How to attach plasterboard to a laminated beam?

[parisrose]

 

  

Hi all.

Wondering if and how we can attach plasterboard to a laminated support beam. We have a flat pine roof and a laminated beam running through the whole house supporting everything (see attached photo). I would like to cover the beam with plaster board to achieve the attached look. We will keep the pine ceilings as is. Wondering how to do this and if it’s possible? 

[JacobZ]

Hi @parisrose,

Thank you for your question and welcome to the Bunnings Workshop community, it is fantastic to have you with us.

Are you just looking to clad the main beam running across the top of the ceiling, known as a ridge beam? 

Or were you looking to clad the beams that run perpendicular to this beam, known as rafters?

Either way, it is possible, but the ridge beam looks like you would need to pack it out with timber so you can achieve a square surface for the plasterboard to be attached to.

Once packed out, you would attach the plasterboard to the beam using 8G x 25mm Plasterboard Screws and Stud Adhesive, using 90° External Angle Plaster Trims for the outside corners and PVC Tearaway L Bead Plaster Trims where the plasterboard meets the timber ceiling.

Once installed, you would coat both the external trims and the tearaway beads with a coat of plaster base coat, followed by a coat of topping compound. Once coated and dried, you would pull the tongue from the tearaway bead before sanding everything smooth and painting.

If you were looking to clad the rafters as well as the ridge beam, the process would be much the same, however each different angle would need to be considered. For example, internal corners would require either paper jointing tape, flexible corner bead or 90° internal angle plaster trims.

It is certainly possible for you to do this yourself, however, plastering is an art form that is not easy to master, so contacting a professional plasterer for assistance is likely a good idea.

Allow me to tag @Nailbag to see if they have any advice they can offer.

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

Jacob
 

[parisrose]

Thanks Jacob.

Really helpful!

We would likely do the ridge beam and rafters. I assume packing the beam out with timber won’t impact any weight/cause issues structurally?

can I also ask, how we would go about plastering the pine ceiling? Could the plasterboard be adhered straight to the pine or would we need to take additional steps?

thank you

[JacobZ]

Hi @parisrose,

It is always best to consult an engineer on structural matters as there is usually a number of variables that need to be considered. It is unlikely that adding timber and plasterboard would have any real effect, but it is better to be safe than sorry.

Without seeing the pine ceiling close up, it is hard to say. Can you locate any screws or nails on the pine ceiling that would indicate there are timber battens above? Is there anywhere you can see the thickness of the pine lining? 

Ideally, you would screw through the pine lining into the timber battens above, however, if the pine lining is decently thick, it may be strong enough to support the plasterboard.

Further investigation would be required to confirm the suitability for attaching the plasterboard to the pine lining. 

I'd suggest contacting a plasterer for their assistance in determining this.

Let me know if you have any further questions.

Jacob

[Nailbag]

Hi @parisrose 

I can't really add more than the excellent advice already provided by @JacobZ  other than when it comes to square setting plasterboard to an exact finish, I would highly recommend a professional plasterer to this part of the project. Especially with the added complexity of being an overhead project. And to that point, fixing plasterboard sheets is a very difficult one requiring at least two people and in your case portable scaffolding. Again leaning towards getting a professional in to do the work.

Regards, Nailbag