Jump to content

Another mad idea. But who can tell me what exactly this Plywood is?


Patrick

Recommended Posts

I just recently picked up a supply of plywood offcuts for my ringbeam shuttering.

IMG_20200108_144455.thumb.jpg.8f02ab063e14b77bee1dab69f2aaf395.jpgIMG_20200108_144447.thumb.jpg.fa81ee1971f2aa96171b4f6dd89ffc6d.jpgIMG_20200108_144439.thumb.jpg.24d1cc613fd8afcbf0eb34af6c4ea2c9.jpg

It s coated 12mm ply, offcuts with 500mm x 1200mm.

Now as I can get them for next to free, I was thinking to do the sheeting of the house, possibly the first floor subfloor, with them. Should be better quality replacing osb with ply.

More work involved as basically 4.5 sheets to fix instead of 1 full one.

 

I m currently mainly interested if anybody knows what kind of ply this is. Couldn't really get any details out of the supplier of the offcuts.

It s like a slippery plastic coating with 1 side being smooth, the other being kind of mesh.

 

Any downsides of using this instead of OSB.

 

 

Link to comment
Share on other sites

14 minutes ago, Patrick said:

Any downsides of using this instead of OSB.

 

I would hope that the core is always waterproof plywood but that might not be the case with some grades.. 

 

https://www.builderdepot.co.uk/18mm-phenolic-film-faced-shuttering-grade-plywood-2440mm-x-1220mm-8ft-x-4ft

 



After pressing the edges are also sealed to prevent moisture ingress. If cutting is required the exposed edges should be sealed with a rubber based paint in order to prevent any swelling.


 

Link to comment
Share on other sites

Hi Patrick,

us boaters know this as Bison board (phenolic ply) and it's used for exposed decks on narrow boats. Last for years in the open. A much better product than OSB both in durability and strength. Get as much of it as you can!

  • Thanks 1
Link to comment
Share on other sites

1 hour ago, SteamyTea said:

Earworm for the day

 

Didn't expect some of you to be such old school bboys. Was more expecting some country music before I clicked on that video,  so once again a pleasant surprise on this forum that not every one here is a mid 70ies Dolly Parton fan ??

 

The second take away from the answers is that it s kind of a good idea to sheet the house with those boards.

 

Thanks for both ?

 

Link to comment
Share on other sites

As it was just mentioned by @Simplysimon

These plywood sheets are probably not really vapour open. As I'm building timber frame with cellulose insulation and wanted to use smartply sheets as vapour barrier on the inside - would these be able to replace them as a vapour control layer on the inside  (taped joints and so on) and if they are (are they?) vapour impermeable, are they then useless for the outside sheeting or can this be overcome by the gaps inbetween the sheets (at the end, there will be a gap every 600mm. If that's not taped towards outside, is that enough for any vapour to escape if needed?)

 

Link to comment
Share on other sites

hi @Patrick,

going by this site, https://www.metsawood.com/global/Tools/DoP/DOPOpenDocuments/DoP_MetsäWood_Birch_Plywood_PF_2019-12-2_en.pdfit states a vapour barrier can be used in the substrate. it does give a vapour permeability, however, i've no idea as to its effectiveness. they are useless for the outside as they definately won't be vapour open. you will need something akin to panelvent dwd, medite vent or egger dhf if you can get it. i went with medite in and out

 

cheers

  • Thanks 1
Link to comment
Share on other sites

On 10/01/2020 at 19:54, Simplysimon said:

@Patrick,. you will need something akin to panelvent dwd, medite vent or egger dhf if you can get it. i went with medite in and out

 

 

cheers

I had a look over this ones again and just can't find any decent answers on here, maybe just keep missing it. But what is the problem with OSB on the outside. I was originally planning to use standard osb3 for sheeting, as so many other houses are build with it.

Plywood on the outside even better as more vapour permeabel but also much more expensive.

It s  disputed how vapour open or vapour closed OSB is, at least I couldn't find a clear guidance on it. Common rule seems to be that OSB3 is too vapour permeabel to use as a vapour control layer on the inside on its own (even though that's still being done)  and at the same time, it has been mentioned that OSB is too vapour tight to use as outside sheeting - not letting enough vapour out (still a lot of houses, even passivhouses, are build with osb3 sheeting on the outside).

Also been looking for any fact sheet of the phenolic resin plywood but can't find any tests or details about its vapour permeability.

(tried to read and understand the metsawood sheet you posted @Simplysimon

But it doesn't make much sense - had to use this  :http://builddesk.co.uk/wp-content/uploads/2013/01/vapourResistances.pdf

 

To calculate what the µ in the metsawood paper actually mean). still not sure if it now is a good air barrier or not. Got in touch with some producers of these boards and waiting for a reply.

 

Link to comment
Share on other sites

29 minutes ago, Patrick said:

I had a look over this ones again and just can't find any decent answers on here, maybe just keep missing it. But what is the problem with OSB on the outside. I was originally planning to use standard osb3 for sheeting, as so many other houses are build with it.

Plywood on the outside even better as more vapour permeabel but also much more expensive.

It s  disputed how vapour open or vapour closed OSB is, at least I couldn't find a clear guidance on it. Common rule seems to be that OSB3 is too vapour permeabel to use as a vapour control layer on the inside on its own (even though that's still being done)  and at the same time, it has been mentioned that OSB is too vapour tight to use as outside sheeting - not letting enough vapour out (still a lot of houses, even passivhouses, are build with osb3 sheeting on the outside).

Also been looking for any fact sheet of the phenolic resin plywood but can't find any tests or details about its vapour permeability.

(tried to read and understand the metsawood sheet you posted @Simplysimon

But it doesn't make much sense - had to use this  :http://builddesk.co.uk/wp-content/uploads/2013/01/vapourResistances.pdf

 

To calculate what the µ in the metsawood paper actually mean). still not sure if it now is a good air barrier or not. Got in touch with some producers of these boards and waiting for a reply.

 

the vapour permeability of the outside sheeting material will depend upon the insulation used in the kit wall. with cellulose it will need something which has plenty of permeability, don't want soggy paper in the kit.

  • Thanks 1
Link to comment
Share on other sites

16 minutes ago, Russell griffiths said:

Whereabouts is your racking strength coming from? 

Inner skin or outer, you would need to check with your frame designer as I don’t believe it will give you the racking strength you need in those small sizes. 

It would if you had "dwangs" across the upright studs at 500mm centers and lots more screws than a 1200x2400 single sheet

suppose it depends how cheap is cheap  by the time you add up the extra framing and screws  and time .

you would still need building wrap on outside to be sure and inner vcl as that would also be your air tightness layer.

 

  • Like 1
Link to comment
Share on other sites

  • 2 months later...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...