The plywood ceiling installed, with the electrical cables for the lights poking out

Putting up the Ceiling

Friday November 13, Thursday November 19, Friday December 11, Wednesday December 16

Give us a break

Most of the lining (both wall and ceiling) in 60k House is 9mm plywood. Ply was selected because it is durable, beautiful and I mistakenly believed it would be comparable in cost to finished plasterboard. As it turns out it has taken longer than anticipated to install the ply lining. I paid $45.10 per sheet of structural pine grade CD 2700x1200x9 plywood; 2400x1200x10 plasterboard was $16.90 per sheet, but then you have to finish it – tape, plaster, plaster again, sand and paint.

 

I wanted to break up the ply lining throughout with a break in material and decided to use plasterboard on the ‘rake’ (the angle part) of the ceiling. The decision to introduce some plasterboard for some of the lining was primarily an acoustic consideration – I don’t want inside the house to sound ‘tinny’ or ‘ringy’ from all of the hard surfaces (think trying to have a conversation in a trendy café). I have a decent stereo and want to be able to use it!

 

I intend to paint the plaster ceiling white and whitewash all of the ply lining – ceiling and walls – so the space is light and bright while still being able to see the timber grain and recognise the material.

 

Pack it out: timber battens to get the depth right for the shadow line between the different materials

Pack it out: Greg nailing timber battens to get the depth right for the shadow line between the different materials

 

Greg fixing the furring channel for the plasterboard

Greg fixing the furring channel for the plasterboard

Release me

As is the case with every change in material in 60k House we have incorporated a ‘release detail’ or shadow line between the different types of material. This shadow line in the ceiling is slightly exaggerated and will hopefully absorb some of the sound echoing around the space. There is no cornice at the wall and ceiling junction – just the shadow line.

 

 

 

A drawing! Working out the detail of the material junction between the ply wall lining, the plasterboard ceiling and the ply ceiling

A drawing! Working out the detail of the material junction between the ply wall lining, the plasterboard ceiling and the ply ceiling

 

Packed to the rafters: the ceiling insulation held in place by the furring channel

Packed to the rafters: the ceiling insulation held in place by the furring channel

 

We packed out the underside of the trusses to get the right depth, before fixing metal furring channel to support the plasterboard. After the furring channel was on we installed the ceiling insulation, applied some adhesive and screwed the sheets of plasterboard up. Once all of the plasterboard was on the ceiling the joints were taped and then plastered over – twice. The holes from the screws were also plastered twice. The remaining steps will be to apply an edge strip at the junction between the plaster ceiling and the ply wall, sand the plaster and then paint it.

 

Stick it: applying the adhesive to stick the plasterboard to the metal furring

Stick it: applying the adhesive to stick the plasterboard to the metal furring

 

Ready to go: insulation installed and adhesive in place - ready for a sheet of plaster

Ready to go: insulation installed and adhesive in place – ready for a sheet of plaster

Pin it

I will attach some caneite around part of the walls – to act as a pinboard for sketches, notes and photos, while also providing some sound absorption. Depending how the space sounds once it is finished and furnished (furniture makes a big difference in a room) I might bring in a floor rug and am prepared to hang soft things from the ceiling to – but I’m hoping that shag-pile carpet on the walls and ceiling is a thing of the past and has been left in the 1970’s.

 

As well as the adhesive the sheets of plaster are also fixed with screws, which are then plastered over for a smooth finish

As well as the adhesive the sheets of plaster are also fixed with screws, which are then plastered over for a smooth finish

 

Demonstration: Greg plastering the first join - it was the only plastering he did...

Demonstration: Greg plastering the first join – it was the only plastering he did…

Prep work

We got some measurements and Greg took the sheets back to his workshop to cut on the table saw; others were measured onsite and cut with a handsaw. Greg arised (tapered) the edges by hand with a hand plane (the old-school type – not an electric planer) in order to take the sharp edge off the sheet joint to allow some tolerance – if the sheets were left square and only slightly out of alignment then it would be obvious; by arising the edges it is less obvious if they are not perfect.

