How to add support for shed ceiling?

[DanniU]

Hi,

I'm slowly creating an enclosed space in the back of my garage.  I have built a frame and now need to figure out the ceiling (yes, I should have done this in advance...)

The spacing between the wooden battens (sorry if wrong term, please correct me) is 850mm, so I don't think I should be attaching plasterboard straight to them.  The spacing between the steel trusses is 1.8m.  The roof pitch is 15 degrees.

My issue is that while I can add a second top plate to my walls, the battens that are in place block me from following the line of the roof.  Am I overthinking things here?  Are there alternatives?  I do not have the wood available for this so I am happy for any change in approach.

Edit: The first photo of roof support - the timber is all non-structural stand-alone frame.  The actual structure is steel frame.

Thanks,

Danni

General roof supportFollowing line of roof and significant blockingexample birdsmouth cut on second top plate

[EricL]

Hello @DanniU 

Thanks for sharing your question about the ceiling for your shed. I was thinking about building the support lower and removing the extra plate and running the timber piece underneath the existing roof support. This particular plan however will require you to get more timber. It also has the unintended effect of lowering the ceiling space. Perhaps a different set of eyes will find a better configuration.

Let me call on our experienced members @Dave-1, @AlanM52, @Remarka6le, @diy_hausdesigns, @TedBear, @JoeAzza and @Noyade for their recommendations.

If you need further assistance, please let us know.

Eric

[Dave-1]

Good Morning @DanniU 

I really like your thinking retrofitting the walls is brilliant and like what you have done.

The way you are are considering doing the roofing I like as well The added block to help with the birdsmouth "nodding my head"  I do have some concerns as to the overall weight you will end up with. You could mitigate this with a central beam underneath the centerline for the shed, supported by your wall (Maybe an extra double stud undirectly underneath the ends). You could then change the angles of the roof blocking so the new fake styled trusses support the existing timber supports of the roof. That way you arnt adding to the roof weight as it will be supported by the frame you have built.

You mention that "I do not have the wood available for this so I am happy for any change in approach." Does that mean you are yet to buy the timber so you could change your plans or that you have no more resources for now? (And yeah I know that second feeling )

Dave

[JacobZ]

Hi @DanniU,

You're correct that 850mm is too far apart to support plasterboard. You need to have framing that is no more than 600mm apart to support specialised ceiling plasterboard known as Supaceil. Have a look at Gyprock | Supaceil™ Residential Plasterboard for some guidance on the installation requirements.

You have a bit of a conundrum here, because unfortunately, I don't see the metal framing being adequate as support for a timber ceiling frame with plasterboard attached to it, but you don't really have the space to make a self-supporting roof structure using a ridge beam and rafters to transfer the weight down through the timber-framed walls.

I would be cautious about adding too much weight as tin sheds are not designed to support a whole lot of weight. 

Using lightweight furring channel as your ceiling frame would likely be a better option, but I would still do so with caution and consider having a professional assess the suitability of the sheds frame for supporting additional weight before continuing.

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

Jacob

[DanniU]

Thanks Dave, I ran out of wood as I built the walls to be sturdy (400mm spacing instead of 600mm) specifically because I was concerned about ceiling weight. However this means I'm not wedded to only using wood for a solution!

[DanniU]

Hi,

Are there any lightweight materials I could use instead of plasterboard for the ceiling? This is for a small office space so I'm not too caught up on plasterboard only.

I really do not want to cut down all walls by 45mm to add the second top plate if possible.

[MitchellMc]

Hi @DanniU,

Unless you are going to consult with an engineer on what loads the roof is capable of holding, you would likely need to create a self-supporting frame to hold your sheets. That would include a central beam and rafters. 

Regarding lightweight material, you could consider 3mm whitecoat MDF, though you'll need to add more mounting points to support it sufficiently.

Mitchell