Tiling Standards (BS 5385) | British Wall and Floor Tiling Standards - IN FULL - TilersForums.com

[Tile Shop]

TTA/BSI vs Tilers:

 

[Italy]

So Matt.......
What is the British Standard recommendation for joint widths for large format (over 3m) sheets of porcelain.

here the minimum allowed is 2mm

 

[Matt V]

Read that in the TSJ and totally agree, 5mm joint in seamless work!
So who accepts responsibility?
Client?
Architect?
Interior designer?
And how does it get signed off?

I’am just a Tiler!

Down to Architect or Designer in my opinion to know what the standard is and apply it accordingly in the installation

 

[J Sid]

at the end of the day must be down to tiler.
whatever the architect or designer say it's the tiler doing the job and has to do it to the BS.

 

[J Sid]

must be down to the tiler not the architect or designer or even the Property owner

 

[Tile Shop]

Nerd alert!!! INCOMING!

Based on the CoLTE of porcelain (4 in general) if a room is 20oC normally and the temp rises to 30oC when the bathroom, underfloor heating or whatever is in use, a 2400x1200 porcelain tile will expand to 2400.096 x 1200.048mm. Would that 0.096 x 0.048 of a millimetre make a difference? 1mm joints might struggle to buffer it, maybe.... but 2-3mm with flexi grout, flexi adhesive and appropriate expansion joints, shouldn't cause much of a problem but that also depends on their deformability.

Also need to bare in mind whether or not the substrate is subject to the same temperature fluctuations and how much they are likely to expand. for the same amount of plaster (2.4m) for example it will expand by 0.408mm.

IMO British standards are a little on the safe side, but not massively. I can see why they thought a need to amend. But the trouble is all the manufactures say their products are only guaranteed if used in line with the current standards. Ultimately if anything goes wrong, the tiler gets the blame, whether they were/weren't aware of the requirements or someone else requested it.

 

[J Sid]

that's for 6mm tile?
how much expansion when ufh is on 34 oC which is allowed on an area no bigger than 1m2 (under building regs, I believe)?
BS may not always be liked or look good on joint size but a good safety margin needs to be worked into the calculations

 

[Waluigi]

Coefficient of Linear thermal expansion?

I remember dealing with that for sheet lead. It’s fascinating stuff, kind of

 

[Tile Shop]

that's for 6mm tile?
how much expansion when ufh is on 34 oC which is allowed on an area no bigger than 1m2 (under building regs, I believe)?
BS may not always be liked or look good on joint size but a good safety margin needs to be worked into the calculations

Thickness wouldn't make much of a difference, only to the time it takes to reach its top temperature. It would be on the assumption that the tile at the overall thickness would heat up evenly. I know thats not 100% realistic as one side would heat up quicker than the other, but the difference is neglegable and wouldn't alter the overall maximum possible expansion.

If you had a 1m room, with a single 1m slab, starting at 20oc rising to 34, gives a maximum expansion of 0.056mm. Still a very tiny and almost insignificant amount.

Even if it was divided into smaller porcelain tiles, the expansion % would be at the same but you would have more grout joints to buffer the effect. so if you had 10 98x98 with 2mm grout joints each tile would expand by 0.0056mm...... which is naff all.

 

[Tile Shop]

Coefficient of Linear thermal expansion?

I remember dealing with that for sheet lead. It’s fascinating stuff, kind of

Thats the one. We probably have different definitions of fascinating

Easy when you know the equation but still need to know the CoLTE of a particular material. Basic ones I work off are as follows. But as you can imagine, its not something I need to use very often:
Porcelain 4
Ceramic 6
Limestone 8
Marble upto 14
Granite 8.5

Plaster 17
Concrete 14
Wood variations 30 average