Is variation in batches of ceramic tile underlay usual?

[sheldo]

Recently bought a bunch of these Prima ceramic tile underlay boards from Bunnings in two separate purchases. It’s my first time using them so I have not experienced how they may vary across batches.

https://www.bunnings.com.au/hume-prima-ceramic-tile-underlay-1800-x-900-x-6mm-1-62sqm_p0710334

The boards from one purchase are much heavier and darker in color than the boards from the other purchase. Color difference is shown in the pic. Not concerned about color of course, but the heavier boards feel much more heavy duty and sturdy so am concerned about performance. The boards both have exactly same print on back identifying what they are and they share the same manufacture date too. I could imagine some slight differences in batches that are manufactured, but noticeably different weight seems very odd. Is variation such as this usual, or is it possible the lighter boards were cut and labelled as tile underlay boards in error?

[MitchellMc]

Hi @sheldo,

It's highly unlikely that these were labelled Prima boards in error. As mentioned, the colour is not of particular concern and can vary slightly between batches, but the weight is a little weird. Do you have any idea what the weight difference is?

The darker batch may have become damp, which would account for the additional weight and darker colour. This could be from being rained on, or depending on your location and whether it's been wet recently, they can draw water in from the air. I've encountered many damp cement boards over the years, and they are always significantly heavier than their dry counterparts.

If the boards are damp, they'll dry out naturally and are not cause for concern.

Please let me know if you have any questions.

Mitchell

[sheldo]

Thanks @MitchellMc 

It was a decent thought around the dampness, but that’s definitely not the case, there’s no wetness observable  or that can be felt, they’ve also had a good few days under cover sitting waiting for install in which they could have dried out. It’s difficult to weigh them, I don’t have anything appropriate to do that on hand but the heavier boards feel about somewhere between 30-50% heavier than the others. They feel like you’re picking up something cement based, very solid compared to the others which feel sort of flimsy in comparison.. but again I’ve not used boards like this before to claim any expertise on it.

[MitchellMc]

Hi @sheldo,

I've contacted Hume and sent your images and description off for assessment by the Prima manufacturer. I'll update you when we have a response.

Many thanks for your patience.

Mitchell

[sheldo]

Thanks @MitchellMc 

[MitchellMc]

Hi @sheldo,

I've heard back from the manufacturer of the boards, and they, too, believe that the darker colour could be due to moisture that has been absorbed. They advise that it will take a few days for the moisture to evaporate out after the boards have been removed from their stack and are not concerned that this is an issue with the product. I do note you've said they had time to dry undercover, but keep an eye on them to see if they lighten up over the next few days.

If you experience any issues, the manufacturer can investigate further.

Mitchell

[sheldo]

Thanks for the reply @MitchellMc 

I can say with complete certainty it is nothing to do with dampness, I could bring samples into a store when I’m next in to demonstrate the difference. They are like entirely different products, color, weight, density etc.. it may be hard for the manufacturer to trace as unfortunately I had already laid all the portions of the “lighter” underlay boards that had complete batch numbers printed on them, I do still have off cut samples though which evidence the differences and have the nail markings and partial print underneath to show they both were both packaged as underlay boards.

Conscious there’s not much can really be done here but ultimately best outcome I could hope for is some level of assurance that the “lighter” boards will perform as expected and not cause the tile installation to fail.

[MitchellMc]

Hi @sheldo,

The board's specifications are 8.5 KG m2 = 13.8 KG ea. I understand the lighter boards are already fixed, but weighing them would be the best method to determine whether they are, in fact, underweight. The board will likely sustain removal damage, but I'd be happy to speak to the store of purchase and have another available for you to collect free of charge.

I'll reach out via PM for additional details to see if we can have a Hume rep attend the premises. However, at this stage, weighing the lighter boards will likely be the only way to determine if there is an issue with them.

Mitchell