Building Today asked Roofing Association of New Zealand (RANZ) chief executive Graham Moor about the main trends and issues surrounding roof installation in New Zealand.
BT: What are the main issues currently surrounding roofing installation in New Zealand? For instance, what types of products and installation techniques can minimise water ingress and improve the health of occupants in both residential and commercial buildings?
GM: Warm roofs are very topical at present. As people are looking to improve thermal efficiencies and create green spaces, we are seeing this type of roofing show up more often.
Typically, these roofs have a membrane system providing the weatherproofing layer. We are also seeing built up systems, which are steel roofs which are used either side of an insulation core.
There are also systems where the metal roofing is laminated to an insulation product.
There are also companies laminating roofing underlays to the underside of the roofing sheet. The focus here is that with all of this innovation we are seeing a more proactive approach to moisture management and building science. And not before time.
Managing internal moisture is key for the comfort of the users and energy efficiency of that building. Ventilation of roof spaces is being considered and included in designs. This is smart.
It is not uncommon to receive complaints about roof leaks. However, it is not the roof leaking — it is the roof collecting internal moisture in plenty of cases.
Adding ventilation enables the warm moist air to be expelled to avoid the problems this moisture causes.
As our homes have become more airtight, we need smarter solutions to prevent excessive moisture build-up in roof cavities. This moisture can also shorten the life of components in the roof system.
Likewise, with the typical time-constrained building methods we use, there is pressure to install the roofing before the timber framing is at the right moisture content.
I think I know the response when the roofer tells the builder that the moisture content of the purlins is too high.
Our industry has seen flashings fail and roof noise issues caused by high moisture content. Purlins should have less than 18% moisture content.
Internal moisture control is very important whatever the roofing product. The roof is the collection point — not the moisture source.
BT: The use of alternative and cleaner energy sources is becoming more prevalent in the residential and commercial building sectors. How much of an increase has there been over the past 20 years in the use of solar panels being fitted to roofs in both the residential and commercial sectors? Are there any particular issues arising with the installation of panels on different types of roofs in New Zealand?
GM: As we continue towards a more sustainable future, solar energy collection is gaining significant traction to harness a free energy source.
There are plenty of options along with plenty of considerations when choosing solar collectors.
We are all familiar with solar panels. There are roofing products that incorporate photovoltaic collectors directly onto the roofing profiles and not just metal roofing products.
When installing solar collection systems, it pays to make considered decisions. Orientation to the sun, ease of access (for maintenance), wind loads, point loads, how trafficable the roofing profile is, creating unwashed areas under collectors (warranty implications) and aesthetics need to be thought through.
Life cycle costs are another consideration. Whoever comes up with the ultimate battery solution which enables the home owner to use the collected energy when they come home at night will really grow this market.
BT: Roofing is a vital part of the housing envelope. How does an industry organisation such as RANZ provide resources and help maintain standards in such an important sector of the New Zealand building industry?
GM: One of the constants for trade associations is making sure you are there for your members and the public. Rightfully, the public expect a level of professionalism and, if needed, accountability from those that belong to trade associations.
Continual education is key to helping our members. We have developed How to Guides which have become best sellers as we lift knowledge in our industry.
We also have great relationships with our sponsor partners, other industry bodies and industry experts.
It is arrogance to think we can know everything ourselves. It is our experience that the previously mentioned groups just want correct methods and products used to improve our building stock. As such, they are very willing to help us help our members when needed.
Like the Registered Master Builders Association (RMBA), RANZ spends plenty of worthy time lobbying for its members. Most of our members are SMEs and have not got the time to spend getting common sense changes for industry.
This is a key reason for our existence — to be the industry voice. Regulatory submissions with MBIE and WorkSafe of late and, of course, the changes coming in industry training, are two great examples of the work trade associations do for their members.
Most of the time we are on the same page. We should also support those that belong to and support trade associations. Collectively we achieve more.
The leadership shown by the RMBA by facilitating Construct is welcomed by our industry.
Out of this, the Construction Industry Accord has evolved as we look collectively to solve the well-known issues which have been around our industry for some time.
Collaboration rather than our current combative approach has to be the way forward. So thanks go to the RMBA and chief executive David Kelly.
BT: What’s your take on the recent fire at the Sky City Convention Centre, particularly regarding the materials used in the roof, and why these materials seemingly hindered firefighters’ efforts to extinguish the flames?
GM: Primarily, we hope that the mental health of those involved is being supported. There will be a rigorous approach to finding out what happened, and poignant learnings to come out of that in due course.
BT: Please add any other information you think is worthy of coverage, especially any new innovations or initiatives RANZ has underway or is planning in the near future.
GM: Our biennial RANZ Roofing Excellence Award winner was named at our 25th annual RANZ conference in Queenstown this year. Check out the article on winning specialist tradesperson Richie Powell from Project Unite on page 38 of this issue.
Gender diversity in industry is an integral part of our industry. Our vice-president Jenny Maxwell initiated NZ Women in Roofing (NZWiR), launched at our 2019 conference, which recognises the many and various roles that women hold in the roofing industry.
Their membership encompasses installers, salespeople, administrators, company owners and any women who participate, whether they are from installation companies or our industry sponsor partners.
One of our members, and a very keen supporter of NZWiR, was announced as the Tradeswoman of the Year at the recent National Association of Women in Construction (NAWIC) Awards. Liz Watson is a very worthy recipient of this award.
It is with some pride that RANZ has watched the development of this Wahine toa and the business she has with her partner Dan at Stone Roofing in the Waikato.
Liz has continued her development from trainee of the year in 2016 to her latest achievement. She loves her trade, and her obvious pride in what she does shines through all the time. She is a great example of what attitude achieves.
Retentions are an accepted part of a construction contract for many. Retentions are held to ensure that we (the specialist trade) complete our contractual obligations.
Yet the contracts are very clear what those obligations are. To that end, we do not want to damage our reputations or our relationships with our clients by not carrying out these obligations.
Our members tell us that they have not had their retentions used because they haven’t met their obligations.
We are also not aware of builders who have had their retentions used by their clients because you have not fulfilled your building obligations.
Now that the law has changed regarding retentions, administering the management of someone else’s money must come at a cost.
RANZ’s view is that retentions are not making a difference — and certainly not being used as intended.
If a financial lever is all you have to ensure performance from your specialist trade then that does not sound as if there is much collaboration occurring. Or, was that specialist trade chosen based on price rather than performance?
The RANZ Executive is considering an accreditation scheme for members with criteria which will help main contractors when selecting roofing companies. We applaud that the RMBA is also looking into this opportunity.
Simply, you will be better off using a RANZ member who has the accreditation.
For more info, visit www.ranz.co.nz.