Hardibacker laid with no adhesive. - TilersForums.com

[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"!

 

[Sean Kelly]

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"!

Funny you say that Grumpy about the flatness of Hardi. I saw 3 sheets of 9mm Hardi 2 weeks ago. They were in with the sheets of 6mm. I know what you are going to say.....Hardi don't make 9mm sheets!
Also, Sorry, I thought because of the water content in SPF and the unstableness of chipboard that it was a no no to use it. Cheers Sean

 

[Rob Z]

....... plus 13 boards of Hardibacker @ £12.49 a board.

Sean, off topic here....it sounds like Hardi is quite expensive there. Hardi here is less than $10 a sheet , either 1/4" or 1/2" (6mm or 12mm?), for 3' X 5' sheets. I think $10 is equal to ~6 GBP.

And then I have seen on this site pricing that you guys have for some materials that is a lot less than we have here.

But most importantly, I think your beer prices are a lot lower.

 

[Thespanishtiler]

you can get hardie board for less than 10 quid for the 900mm x 1500mm - 6mm thick

I use mapei or benfer spf with a trowel notch selected acording to the likely deapth of any void, use good quality screws (turbo gold) and grid these out at 200 mm ctrs.

this is how i do it and it works, i have never had a failure.

probably laid over 200m of board since i dropped ply 18 months ago.

personally, the opinion of a rep or tile shop staff is of no relevance to me when i spec a job and if some one trys to dictate to me how to do some thing i will decline the work, so I am with you on this one Grumpy.

the choice is yours Sean

 

[Alberta Stone]

If they are spec-ing to dry lay a cementitious underlay....they are nuts.
Those boards, in particular the 1/4 inch offer zero structural support, just a smooth surface.

I do know how stubborn the chain of command gets at times, so if they insist on their orders just make sure that it is "specified" in writing as you could put the tiles in upside down and not be liable if such was specified by those who hold the warranty.

BTW, how thick is the actual deck under the lino and how is the subfloor constructed?

 

[Sean Kelly]

Took the lino up and found 18mm T&G chipboard nailed onto joists. I banged in the nails and screwed screws into the joists. I then layed the Hardiebacker 6mm onto fastflex (used 6mm square notched trowel). The thing I find with the Hardibacker and the Hardie screws is that some screws drive in nice and flush to the Hardie. Some screws go straight through the Hardie. About 6 screws per pack of 100 were defect and could not be used at all. Will find out the name of the chipboard for tomorrow. Cheers Sean