Cutting roofing sheets; what's the best technique?

[Gareth0123]

My workshop needs reroofing and I wanted to remove the felt covered tongue & grove and replace it with corrugated plastic covered steel sheeting.

I bought 14 x 5metre lengths of used red pantile sheeting, 4 x 3metre lengths of apex and 6 X 3 metre lengths of 90° gable along with various angled cut bits of each for the princely sum of £150.00 but from 25 miles away from. It was already down on the deck and loaded on a pallet for me when I arrived and he even threw in an IBC for an extra tenner!.
They were cheap because a farmer/haulier had extended his storage barn and instead of using red Norfolk pan tiles he used these sheets........ and the inspector caught him and he had to take it all off and do a proper job with clay pantiles!


These pantile sheets are 5000mm X 1100mm and I need to cut them down to 2450.
Taking into account the peaks and valleys across the sheets what is going to be the best way for me to cut them without doing too much damage to the plastic coating?

 

[angellonewolf]

as a guess id be trying a few ideas but fine tooth circular saw blade in a evolution saw plunge saw type clamp the steright edge ?

would my idea

 

[8ob]

Use an offcut as a straight edge, its the only easy way of accurately marking in and out of the profile. Then cut with a thin disc in an angle grinder.

Bob

 

[SierraV6]

Use an offcut as a straight edge, its the only easy way of marking in and out of the profile. Then cut with a thin disc in an angle grinder.

Bob

Correct answer!

Use a 0.8mm slitting disc if you can but 1mm will be fine.

 

[James1979]

This^^. You need to sort of gum your way through it rather than cut it! Anything reciprocating will just catch and smash it up. I know this because I replaced some wriggly tin on the workshop with clear earlier this summer. I had to work this out by trial and error and wasted a sheet.

 

[bricol]

I just used a 9" grinder. Laid them on the lawn and cut them, and the grass. The disc was big enough to cut through without worrying about following the profile.

10 yrs on, no rust, so I'm guessing mine were galvanised under the plastic and that's still giving it protection as I didn't treat the cut edges.

Grass didn't seem to like the extra metal ration though.

 

[defender dan]

+1 for 9" grinder & thin cutting discs. Always used this for cutting cladding & roofing sheets for barns etc.

 

[AndersK]

as a guess id be trying a few ideas but fine tooth circular saw blade in a evolution saw plunge saw type clamp the steright edge ?

would my idea

Do like this and save a lot of work.

Most I did was 12 sheets in one go, less than one minute

 

[Gareth0123]

The 9" grinder and thin disc it is then. ....... I don't have an evolution saw.

Thanks guys.

 

[mike os]

angry grinder

 

[Turbo]

You can use a nibbler but they are difficult to keep straight on profile sheets if you are inexperienced. Using a piece of 2x1 timber as a guide helps.

I watched a roofer sheet a hexagonal gazebo with corrugated iron, not an easy job with loads of angled cuts. Everything was cut freehand with a nibbler, just following a line drawn with a sharpie. It was an amazing bit of skill that made me really jealous!

On tip I can give you is go as slow as possible with light pressure to avoid melting the plastic. I used a cordless grinder running on its lowest speed, using a length of 40x10 flat steel to keep me straight & vertical.