In the ‘old days’, metal roof sheeting came in stock lengths. There are many old metal corrugated roofs in Sydney with 6 foot (2.4m) long roof sheets end-lapped together along the length of the roof – to achieve the required total sheet length.
….And because end lapping of corrugated roof sheeting was so common back then, the old roofers knew how to install the roof sheeting so that the end laps did not leak.
Nowadays, roof sheeting is available to any custom length. So your roofer will measure your roof and order the roof sheeting in single lengths. There are no end laps and one less place for leaks and corrosion to start.
However, if the roof is very long or if access is difficult, roofers in Sydney will still be forced to install metal roofs with end laps. So a long roof may have one or two end laps in it.
If the end laps are done correctly, it will produce a very serviceable roof. But end lap skills have disappeared a bit and many morden-day Sydney roofers may find it difficult to install an end lap correctly.
Recently, I was called out to a leaking metal skillion roof in the inner west of Sydney. The roof was large and long and it had two end laps on it. There were no corrosion problems and apart from being laid a bit ‘flat’, there were no easily observable reasons why the roof was leaking.
Upon further probing, I finally discovered that some of the end laps were installed incorrectly (funny enough, most of the other end laps were done right).
…So, how can an end lap on a corrugated roof be installed incorrectly and why does it make it leak?
Check out the video below to find out….