Chipboard floor

[rj1884]

Good afternoon

went to look at a job this morning. 4 upstairs bathrooms including a loft extension bathroom and all of the floors are the wonderful 22mm moisture resistant chipboard straight onto the joists. All the floors are solid so no deflection issues. It's been explained that it needs overboarding which he understands. My question is, is if I use hardie backer or an insulation board like marmox glued and screwed am I right in thinking that it's really only the screws holding the board down as the adhesive doesn't adhere to the chipboard or am I way off the mark.
Also what would you guys recommend using in this situation.

Thanks in advance

 

[Plumbing Tiler]

Stick in some extra screws (take care with any pipes/cables of course) to make extra sure the boards are properly fixed, then prime them with SBR and then use adhesive to fix the Hardie down, and then screw it as well to pull it into the adhesive and hold it in position until the addy dries!, simple, and solid as a rock for tiling!

 

[rj1884]

Thanks for your reply. What adhesive would you recommend using to fix the hardie to the chipboard. Also I'm thinking of laying ditra to the hardie/marmox due to the movement I'm the chipboard as it's a new build.

 

[Mr Tiler]

what tiles are going down... and im going to stick my neck out and say spf to glue down and screw in 30mm centres... im sure I will be corrected tho lol

 

[Mr Tiler]

prime the boards before applying the adhesive and it will bond its just not a good enough bond to tile straight onto... I think

 

[Mr Tiler]

in a recent thread that was bumped from a couple of years ago a chap took the risk of tiling straight onto chipboard and it paid off for him so far... but my mother inlaws kitchen floor was straight onto chipboard about 3 years ago and now the tiles are popping up from the area around the washing machine is... don't know if the tiles were fixed correctly but I will when I come to re-do it

 

[Ian]

Hardiebackers have pre-marked points on the boards at 200mm centres, I use these as it makes life easier. It works out at 35 screws per 1.2x0.8m board. Either flexible or non flexible cement based adhesive can be used to fit the boards, it's only to fill any voids in the substrate.

 

[Mr Tiler]

but my guess is he will be using spf anyway so may aswell use that? or can non flexi be used on cement boards that are fixed to ply/chipboard floors?

 

[Ian]

but my guess is he will be using spf anyway so may aswell use that? or can non flexi be used on cement boards that are fixed to ply/chipboard floors?

Not for fitting the tiles no, I use SPF for fitting the boards and then the tiles, like you say, makes life easier. Why use two different types of adhesive when one will do.

 

[Mr Tiler]

I don't know why I said spf though because I did already know you can use either! dumbass!

 

[rj1884]

Hi. Thanks for your replies. The tiles are large format porcelain tiles. When you guys fix hardie to chipboard do you screw just into the chipboard or through to the joist due to the chipboard potentially breaking up due to movement or would put ditra to take the stress of the expansion and shrinkage in a new build.

 

[Mr Tiler]

I cant comment on the use of ditra but I don't 'think' it is necessary in this case. but with the screws you just want them to go into the chipboard no need to go through

 

[Stef]

As Bri says there are pre marked holes on the Hardie fix through those into the chipboard.
Use 25mm turbo gold screws & it will be sound.
I always use a flexi addy to stick down Hardie,
I know Hardie state a non flexi can be used but I have ripped Hardie back up & believe me the addy sticks the boards really really well.

 

[beanz]

According to shluter, you can Ditra straight onto a deflection free chipboard floor.. What's everyone'sthoughts on this? I've not tried it, so am just curious...

 

[Andy Tiler]

According to shluter, you can Ditra straight onto a deflection free chipboard floor.. What's everyone'sthoughts on this? I've not tried it, so am just curious...

You can do that but I would stick it with Ardex af 200 rather than a cement based adhesive

 

[beanz]

What's the reason for that Andy?

 

[Andy Tiler]

What's the reason for that Andy?

Sticks better!! More elastic.Evan Schluter recommend it?

 

[beanz]

Sticks better!! More elastic.Evan Schluter recommend it?

ok mate, cheers for that

 

[thompsonbrown]

Good afternoon

went to look at a job this morning. 4 upstairs bathrooms including a loft extension bathroom and all of the floors are the wonderful 22mm moisture resistant chipboard straight onto the joists. All the floors are solid so no deflection issues. It's been explained that it needs overboarding which he understands. My question is, is if I use hardie backer or an insulation board like marmox glued and screwed am I right in thinking that it's really only the screws holding the board down as the adhesive doesn't adhere to the chipboard or am I way off the mark.
Also what would you guys recommend using in this situation.

Thanks in advance

The Glue or adhesive (dependent on board manufacture) is the main sorce of contact for the board. The screws will help but are also there to hold the board in place while the glue/adhesive set.
Prime the floor first as this will adhere to chipboard, then your glue/adhesive will adhere to your primer.
Hope this makes sence as i'm having a few beers repling to this, while the missis is out.:lol:

 

[Andy Tiler]

The Glue or adhesive (dependent on board manufacture) is the main sorce of contact for the board. The screws will help but are also there to hold the board in place while the glue/adhesive set.
Prime the floor first as this will adhere to chipboard, then your glue/adhesive will adhere to your primer.
Hope this makes sence as i'm having a few beers repling to this, while the missis is out.:lol:

A lot of adhesive company's don't recommend priming timber now!so always check with the adhesive manufacturer beforehand

 

[rj1884]

Thanks for your replies. Andy I was told not to use af200 on chipboard only on ply. I take it you've done this many times before. I'm thinking to be on the safe side I would still over board then ditra. What's your thoughts on this.

 

[Andy Tiler]

Thanks for your replies. Andy I was told not to use af200 on chipboard only on ply. I take it you've done this many times before. I'm thinking to be on the safe side I would still over board then ditra. What's your thoughts on this.

As you I would always overboard!cement board is always the best substraight to tile on to. If it's not recommended then I wouldn't use it!
I always make the phone call if I'm unsure?
Hope that helps?
Cheers Andy

 

[thompsonbrown]

A lot of adhesive company's don't recommend priming timber now!so always check with the adhesive manufacturer beforehand 

Intrested in your advice.
always prime my floors usally use granfix adhesive.
Which adhesive manufacturers dont ask chipboard floor to be primed?
Not saying your wrong, just interested.

 

[rj1884]

Cheers Andy. Can ditra be used on top of hardie. I know it can on marmox. Has anyone used it on hardie.

 

[Andy Tiler]

Intrested in your advice.
always prime my floors usally use granfix adhesive.
Which adhesive manufacturers dont ask chipboard floor to be primed?
Not saying your wrong, just interested.

I don't tile straight onto chipboard! It's to risky
I use Tilemaster adhesive for everything!
..