Slate - White marks on slate

pianello · Post: # 66509Post **pianello** Tue Jul 26, 2011 4:01 pm

Hello
I wonder if anyone can advise on the appearance of my slate patio. We had the patio laid 2 years ago and did our research through this site which was very useful at the time. We followed all the guidelines that you all recommended and we used an installer that had the approval of one of the leading suppliers of stone. The slate was purchased through a large long established local supplier.
About 12 months ago we noticed white marks on the surface of the slate some appear circular and some are irregular. We thought these marks would go away but after 2 years they are still there. The slabs are all 2 feet by 2 feet.
Can anyone advise what this could be. We haven't sealed the slate and no other chemicals have been used.
I can't work out how to add the photos.
Michael

London Stone Paving · Tue Jul 26, 2011 4:22 pm

Hi Michael

email the photos to me and I will post them

steven@londonstone.com

London Stone Paving · Tue Jul 26, 2011 6:01 pm

Posted on behalf of Michael

London Stone Paving · Tue Jul 26, 2011 6:10 pm

Michael

This marks visible are a natural occurence within the stone. We source this exact material. It comes from Jiujiang province in China. We get a few of these markings on the stone we import, I would say 1 in 25 are affected by the marks. These marks run through alll the way through the stone and cannot be removed.

Its something you will have to live with unfortunately. If Chinese manafacturers removed all stone with these marks on at QC then the price of the slate would be much more expensive to the end user.

You dont get these marks on Brazilian slate but the price is at least 50% more expensive.

You cant win them all I'm afraid

pianello · Post: # 66521Post **pianello** Tue Jul 26, 2011 8:21 pm

Hi
Is this the only possibility as these marks weren't apparent when they were laid and we think the marks are only on the surface as one or two flakes have come off and underneath is the grey slate. We have tried chipping some more away but it wouldn't move. The display of slate at our suppliers doesn't show any of these imperfections when we looked recently. If we had known about the imperfections in the Chinese slate we would have insisted on Brazilian slate. Thanks again for uploading the photos and for your reply.

London Stone Paving · Tue Jul 26, 2011 10:00 pm

How much stone did you buy in the first place and how many slabs are affected by the problem Michael?

pianello · Post: # 66542Post **pianello** Wed Jul 27, 2011 9:17 am

101 slabs in total, 2feet by 2 feet, and 15 are affected.

Regards
Michael

London Stone Paving · Wed Jul 27, 2011 10:51 am

Hi Michael

Thats quite a high percentage compared to what you ordered. If it is really bothering you then why not replace the effected slabs with some new ones. Its not going to be a big job. A competent landscaper could knock it off in a day.

Steve

pianello · Post: # 66551Post **pianello** Wed Jul 27, 2011 12:29 pm

Hi Steve

Thanks for taking the time and giving us your thoughts. Much appreciated. We will have a look at that option.
It's a pity that they didn't tell us at
the time so we might go back to the supplier
and see what they say.
If we get anything positive from the supplier I'll post the results.

Regards

Michael

London Stone Paving · Thu Jul 28, 2011 7:36 am

Out of interest Michael, how much did the stone cost?

Thu Jul 28, 2011 8:13 am

London Stone Paving wrote:Hi Michael

Thats quite a high percentage compared to what you ordered. If it is really bothering you then why not replace the effected slabs with some new ones. Its not going to be a big job. A competent landscaper could knock it off in a day.

Steve

landscaper?
a day?
really steve,you should know better
what about removing the bedding and repointing?
its a can of worms removing individual flags,we all know that
LLL :;):

London Stone Paving · Thu Jul 28, 2011 8:51 am

Its only 15 slabs Tony. Surely they could be carefully removed and prepped in the morning. Then in the afternoon a couple of hours to lay them back in. Couple of hours to rompox and tidy up.

Thu Jul 28, 2011 12:43 pm

hehe let us know how you get on
I have come a cropper before with the "its only a day's work " routine" mainly spouted by clients
:;):
LLL

DNgroundworks · Thu Jul 28, 2011 4:41 pm

Me to LLL, ends up being a waste of time, I tell them the hourly rate on stuff like that.

pianello · Post: # 66631Post **pianello** Fri Jul 29, 2011 5:33 pm

Thanks for the replies. I did think that if we did have them taken up the same problem could happen again. The display at the suppliers doesn't show any of this so you can imagine our disappointment.
We know it is a natural material and accept that each slab will be different but this isn't what we had in mind. Some of these marks are quite big. We purchased the slate through our installer but the current price for the 2 x 2 slab is Â£13.25 per slab including VAT with some discounts available.
We are going to have our drive done next so I think we will stick to asphalt.
Michael