Hardibacker laid with no adhesive.

[DHTiling]

I'm not sure at the moment. The floor is covered in lino. Won't be sure until the lino comes up......next week. When I spoke with Bal Tec they said that even if its floating and there is no deflection they would use Fastflex.

That will virtually nil to achieve on a floating floor..i haven't come across one that hasn't had at least some deflection , especially around the edges and door ways etc..

But only you can make that call as to how safe it will be to tile...wait till you get the lino up before making a decision mate...

 

[grumpygrouter]

The chipboard is flat, has no deflection and is in a kitchen. It covers approx 11sqm.
A Hardibacker rep as stated that Hardibacker boards can be laid directly onto 18mm chipboard and screwed down. If the chipboard is flat there is no need to use addy.

Is the above true?

Also, I’ll be using Fastflex next week. I have told the customer I have to buy a special solid bed tipped trowel for spreading Fastflex so I added £20 to the estimate. They came back and said they will not pay for it. It’s ok to use a 10MM half round trowel for laying 500x500 tiles?

Cheers
Sean

Just out of interest Sean, the Hardie installation literature stipulates that you should use adhesive beneath the board. This fills any potential voids giving a solid bed. Not sure why the rep was ignoring his own company's instruction manual. :dizzy2:

 

[Sean Kelly]

Just out of interest Sean, the Hardie installation literature stipulates that you should use adhesive beneath the board. This fills any potential voids giving a solid bed. Not sure why the rep was ignoring his own company's instruction manual. :dizzy2:

I agree Grumpy. I've done loads of researh on this one, and was very surprised with what the Hardi rep has stated. I personally did not speak to the rep, it was the Manager of Topps. This is a Topps Approved Fitter job so it's guaranteed by Topps for 12 months. I have already advised using addy under the Hardi. The rep stated that if the substrate was flat then there is no need for addy. If the substrate were floorboards, well then thats a different story. Cheers Sean

 

[smurf21]

not 100% sure but i think you will find that not installed correctly ie addy under hardi then any guarantee by hardiebacker is void check it out.

 

[White Room]

If your going for screwing the hardie might as put ply down

 

[Thespanishtiler]

for the sake of a couple of spf's and an hours work just stick them down, why chance it ?

 

[Sean Kelly]

for the sake of a couple of spf's and an hours work just stick them down, why chance it ?

It's 12sqm onto chipboard. The only addy to use is Fastflex @ £80 for 3sqm coverage (maybe a little bit more coverage with a 6mm trowel under the Hardibacker). Anyway, the customer is paying full retail for this adhesive as it's a Topps approved fitting job. Basically I have told them they will have to purchase 8 'portions' of Fastflex @ £80 a portion! plus 13 boards of Hardibacker @ £12.49 a board. Plus all the materials for 2 more rooms. The job is guaranteed by Topps for 1 year. I have done all my research and if they choose to ignore my advice about addy under the Hardibacker I am getting that in writing. However, the Hardibacker rep has spoken to Topps manager and agreed that it is ok to lay the Hardibacker straight onto the floor if it's level enough. Again, I have asked for this in writing. At the end of the day this job is worth over £700 to me, plus if there is any comeback then it's Topps that has to sort it out.

 

[Thespanishtiler]

hi sean i have layed alot of hardibacker board and use it in preferance to ply.my understanding of the use of spf with the hardibacker is as a void filler, that possible small bit of vertical movement is enough to cause a failure imo.bearing the spfs role in the instalation the use of fastflex is not needed, any good quality spf is fine imo, it seems to me there are too many cooks spoiling the broth on this job but it is your job so get a written disclaimer drawn up and signed by topps, the rep and customer to cover you and work to the spec outlined in it. hope it works out for you.

 

[Sean Kelly]

100% agree with you about filling the voids, but it's the interaction between SPF and the chipboard that is an issue. I can't use SPF on chipboard. You are also right about the number of cooks. Not looking forward to this job. The customers are taking time off work and I feel they will be checking my every move! Cheers for advice. Sean

 

[grumpygrouter]

100% agree with you about filling the voids, but it's the interaction between SPF and the chipboard that is an issue. I can't use SPF on chipboard. You are also right about the number of cooks. Not looking forward to this job. The customers are taking time off work and I feel they will be checking my every move! Cheers for advice. Sean

You can if it just to fill the voids! You can then use the fastflex (oh the joys!) to stick the tiles to the Hardie. If ti was me, and they were spec-ing dry lay Hardie I wouldn't do the job. I haven't yet seen a sheet of 6mm hardie that is "flat"!