofs is part of the Fletcher Building Roof Tile Group. We have four plants around the world and sell into over 130 countries. The New Zealand plant alone has ample manufacturing capacity.
We have plenty of installation capacity in Canterbury. But to be sure, we have also surveyed our nationwide network of certified installers and have identified teams able to move to the region to help out.
A. Your first point of contact is Gerard Roofs in Canterbury. You can call them on 0800 857 857 to discuss your requirements and arrange for a representative to come to your home.
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If you have a heavyweight concrete or clay tile roof that was damaged in the earthquake, fill in this form to find out how you can replace it with a modern, lightweight Gerard steel tile roof.