Jackoboard on ply

[Barnboy]

Evening all.

 

I have some marine ply boxes that I've made to frame out my internal window reveals.

I don’t have too much depth to play with so am looking at lining the ply with 6mm Jackoboard as a base for plaster.

I've searched about and am planning on using a thin layer of tile adhesive and some screws with proper washers to fix the Jackoboard to the ply.

In my searching I haven't been able to come up with an answer to whether or not I need ro prime the ply for the adhesive or not, and if so with what exactly and also which adhesive is best to use.

Has anyone gone down this route with success that can guid eme please ?

Thanks 

[nod]

You would be better using 6 mil plasterboard for a base for plaster J board isn’t suitable for plaster

If your tiling You can tile directly on to ply with a flexi adhesive 

[Russell griffiths]

Stick whatever you choose to the ply with a hybrid adhesive 

something like stixall. 

Jackoboard needs a special primer before you skim. 

Ring technical to get spec. 

NOT PVA. 

[Barnboy]

I've looked for 6mm plasterboard and can only find Gyproc glassroc, which would be ok, but I'd like a tough of insulation from the jackoboard to try and reduce any risk of thermal bridging. I'm just trialling a piece onto some ply to see how it holds with some adhesive foam and a couple of plain screws. When I tried the proper washers the screws started to spin in the ply before pulling the washer dome head in flat.

[Russell griffiths]

[Barnboy]

I take it that hasn't fallen off then @Russell Griffiths?

47 minutes ago, Russell griffiths said:

My reveals are about 500/600mm deep so a few screws to give me piece of mind and hold them in place whilst the foam goes off.

[Russell griffiths]

The foam is soudalbond, you would need a hammer and chisel to get it off. 

[Barnboy]

I did a small piece as a trial last night with some everbuild construction pro foam adhesive, seems solid as anything to me, the only thing is, I put a couple of screws in to stop the board sliding about, this has held it in place but it seems to have bowed slightly away from the screws where the foam has expanded.  

I called Jackoboards technical guy, he recommended using a flexible tile adhesive, plastering over is not a problem, just prime with SBR and go for it. 

I think I might try another piece with foam but leave the screws slightly loose until the foam has gone off.

[Russell griffiths]

Use a foam that doesn’t expand. 

[Barnboy]

I tried just foam adhesive on the first head with some screws to hold it in place, this worked OK but buldged about 3mm between the screws.

I've now done the rest of my 1st floor reveals using foam, then stapling the board in place before wedging some ply in-between until the adhesive has gone off.

I'm pretty pleased with the outcome .

[Russell griffiths]

Your putting the screws in too tight, before foam has gone off. 

Spay glue, put in place, screw very lightly to hold in place, wait for glue to cure 20mins, screw screws up. 

 

Looks good. 

[Barnboy]

I was using countersunk screws just to hold it in place, the tip of the countersink was only just touching the board when I walked away, cane back later abd it had buldged. 

All good now with the staples and ply.