Laying of cement sheet

[AB..]

Hi all, Iam after any advice on points to look out for when laying cement sheet on to a timber floor. How close to the edges should it be ? and does it need to be glued and nailed or nailed only? What is the best way to cut it to fit around door jambs etc?? Thanks for any help. AB..

[Pulse]

Do you mean ceramic tile underlay? It is usually 6mm and nailed with ring shanked nails at 150mm centres I think. Gaps around the edges are not critical.

Cheers
Pulse

[mic-d]

I've laid cement tile underlay on particle board before and it must be glued and nailed, but I have never done a timber floor. The James Hardie manual is confusing, it explicitely says if laying on particle or ply it must be glued and nailed, so by omission, timber floors may only need to be nailed?? It does say leave a 3mm gap around walls and cupboards, and sand the floor if the boards are cupped.
Cheers
Michael

[les88]

If you mean cement sheet that is as heavy as lead. I fix it with glue and screws, don't trust nails.

[Sturdee]

I just nailed the cement underlay to my timber floor as per instructions, one nail on each dot, prior to tiling. A small gap at the walls is not a proplem as it is filled up with tile glue and grouting.


Peter.

[AB..]

Thanks for all the replies, yes the correct term is ceramic tile underlay and I bought the one with all the indents on it so I take it I need to nail each one. Sturdee you say a small gap is ok at the walls, how accurate do I need to be around door jambs, etc? Is there a type of nail gun I can hire to do the job and what is the best method to cut it?? Thanks for the help.
AB..

[SilentButDeadly]

Glue and nails. Nail each indent. Still need gap around door jambs to cope with movement - not too much otherwise tile won't be adequately supported. No idea about the nail gun but I doubt it - the nails aren't that long and have a very wide head. Cutting is straightforward - score it deeply with a scoring tool and crack the score over a straight edge like a length of timber.

[silentC]

Yes you can use a coil nailer with ring shank nails, well that's what I used anyway. I glued mine down but that was to particle board. I don't know why you wouldn't glue to floor boards but they don't mention it in the installation manual - glue is only mentioned in connection with particleboard or ply flooring.

Here is the manual: http://www.jameshardie.com.au/NR/rdonlyres/7F4FE743-11C6-4052-ADD7-A02235438F00/0/Underlays.pdf

It is doubly confusing because on page 3 it says:


JH stud adhesive
Used for adhering underlay onto particle board or
plywood floors in tiled applications.

but on page 7 it says:


Step 3 - Ezi-Grid and vinyl and cork underlay only
For tiled applications James Hardie recommends the use of
James Hardie stud adhesive for use as an underlay adhesive between
the Ezi-Grid and vinyl and cork underlay and the floor substrate. Spread
the adhesive on the back of underlay sheet with a 3mm notched
trowel/spreader paying particular attention to the sheet edges.


I suggest you give them a call, rather than relying on us to come up with the right answer.

It also says to leave the sheets 3mm from the walls.

[silentC]

More on gun nailing. Hardies recommend these:

27mm x 2.1mm bright steel, annular thread,
flat head collated nail.
C21/27R by DuoFast

Annular thread was what I meant when I said "ring shank" :doh:

[Sturdee]

Sturdee you say a small gap is ok at the walls, how accurate do I need to be around door jambs, etc? AB..


Most of the gaps around the walls were 3 or 4mm but around the door openings the were up to 10 mm.

At a couple of doors I misjudged and the gap was too much, it happens :oo: , but rather than pull it up and do it again I cut some small pieces to fill the gap and when tiling I glued them in place with tile adhesive. No problems with the tiling as it gave the support to the tile where needed at the edge.


Peter.

[AB..]

Sturdee, thanks for the info on gaps around doors, will attempt to do the same, silentC thanks for link to pdf, its exactly what I need and SilentButDeadly thanks for cutting info.

[Bloss]

As said above - always use annular nails (or screws) and always use adhesive whether directly onto joists or onto panel flooring.

If it doesn't stay fixed there is no way to make it solid again without ripping up the tiles so use the one chance you get to do it right.