# Forum Home Renovation General Odds & Sods  Cutting into Cement Sheet

## Bwennywenny

Hi all. I am installing a Whirly Bird on the roof and I need to put in some air vents under the eaves. I have to cut into the cement sheet. I used a jigsaw and stuffed my blades pretty quick. My questions are - Is there a diamond tip jigsaw blade available? Or alternatively is it better to use a angle grinder. I have a grinder but it uses 100mm discs. I saw in the hardware store that the dry diamond tip discs were 105mm - will these discs fit my grinder?

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## David.Elliott

I found Bosch (multi use) including Fibreboard jigsaw blades at the BLUE shed in 3s at $76.00 yep that's right $76.00.
Cut quite a bit so far incl. some 10mm thick with no appreciable wear on the blades. Trick is apparently go slow...ie: don't push too hard... 
David

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## ringtail

First and foremost  - what sort of sheeting is it ? FC or AC ?

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## David.Elliott

OOOPPPS forgot that! 
stupid me!

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## Gaza

Hole saw then trim up crns

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## Bwennywenny

> First and foremost  - what sort of sheeting is it ? FC or AC ?

  What is AC or FC? I am guessing Asbestos & Fibre. Is there a way of knowing. It is bloody hard to have a look at the eaves from inside the roof. I reckon the house was built in the early eighties.

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## johnc

> What is AC or FC? I am guessing Asbestos & Fibre. Is there a way of knowing. It is bloody hard to have a look at the eaves from inside the roof. I reckon the house was built in the early eighties.

  Early eighties would have a strong possibility they contain some asbestos in the cement sheet, so least dust made the better. Take the appropriate precautions with breathing and avoid sanding the stuff or using that grinder. Try scoring the vent outlines first with a fibreboard scorer, if you do use a grinder spray the surface with water and keep moist as you cut cut no more than three lines and snap the fourth on the score line.

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## Bwennywenny

Thanks I will try and score and punch it out. Either way I am off to Bunnings because I don't have a scorer, I don't really want to pay 70 bucks for a jigsaw blade and the grinder doesn't look like a great option.

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## johnc

> Thanks I will try and score and punch it out. Either way I am off to Bunnings because I don't have a scorer, I don't really want to pay 70 bucks for a jigsaw blade and the grinder doesn't look like a great option.

   I've also used a plasterers hand held hole saw with some effect. It doesn't do much for the teeth though.

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## ringtail

> What is AC or FC? I am guessing Asbestos & Fibre. Is there a way of knowing. It is bloody hard to have a look at the eaves from inside the roof. I reckon the house was built in the early eighties.

  ( Asbestos cement vs fibre cement) early 80's.I'd bet that it is asbestos. In which case you should totally forget the grinder option. You would be crucified if caught

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## sundancewfs

Bosch do TCT jigsaw blades that have no problems with cement sheeting.
Avail from Bunnings and Masters etc...

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