Plywood Lengths and dimensions

[diyman]

G'day All

I've just been planning my renovation on the old Globetrtter and have made a few troubling observations. The roof is about 7'(ft)wide and about 13'(ft)or so long but appears to be one sheet of ply. On making a few enquiries I can't find anywhere that supplies Plywood that big. Furthermore the exterior walls (which have to be replaced) are exactly 4'(ft) (48") wide and nowadays being metric the nearest is 1200mm which makes the sheets 3/4" short of the 4'. This makes me think that there will be problems locating a frame to attach to when the time to attach the new sheets arrives. I am assuming that the sheets join over a "stud" part of the frame.At the moment with the 'van still intact I can only assume that I would have to build a new frame or modify the old one but would like your ideas.

As to the roof how does one get around that problem, is it possible to join sheets successfully on the roof that are able to stay waterproof. The old Plywood by the way is about 3/8" or 9mm thick.

I've been trawling through this technical section and I think it's fantastic especially for someone like me who is about to undertake his first renovation.

Any help or sugestions will be greatly appreciated.

Cheers
Jim

[Roehm3108]

Hi Jim
Some of the other Vic guys might know of a plywood supplier who could still have some imperial sheets hidden away somewhere, otherwise, I would say you will need to add some extra framing wherever that final overlap will go. It may also be possible to place you sheets in such a layout that you don't have that 3/4 inch strip to add on th edge. Generally, a beading is placed over the joins to stop the water coming through, and having a beading an inch from the edge wouldn't really look too good. Another thought is whether you can pick up that 3/4 inch by placing ithe sheets in such a way that that shortage is split between the front and rear of the van and then let the edge strip cover the gap. With adequate sealing that could work.

Sounds like your roof doesn't have ribs in it - is that right? Otherwise why is there such a thick ply being used there? Makes for one heavy duty roof if there is ribbing and ceiling liner used too. Here again, you can only cover the joins with either ally or timber beading.

Ray

[dntpitts]

Hello Jim, Hi Ray,
A good joiner or cabinet maker will be able to join sheets of ply if you need, done well the join is as good as the original material and should be undetectable once painted, used to do this for the boat club in Ballarat, Lake Wendouree.
Cheers
Dave Pitts

[diyman]

Hi Ray

Thanks for your input and as yet I dont know of anybody who stocks the old imperial measure sheets.Thinking about it though I'm sure I'll have to put in additional framework for the smaller sheets. The edges are not a problem as they are only a part of a sheet. As I said I have'nt actually started work yet so I don't know if the roof has "ribs" (is that framework?) but it's definately 3/8" Ply as are the sides. The caravan is a Globe from maybe the 40's or 50's.

Incidentally there is no beading anywhere on the 'van where the sheets join except around the edges.The sheets just butt up flush to each other but on the roof I can't find any joins.Looks like I'll take your advice and use beading on the roof to join sheets.

As you can see I'm an amateur so thanks for your help.

Regards
Jim

[diyman]

Hi Dave

I'd be interested in the process used in that operation. Obviously it would make use of some sort of glue or resin, is there a specific brand that should be used.?

Regards
Jim

[Roehm3108]

Hi Dave -thought you'd dropped off the radar, or are you too busy doing donuts in town ;D ;D ;D
Would it be a form of finger-jointing that's used in the process??? Wonder what Retro1 did with his van? Perhaps he could comment here??
Ray

[Franklin1]

Hi diyman, Unfortunately with the drop in popularity of "wooden" caravans and boats by the 1970s, the demand for large sheets of plywood (bondwood) also dropped accordingly. As you have found out now, sheets are only made in two sizes: 2700 x 1200, and 2400 x 1200.

Boral Hancock Plywood are one of the two Australian manufacturers making marine plywood, and Boral will join sheets in the factory where the thickness is 7mm or greater. Maximum length of sheeting is 12 metres with max width 2400mm. Cost will be high for 9mm, I should think, given the manufacturing, transport and handling costs involved. Sheets are joined with what's known as a "scarfed joint", the details of which can be found here:

www.boral.com.au/Brochures/orders/PDF/040_Plywood%20Scarfing_Joining.pdf?company=PLYWOOD

You might need to explore some other options, such as using multiple sheets of 3mm to make up the 9mm. You could then stagger the joins from layer to layer (like brickwork). Here again, costs of you bonding the layers together with adhesive need to be taken into account. No easy solution here, so extra large thinking cap required!! ;D ;D

Do you really need to replace so much ply, or could smaller area repairs achieve the same outcome?

cheers,
Al.

[diyman]

Hi Al

Thanks for some great information, I've had a look at the link to "scarfing" and find it very interesting, in fact I've used the same process myself once when I was building my house.Maybe if I set up a jig for my electric planer I could do the scarfing myself, I'll have to give it some more thought.

