What are the White marks on the under side of the Onduline sheet?

The white raid on the bottom surface of the sheets results from the standard manufacturing process of our products and is a very rare but completely natural occurrence. It comes from agents used during the manufacturing process. The dose of these agents depends on the characteristics of the raw materials used. Therefore, it may appear on sheets from one production batch, and on the overwhelming majority of others, it will not appear at all.

The main component of the raid (approx. 90%) is calcium lactate hydrate. It is a water-soluble compound, hence it has the ability to reach the surface and crystallize on the sheet. This compound is not classified as dangerous. In the food industry it is used as a preservative under the symbol E327, it works mainly against fungi and yeasts.

The white raid is not a factory defect, but is only aesthetic. It occurs when the sheets are new and wears off after a few months of use. It in no way affects the waterproofing of the cover and the performance of the product, which we guarantee as a manufacturer. The sheets are a full-value product.

The white raid will go away on its own with time. However, if you want a quick effect, it is enough to wash the sheets with water and ordinary dishwashing liquid (without vinegar), using a sponge, a soft cloth or a brush.

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