A common practice the world over but not used at all in Australia on residential homes where the preference is for ‘wet fixing’ with mortar and pointing.
Dry-Fix roofing is the term used to describe the mechanical fixing of the roof perimeter at the ridge, hip and verge without the use of mortar and pointing. Traditional mortar bedding is still the most widely used fixing method in Australia in contrast to say Germany where 99% of roofing are mechanically fixed.
However, the increased incidence of storms over the last few years has clearly highlighted the unreliability of mortar not to mention the required maintenance on the traditional wet method. It’s a wonder that Dry fixing of the roof is not more popular given the multiple advantages over the traditional mortar and pointing method.
The roof is the most exposed part of any building. Using mortar to secure vulnerable areas of the roof, such as the verge, will inevitably lead to future maintenance. Differential movement causes mortar to crack and no reliance should be placed on its tensile or shear strength. The action of alternating temperatures over summer and winter with rain will exploit the development of hairline cracks and the home owner needs to stay on top of this. Here is a video from the UK demonstrating the issues with traditional method https://www.youtube.com/watch?v=ONGiIprubXc It should be acknowledged that pointing which is a requirement in Australia does provide protection on the ridge but maintenance is still required over time.
In contrast because Dry-Fix roofing is mechanically fixed, It is both safe and secure and offers better resistance to wind uplift and water penetration over time. It complies with building codes and in some cases is stipulated in AS2050 in high wind situations. Fixing need not be a problem in bad weather because, unlike mortar, many Dry-Fix roofing products can be easily installed, even in damp or wet conditions.
Dry or mechanically fixing is fast and simple and in fact has been assessed at being twice as quick to install compared to the traditional method that requires two visits to site on different days to allow the mortar to set and the follow up with the application of pointing. Here is a video time comparison with a wet v dry fixing timed comparison. As you can see the wet or mortar solution takes 6.5hours and this does not even include the pointing part to be done at a later time compared to 2.5hours with the dry method https://www.youtube.com/watch?v=nwfvv6rmMFM
There is also the added obvious advantage with Dry fixing where there is no mess and inconvenience of mixing, carrying and using mortar. No special skills or tools are required also for dry fixing, consequently Dry-Fix roofing can prove highly cost effective. It also means a more consistent appearance, with none of the longer-term maintenance problems and costs associated with mortar bedding.
With mechanical fixing the ridge there is also the major advantage of being able to allow the roof to breathe with cross ventilation. The traditional method closes the roof off trapping the heat that radiates through the roof tiles, a mechanically fixed ventilated ridge does not have this problem.
See www.rapidridge.com.au for more details on this method.