Best product or way to clean outdoor slate tiles?

Turnipfarmer

I've just had some work done in garden and had slate slabs put down however are proving difficult to clean up.

Is there a proven way or product to clean them with?

Been looking at the lithofin stuff but not sure which to go for.

keystone

Depends on what they are stained with. What is it?

Cheers

Canucklehead

Turnipfarmer wrote: »

I've just had some work done in garden and had slate slabs put down however are proving difficult to clean up.

Is there a proven way or product to clean them with?

Been looking at the lithofin stuff but not sure which to go for.

See the Paving Expert...brilliant site.

cyclonebri1

As they are outside it's unlikely that they have been sealed.
Internally it is standard practice to seal as slate accepts stains very readily and it gets in deep.

I had some waiting for a job recently and had left them under a hanging basket. The peat stains from watering made a real mess of the top 2.
Chlorine bleach cured it.

Turnipfarmer

cyclonebri1 do you recommend I should seal them then? Surely they have to be clean before sealing or not?

Also would just a bit of bleach and some water clean them like you suggested? Been looking at the lithofin stuff.

My only problem is that I haven't used traditional mortar for the pointing, used some silvery black stuff like sand and then mix it with water and put it in the pointing, can;t remember the name though. Would that be ok to use with bleach etc?

Turnipfarmer

Its this stuff

www .pavingsuperstore.co .uk/gftk--basalt--easy-joint-mortar-4720-p.asp

cyclonebri1

Turnipfarmer wrote: »

cyclonebri1 do you recommend I should seal them then? Surely they have to be clean before sealing or not?

Also would just a bit of bleach and some water clean them like you suggested? Been looking at the lithofin stuff.

My only problem is that I haven't used traditional mortar for the pointing, used some silvery black stuff like sand and then mix it with water and put it in the pointing, can;t remember the name though. Would that be ok to use with bleach etc?

No, not really, I'd say if you use slate outside then you need to live with the issues of staining.

Plus I'm a traditionalist, or old fashioned if you like. I like anything outside to look weathered, as if it's been there many years.

Can't comment on the pointing compatibility, but I'd give it a try, God they put Chlorine in swiming pools and we survive, :D:D

keystone

To remove mortar staining (which is what I think you mean rather than natural staining with age) you need an specialist acid cleaner - bleech won't do. Unfortunately the longer you've left it before you start the more difficult it is going to be as slate is porous and it will be in tiny little holes in the surface.

Both HG and Lithofin make one and they are quite good but I'm afraid if the mortar has really gone off you ain't going to shift it all. Some fine wire wool will help. Wear some marigolds or similar too or you'll burn your hands.

Best of luck with it.

Cheers

cyclonebri1

keystone wrote: »

To remove mortar staining (which is what I think you mean rather than natural staining with age) you need an specialist acid cleaner - bleech won't do.
Cheers

I must admit I was looking at it from the point of view of more natural staining, ie peat and general muck rather than mortar stains, but the op has answers to both now

keystone

Yes I thought so - hence my wording in round brackets. Thanks for confirming.

Cheers