Possible acid damage to real slate flagstones - Spoilt patio/pathway slate

[GB_Groundworks]

wide joints and 4 corners touching in a few places, yeah they are level but thats about it,

[gardener123]

Thanks to London Stone Paving for posting my photos.
Rightly or wrongly, we managed to clean the slate up with stainless steel wool (advised by a local builder who has done a lot of work with slate). They've come up really good, (no efflorescence) only problem they are very pale in colour. Just as they were when the builders used the acid. Remnants of that possibly (does acid lighten slate ?) Builders want to use ltp colour intensifier and stain block but we are so scared it'll cause the whiteness/efflorescent to re-appear. In anycase, we don't know how long the product will last. Don't want to have to re-apply every year or so, and also would the rain droplets stain it. (done a test with a similar paving sealer and the rain drops stained it all). Any ideas whether we should do this or not ? Thanks in advance for any replies. So good to have this forum. Lot of helpful information here.

[cookiewales]

try a test of linseed oil or 3in 1 oil or wd 40 this normaly brings them back to original but remember all slate fades when dry comes back when wet even welsh slate :;):

[London Stone Paving]

Looks better now. I like the pattern, not seen that one before.
You say the builders want to use LTP on it. I wouldn't let them anywhere near it. Dont rush in to seal it. Speak to extensive and take some sound professional advice.

http://i814.photobucket.com/albums/zz65/StevenWalley/IMG_1111.jpg

http://i814.photobucket.com/albums/zz65/StevenWalley/IMG_1109.jpg

http://i814.photobucket.com/albums/zz65/StevenWalley/IMG_1107.jpg

[gardener123]

Hi everyone

Thanks London Stone Paving for uploading my photos. Much appreciated.

We've phoned LTP and they say the slates have turned pale because of all the chemical treatment. They say colour intensifier would help. To cut a long story short. As we've now got them back into a reasonable condition (something we can now live with) we've decided not to put any further chemicals on them, or indeed to do anything else other than the occasional wash. LTP told us if we applied their colour intensifier it would have to be redone every 3yrs or so plus continual maintenance of a wash/wash. I suppose it's all a learning curve for all of us. Just hope all this intensive chemical treatment hasn't caused any detrimental damage to the slates. Does anyone know whether it has ?

Thanks everyone for your help. Hope our unfortunate incident will help others wanting to instal a slate patio/pathway.

[gardener123]

Thanks London Stone Paving for your kind comments re the pattern. We worked that one out for ourselves on graph paper

[lutonlagerlout]

its a natural stone ,give it a few years and you will never notice
after all there are slates on roofs 200 years old and they still look good
LLL

[GB_Groundworks]

Wonder why they didn't lay them more random than then regular straight joint every 600mm they've got? Like brick bond etc?

[lutonlagerlout]

gardener123 did the design himself giles
if they followed the design everyones a winner
its not my cuppa tea,but i didnt design build or live on it
LLL

[gardener123]

Had to do the design ourselves as the builder didn't have a clue. Whilst he laid the slate fairly well, he knew very little about anything else. He even got the pattern wrong on one section! We were told not to buy slate too heavy i.e. too big slabs, hence only two sizes.

The Company in question deal mainly with tarmacadam/council paths/road works and have branched out into patio laying. Unfortunately we were'nt aware of this and I suppose were used as guinea pigs. We're rather disappointed that our slates had such bad treatment with all the chemicals leaving them a light lighter but with hindsight if they hadn't grounted in the rain this would never have happened. It's all too late now to do anything about it.

We thought we had employed a Company with expertise/patio laying skills. Obviously not. The tarmacadam was perfect.