unlevel floor

[Burnz0]

Hi All. I posted some while back asking how I should go about tiling my bathroom and I'm now about ready to start.
I did the glass of water test for the floor and it seems quite sound (i used a mug instead of a pint glass so I guess this may absorb some of the vibration). I'm leaning towards putting the tiling board down (aqualpanel?) instead of ply as i've read from here that its much better, not as thick and works out roughly as cheap as ply given the time taken to put it down etc.
My questions are:
after putting a spirit level down ive noticed the floor isn't that level - it seems to be a common problem throughout the house. In the bathroom it may be because some of the joists have sagged a little due to a rotten wall plate from a leak before my time. This has now been ripped out and replaced with concrete so not much option to push the joists back up (if they have actually dropped). The drop in the level isn't massive so i should probably just ignore it but im also leaning towards trying to fix it now whilst i can. The rooms only 2-2.5m wide and i'd guess the drop is probably 5mm from side to side - again some of the boards seem worse than others. Is this something i should try and fix and if so how would i do it? put some wedges under one side or will i then create voids under parts of the board that aren't touching the floorboards underneath?

the other question was regarding fitting the tiling board - how do i actually attach it as i've read i need to use adhesive and screws? if i put adhesive down won't it just fall through the gaps in the floorboards underneath? won't screwing alone be adequate and if so, is it a case of hundreds of screws or just a few round the edge?

finally, are there any particular tiling board makes recommended, especially if im on a budget? the area is about a 2.5m square so from the looks of it i can probably get away with ordering a couple of large sheets to cover everything (especially given that i won't need to go all the way due to the bath)

[royaloakcarpentry]

The tile backer board needs to be set onto adhesive and then screwed down as per instructions. You have to use adhesive underneath as this takes out any air pockets/voids and makes for a stable job. If you do not do this then you can in theory have deflection of the backer board and in turn a failed tile finish. Either cracked tiles or cracked grout joints.

You get the floor level when you lay the tiles by varying the thickness of the adhesive. Flexible rapidset cement based adhesive will be the one to use.

[Crooksey]

When using adhesive under backer board you can use more/less in certain areas to level th boards up

[m3 fitter]

As Royal said, screwed and glued is the answer, Knauf Aquapanel should be screwed every 250mm centres to ensure a belt and braces job, try using an 8mm trowel at an increased angle for the raised area and a 10mm trowel at 90 degrees to achieve a level floor. Hope that all helps , don't forget to acrylic prime the wood prior to ;-)

[royaloakcarpentry]

M3....are you a member of the TTA.....was thinking about joining.

[m3 fitter]

Never seen the need, but looks like a good idea, a body of authority to cover you, if anything arises ?

[tictic]

Never seen the need, but looks like a good idea, a body of authority to cover you, if anything arises ?

IMO...
In all my years of fixing..never thought off joining them...never will....

Firstly ...cost and a wee sign to put on your van....

Few fixers i know have joined it....but never renewed after first few years...

I have done a few small courts for clients..regarding...lets say...not very good work done by..tilers...lol

And the cost to my clients has always been a lot..lot cheaper than you would pay a TTA accredited fixer...

At the end off the day, it's down to the individual if they feel the need to join it...
Yes it is there for a reason,just like let's say gas safe....but they don't have the clout...so to speak...they go by mfr spec ect..(at all times)...while I know sometimes I don't think there is a need..some mfr for materials will always...over spec...

It does have its pro and cons....I suppose...but not for me...

[m3 fitter]

Had a problem 2 years ago, where a lawyer refused to pay as he could feel the grout lines under his bare foot and he said the tiles were lipping 1-1.5mm in places, he said take me to court... tried to get an independant architect to inspect for court and he refused access, the TTA wanted £990.00 + vat to inspect as over 50 sq.metres.. was informed by the legal dept. of my insurance company that costs would amount to £2k but as the guy would represent himself and the courts favour the client in most cases, and it would take upto 3 years as the guy was being unreasonable with access, to drop it !! Apparently the lawyer had knocked 3 other companies and is renowned for it, if i had been a member of the TTA they would have persued it.. but its the only time i wished i was a member..

[royaloakcarpentry]

Twas just something I was mulling over.