Update! I really want tiled flooring...but I have floating chipboard

Alan_M_2

bails1964 wrote: »

agreed, for 2400 x 1200 centres should be 400mm.

600mm centres is fine for 25mm ply when it's being entirely supported by a concrete substrate.

It would only require 400mm if it were a suspended floor or only 18mm of covering were used.

Of course, the less the joist span, the less movement so there's certianly nothing wrong with fitting 400mm centres, it'll just use a little more timber and a little more time.

Alan_M_2

lambo28 wrote: »

Thanks everyone for the help! My kitchen is north facing (so screeding might make my kitchen too cold) and actually quite small (3220mm by 1920mm) so I might have trouble with 2400 by 1200mm ply and how can I do 600mm centres? Also, I don't think any joists exist at present, all of the current chipboard is suspended by polystrene.

Oh why did they not build 'proper' flooring in when the house was built? Cost cutting? Btw house built around 1988.

You pull up all the chipboard and the polystyrene so all you're left with is the concrete base of the house.

You then make a frame of appropriate thickness timber with the cntres of each timber being 600mm apart (or 400mm if you prefer).

Fit noggins in between these timbers also at 600mm centres.

You're effectively making a frame over your entire floor of 600mm squares like a chequerboard. You then fill all these squares in with insulation and screw down plywood over the top of it.

tony6403

keystone wrote: »

Thanks Tony but you missed my point whereas bails didn't. Never mind I was being a tad obscure.

Why are you recommending chipboard flooring as the OP wants to tile?

Cheers

Keystone - You are quite right to question this as I neglected to say that cement board should be laid under any ceramic tiles in this situation.
Got my attention focused on the noggins issue.
(Quarry tiles should not be laid onto this surface and I didn't think that anyone these days would be contemplating this).

lambo28

Just another question, would I be using metal brackets to attach the joists to the concrete base? And what type of screws (for the timber and concrete) / plugs (for concrete) would I use? And do I need a damp proof membrane below the timber frame?

Thanks for the help everyone, I'm starting the project tomorrow - I hope it'll go well (fingers crossed!)

lambo28

UPDATE:

I spent today ripping up the old/rotting chipboard flooring down to the concrete substrate. Now the question is, is there a minimum thickness to build the timber frame? Would I screw the timber frame through the timber and into the concrete. The original floor is a total of 53mm (18mm chipboard and 35mm polystrene) which is quite shallow. Also I have no joists at all currently.

keystone

Just over an inch? You do not have room for joists and ply with or without cement board to create a stable timber framed substrate. More concrete to the right level.

Cheers

vax2002

Well thats all the trade secrets out in the open and they wonder why they have no work....

lambo28

keystone wrote: »

Just over an inch? You do not have room for joists and ply with or without cement board to create a stable timber framed substrate. More concrete to the right level.

Cheers

How many inch would be stable? Thanks

Alan_M_2

53mm is a nuisance, it's not really deep enough to fit joists.

You're better off looking to screed the floor, it's going to cost the same as any other solution.

The only other option that springs to mind is a 25mm layer of solid foam type insulation, glued to the concrete floor with a flexible cement based tile adhesive covered with two layers of Aquapanel cement board at 12.5mm thick per layer, again all glued down with flexible tile adhesive.

The problem with that is cost - it's going to be cheaper to get someone in to screed it. At 53mm I'd like to see fibre reinforcement in the sand/cement screed.

lambo28

Alan_M wrote: »

53mm is a nuisance, it's not really deep enough to fit joists.

You're better off looking to screed the floor, it's going to cost the same as any other solution.

The only other option that springs to mind is a 25mm layer of solid foam type insulation, glued to the concrete floor with a flexible cement based tile adhesive covered with two layers of Aquapanel cement board at 12.5mm thick per layer, again all glued down with flexible tile adhesive.

The problem with that is cost - it's going to be cheaper to get someone in to screed it. At 53mm I'd like to see fibre reinforcement in the sand/cement screed.

Thank-you so much for the help Alan! Are there any other disadvantages with the Aquapanel option? It definitely sounds easier lol. Is it rigid/supportive enough for tiles? Would an adhesive such as Bal flexible floor tile adhesive work?

Thanks again