I am flabbergasted to read that some people are still purporting that keeping heat within the roof cavity by sarking during winter is a good thing.
At least they are admitting that the heat that escapes from the home stays trapped below the sarking in the roofspace.
This heat that is trapped in the roofspace needs to be removed out of the roofspace by an effective roofspace ventilation system especially when it is sarked to alleviate the possibility of condensation.
THE EVIDENCE FOR ROOF VENTILATION
However, they make no mention about effective roofspace ventilation or if they do, they recommend one whirlybird that will do nothing to circulate the ambient temperature throughout the roofspace. We reiterate, once you have lost heat from the home into the roofspace that is exactly what it is lost with no benefits only problems can come from this lost heat in winter.
As far as reflecting heat – this is also a porky – in order to really make any difference to reflect heat, the sarking would have to be laid upside down, silver side up. The reason the colour is on the top is when I started roof tiling, more than 50 years ago, the sarking was double sided, silver both sides, and we used to have a lot of accidents due to the mirror like finish, I myself broke 2 ribs from sunstroke by falling off the run up we used to have before we used tile elevators. Back then one out of 20 houses were sarked, we usually sarked terracotta tiles because they were more vulnerable than concrete tiles however concrete tiles are the same today as they were then.
CLAIMING SARKING WILL SAVE YOU FROM STORM DAMAGE IS ALSO A VERY LOOSE CLAIM
My experience is that if a roof is damaged by a storm i.e. trees or tree branches or tiles being blown around or down on a roof the sarking is also damaged and will also allow water to enter the roof and as my business was previously primarily re-roofing and repairs I have seen all the damage that storms can wreak on homes to tiles, sarking and roof timbers. Sarking may have a very small effect however I would not say it would get you out of trouble if heavy branches or flying tiles fall on your home, hail will go straight through like a bullet and as for sarking saving embers from the roofspace the last place I would use roof tiles is in a bushfire area, corrugated colorbond is the only roof covering I would recommend for ember attack.
I reiterate if you were to ask my professional opinion as long as your roof has been professionally installed or sarking has been mandated, leave the money in your pocket, an effective roof ventilation system will give you more value for your money whether your roof is sarked or not.
It reminds me of McDonalds do you want fries with that – it’s called upselling or cross selling – do you want sarking with that.’
Here are the links to the aforementioned blogs – “A Very Happy Customer”and “Warning! Read Before You Design Your Next Housing Project”