# Forum Home Renovation Tiling  ceranic tiling over timber floor

## nbr

g'day  Im tiling over timber floors as i want a hard wearing floor. my question is are control joints really necessary every 5metres as recommended by the web sites. I want to lay them in a diamond pattern and don't want to have to cut through the pattern to make the joint. The area is about 80m2 in total lounge,family,hall way,entrance and kitchen all open plan. I thought that if i leave 10 to 15mm gap at the walls with skirting replaced on top of tiles and use silicon instead of grout at the cupboards etc.... I'm thinking this will allow the floor to move enough without causing tiles to crack. I was told by someone to leave a 2mm gap between the ctu ( cement tile underlay) sheets to allow for movement. The james hardy site says ctu sheets should be layed flush together. As im not an experienced tiler but have some experience on small jobs any advice would be much appreciated. Also can ctu be layed using a nail gun. http://www.renovateforum.com/images/.../2thumbsup.gif  :2thumbsup:

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## Honorary Bloke

G'day nbr, 
Movement joints are essential and vary by the size of tile and exposure to the elements. Find a wealth of information on that and other tile questions here:  http://www.schluter.com/5811.aspx 
HTH  :Smilie:

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## Bloss

Follow the manufacturer's advice re laying of the fibre sheet underlay and you will be fine - see the following (and although it goes against the grain for most males you should read all the instructions before you start)  http://www.jameshardie.com.au/Produc...llationManual/ 
Expansion control joints need to be incorporated although how many can vary according to climate and the age of the floor etc. These joints can follow the tile edges and do not have to run with the direction of the flooring so you will not have to cut across the diagonal for control joints. 
The underlay is fixed with nails (and staples if into hardwood, not in to softwood) and stud adhesive and this helps to stabilise and even out movement of the boards. 
Although it is commonly done I do not use a nail or staple gun as the specially designed underlay nails need to be flush and staples a little below the surface as per the installation manuals. This is not a hard nailing job and even large areas can be done quickly.

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## surfbum

Nbr, Ive been out of the trade for 15yrs but believe things havent changed dramatically, so for what its worth
<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com :Shock: ffice :Shock: ffice" /><o :Tongue: ></o :Tongue: > As a first choice I would tile directly onto the timber floor using one of the speciality flexible glues, Tile on timber, Kemflex etc. Kemflex was pretty well my favoured glue for everything anyway. Thats only if the timber floor was sound and the levels were ok. I would also then use a flexible grout, beware though unless they are much better now flexible grouts were a mongrel to wash off  dont do too much at one time! With this method I would probably not worry about expansion joints or perhaps just one along the tile joint across the beginning of the hallway. Just follow the glue's instructions re prepping and stick down a test piece if unsure whether youve done enough.
<o :Tongue: ></o :Tongue: > I never liked or recommend the sheet underlay method as my experience has been that cracks are almost guaranteed along the sheet joins.
<o :Tongue: ></o :Tongue: >  A messier and more demanding option but unavoidable If the existing floor was too sketchy or needed levelling I would lay on a sand cement bed 1&1/2 thick with visquene on the bottom and chickenwire for reinforcing. The tiles could then be wet beded immediately or glued like a normal concrete floor a few days later once fully dry. I would still use the flexible glue but not the flexible grout. I would have expansion joints at the entrances to the lounge ie hallway, kitchen, entrance. Extra expansion joints would be added if there looked to be a weak point ie at a big change in direction or size or perhaps half way down a long rectangular area. 
<o :Tongue: ></o :Tongue: > If it was my own house I would have less rather than more expansion joints, for a builder though I would have what I thought + what the current standard wants + what the glue manufacturer wants + what the builder wants + what the owner wants + anything on the plan or in the specs. I.E its all about covering your butt!
<o :Tongue: ></o :Tongue: > Ps: dont forget about colored caulks

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