Terracotta tiles

[Vanman]

I'm hoping to be able to tile an outside terrace with terracotta tiles. We've already used similar tiles inside and found that the tiles were extremely porous: we used a large quantity of an oil sealant (sold to us with the tiles) but even then we weren't really happy with the result. I hadn't ever used unglazed terracotta tiles before so maybe they are always like this - please make plenty of allowance for my ignorance.

First - are terracotta tiles suitable for use outside?

Second - do they need to be sealed?

Third - if they do need to be sealed, should that be done before, or after, grouting them?

Finally - can anyone recommend a good sealant from personal experience?

Thanks in advance!

[Richard & Tracy]

Yes most are suitable for use outside but worth checking with the supplier just in case.

Yes they need to be sealed. The traditional method is to use boiled linseed oil and then a polish afterwards. Some are more porous than others so just keep applying it until the tile wont absorb any more. If the tile is not very porous you can thin it with white spirit. Generally, leave 8 hours between coats. Dont let it dry on the surface.

Its better to seal before grouting because as its so porous, the grout is liable to stain the tiles.

LTP is a good product but there are a few others incl Lithofin and Aquamix.