Change from tile to metal roof

[purpledino 1]

Hi my builder is suggesting as part of major reno to get a roofing guy to check the integrity of my 20y tile roof KIV change the tiles/battens.

He says changing to metal roof will cost more because it involves changing the timber rafters & replace with new steel structure/purlin & metal sheet, plus need to check on the existing structure to design the steel support for the roof. Is this true? He generally knows his stuff but I wanted to check w u experts, as professor Google says metal roofs are generally lighter than clay roofs.

[snoozee 98]

metal roof sheets itself may be lighter. but the metal roof comprises of multiple layers like aluminum foil, wiremesh, rockwool, bitumen sheets, zinc sheets so these add on to the weight. all these substrates are sandwiched between the purlins and the metal roof and the substrates are normally fixed by having the zinc sheet screwed using self tapping screws into the purlins. also, depending on the metal roof system used, there may also be mounting clips which are screwed onto the purlins as well to lock the metal sheets in place.

[IceEyez 4]

Actually the structural support system for metal roof required is slightly different from metal roof - got to do with how the direction the sheets are being layed versus individual clay tiles. So yes it is possible true that your roof will need to add new purlins. The contractor will need to check the existing structure first. 

Did a few projects recently - tile roof change to metal roof. Based on the existing timber roof structure, engineer had advised that we need to add some 100X50mmX20mm intermediate lipped channels to allow the actual laying of the metal roof sheets.

[GoodVictor 0]

Tile roofs can look good for a while, but there comes a time when they begin to show their age. Tile roofs most commonly give way to the cobwebs of mold and mildew. Over time, this degradation makes the tiles more difficult to clean and install a new home cost. On the other hand, a metal roof is corrosion-resistant and stemless, making them the ideal choice for more permanent installations. I got minor problems with it, and I contacted the guys from roof repair Sydney. They did a great job! They came and consulted me on what I have to do.