Laying Floor Tiles in bathroom?

[Gees]

I have a floorboarded bathroom floor ( standard joists etc )
I wish to lay floor tiles and need to know the correct way to go about it.
The boards are solid with no noticable movement at all when stood on.
I have heard that its best to lay plywood ?

 

[Richard C]

I prefer to take up the original floorboards & lay new WBP ply 18-25 mm thick, depoending on local circumstances, & tile directly onto that; avoids any risk. You could overboard the existing floor boards but should use minimum 12mm WBP ply which will increase the door threshold considerably by the time you get the tiles on there.

For more info read the tiling forum Sticky & have a look back through the archive posts. Lots of info in there about how to go about it & what products to use to make sure it lasts; come back if you have specifics.

 

[nicktiler]

6mm hardie backer board and a good 2 part flexi is also an option !

 

[bathstyle]

Manufacturers will suggest the use of an elastomeric adhesive if yoy tile straight onto boards, that's even if you replace the boards with Plywood, even up to 25mm.

Overboarding is the way to go here, as mentioned, 12mm minumum or I often glue and screw thicker tile backer board, tape joints etc, which really is the better option.

 

[Richard C]

Manufacturers will suggest the use of an elastomeric adhesive if yoy tile straight onto boards, that's even if you replace the boards with Plywood, even up to 25mm. Overboarding is the way to go here, as mentioned, 12mm minumum or I often glue and screw thicker tile backer board, tape joints etc, which really is the better option.

Personally I would never tile straight onto boards no matter how good they look & firm they feel. As I said, I will always rip up & replace rather than overboard with ply or tile backer boards, some of which (IMO) will not provide sufficient rigidity despite the manufacturers claims! The biggest problem with over boarding is the serious increase in the threshold height & I find most customers will not accept or appreciate why it’s necessary!

In most cases a well fixed 18mm WBP base is sufficient but it depends on local circumstances; joist size/ section, joist spacing & location of the room, basically it comes down to assessing how much the floor is likely to flex & sometimes I consider it necessary to go to 25mm. Once you have a firm base, a decent trade flexible adhesive & grout is all you need; I’m a bit of a one trick pony & won’t use anything other than BAL products, Rapidset Flexible & Superflex grout is generally all you will need.

 

[bathstyle]

Contact Bal, tell them that you fit 18mm ply onto joists and they won't recommend Bal Rapidset flexible for the floor, they will suggest an elastomeric, like Bal fastflex.

 

[Gees]

Thanks for the information. I think its time to replace with plywood as I have to have all the stuff out anyway. Her indoors isn't too keen on the extra height if I overboard...

 

[Richard C]

Contact Bal, tell them that you fit 18mm ply onto joists and they won't recommend Bal Rapidset flexible for the floor, they will suggest an elastomeric, like Bal fastflex.

OK, they recommend min. 25mm (along with many) but are playing it very safe. As I said, sometimes you need 25mm but it depends on the joist structure; if the floor is rigid enough it's OTT & you don't need it.

 

[bathstyle]

Ask Bal if you need to use Elastomeric on 25mm Ply. They will say yes.

I have myself tiled many floors simply by fixing 25mm ply directly onto joists, if there is a join anywhere on that floor then it needs Ditra, especially if it's natural stone. I think a lot of the time, these Manufacturers will always find a way to wriggle out of a claim, that's why there are so many contradicting ideas on forums.

I have never understood these issues with height when overboarding though, unless the customer has wafer thin carpet with no underlay then it could be a problem. Another big problem is when people use those awful chrome threshold strips or door bars, I like to use a nice piece of oak at the door

As mentioned, depends entirely on the job, I change my working methods all the time.

.....finally, lose the rolling eye smileys otherwise i will be forced to do one back

 

[jefoss]

do you make many claims then bs?

 

[bathstyle]

Nope, not yet although I have had a failure of a travertine floor, 25mm ply onto joists fully supported on joints and board end, that's why I always fit Ditra when not overboarding.

A hairline crack running parallel to a joist, actually along that joist

 

[Richard C]

Ask Bal if you need to use Elastomeric on 25mm Ply. They will say yes.
I have myself tiled many floors simply by fixing 25mm ply directly onto joists, if there is a join anywhere on that floor then it needs Ditra, especially if it's natural stone. I think a lot of the time, these Manufacturers will always find a way to wriggle out of a claim, that's why there are so many contradicting ideas on forums.

The Rapidset Flexible spec. sheet says it’s suitable & my experience is its more than adequate over a solid 18-25mm WBP ply base; why use a much more expensive product you don't really need. As I said it’s down to site assessment & never had a problem with it; but perhaps I’ve been doing it all wrong the last few years.

Manufacturers will say lots of things to encourage you to buy their most expensive products. I can give other examples where they say you can’t do this or that but in fact you can, I do it all the time. So they may wriggle out of a claim if I invalidate their warranty, so what; I’m happy to rely on my judgment & fix it if there is a problem.

I have never understood these issues with height when overboarding though, unless the customer has wafer thin carpet with no underlay then it could be a problem. Another big problem is when people use those awful chrome threshold strips or door bars, I like to use a nice piece of oak at the door

That’s your personal opinion, mine is I don’t like it & think it looks amateurish; many customers don’t like it & many of the modern, cheap panel doors don’t have enough meat on the bottom to allow trimming to clear. I usually always use oak door bars.

.....finally, lose the rolling eye smileys otherwise i will be forced to do one back

Stop nit picking at posts then; I thought I was the bloody fussy one!

 

[bathstyle]

So you're saying that you use 25mm ply instead of overboarding as the customer won't accept the 5mm increase in height ?

I thought I had Fussy customers

I don't think you even give them the option, like myself you just do it.

I don't purely overboard, I replace onto joists probably on 80% of the jobs.

I'm simply voicing my opinion that overboarding is totally acceptible and give's an increase in height of just 5mm against using 25mm ply and 12mm increase against using 18mm ply onto joists.

Most underlays and carpets are a good 20mm at least, as mentioned, Oak threashiold as your trasition....... perfectly Fine and by no means amatuerish.

Edit: just to add, I'm not nit picking, we're having a light hearted discussion with a bit of friendly banter chucked it, I for one enjoy it, I reckon you would too if you joined in.......now.....I expect a couple of rolling eye smileys and a wink at the end the next time we clash on anothe threadif you're up for a bit of banter


Oh yeah, the last five or so jobs I have done I have gutted the room, replaced boards with green grade chipboard then glued and screwed Aquapanel onto it, a few were wet rooms, a couple were stone floors. You can't beat tiling onto a backer board. I know a lot of people that do what you do (18mm ply onto bare joist) then use the 6mm Hardibacker, and are OK.

 

[bathstyle]

Why aren't you at work R?

 

[Gees]

One more thing.. I am replacing the whole bathroom. Is it best to lay the tiles before I get the stuff installed or work round afterwards? I reckon the first choice is best but there may be a reason why not..?