uneven bathroom floor

[Ricky H]

hi all first job first problem
im going to be tiling my bathroom floor the floor is uneven got a 10-15mm run in places the floor is chipboard.
if i use a self leveling compound can i tile straight on to it? or should i ply the chipboard first then self level all replies appreciated

 

[AllurePTS]

thanks allurePTS,could i use 9mm ply straight onto a chipboard floor that is level or would i have to use 12mm ply to make the chipboard more rigid?
thanks again

the standard is 18mm mate so anything less has an element of risk, it's always difficult to understand the full situation too ......for me personally, provided the chipboard is 22mm, in good nick and well screwed down ....I would be happy to use 12mm ply well screwed and glued ...it's a compromise mate and depends on your view of the situation really

 

[doug boardley]

i always thought it was 18mm ex ply onto joists (minimum) just out of interest what is the minimum ply overlay, provided sub floor is firm etc etc?

 

[AllurePTS]

I've always thought it should be 25mm marine onto joists for tiling and 15 for overlay ...realistically that means either go up to 18 or down to 12 ....is that all wrong then Doug ?

 

[grumpygrouter]

Lets not get confused with the reason ply is mentioned in BS for tiling. It is my understanding from what I have read (and no, I don't have a copy of the BS, just read extracts off the net) the ply of minimum thickness 15mm is to be screwed at no more than 300mm centres to strengthen the floor to avoid deflection. If there is no or acceptable deflection and I believe there is a formula for this of L/360 where L is the length of the room, then ply is actually not needed. Now, most people on here will not tile onto chipboard under any circumstances as they believe it is not stable enough and to a point I agree, but if you are tiling a floor of say 2m2 with chipboard, how much movement is there really going to be? Obviously this is a generalisation as I always do a bounce test with the good old glass of water before drawing conclusions, and generally any floor of more than say 2mx2m is starting to get towards dodgy ground. If there is no movement, why use 12 or 18mm ply when 6mm backerboard will the job?

As I have stated in previous posts, if the ply is too thin, I feel it can cause more problems than it solves with the possibility of introducing voids between it and the sub floor. In this case I would prefer to tile directly to the chipboard with appropriate adhesive than risk failure because the two surfaces have gaps between them.

If anyone can provide definitive, written documentation as to why chipboard MUST be overlaid at all cost, please post it up on here so that I can be educated. I am always looking to learn.:yes:

 

[AllurePTS]

Thanks Grumpy, very useful explanation there....I guess I'm stuck in my ways from what I was taught in my construction days .....always ply overlay if possible (unless it's Kaberdek) ...there's always been a lot of debate about it, I've always been inclined to work on the cautious side too. arty3:

 

[CTD inverness]

hi, you can get a product called mapei fiberplan a leveller that can be used straight on to chipboard when used correctly it is like putting ply down and yes you can tile straight onto it.
if the hieght you need to raise is more than the recommended thickness you simply lay the first coat to rec hieght then prime and lay a second layer and so on.

very good for going over the top of undertile heating systems aswell!!!
:santa_cheesy:

 

[tilum]

what addy do you recommend to go on the fiberplan and thanks for your help

 

[grumpygrouter]

what addy do you recommend to go on the fiberplan and thanks for your help

Mapei Keraquick and if you have UFH, mix it with Latex Plus.

 

[DHTiling]

I have used a few types of levellers over the years....but nowt is even close to Mapei fibre plan..IMO...

Here is some tech spec for it...

Water-bored ultra-fast hardening self levelling fibre reinforced smoothing compound.
Applications:
Fiberplan is used for smoothing and levelling from 3 to 10 mm over adequately anchored wood substrates and wooden boarding where good resistance to loads and traffic is required; Fiberplan is suitable for wheeled chair traffic and for heated floors.
Fiberplan can only be used internally.
Smoothing of old and new timber floors: wooden boarding, chip-board panels, plywood, parquet.
Smoothing cement, terrazzo, old ceramic tile, natural stone substrates. Coverage
1.6 kg/m2 per mm of thickness. Packaging
25 kg bags.




