tiling over floor grade chipboard

[sharpfamily]

i'm tiling (500*500 tiles) over floor grade chipboard using bal single part flexible. do i need to apply a primer, if so why, and which primer?
thanks

 

[grumpygrouter]

Hi Sharpfamily, welcome to the forums.

Your question.... Sadly I must inform you that BAL single part flexible is not suitable for tiling straight onto a chipboard floor. BAL recommend at minimum there Fastflex product which is a 2 part latex based adhesive. They would also strongly recommend that your floor is overboarded with 18mm WBP ply sheeting screwed at a minimum of 300mm centres.

It is imperative that you ensure that your floor has as little deflection as possible as your tiles WILL crack.

If you can not, for some reason, over board your chipboard there are other ways to deal with this, but currently your chosen adhesive is not suitable.

 

[sharpfamily]

thanks for the advice. there's a bit more info below. I'd be grateful for some more advice as I don't want the tiles to crack! and I've already got the BAL single part flexible adhesive.

The chipboard sheets are glued along their halving joints and nailed down on to battens @ 14" centers (with insulation between) over a damp proofed solid concrete base. ( new construction 1991).
the floor is very solid and there's no sign off any movements or squeaks. There is definitely no movement between the joints in the chipboard.

why is an additional layer of ply wood necessary?
thanks

 

[grumpygrouter]

thanks for the advice. there's a bit more info below. I'd be grateful for some more advice as I don't want the tiles to crack! and I've already got the BAL single part flexible adhesive.

The chipboard sheets are glued along their halving joints and nailed down on to battens @ 14" centers (with insulation between) over a damp proofed solid concrete base. ( new construction 1991).
the floor is very solid and there's no sign off any movements or squeaks. There is definitely no movement between the joints in the chipboard.

why is an additional layer of ply wood necessary?
thanks

Chipboard itself is quite an unstable material for tiling onto. Adhesive manufacturers recommend overlaying with plywood for 2 reason, 1. To impart more stiffness to suspended floors to reduce deflaction as much as possible and 2. if chipboard does get wet, it can "blow" i.e it can swell up and push off the tiles.

All timber and timber based substrates are are prone to "movement" because of differing moisture content of the environment meaning the timber will expand and contract. All materials expand and contract to some extent but it is when materials "move" at different rates that causes the problem. Your tiles would expand/contract at a different rate to the chipboard, hence your problem.

However, your problem is not unsurmountable as you can, I I have done successfully, tiled straight onto chipboard if you use appropriate materials, AND THE FLOOR IS SOLID! Please note the emphisis there.

There are a number of alternatives. Your BAL Single Part Flexible is not part of it unfortunately. If you really want to tile straght onto your chipboard floor, this is what I would do.

Firstly i would go over the floor and screw the boards down to the joists at no more than 300mm centres with corrosion resistant screws (nails work loose too easily) leave it nailed as well. Then I would prime the chipboard with a product called Ardex P51 primer. Once that is dry I would use an adhesive called Ardex-flex 7001 to fix the tiles.

If you are unable to get hold of the Ardex products you would need to seek out something like BAL fastflex adhesive. This is a 2 part latex based adhesive but it is very expensive and messy to use but it will certainly do the job.

There are other alternatives as well but these include laying a "decoupling" mat of some sort and again will entail additional cost.

 

[bigandy]

good replies there grumps.please take note of what your being advised as spending a bit more now will stop it costing you more in the long run!

 

[sharpfamily]

thanks again for taking the time to give me all the info.
I'm now thinking that my chipboard is the moisture protected flooring grade and it's over a concrete base (with damp proof membrane under). The floor is bone dry and the room is a lounge/dining area & 17years old. So movement due to moisture shouldn't be a problem. The temperature range/thermal movement hopefully shouldn't be a problem as the room is nearly always occupied and is very well insulated.
Gravity loads/movement are not a problem as the floor is solid & I'll put in lots of extra screws as you suggested.
So I'm going to take a chance and use the BAL single part flexible - I've already got the 10 bags of this and as you say the BAL 2 part is very expensive and messy. If it goes wrong....I've only myself to blame!

thanks again.

 

[grumpygrouter]

thanks again for taking the time to give me all the info.
I'm now thinking that my chipboard is the moisture protected flooring grade and it's over a concrete base (with damp proof membrane under). The floor is bone dry and the room is a lounge/dining area & 17years old. So movement due to moisture shouldn't be a problem. The temperature range/thermal movement hopefully shouldn't be a problem as the room is nearly always occupied and is very well insulated.
Gravity loads/movement are not a problem as the floor is solid & I'll put in lots of extra screws as you suggested.
So I'm going to take a chance and use the BAL single part flexible - I've already got the 10 bags of this and as you say the BAL 2 part is very expensive and messy. If it goes wrong....I've only myself to blame!

thanks again.

SERIOUSLY DONT USE THE SPF! There is not enough flexibility in this adhesive for what you want. Take it back and change it for something more suitable. I really think you will regret it if you continue!!

