How do I seal my slate sign?

So  I was asked by a customer today how to seal their slate house sign.

They had experience of natural materials and currently had Indian sandstone paving which they sealed regularly.  However, they wanted to know how to seal their slate house sign. Sealing Indian paving stone is a very good idea to reduce its porosity and slow the ageing process down as the Indian sandstone might have up to 15% porosity – this is the amount of water the stone can absorb . Welsh slate has a porosity of 0.2 %, so as you can see, water absorption is virtually zero and so using a water based sealant like the ones we recommend for Indian sandstone and Limestone would be a waste of time on Welsh slate.  It would sit on the surface and create a smeary mess.

Should your sign be dirty, a quick once over with a damp cloth, including the letters , to remove a build up of dust/cobwebs is all that is required.  If the sign’s face is a little smeary or you want to enhance the natural beauty of the slate, apply a small amount of WD40 all over the face of the sign and wipe the excess off with a dry cloth.  Any residual oil will soon evaporate giving a beautiful matt appearance.

We took the picture below this week of a customer’s slate house sign that has been in situ for over 10 years now!  As you can see, the letters are still extremely easy to read, with the paint still in perfect condition, and the slate itself shows no signs of ageing.


To explore more about our signs, including sizes and prices, please visit our Slate House Signs page.