A Matter of Degrees – dramas with metal roofing

25 Nov A Matter of Degrees – dramas with metal roofing

“A matter of degrees” or “Close enough is not good enough”

Australians love their metal roofing products and with the massive contemporary housing market boom, metal roofing like Colorbond and Zincalume has become the product of choice for the majority of building construction projects.

Metal roofing comes in many different profiles – but all of these profiles are designed around average rainfall recurrence intervals – up to or greater than what will fall in major storms which statistically are expected to occur only once in every 100 years (although of course there are no guarantees and you may be lucky enough to experience several in a lifetime!).

The rainwater carrying capacity of a roof is however entirely dependent on the angle, or pitch, of the roof and the roof sheeting profile.  Unfortunately, some impractical architects and drafts-people have taken to specifying minimum gradients for metal roof sheeting projects and in some cases have also specified the wrong roof sheeting profiles.  The poor old Builder then tries as best he can to build the roof structure to the plans while not realizing what ramifications will play out if the roof structure is not adequate for the roof profile actually being installed.

There’s also the problem of the builder trying to match the specified minimum of 5 degrees for a corrugated profile or the specified minimum of 2 degrees for a metal deck profile, without any measure of leeway.  As they say, Murphy was an optimist and inevitably the Builder ends up constructing a roof structure which is somewhat flatter than the absolute minimum gradient which has been specified on the plans.  It should be simple but experience shows it isn’t.

The Licenced Roof Plumber then rides into town and without so much as getting out his spirit level plonks the specified roof sheeting product (or perhaps his own chosen cheaper product!) on – which is now installed at less than the roof sheeting product manufacturer’s absolute minimum pitch requirement and/or may also be totally inappropriate for that roof in the first place.

The long and the short of this scenario is that the roof product in question now does not have the all-important water carrying capacity that it was designed to provide during a heavy or even medium intensity rainfall event.  The water tightness of the roof is also increasingly affected by wind conditions and it becomes very difficult to flash (i.e. seal) the edges and penetrations on the roof.  The roof may even hold water due to natural sagging of the building, something which acts to further lower the already compromised pitch of the roof.

The roof sheeting product manufacturer’s normal 25 year+ warranty is also voided if the roof has not been installed as per the minimum requirements or is the totally wrong product in the first place.  This is very bad news for a new home or building owner.

The first the Property Owner knows about any of this on their lovely new contemporary house is when water starts to leak in here, there and quite possibly everywhere during a storm.  This then sets up the merry-go-round of having the original plumber, original Builder and/or any local roof plumber they can lay their hands on to all re-attend site with their trusty silicone gun to bog up the latest flash point for water ingress and then assure the Property Owner that “she’ll be right now mate”. Rarely are the key defects ever identified.

If the Property Owner also then needs to make a claim on their own Home & Contents insurance due to water entering the home, they will often then find themselves at the extremely unhelpful end of a big, nasty insurance company claims department which after sending out their own expert then denies the claim based on ‘faulty workmanship’ by the roof plumber and builder (a standard exclusion in virtually all policies).  A house full of wet carpet, sagging ceilings, mould growing, damaged furniture, electricals, clothing, bedding, swollen timber floors…it goes on and on.  And your own insurance will not help you – it’s a complete and expensive disaster nobody wants.

Metropolis Solutions has a wealth of experience about roof plumbing problems and we actually understand the details of the underlying defects which are causing water ingress.  We identify roof profiles and products, scrutinise original plans and specification documentation, and use highly accurate tools to methodically assess the entire roof installation.  We can also help you fully prepare any claim for rectification of the defects and for the damage caused.

A non-compliant roof does not need yet more silicone!  Rather, a holistic investigation is required to pin-point all defects including any underlying issues that will need to be addressed to properly resolve the situation.

If you are having problems with water ingress, do not allow your 6 year metal roof plumbing workmanship warranty to lapse without having Metropolis Solutions investigate your roof and see how it stands up to the stringent roof plumbing regulations and roof product manufacturer’s requirements. 

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ABOVE: This custom orb corrugated roof sheeting product requires a 5 degree minimum roof pitch for compliant installation.  Unfortunately as can be clearly seen, this installation on a 2.85 degree roof is not even in the ball park.  This means that the roof product manufacturer can immediately void their product warranty and the roof is highly vulnerable to leak around the flashings, lap joins and any penetrations.  Very expensive to fix however the good news is that this workmanship defect is covered by the Victorian Plumbers Warranty insurance so long as the work is less than 6 years old.

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ABOVE: This roof is truly a flat roof – it has 0 degrees gradient.  This metal deck roofing product however requires an absolute minimum of 2 degrees gradient for compliant installation.  This building experiences ongoing water ingress leaks which have turned into the nightmare for the Owners Corporation and the individual owners.  The licenced roof plumber is responsible for this serious roofing defect.  Thank goodness he’s insured for his workmanship and the Owner’s Corporation found and engaged Metropolis Solutions prior to the expiry of the licenced plumbers 6 year warranty insurance period.

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ABOVE: This metal deck roof actually grades in the adverse direction therefore is directing towards towards the flashings on the building rather than safely away towards the box gutter drainage system.  We measured 0.4 of a degree of ADVERSE gradient when this roofing product actually requires a 2 degree minimum fall (in the correct direction!).  Therefore the roof has to actually fill up with water before it has any hope of overflowing into the box gutter.  This roof is covered in slime and dirt and the building is uninhabitable as a result.  Once again, luckily the Owners Corporation found and engaged Metropolis Solutions prior to the expiry of the licenced plumbers 6 year warranty insurance period.

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