How to add ceiling strapping?

[FredB]

I have been advised to add straps to a sagging gyprock ceiling to strengthen it after it has been fixed back into place. I see the following products for this on the Bunnings website. 

Gyprock CSR 6kg Pre Mixed Cornice Cement

Gyprock CSR 1kg Fibreglass Rovings

Features

Helps add strength to old, sagging ceilings
Use in conjunction with Gyprock Casting Plaster for fibrous plaster or plasterglass surfaces
Use in conjunction with Gyprock Cornice Cement for paper-faced plasterboard surfaces

Small amounts of fibreglass rovings are ‘dunked’ in the plaster mix and applied like a strap over the ceiling joist or batten, making contact with the plasterboard on either side. Make sure dust is removed before the plaster/roving strap is applied. This helps support and strengthen old ceilings that have sagged. It is recommended that the ceiling is propped and screw fixed before the plaster/roving straps are applied.

I have looked at the CSR and Gyprock websites for more information about using their products for this purpose and also contacted them for more information, this is a reply that I have received ....

"You may like to talk to a Gyprocker, as we are the manufacturer only and do not have a great knowledge of some of these techniques created on site by installers. I have heard that one common practice may be to use sisal or hemp along with casting plaster or Cornice Cement. Feather out the ends and stick to the back of the plasterboard while the centre section lays of the framing member. Please note this information is general in nature and should be tested or checked by an installer."

Is there any information available to give more guidance on using fibreglass rovings and cornice cement for this purpose. Other than safety precautions in the roof space and doing a huge cleanup first it looks fairly straightforward, although messy, but any tips would be much appreciated.

[EricL]

Hi @FredB 

Welcome to the Bunnings Workshop community. It's wonderful to have you join us, and thank you for sharing your question about ceiling strapping.

It looks like you've done a fair bit of research concerning ceiling strapping. 

Are your installers adding extra timber ceiling framing? If they are, have you considered replacing the old ceiling gyprock with new sheets? It looks like the old ceiling sheets are losing their structural integrity. I propose thinking about replacing the sheets rather than trying to repair the old ones.

Allow me to make further inquiries regarding the fiberglass rovings. As soon as I have more information, I'll get back to you.

Thank you for your patience.

Eric

[FredB]

Thanks for your reply Eric

I was up in the roof space today (starting a huge clean up !!) the existing sheets look ok so far. They were attached with glue and clout nails. No strapping has been done to them so far and the ceiling looks ok over the rest of the nearby areas. I'm intending to strap it all though.

The backs of the sheets show no water stains but I still need to get deeper into a corner section to confirm. The roof above is in good condition.

After removing some insulation batts and doing a quick clean-up of the back of some sections of the sheets the surface looks good enough to bond cornice cement to after it has been wiped down.

[EricL]

Hi @FredB 

I've been in contact with our provider, and it looks like you've pretty much covered all the available information regarding fiberglass rovings. Unfortunately, there are no video tutorials regarding the application of fiberglass rovings. 

However, they did mention that if you wish to discuss it further to give their Sales Representative a call. I'll be sending that information to you by PM.

Please keep us updated with your progress, I'm looking forward to seeing how the fiberglass roving will perform.

Eric

[FredB]

Thanks Eric

I'll try researching it a bit more, if I don't find any more info I'll just have a go at following those product features notes on the Bunnings website ...

Gyprock CSR 1kg Fibreglass Rovings - Bunnings Australia

" Small amounts of fibreglass rovings are ‘dunked’ in the plaster mix and applied like a strap over the ceiling joist or batten, making contact with the plasterboard on either side"  

Thanks again for your help with this