Will James Hardie panels sag as ceiling?

Homersan

Hello, I am considering using James Hardie 2700 x 1200 x 7.5mm on external veranda ceiling. Would this be suitable and how far apart would I need fixings to be to prevent sagging?

The area is 8000mm x 1850mm, I plan to fix 2 pine framing timbers (70x35 should do) along each 8 meter edge (there is already a fixing point through the middle) Will this be enough to properly support the Hardie panelling of will it need more? At the moment this would mean the fixing points are about 900 between? Cheers.

JacobZ

Hi @Homersan,

Welcome to the Bunnings Workshop community, it is fantastic to have you with us.

I am assuming, based on the measurements, that you are looking at the James Hardie 2700 x 1200 x 7.5mm Hardie Groove Lining. If so, then James Hardie always provides comprehensive installation guides for their products. The installation guide for Hardie Groove can be found here - Hardie Groove Installation Guide.

You'll see on page 7 that they have a detailed diagram showing the spacing of framing and the spacing of the fixings on that framing.

You'll see that the maximum spacing between framing is 600mm, and that your fixings must be spaced no more than 250mm apart in the centre of the sheet and 200mm apart around the perimeter. This means you would need to add additional framing to use this material for your ceiling.

A simple way to do this is to add framing perpendicular to the long lengths you have mentioned. They will have to be no more than 600mm apart to fit within the requirements of the installation manual.

They also indicate which fixings you'll need to use. These Paslode 30 x 2.8mm 500g Galvanised Clouts are what you'll be required to use.

Let me know what you think and if you have further questions, please don't hesitate to ask.

Jacob