Frost damage to quarry tiles

[housepuzzle]

I have quite a large number of original Edwardian quarry tiles which I took up from the kitchen floor a number of years ago. Since then, they have been kept in an unheated outbuilding and I am concerned that they might now be frost damaged. Unfortunately, I cannot identify whether they are damaged or not, and I cannot find any business in South Yorkshire that is willing to take a look at a few and tell me if they are frost damaged. Is anyone able to tell me how to identify any possible frost damage to my quarry tiles? I look forward to your replies. Thank you.

 

[malcolm]

If there is frost damage it'll be easy for a novice to spot - the face will have fallen off. I store mine outside without worries as they are resilient to frost.