Where did you buy it from and who advised you?

 

[DHTiling]

No telling some peeps Russ....:huh2:

 

[grumpygrouter]

Well, I have tried my best Dave. I know it will crack, maybe not in a week or a month but certainly before the year is up! Such a shame to spend all that money on tiles and not use an appropriate adhesive.

I really hope he takes on board what is said.:yes:

 

[bigandy]

unfortunately, they sound like the customers who dont beleive when you tell them what they need to do the job properly and insist on going ahead anyhow. ah well you can lead a horse to water!

PLEASE LISTEN TO US WE ARE NT GIVING THE ADVISE TO MAKE ANY MONEY BUT TO SAVE YOU LOTS!!

 

[sharpfamily]

thanks to all contributors.
I can't understand a mechanism that will cause the tiles to crack.
- as regards gravity - the floor is solid and vibration proof
- temp - tiling at summer temps, so any differential thermal contraction will only occur over an individual tile, ie given that the grout's tensile strength is weaker that the tile. Thermal expansion and possibility of the tiles buckling not an issue given summer temps.
- moisture. the floor is bone dry, and any small expansion in the chipboard would only have affect across one tile width, and there should be sufficient flexibility in the bal spf to cope with that.

hence I'm going to proceed with the bal spf. I'll be sure to let you know if the tiles crack within the year.

 

[grumpygrouter]

thanks to all contributors.
I can't understand a mechanism that will cause the tiles to crack.
- as regards gravity - the floor is solid and vibration proof
- temp - tiling at summer temps, so any differential thermal contraction will only occur over an individual tile, ie given that the grout's tensile strength is weaker that the tile. Thermal expansion and possibility of the tiles buckling not an issue given summer temps.
- moisture. the floor is bone dry, and any small expansion in the chipboard would only have affect across one tile width, and there should be sufficient flexibility in the bal spf to cope with that.

hence I'm going to proceed with the bal spf. I'll be sure to let you know if the tiles crack within the year.

We have tried to give you advise based on combined dozens of years of experience and tried to explain what problems you are going to have. You have chosen to ignore what has been suggested sadly.

Hopefully things will be OK for you. Good luck, I hope you are still crack free at christmas.

 

[spacedout]

I think that you should listen to these guys they know what they are taking about. However. If you want to take the risk then so be it. Chipboard is not suitable to tile on and even ardex will not advise you to tile over it, please ply first then the right adhesive (ardex s16 with ardion 90) you will have no problems

 

[GazTech]

thanks to all contributors.
I can't understand a mechanism that will cause the tiles to crack.
- as regards gravity - the floor is solid and vibration proof
- temp - tiling at summer temps, so any differential thermal contraction will only occur over an individual tile, ie given that the grout's tensile strength is weaker that the tile. Thermal expansion and possibility of the tiles buckling not an issue given summer temps.
- moisture. the floor is bone dry, and any small expansion in the chipboard would only have affect across one tile width, and there should be sufficient flexibility in the bal spf to cope with that.

hence I'm going to proceed with the bal spf. I'll be sure to let you know if the tiles crack within the year.

Hello, I am a Product Support Technician for BAL. Unfortunately for you, everything the boys have said is true. If you will not seek the advice of the professionals, or a technical representative of the company who makes the adhesive you are going to install incorrectly, (and if money is the biggest issue) I would ask to be refunded the tiles and adhesive and put a cushionfloor down that looks like tiles. What was the reason for seeking advice if you are not prepared to heed it ? I also think de-bonding of the tiles will occur before 12 months is out......I hope I am wrong !

 

[CJ]

:mad2:

 

[sharpfamily]

I can see why is chipboard not suitable for tiling in some circumstances.

However my chipboard floor is solid, no deflections....therefore I see no need for adding ply for extra stiffness.
the chipboard is bone dry, been down for 17 years and is not subject to any wetting or moisture.
please explain in more detail why you foresee cracking or debonding before Christmas.

 

[Holohana]

i dont think they are going to bother anymore do you?

 

[CJ]

Is this a wind up :mad2:

 

[grumpygrouter]

I can see why is chipboard not suitable for tiling in some circumstances.

However my chipboard floor is solid, no deflections....therefore I see no need for adding ply for extra stiffness.
the chipboard is bone dry, been down for 17 years and is not subject to any wetting or moisture.
please explain in more detail why you foresee cracking or debonding before Christmas.

What you appear to be not understanding is that the atmosphere around your floor will vary constantly with temprature and moisture content of the air. Even though your floor is "bone dry" the atmosphere containes moisture and you have heard of this referred to as humidity. Different weather conditions WILL affect your floor even though it is dry. This is the reason you have ventilation under a suspended floor and also the reason why you have insulation boards between your joists.

Ceramic tiles (or natural products) do not have any flexibility and WILL expand and contract at a different rate to your floor. Yes your floor WILL expand and contract with differing atmospheric conditions. Even your chipboard surface will move at a different rate to the wooden joists they are attached to as they are different materials. These movements are inperceptable to the eye but they ARE there.

