How would this be boarded?

[Grazza]

Hi,
Any ideas how I would attach a foam backer board (or indeed any type of backer) along the right side of the window in the attached picture.
The right side is about 130 mm.

 

[Grazza]

Its a block wall with hardwall undercoat and multifinish skim.

 

[Grazza]

For those interested, this video shows a similar slim section of board being used:
View: https://youtu.be/JMkKcclCauM?t=26



My issue is that mine is right in a corner with no large tiles to ovelap as in the vid.

Still not sure whether hardie backer or foam backer though....

 

[Ben-gee]

Is this a joke?
Mechanically fix; screws for cement boards, screws and big washers for foam XPS boards.

 

[Grazza]

Is this a joke?
Mechanically fix; screws for cement boards, screws and big washers for foam XPS boards.

Why do you think its a a joke? What do you think this forum is for? LOL

That section is just 130mm wide. Ideally I would put a screw in the left and the right hand side because just a single screw in the middle would potentially pivot.
Apparently I dont need adhesive if its an even surface, but obviously the adhesive would prevent any movement.
The down side with putting a left and right fixing is that its really close to the window reveal and as Im sure you know you cannot drive to close to the edge else the block will split off. esp with spanker dowels.

Im also wondering if there is reason for using 1200 hardies over 2400 foam backer? So sorry Ben if that question isnt valid enough for you. Maybe someone else has some less negative advice?

 

[Ben-gee]

I’m messing with you pal!

As you say adhesive not needed but if fixings are poor it’ll help you out.
I’d put screws down both edges to stop it rocking.
Drill a couple of test holes if you like to see how plugs hold- if suspect just stick it on , then when dry a couple of mechanical fixings gently in the centre will be fine and stop it ‘peeling’ - much as one does when dot/dab plasterboard.

 

[Grazza]

Thank you Ben

I figured a little adhesive along the side of the window would be best, but was just worried it would be proud compared to the rest of the wall - Im sure a couple of few mm wont show.

 

[Ben-gee]

What thickness board are you using?
You could always buy one board of the next size down so that with adhesive it became flush with the others.
To clarify- if you’re using 10mm, buy one 6mm board.

 

[Grazza]

Thanks Will consider.
Not sure whether to go with 6mm hardie backer or 10mm foam backer.