Bathroom flooring advice

[Franko]

Hi Guys and Gals,

As the help you all gave in response to my last post was so useful, I thought I'd pose another. We need to replace the tongue and groove floorboarding in the bathroom (due to a combination of botched cork tiling and central heating projects in the past - nothing to do with us I must add!), as we're planning to eventually tile the floor, what is the best replacement for the floorboards?

Cheers,

Franko

[brian c]

rip the boards up...put extra noggings in between the joists at 450mm intervals and then use marine ply 18mm and depending on the product prime the ply and use flexi adhesive and grout.

Alternatively make old boards sound and secure.PLY OUT with 12mm ply and use flexi adhesive and grout and of course prime if directed to by manufacturer.

[DERBER]

rip the boards up...put extra noggings in between the joists at 450mm intervals and then use marine ply 18mm and depending on the product prime the ply and use flexi adhesive and grout.

Alternatively make old boards sound and secure.PLY OUT with 12mm ply and use flexi adhesive and grout and of course prime if directed to by manufacturer.

SPOT ON

[doug boardley]

aye, spot on again Brian

[Franko]

Cheers Guys,

Will Do!

[silver]

Hi all,
another option ??
If height issues brought in with using the 12mm ply over board plus addy then tiles are a problem and you can secure the boards underneath to eliminate movement...you could lose some height by using the 6mm hardibacker board instead of the ply. Stick down / Screwfixed at the intervals marked on the board......
Or
If you are ripping up anyway..add the extra noggins as already advised, and use the 12mm hardibacker board. This plus addy then floor tile (prob 8mm) will possibly bring you level or very close to adjacent floring at the door in....

Depending on the size of your bathroom ? The cost may turn out to be less than the 18mm marine ply . CTD are good for hardibacker prices at the mo.

Hope this adds to the help you have already had
Silver

[Franko]

Cheers Silver,

Hardibacker OK to fix directly to floor joist with no further support?

[silver]

Hi Franko
Hardibacker I treat with same thought as ply...(Its just a bit tough for cutting !....best method I have found is a Marcrist (porcelain) blade on my small hand whizzer)..you will go through jig saw blades like no tomorrow ! its handy that they mark/mould while making these where to screw fix(on the 6mm ones). It wont do you any harm to put more in.....to contact any extra noggins you may have added at external corners in your room (IE boxed verticals) or ? ..
Provided your joists aint moving.....all will be fine. You dont add anything behind it when fixing to wall batons....plus you have the added properties as it is used for wetrooms. Just make sure all old nail heads on the joists etc are knocked in or removed and its all flush before you board.
Mail me at tmt@midastiling.co.uk and I will scan in the product sheets I have here and mail you them back..if it helps ?..or look them up on "tinterweb"

[grumpygrouter]

Hardiebacker adds no strength to a floor. Hardie do not stipulate 12mm for floor use as 6mm is designed for this and it is designed just to be a waterproof tiling surface is is supposed to be used with a bed od appropriate tile adhesive and screwed through to the boards. If you need to add strength to the floor then this is not a solution!

[silver]

mmmmmm
I have done one small toilet area in a converted flat like this..with extra noggins etc ..(emphasis on height issues with existing other levels in the hallway)...hence my suggestion.
I have had no problems. Though I bow to your experience on mine.

I did not anticipate huge weight isues in a small area ....so at the time this never entered into my head.....fortunately......it will from now on.

In mitigation....
I was working from the Hardibacker 500 spec (12mm) sheet that says the same wording (Installation Instructions) for both 6mm and 12mm...It says on both for "Walls , floors and worktops"....but I went with the details on the
500(12mm) sheet and looking at the pic headed Foundation ...it shows it fixing direct onto wall studs with a recommendation of no more than 400mm between centres...and under the Fixing sheets it says use galvanised nails or Backer on screws.......I screwed mine and mine were much closer than that.....at 150mm.
also it doesnt actually say anything about putting adhesive down first on the Hardibacker 500 spec sheet like it does on the Hardibacker 250 spec sheet.....it only shows it being screwed to batons / studs.

If I believe I have addressed the weight / flex issues by my added noggins..to solid joists......in my mind its just the same as screwing to wood batons...only horiziontal ...not vertical.

My thinking was this veratility of use combined with tight spaced noggins would be good enough as long as the joists are good with no movement....keep my fingers crossed then !

We all have to "adapt" now and again for different situations and with reference to the Hardibacker 500 installation instructions / pic I adapted to the conditions using their product.

I aint disagreein with you GG....but I just put a slant on their guidance to get me through a height issue and felt I had everything covered....just wanted to say it wasnt a blind assesment and total guess.

Like always...you learn every day....thanks GG.....

[silver]

Hi Franko,
I have mailed via their website, James Hardie explaining how / why I have used their 500(12mm) board.
I wouldn't be happy thinking I have offered improper suggestion of use.....albeit unintentional.....there is no mention of using adhesive with12mm board on their installation instructions.....just screwfixing.
I would also like to know for my benefit should I find myself in a similar future dilema.

So fella, I will add the reply to this topic when it arrives.

Hope this helps