Wil my newl bath crack my tiles

[hightails]

I’m a reasonably experienced DIY guy, nearing the end of a complete bathroom refit including install of new shower, velux window, full tile etc. All very carefully planned, researched, and as far as I know complying with regs.

Unfortunately, I’m now getting cold feet because I think I might have missed an important factor. I didn’t realise how heavy a bath full of water and person is - I assumed that because the bath is only acrylic and it’s going in the same place as the old cast iron bath which sat there for 35 years on chipboard, it would be OK. And I still think that’s true structurally, as I have upgraded the floor by replacing the chipboard with ply and adding some noggins.
The problem I am concerned about is that I have already tiled the area where the new bath needs to sit, and I’m wondering if the tiles will crack when the bath is full.

It’s a free standing double ended egg shaped acrylic bath, positioned near a wall. It sits on 4 feet arranged in a diamond shape, which are hidden by the skin of the bath. Quoted capacity 280 litres, though I don’t know whether that is when full or when filled to normal level. Floor tiles are 300x300x10 ceramics on 18mm ply plus 6mm Hardibacker.

Because it's free standing I couldn't put substantial bearers underneath it, but I could rip up my nice new tiles underneath the bath footprint so that the feet went directly onto the ply, though obviously I'd rather not do that unless its necessary.

400kg is a lot of weight. But brochures have loads of pics of the claw-footed type of free standing baths sitting on floor tiles, so am I worrying too much?

 

[Riley]

I think a lot of it will come down to how confident you are in your own tiling. Have the tiles been put down with a decent amount of muck so they aren't going to go anywhere and if so they shouldn't crack if the weight is spread evenly

 

[Phil]

Did you bed the Hardiebacker down on cement based tile adhesive and are the floor tiles on solid bed of adhesive? What notch trowel did you use?

 

[oz-plumber]

Is the bath installed on the ground floor or is it installed on a floor with rooms below?

Worst case scenario, the feet will only fall through the floor. I doubt in any situation the entire bath would plummet through the floor

 

[hightails]

Guys, thanks for the responses.

Phil : Yes, the Hardibacker is bedded on adhesive using a 6mm trowel as per manufacturer’s instructions and screwed at recommended intervals. Can’t remember if I back-buttered the boards. Tiles are down with a 10mm trowel, definitely back-buttered, but not solid bed. Granfix Fast Set Flexible throughout. Floor/joists meets L/360 requirement.

Riley : Am I confident in my tiling? I'm fairly confident. I’ve done half a dozen bathrooms/kitchens over the years, including travertine on downstairs rooms. These particular tiles went down with a lot of care and reading up on techniques and materials, but I’m not a pro and recognise my limitations, which is why I am asking on here.

Oz : As you will have gathered by now it is upstairs. Appreciate your reassurance that the worst is unlikely to happen. As I said already, I’m assuming the floor structure will be OK because there was a much heavier bath in place before, but I must admit it did have some chunky spreaders under the feet. Problem is, you just can’t get substantial timbers underneath one of these free standing things.

 

[Phil]

You'll be fine, think of all the 4 feet open freestanding baths on tiles, as long as you have not dot and dabbed the tiles.

 

[hightails]

OK, Phil. I will go with that. Thanks for your advice.

 

[Radioman]

Sounds like a better installation than a lot of so called professionals do!