We get this question quite frequently, mostly from architects and builders, so we wanted to answer it as best we can. There are of course variables and we’re answering it from the perspective of our market here in Melbourne, AU but the principles apply elsewhere. The answer is also technical, but that’s okay since usually only technical people ask it.

The simple answer is to design and build according to the structural requirements used for terracotta roofing tiles. The weight of the lightest “Marseille” pattern terracotta tiles currently available in the Melbourne area is almost 10 kg/sqm heavier than the commonly used Del Carmen 500×250 slate tiles.

Here are some approximate weight comparisons for roofing tiles:

• Natural slate – Del Carmen 500×250: 30.5 kg/sqm
• Terracotta tiles – Marseille pattern: 40kg kg/sqm
• Terracotta tiles – Swiss pattern: 43.5 kg/sqm
• Concrete tiles – – Flat slate pattern: 52 kg/sqm

The terracotta and concrete tiles listed are also the lighter weight options available. Other tiles on the market are considerably heavier. Also be aware that slate tiles vary in thickness and therefore also in weight. Plus, as the dimensions of slate tiles decrease, the weight per sqm increases conversely. Larger tiles reduce the per sqm weight.

The 500×250 though is the most commonly used in the Melbourne area. Other options include 400×250, 450×250, and 500×300.

Another consideration during roof framing is the heights at which fascias, tilt battens, verge, sole and lear gutter boards, etc., are set and finished at. This is nearly impossible to give a generalized answer on since there are many factors at play and each job has its own set of unique circumstances.

If you’re in our service area, a simple phone call to Abardeen Slate Roofing at (040) 302-2137 is the best answer we can give. We work directly with architects, builders, and the carpenters doing the framing to assure the framing method matches the slate roofing tiles that will be used. If you’re not in our service area, a good slate roofer will offer the same service because it benefits everyone.