WHERE TO USE
Fiberplan is used for interior levelling, smoothing
and removing differences in thickness from 3 to
10 mm on properly fixed timber substrates and
wooden boards, where good resistance to loads and
traffic is required. Fiberplan is suitable for wheeled
chair traffic and for underfloor heating systems.
Fiberplan can only be used internally.
Some application examples
• Smoothing old and new timber floors, floor boards,
chip-board panels, plywood, parquet.
• Smoothing cementitious, terrazzo, old ceramic
tiles, and natural stone substrates.
TECHNICAL CHARACTERISTICS
Fiberplan is a grey coloured powder consisting of
special cements with rapid setting and hydration,
synthetic fibres, graded silica sand, resins and
special additives prepared according to a formula
developed in the Mapei research laboratories.
Fiberplan, when mixed with water, produces a very
smooth easily workable paste, perfectly self-levelling,
with high adhesion to the substrate and extremely
rapid drying.
Fiberplan can be spread in thicknesses from 3 mm
to 10 mm per coat without shrinkage, cracking and
crazing, and develops very high compressive and
flexural strength, as well as resistance to indentation
and abrasion.
It is possible to proceed with the installation of
floorings approximately 24 hours after spreading
Fiberplan, depending on the ambient temperature
and humidity, regardless of the thickness.
RECOMMENDATIONS
• Do not add more water to the mix that has already
begun to set.
• Do not add lime, cement or gypsum to the mix.
• Do not use for exterior levelling work.
• Do not use on substrates that are subject to
continuous rising damp.
• Do not apply another coat of Fiberplan after the
previous one has completely dried: in this case
first apply a primer based on Primer G
(1 part Primer G to 3 parts water).
• Do not use on metal surfaces.
• Do not use Fiberplan in temperatures below +5°C.
APPLICATION PROCEDURE
Preparing the substrate
Supports must be dry, sound, free of dust and loose
parts, paint, wax, oil, rust and traces of gypsum.


and solidly fixed to the supports.
The moisture in wood substrates must be
at a level which is typical for equilibrium
with the ambient conditions.
Where the floor is formed by wooden
boards with open joints, they must be
sealed with Nivorapid + Latex Plus before
the application of Fiberplan.
Having sanded the substrate and removed
the dust, prime the wood substrate with
Mapeprim SP or Eco Prim R.
Cementitious surfaces that are not
sufficiently solid must be removed or,
where possible, consolidated with Prosfas,
Primer EP or Primer MF.
Cracks and crazings in substrates must be
repaired with Eporip.
Dusty or very porous concrete surfaces
must be treated with a coat of Primer G
(1 part Primer G with 3 parts water) or with
Livigum (1 part Livigum with 5 parts
water), in order to fix the dust and to
provide uniform absorption of the
substrate.
Anhydrite screeds can be levelled with
Fiberplan (only after a prior coat of
Primer G, Primer EP or Mapeprim SP).
On ceramic or natural stone surfaces first
apply a coat of Mapeprim SP after the
surface has been cleaned with detergents
and mechanically abraded. Level before
Mapeprim SP has completely dried
(indents must still be possible to make).
Preparing the mix
While stirring mechanically, pour a 25 kg
bag of Fiberplan into a bucket containing
6.3-6.8 litres of clean water and mix with a
low speed electric mixer until a
homogenous, lump free, self levelling paste
is obtained.
Allow to slack for 2-3 minutes, then briefly
remix the paste after which it is ready for
use.
The quantity of Fiberplan to be mixed at
any time should be the amount required for
use within 20-30 minutes (at a temperature
of +23°C).
Spreading the mix
Spread the Fiberplan in a single coat of
3 to 10 mm with a large metal trowel or
with a rubber spreader, leaving the trowel
slightly inclined to obtain the desired
thickness.
Due to its extraordinary self-levelling
characteristics, Fiberplan immediately
loses the imperfections (trowel marks,
etc.).
Whenever a second coat is required it
should not be applied before the first coat
can be walked on (approximately 3 hours
at +23°C).
Levellings with Fiberplan are suitable for
the installation of resilient, ceramic and
wood flooring bonded after 12-24 hours at
+23°C (this time can vary depending on the
temperature and humidity of the
environment).
Cleaning
While still fresh, Fiberplan can be cleaned
from tools with water.
CONSUMPTION
Consumption of Fiberplan is 1.6 kg/m2 per
mm of thickness.
PACKAGING
Fiberplan is available in 25 kg bags.

 

[White Room]

Phoned a tile shop who supply Mapei and asked for Fiberplan, He said is it the soft stuff that goes under laminate flooring:dizzy2: