Using internal tiles outside - risk of frost damage?

Sunbed · 30 Oct 2017 at 12:10

I'm trying to find some wall tiles to use externally in a porch for that old Victorian look. For example:

http://www.castelnautiles.co.uk/wp-content/uploads/2014/05/porch.jpg
https://www.originalstyle.com/media/106579/os-346-cyncoed-road-028.jpg

ToppsTiles have some nice Minton Hollins skirting, plain and dado tiles which would be perfect but they warned me that they shouldn't be used externally due to risk of frost damage. My problem is, the only tiles which supposedly can be used externally are about twice the price and don't come in the colour I'd want.

So, I'm considering taking a risk on the basis that the tiles will be under cover and generally won't be exposed to the elements much.

Does anyone have any experience with this sort of thing? Is there any solution I can put on tiles to repel condensation/dew etc? (I know nothing about tiling)

The porch roof actually extends beyond the lower step in this photo so even when it's windy it's still pretty dry in the porch:

Mercenary Keyboard Warrior · 30 Oct 2017 at 12:19

Sorry i cant help in regards why you wouldnt use internal tiles externally, I just wanted to add that you can get tile sealant
In fact some internal tiles require it, such as split slate

It would make sense that as internal tiles are not fully sealed on all edges that water could get into them and then if it froze it would probably crack the tile.
I suspect more than anything its easier for manufacturers to say not for outside use at that way you have no comeback if you do use them outside.
I doubt the victorians did anything differently to be honest so normal internal tiles would probably be fine, as you say they are not really outside as such in that environment

Sunbed · 30 Oct 2017 at 12:40

OK thanks. When you say sealant, does that mean your typical grouting or something else?

Mercenary Keyboard Warrior · 30 Oct 2017 at 13:31

Sunbed said:
OK thanks. When you say sealant, does that mean your typical grouting or something else?

Something like this, it soaks into unglazed areas and pretty much makes them waterproof
You shouldn't apply to glazed, I think it goes sort of hazy, but with a small brush you could go over the grout lines and then wipe the tiles clean, ie you grout as normal then apply this

http://www.sealantsandtoolsdirect.c...jggEr-lXhzTeiBbVmS0eaD35d9FikF2oaAgO0EALw_wcB

Sunbed · 30 Oct 2017 at 14:17

Mercenary Keyboard Warrior said:
Something like this, it soaks into unglazed areas and pretty much makes them waterproof
You shouldn't apply to glazed, I think it goes sort of hazy, but with a small brush you could go over the grout lines and then wipe the tiles clean, ie you grout as normal then apply this

http://www.sealantsandtoolsdirect.c...jggEr-lXhzTeiBbVmS0eaD35d9FikF2oaAgO0EALw_wcB

Ah OK. Spot on, thanks!

RoyMi6 · 30 Oct 2017 at 15:14

Frost damage is actually very likely to break something that's not rated for it.

Frost damage isn't just something getting cold, it's water getting inside it and expanding as it freezes.

"Depending on its state, freezing water (or ice as temperatures continue to drop) can expand by as much as nine percent at a maximum force between about 25,000 and 114,000 psi."

Tiles that are rated to be kept outside likely aren't much stronger than regular tiles, just they likely won't be very porous, so no water can get inside.

It seems you SHOULD be OK with any porcelain tile, but with ceramics tiles (that are normally used in hotter climates with less chance of freezing) you need to rely on them being made to a higher standard than they used to be made in the past.

One sure fire way to test it would be to buy a sample, submerge it in water for a day, then put it in the freezer - see what happens

As Warrior pointed out, you can get sealers for tiles which would technically stop any water ingress, but you do run the risk that over time water might still get in. Saying that, giving all the tiles a bath in the sealant would likely sort them for a good couple of years. Again, buy a sample and test - you may find it's not necessary.