You say that any movement would only be taken up within 1 tile width, if that tile width goes along the entire length of your floor you have 1 big long crack to either look at for years or a lot of re-tiling to do.

The deflection issue you mentioned has ways of being overcome as mentioned in my previous posts without overlaying with ply. The real problem you have is the fact that you are going to use an ADHESIVE THAT IS NOT DESIGNED TO FIX TO TIMBER.

We here on the forum are only trying to stop you from having big problems in the future and wasting a lot of money and time. Bear in mind that if one of the professional guys on here came to do the job for you, using exactly the same materials and procedures you intend to do, when it cracked you would be striaght on the phone to get him back to fix it at his own cost. We are only advising you what we would do to do the job correctly and reduce potential problems to a minimum.

Your chipboard floor is solid. That is fine. Tile straight onto it by all means but please, please, use the correct adhesive. BAL Single part Flexible is not suitable for this job.

As an aside, it will be much less hassle to go and change your 10 bags of adhesive than to retile 35 or so square metres of floor. ( I assume that is the area looking at the number of bags you have).

 

[sharpfamily]

Grumpy,
Thank you for sharing your practical knowledge so patiently.
That's what will make this forum work.
Others perhaps should take note the good example you set.
best,
graham

 

[grumpygrouter]

Grumpy,
Thank you for sharing your practical knowledge so patiently.
That's what will make this forum work.
Others perhaps should take note the good example you set.
best,
graham

Thanks for your comment Graham. I am here to help if I can.

 

[ad tiling]

i'm tiling (500*500 tiles) over floor grade chipboard using bal single part flexible. do i need to apply a primer, if so why, and which primer?
thanks

And he only asked about primer :lol:

 

[Rab78]

ive not long tiles a chipboard turn and grrove floor 110 m2 most of the floor needed extra support underneath and had to be well bonded with universal bonading agent, i use dunlop/bal. I used dunlop tile on wood as it is suitable for this kind of floor, but is a bit expensive, abot £23 per 3m2. I used dlexi addative for the grouting. Has been down for 2 months with no problems.

 

[andy-p]

I can see why is chipboard not suitable for tiling in some circumstances.

However my chipboard floor is solid, no deflections....therefore I see no need for adding ply for extra stiffness.
the chipboard is bone dry, been down for 17 years and is not subject to any wetting or moisture.
please explain in more detail why you foresee cracking or debonding before Christmas.

graham , if the floor is solid overboard with 9mm ply screwed every 150 centres, it wont cost much and is a fairly easy job, time and money well spent for peace of mind and will save you a packet on the long run..

 

[Droopy]

thanks to all contributors.
I can't understand a mechanism that will cause the tiles to crack.
- as regards gravity - the floor is solid and vibration proof
- temp - tiling at summer temps, so any differential thermal contraction will only occur over an individual tile, ie given that the grout's tensile strength is weaker that the tile. Thermal expansion and possibility of the tiles buckling not an issue given summer temps.
- moisture. the floor is bone dry, and any small expansion in the chipboard would only have affect across one tile width, and there should be sufficient flexibility in the bal spf to cope with that.

hence I'm going to proceed with the bal spf. I'll be sure to let you know if the tiles crack within the year.

As soon as you put any adhesive onto it, the floor will no longer be bone dry.
The water in the adhesive will make sure of that.

Save yourself any hassle and take the SPF back and change it for BAL FastFlex.
Yes the cost is greater. But this difference will be far less than ripping up and redoing, or overboarding with 18mm ply (which will be needed if you intend to use the BAL Single Part Flexible)

 

[mark1966]

the adhesive your going to use is cement based and will only flex so much bal fast flex cost alot howtex wf21 is the same product but cost less do as the guys said prime the floor first and use the wf21 i did a floating floor years ago and to this day they havnt had a prob with it hope this helps ps the wf21 goes alot further and probally will only be about 30% more exspensive depending on what you paid for your originail adhesive mark

 

[Brindle]

I have recently tiled onto chipboard on 2 floors (against my advice) with the only adhesive I would have trusted - Bal Fastflex. Worked a treat, not very messy to use either. I also used the GT1 (?) Admix to the grout to prevent cracking in the grout. No problems. Definitely wouldn't have used a single part.

Good luck with it

 

[grumpygrouter]

I have recently tiled onto chipboard on 2 floors (against my advice) with the only adhesive I would have trusted - Bal Fastflex. Worked a treat, not very messy to use either. I also used the GT1 (?) Admix to the grout to prevent cracking in the grout. No problems. Definitely wouldn't have used a single part.

Good luck with it

Ardex-flex 7001 is a single part addy designed for the very same thing and also works a treat. Cheaper too.

 

[Brindle]

Cheers Grumpy, had to get readily available stuff in my location, which was Bal (which is blinking dear

 

[woodie]

i wouldn't advise using single part flex' i agree with grumpy you're better off being safe than sorry