Outline of my job - comments welcome - TilersForums.co.uk | Tile Forums

jgw1 · 10-07-2008

Hi all,

Am tiling my floor this weekend with some slate tiles, I have not done this before so thought I'd check here that people thought my plans were sound.

Floor is 18mm chipboard, solid but with a bit of movement.

I want to use BAL Fastflex to glue 6mm Hardibacker to the chipboard subfloor then after this is dry screw it down. Because 6mm+18mm=24mm I can't use the Hardibacker without worrying about the pipes below so I have 1" drywall screws.

On top of this I want to add another layer of BAL Fastflex to the Hardibacker for the tiles.

How does this sound. Does the Hardibacker-Tiles adhesive have to be Fastflex or is that overkill (bit pricey).

Also do I have to tape the joins of the backer? I don't want to raise these is it can cause a problem?

Any advice greatly received.

Grace'sDad · 10-07-2008

Quote:

Originally Posted by jgw1

Hi all,

Am tiling my floor this weekend with some slate tiles, I have not done this before so thought I'd check here that people thought my plans were sound.

Floor is 18mm chipboard, solid but with a bit of movement.

I want to use BAL Fastflex to glue 6mm Hardibacker to the chipboard subfloor then after this is dry screw it down. Because 6mm+18mm=24mm I can't use the Hardibacker without worrying about the pipes below so I have 1" drywall screws.

**I wouldn't bother with the extra cost of fastflex (unless customer is happy to pay. RSF would be ok, as long as you don't have excessive deflection in the floor - in which case you should address this physically i.e. sort out with extra noggins and screws 1st. Also - screw the boards down whilst still wet**

On top of this I want to add another layer of BAL Fastflex to the Hardibacker for the tiles.

**If you are going to use fastflex - there is little point in using hardibacker too - fastflex is good enough to use direct onto the boards (some may say different - but in my experience it's fantastic stuff for this!)**

How does this sound. Does the Hardibacker-Tiles adhesive have to be Fastflex or is that overkill (bit pricey).

Also do I have to tape the joins of the backer? I don't want to raise these is it can cause a problem?

**Tape is used as an expansion joint - limiting the potential boards movement transfering to the adhesive/tile - using fastflex I see little point in using it to be honest - but like primer - doesn't hurt to be on the safe side!**

Any advice greatly received.

Hope this helps! ( Oops - see ** replies above (my bad)

jgw1 · 10-07-2008

Thanks for the quick feedback, I have bought the Fastflex and its sitting at home but not the Hardi.

So you think that Fastlflex onto the chipboard and tiles ontop of that?

jgw

Grace'sDad · 10-07-2008

How big is the floor area? Is it floating? If so it will need lots of screws putting down. I would be confident using fastflex direct - I have done this quite a few times. The only downsides to it - it will stick to the slate like superglue, so work very cleanly - keep a clean sponge and water to hand to sponge off excess. It also mixes quite thin, so don't expect to be able to build a thick bed. It does slump and spread, so spend time grading your slate carefully into groups of thickness, because back buttering is pretty much useless with fastflex - it will all come oozing out of the joints like cream cheese, very very very sticky cream cheese!

(PM GazTech (Bal technical guru) for more clarification on use)

jgw1 · 10-07-2008

Quote:

Originally Posted by Grace'sDad

How big is the floor area? Is it floating? If so it will need lots of screws putting down. I would be confident using fastflex direct - I have done this quite a few times. The only downsides to it - it will stick to the slate like superglue, so work very cleanly - keep a clean sponge and water to hand to sponge off excess. It also mixes quite thin, so don't expect to be able to build a thick bed. It does slump and spread, so spend time grading your slate carefully into groups of thickness, because back buttering is pretty much useless with fastflex - it will all come oozing out of the joints like cream cheese, very very very sticky cream cheese!

(PM GazTech (Bal technical guru) for more clarification on use)

The total area is around 3m2 (pretty small bathroom), the floor is nailed into the joists below (ringed nails)- the joists are a little far apart for my liking (on top of a concrete floor) there is a fair bit of creaking which tells me that there is some movement.

I was going to use a thick bed solid bed trowel on the floor, say 5-6mm. How does that sound with the consistency?

Cheers for the tips (very friendly round here)

Grace'sDad · 10-07-2008

You'll have no problems with a 3sqm area. Just make sure you screw the boards down well. Any creaking will not affect your tiles - it will just anoy the customer

. BAL recommend large format floor trowel for 30x30 onto floor, but I would use a 5-6mm normal trowel quite happily. (also makes the expensive stuff go further)

jgw1 · 10-07-2008

Just to confirm, when you say screwing the boards down, you are talking about the existing chipboard not the Hardi which you are saying that I don't need.

Saves a bit of cash - that and I can take my Bal tanking kit back too as I'll be using Hardi to replace the decaying plasterboard walls.

Grace'sDad · 10-07-2008

Yup that's right - I mean the chipboard floor - not the Hardibacker.

jgw1 · 10-07-2008

Thanks again!

I won't be priming the chipboard as I understand that this isn't recommended by BAL, is that right!

Sorry so many questions - its finally nice to find a forum that gives some answers.

Grace'sDad · 10-07-2008

No, don't prime - just make sure it's as dust free as you can.
(good forum isn't it? I've learnt loads on here. Most will be working today, most replies come through in the evening)
Happy to help, as they say in Asda

jgw1 · 10-07-2008

Right all set, still not sure how I am gonna cope without a loo while doing the work. Might have to keep popping to local for use of facilities (including the bar).

One final thing is that the current floor is vinyl tiles, I can get them up but the the adhesive is difficult to remove. Do I need to remove the current vinyl tile adhesive.

If so I guess I'll have to use a chemical remover.

**MICK the Tiler** · 10-07-2008

If there is vinyl tiles to come up I would sheet over them with hardie backer. The adhesive that holds down the vinyl can affect the tile adhesive for the slate.