Jakoboard thicknesses

[Steve Griffiths]

Advice please as I am starting a house refurb and working out the floor level for joists, as the bathroom is upstairs I am going to lay the floor in the style of a wetroom, sloping slightly to one corner.

What is the best makeup of the floor from the joists up, flooring grade chipbord overlaid with ply then Jakoboard or is that overkill and a 22mm ply and jakoboard adequate?

Also I see that Jakoboard is available from 6 to 50mm are different thicknesses required for the floor/walls?

 

[Time's Ran Out]

No!

 

[Blunt Tool]

Why not use the likes of
Knauf GIFAfloor | Gypsum Raised Flooring System - Knauf - https://www.knauf.co.uk/product-range-overview/flooring/knauf-gifafloor
Right onto joists level and install Wetroom tray that already has the required runs

 

[Waluigi]

I know these boards seem to be the latest recommendation on here but has anyone actually fitted them? I’ve not done a huge amount of research into them but they seem to come in 600mm x 1200mm sheets. Do you simply tile straight on top? Surely a crack membrane needs to go on.

 

[Waluigi]

Just read this about the GIFA floor:-

ideal for stone floors laid without the need for an additional de-bonding layer.

 

[Blunt Tool]

Just read this about the GIFA floor:-

ideal for stone floors laid without the need for an additional de-bonding layer.

The ones I have done used Mapei wp200 mat but that was because they were wetrooms

 

[Blunt Tool]

Think I would still lay a thin mat for stone even if it was a dry area, but porcelain straight on

 

[Waluigi]

I take it you glue the joints?

What about supporting joints at 90 degrees to the joists? It’s got to be incredibly strong. Would be a struggle to fit together if the joists are uneven.

I’d like to see this system demonstrated somewhere.

 

[Steve Griffiths]

Why not use the likes of
Knauf GIFAfloor | Gypsum Raised Flooring System - Knauf - https://www.knauf.co.uk/product-range-overview/flooring/knauf-gifafloor
Right onto joists level and install Wetroom tray that already has the required runs

Thanks for the link, main reason is it's what my local merchant stocks, they have a trade night coming up in a few weeks so I will have a chat to the CTD rep and pick his brains.

The reason I said wetroom style is that it will be a traditional bathroom, this is a failsafe to help prevent damage in the case of a tenant leaving a bath running or a burst pipe, it is not a wetroom in the traditional sense, hence not needing a tray etc

Most terraced houses have a downstairs bathroom and I normally incorporate the same into the screed with a very gentle fall.

 

[Steve Griffiths]

I'm getting these are not ommonly used by the number of responses?

 

[Steve Griffiths]

Well interestingly or not, judging by the number of responses I got to the initial post, went to a trade night and spoke to the local rep who supplies the stuff and couldn't get a direct answer and was referred to their literature to make my own decision!

An experienced tiler who works closely with a tile manufacturer and the technical rep from an adhesive company both said that they would use flooring grade chipboard a decoupling mat and tile as normal and for my purposes it would be fine, in the case of a wetroom they recommended tanking the floor/walls as usual.

Hope this is of use to someone else who may be considering it, as others have said the principle of using cement boards as a flooring directly sounds good, but seems not to be a common method and I am not sure why?

 

[Waluigi]

This has been brought up recently. I’m all for trying new methods but I still don’t fully trust a cement board directly onto joists and then tiled straight on top. I await for my concerns to be dismissed.

Perhaps some feedback from NMP, Knauf or even Hardiebacker as to why their board (HB) is no longer sold in the UK.

Years ago I remember speaking to Bal technical as I was faced with tiling a 25mm ply floor ( the good old ply days) and Bal said it still needs over boarding or an elastomeric adhesive should be used (fastflex)

 

[hmtiling]

This has been brought up recently. I’m all for trying new methods but I still don’t fully trust a cement board directly onto joists and then tiled straight on top. I await for my concerns to be dismissed.

Perhaps some feedback from NMP, Knauf or even Hardiebacker as to why their board (HB) is no longer sold in the UK.

Years ago I remember speaking to Bal technical as I was faced with tiling a 25mm ply floor ( the good old ply days) and Bal said it still needs over boarding or an elastomeric adhesive should be used (fastflex)

I was told by hardie they no longer sell the 22mm here because it is produced in Australia and demand isn't high enough to make it economical

 

[Waluigi]

Cheers- That makes sense.

 

[Steve Griffiths]

I guess ply differs in that it can delaminate?

 

[Blunt Tool]

I’ve done a kitchen floor 600x600x10mm porcelain tiles approx 24 square metres the Gifa boards were installed onto joists with extra noggins even tho it was T&G. The kitchen was installed bar the island, joints fibre taped and filled with fast set flexi. Primed, tiles installed and grouted. That was 3 years ago I think and I’ve been back twice to do a bathroom and en suite. The kitchen floor is still as good as the day it was installed and would recommend to any customer who was going to start from scratch. Trust it more than all the layers needed usually and keeps height uniformed thru house

 

[Waluigi]

I suppose once you weigh it all up- the ply, the overboarding, the labour etc vs the thick cement boards, I don’t think the cost would be all that different.

No membrane on top of the Gifa though?

 

[Blunt Tool]

Think if it had been 24 metres of stone I would have put Mapei wp200 mat down, normal size bathroom stone right onto Gifa yes.

 

[Waluigi]

Sounds sensible. Yes I agree about the stone. Porc doesn’t seem like it needs it but I suppose you can never be too careful.

 

[Blunt Tool]

All stone have natural holes, fissures/cracks, some parts of their composite is very hard other parts very deceiving and brittle, no two the same. That’s why a thin crack mat just gives that extra protection over a long stretch of floor. It’s more to give the stone a bit of relief, let it breathe