The Ply all over this van is very poor with those rotting little cracks in it that come through the paintwork everywhere.I know that if these cracks are sanded etc then painted they always seem to come through again.On the roof it's particularly bad with the four corners rotted away(including the frame) so even if I attempted to do smaller repairs I would still have to do some joins and it may not be as successful.

Whilst trawling through the forum I came accross a terrific reconstruction in pictures from the floor up (can't remember the members name) and was interested in his construction.He had a frame with ply lining on the inside and ply lining on the outside of lighter grade than mine. Mine has no lining on the inside, if you remove the external wall your left with the frame.I must look up that reconstruction and see if I can find out the grade/thickness of ply he used and how he joined his roof, or can you get longer lengths in lighter ply?

Anyway I'm biting a litrtle harder on the bit now which is now well and truly between my teeth so thanks again for the input and I welcome all your comments.

Regards
Jim

[Roehm3108]

Jim, that was probably Retro1's Castle rebuild you're referring to.
Ray

[diyman]

Yes your right Ray it is Retro1's Castle and very informative for someone who's new to Caravans.The photo's say more to me than words,always have, in my case it really is true that "one picture is worth a thousand words"

Did another couple of hours on the 'van yesterday to ascertain the damage to the frame and discovered that in the corner part of the frame is missing and because of rot nothing else joins together. (hope that makes sense). Going to have to replace that part of the frame I thought and commenced trying to remove the exterior panel. I freed the panel all around the corner(easy no frame but where it joined to the next panel I found it had been glued as well as nailed/screwed to the frame. I don't know what type of glue they used in those days but it's impossible to free the panel without wrecking it so it's thinking cap on for another plan of action because if I can't take off these 48" wide panels individually the whole van will be wrecked. I'm now thinking of doing lesser repairs and then a big sanding, patching and repaint job.

All good fun though and keeps the old brain ticking over and stops it going "rusty".

Regards
Jim

[diyman]

Couple of photo's here which gives you an idea of the job ahead.

[Deleted]

Hi Jim
After looking at your photos you have my sympathy.
Keep the bondwood faith old mate. These things where sent to test us.
You may have some luck with bigger than standard sheets from a company here in Newcastle called "Mr Ply and wood"
Newcastle Rd , Lambton.

Reddo

[diyman]

Hi Reddo

Yes those photo's are a graphic example of the deterioration in this van,but you should see the worst bits ;D. Only joking, they are the worst bits and at least two corners are like that. Probably if I had any knowledge of renovating caravans I would'nt have even attempted it, but fortunately I have'nt so it will be a big learning curve.

I'll keep studying the excellent threads on this site,there's a wealth of info here.

Regards
Jim

[John]

G'day there,
I had the same problem when re-building my van although my ply wasn't as thick.

It maybe crude, but I bought 2 sheets per side, planed a 45 degree angle on the two joining edges, ''butted'' the edges together over a stud and then filled the join with builders bog. I did the same over the roof ( 4 or 5 joins ) See "finally finished" page 5 of the members photo album, the 4th photo shows the ply on the frame.

With that being said, I've noticed that I have some small cracking where the bog is. Its only happened on one side which was the first side that I did and it was the first time using bog, so I may have been a little tentative.

It doesn't leak though. I think its one of those things, I know where to look!!

All the best,
John

[raym]

Hi Diyman You could use hard board 'Masinite' as the sheat size is 1220 mm (4feet ) wide useTempered externaly and standard internaly raym

[scootman]

That was exactly what I did. My joins are all good, except for one on the back on a major corve. I boggged and sanded and sanded and bogged but I couldnt get a nice neat curve like the rest of the van.
But the restof the van is pretty good
Cheers scoot

[diyman]

Thanks fella's, you guys are great and all the ideas and tips are going 'round and 'round in my head but before I decide which way to jump I have to solve the problem of the glued walls. As I said the joins are all glued and screwed with some immovable glue, god knows what it is but it's damn tough.Just taking of one panel is not possible until I find a way around it.

John
That was a great job you did and the end result looks terrific but the 3 years made me sit up and realise that I

[diyman]

Thanks fella's, you guys are great and all the ideas and tips are going 'round and 'round in my head but before I decide which way to jump I have to solve the problem of the glued walls. As I said the joins are all glued and screwed with some immovable glue, god knows what it is but it's damn tough.Just taking off one panel is not possible until I find a way around it.

John
That was a great job you did and the end result looks terrific but the 3 years made me sit up and realise that I may have underestimated how long it will take for my renovation/rebuild.

Raym and Scootman
Nice tip about the Masonite but as say I don't know whether I can repair my 9mm thick walls/roof or whether I will rebuild using lighter materials such as masonite.

Cheers
Jim

[diyman]

OOPS !!!! Sausage fingers, don't know what happened there.

[John]

Hi Jim,

Please don't let the time that it took me to finish mine put you off! A lot of things happened in that time, bought a house, joined the ADF which meant I was away for 3 mths on training, and away with work a lot!!
Thanks for your comments though, its very rewarding once everything is back together and you can actually use it!!
All the best.
John