 

More battens: Greg fixing the ceiling battens to hold the flat plywood ceiling

More battens: Greg fixing the ceiling battens to hold the flat plywood ceiling

 

Straight cut: Greg cutting an edge of sheet with a hand saw

Straight cut: Greg cutting an edge of sheet with a hand saw

 

Plane sailing: Greg using a hand plane to aris the edges of the plywood sheets to conceal any inconsistencies along the edges

Plane sailing: Greg using a hand plane to aris the edges of the plywood sheets to conceal any inconsistencies along the edges

Keep me warm

In basic terms, insulation is a material to reduce transmission of heat or sounds, by lowering the conductivity. Insulation in buildings is to prevent or slow the transfer of heat – to stop hot air coming inside from the roof when it’s hot or to keep warm air inside and prevent it from escaping when it’s cold. The effectiveness of insulation is rated by its ‘R’ value – how much resistance it has. Batts are the most common form of bulk insulation and come in a range of thicknesses – the thicker the batt, the higher the R value and more effective it is in preventing heat transfer. In the ceiling we installed R 4.1 batts; in the walls R 2.5 batts.

 

Getting there: half of the ceiling insulation installed and the battens for the plywood ceiling

Getting there: half of the ceiling insulation installed and the battens for the plywood ceiling

 

Filling up: the ply sheets cover a lot of area - a large part of the ceiling was done quickly

Filling up: the ply sheets cover a lot of area – a large part of the ceiling was done quickly

Heed the warnings

I would describe installing batts as a ‘shit job’ – I have tended to do most of these kind of tasks in the building of 60k House. The batts used are recycled glass fibres – good in slowing the transfer of heat but not good to breathe down your throat and into your lungs. The manufacturers recommend using protective clothing – gloves to prevent tiny glass splinters and a dust mask to prevent inhaling them. I completely endorse the recommendation of safety equipment, and can testify you will have a sore throat and itchy skin if you don’t (I didn’t the first time and was coughing for a week after).

 

Gun control: Greg using the nail gun to fix the plywood sheets in place

Gun control: Greg using the nail gun to fix the plywood sheets in place

 

The ply ceiling went up relatively quickly – all it needs now is maybe a light sand and then a coat or two of white wash and that’s it – finished. The plasterboard still needs sanding and painting, but overall the ceiling is nearly done.

 

Little ray of light: the reflected sunlight on the ply ceiling

Little ray of light: the reflected sunlight on the ply ceiling

 

Done: the ceiling in place, just needing a sand and some paint

Done: the ceiling in place, just needing a sand and some paint

 

Costs: plywood – $586; plasterboard – $118; plaster & tape – $22; framing timber – $104; insulation – $396

 

Disclaimer: Any advice contained within this blog is of a general nature only and cannot be relied upon. Details provided are in good faith and relate specifically to this project. Any author will not be held responsible for advice or information presented.

4 Comments

  1. Great stuff – thanks for sharing. What are your thoughts on adding in a vapour barrier directly under the plasterboard and ply – to stop the humidity from escaping into the roof cavity? I can’t recall the vapour membrane you put under the roofing but if it is impermeable than the water vapour from the roofs will rise into the ceiling cavity, and can’t escape. If it gets too humid up there (in ceiling cavity – underside of roof) in winter, you may end up with condensation, which might encourage mould to grow, or if you get water drops forming in the area above the ceiling you may end up with wet plasterboard. I am planning on having a impermeable vapour barrier on the inside of my dwelling, and a vapour permeable wrap on the outside of the building (under the exterior cladding). I am planning on building in a cold climate, so having an inside air barrier helps also to keep my warm air inside.

    What do you think?

    1. Andrew Kerr

      Thanks for your comment Hamlet,
      Last week I attended a professional presentation titled “Moisture Control in Construction” that was focused on this issue. Condensation is becoming an increasingly common problem in Australia now that we are using heat pumps and sealing our buildings better. In Europe and North America the problem has been known about for longer and technology and techniques developed to tackle this problem, however they are only now being seen in Australia. As the problem of condensation becomes more common in Australia I expect to see more construction resembling the system you are looking at. The recommendation is to seal the inside of your building to prevent moisture, and heat, escaping. Specify air tightness and a vapour control layer. Then use a non porous (so rain won’t infiltrate during construction), vapour permeable (so moisture can escape through to the outside) roof sarking. Ventilation should be between the top of the roof sarking and the underside of the roof cladding. An uninterrupted travel path should be created for any moisture that forms in this cavity by raising the roof purlins or battens on a dummy rafter.

  2. Hi Andrew – what did Greg use to secure the plywood sheets? Just a nail gun and adhesives or did he use screws? If he used the latter, did you conceal the heads with an appropriate putty? Cheers, Wayne

    1. Andrew Kerr

      Hi Wayne, thanks for your comment. Greg only used a nail gun with quite small nails/brads – no glue, no screws. This was different for the plasterboard where we used both glue and screws to fix to the furring channel. I haven’t filled the nail heads in the ceiling (might get around to it) but did use a water-based woodfiller to fill the nail heads on the walls before whitewashing them. Cheers

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