Plywood Ceiling - Suggestions on fixing

[mudguard]

Hi Guys,

I have 3 spaces that I would like to use plywood for the ceiling.
A bathroom, a kitchen and a hall. The house is far from conventional, uses a lot of steel and I would like to soften the interior using wood.

In these three spaces the ply would be fixed to "boxspan" a metal joist , the centres are between 300 - 350 mm.

What is the best wa to join the sheets so that the joint is seemless? Is there a way.

I have attached a pic of the outside of the house.

Cheers

Steve

[journeyman Mick]

Steve,
what's the wall thickness of the boxspan? If it's not too thick you could fix using metal tek screws, but you may not want to have visible fixings. When you say you want a "seamless" joint do you mean that you don't want the sheet joins to be visible? If that's the case then ply is not for you as there's no real way to do so. If you want a seamless finish you'd be better off with plasterboard or villaboard. If you use ply you'd be better off with expressed joins, ie you make the joins a visible feature. That way it won't look like youve made a bodged up attempt at hiding them.

Mick

[pharmaboy2]

hiya, i agree with mick - expressed joins in ply are the common method - I used a 6mm villboard piece to get my spacings even, and am extremely happy with the result (hoop pine 6mm ply). FWIW I used plasterboard glue plus 32mm finish nails then timber putty. NB - i suspect plasterboard glue isnt going to stick to steel section!

with metal screws, countersinking and filling is going to leave a pretty decent amount of timber putty which may show a little too much. Personally I'd go with a ss head and make it a feature with a neat setouit for spacings. perhaps buy a sheet just for experimentation for fixing spacings - dont want to stick in 20 screws per length if only 6 will do the job without sagging.

[bitingmidge]

The comments above re: "seamless" are pure and true! but butted joints will work quite nicely. Set the sheets out so they make some sense rather than just starting in the corner of the room.

I've used art-deco style patterns with timber battens in the past, to provide a deliberate design which covers the screw fixings. Just set out the screw fixings so they happen where the battens will go.

If you want to use simple glue and nail "almost invisible" fixings, you could screw fix timber battens to the underside, or side (if you want to keep the ceilings hard against the steel) of the existing framing.

I've had a hopefully momentary lapse of memory (been ten years so far) here, so can't think of the name of the nails to use, but they are like little fine clouts, with heads about 4mm diameter. Don't worry, the heads will be barely visible after the sheets are up, but do take care to space them evenly.

Cheers,

P

[mudguard]

Point taken with the expressed joints, easier to show that to hide.

In that case maybe I should express the fasteners and use the very large headed Pop Rivets that are made to use with plywood.


Thanks
Steve

[journeyman Mick]

Steve,
There's a couple of options for concealed (almost) fixing. Like the Midge said, you could nail to timber battens using bullet head nails (I'm assuming this is what he was trying to describe) or, better still use glue and a few brads to hold it whilst the glue sets. I'd reccomend a 16 gauge or so finishing gun which leaves very small holes which could then be filled to make them almost invisible. I'd still measure them out at even intervals just in case they are noticed (most probably by some picky bloody carpenter or architect ). The other way, depending on what species of ply you're using is tek screws and "fast caps". These should be available from cabinet makers suppliers. They're small sticker "dots", availablein a range of colours to suit different melamines as well as different woodgrains. You just peel them off and stick them over the screw head. May be worth buying a card of them and sticking them to a sheet of ply and then clamping it up in position too see what it looks like. If that works it may be quicker and more cost effective than battening out and nailing.

Mick

[pharmaboy2]

just another thought - if you do end up screwing and expressed joints then you need something behind the expressed joints - ie it might not look too flash if soime joints have gal steel behind them while others have insulation or blackness, so you need to back all the joints first.

having said that, I have seen what looked like a sheet that had a rebated edge (routed perhaps) such that each sheet slightly overlapped and created the joint - for an idea, look at shadowclad and how they rout the edges in the vertical lines product to keep the lines even - try the woodlogic site.

Now the other thought is that what ply to use. I used Austral's BB face hoop pine 6mm - the price of AC was stratospheric! Further the price od the thicker dimensions is also pretty exxy. So I would consider screwing up a cheap board product - perhaps 16mm melamine? or 16mm chipboard, even yellow tongue to the bottom of your roof boc section. Then put up the thinner cheaper ply with a bradder and glue (possibly paint where the joints will go with black paint for the expressed joints).

for putting up the sheets dont even think about doing it by hand, hire the sheet lifter at bunnings for $35 a day - it makes getting straight lines etc very easy indeed, and also a one man job! Finally, its easier if things arent precisly square to lay it in a brick bond pattern rather than stacked pattern. Oh and getting a great even finish at the wall junctures is a PITA - I gave up and used 19mm square pine moulding to edge the junction - this is in existing renovated home so walls were not dead straight.

[flynnsart]

Check out how Burnsy did it here http://www.byohouse.com.au/forum4/vi...r=asc&start=30

Looks good, but go and make yourself a coffee while you wait for the page to load, as there are quite a few large pics in the thread.

Donna