Bathroom Chipboard floors - what do you do??

[SteveyJ]

Hi all

For years now, I've been over plying chipboard floors in bathrooms, and never had any failures (to my knowledge ) and all is good, but recently customers have been talking to me about the raised height level etc, especially if I then overlay 4mm marmox board to repel the UFH cable heat upwards to the tile then SLC etc. So really just wondered what you all regularly do, alot of the time removing existing chipboard floor isn't cost or time effectiove especially if its tongue and groove and runs under partition walls.

So what thickness WPB do you use for overplying?
Never used it on timber but will a de-coupling membrane work well on existing chipboard?
Can I use a thinner ply if I lay a de-coupling membrane over the top?

Thanks Steve

 

[Alan.P]

As a wise man I worked with once asked me, what's the point of using a flexi addy and then screwing the sheets down ???

 

[AliGage]

As a wise man I worked with once asked me, what's the point of using a flexi addy and then screwing the sheets down ???

Because you'll never make a wooden floor 100% deflection free. You also need to allow for the natural expansion and contraction of the timber.

 

[Concrete guy]

I always used to fit 12mm Aquapanel glued and screwed then tape the joints. But most of my work was stone so I wouldn't consider 6mm.

The idea of using SPF is not only to deal with shear loads but also vibration and deflection.

More often than not I would get oak thresholds made to the thickness of the door to take up and height issues, either flat or sloped to take up any height issues.

 

[Two-Trowels]

Bit confused here - you have a bathroom floor that is boarded with plain floor boards, or even T&G - it's pretty solid but there will be at least some movement, so you decide to overlay with a cement board of some kind and laid on a bed of SPF to take up undulations and also enable you to flatten and level the floor at the same time, handy bonus.

Why do you screw it down too? anything that comes into contact with SPF is usually stuck fast :smilewinkgrin:

I think I've worked out that SPF actually means single part flexible :hurray: I usually use Mapei Pro Flexible, I wouldn't want to try and take up cement boards stuck down with this stuff - are screws really necessary?

 

[kilty55]

hi there yes the screws are needed

 

[macten]

The adhesive is there just to fill the voids.