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Design Dilemma
nickyt75

Slate patio - filthy and its new!

Nicky T
6 years ago
last modified: 6 years ago

After building up a nice big scrapbook on Houzz of beautiful slate patios with rendered white walls surrounding them, we have almost finished our version! The patio went down in November and we had to wait til May for weather warm enough to render the surrounding walls. I am, however, horrified at how filthy and pale the slate patio looks. Despite covering it where the render is going on, it shows every dusty footprint and however much I wash it, it dries dusty and dirty again. Wish I would have known how hard they are to care for before having it laid. Does anyone know how best to clean them/restore them/maintain them? Thank you


Featured Answer
  • PRO
    Floors of Stone
    6 years ago

    Hi Nicky, we would always recommend to seal natural stone - once before grouting and once after. This makes it much easier to clean any grout residue off so there isn't a haze left over the tiles.

    We would recommend a impregnating sealer (we sell a product call SEALAStone) this then protects the tiles and makes them much easier to clean. You can then use natural stone cleaners, eco cleaners or just soap and water to clean the tiles. Do not use anything with bleach or harsh chemical in, as this can strip the sealer and damage the stone.

    A lot of customers like to enhance their slate to make it appear darker and glossier. Fila satin wax is great for this (apply the first coat in one direction, then the second coat in a perpendicular direction) and can be used on top of the penetrating sealer.

    Finally, you can use a product called Lithofin Algex to keep the tiles clean from algea and moss, which can grow on tiles when they are outside. A pressure washer is a very effective and easy way to clean the tiles.

    Hope this helps and good luck!!

    Comments (54)

    • Nicky T
      Original Author
      6 years ago

      It has just rained and it looked lovely when they were wet but its drying and the dustiness is still there. My partner is rendering the walls & he puts plastic sheeting down where he's working but there's cement dust everywhere and he's walking onto the grass and back all the time. I brush it and he rinses it down, I've even tried my antibac floor wipes on it. I've done patches with soap and water and its better


      but it doesnt come up like new. Want to get it back to new looking and then seal it if necessary. It is Brazilian slate. The fitter, just a reg builder, never said to seal. I'll check the website we ordered them from.

    • Nicky T
      Original Author
      6 years ago

      Campo - they used some sort of compound for the joints which should never come out/shrink/move

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    • Ocean Clarke
      6 years ago

      Hi Nicky,

      I've added your photo to the discussion and featured it so hopefully, we'll find a solution!


      Nicky T thanked Ocean Clarke
    • Nicky T
      Original Author
      6 years ago
      ..and this bit where we're having a fridge - that hasn't been walked on! I scrubbed that the other evening & it's dried cloudy again #confused
    • Luciana
      6 years ago
      last modified: 6 years ago

      HI Nicky,

      I had the same problem in my garden. When I mentioned it to the staff of the place where we bought the slate from, they recommended this sealer/protector that gives it a shine too. They told me to use a pressure washer to clean the slate, then apply this Fila stuff when it doesn't look like it would be raining for at least a day...

      http://www.mandarinstone.com/sealant-selector/

      http://www.mandarinstone.com/product/_/517/fila-satin-finish-liquid-wax/#.V1qnoBWqOHs

      Aparently nobody should touch/ walk on it until is properly dry (ours took almost 3 days...) I did as they told me and the slate looked great for about 2 years, this year I have to do it again, as they lost the lustre (see pics below). I also found this on Amazon, but I'm not sure if it works outside. https://www.amazon.co.uk/Flawless-Diamond-Polish-Sealant-Solids/dp/B003ZVXSG4/ref=pd_vtph_201_bs_t_1?ie=UTF8&refRID=A6A0PFRSQZEEACYHHFRH

      I hope this helps - good luck!

      May '14 · More Info

      May 2016 · More Info

      Nicky T thanked Luciana
    • Nicky T
      Original Author
      6 years ago
      last modified: 6 years ago

      Hi, thank you so much. I have just called the supplier and they said it DOES have to be sealed (wish they would have mentioned it, and/or the builder known about it). He said its ok to clean it with a jetwasher. And said we need an impregnating sealer, not a lacquer that just sits on top. Yours look lovely 2 years later, much nicer than our 6 month old ones! We are thinking of planting red acers in our rendered boxes too, nice to see how they would look. Thanks everybody. It seems slate is very porous and prone to marking and that it should definitely be sealed straight after installation!

    • PRO
      Kitchen Republic
      6 years ago
      last modified: 6 years ago

      To be honest Nicky the installers should have know this. The standard procedure is to seal once before laying (this protects the stone from dust and dirt created while laying) and then again straight after. The supplier is correct in that you need an impregnator (one that soaks in) rather than a topical sealer (one that sits on top) as over a period of timer a topical sealer will wear off, even more so with an exterior project.

      I would suggest you take careful consideration in the type of sealer you use and how it is applied. Many sealers require the stone to be extremely dry before application, as if too much moisture is present it will turn the sealer cloudy and you are back to square one with the added hassle of having to try and strip the sealer to start again. In addition if it is applied to thickly it will also cloud. So best to get a good tiler in to do this unless you are confident of your own results and can practice. One of the more friendly impregnators that can be applied to stone whilst it still has some moisture content, namely a product called Rapid-all-in-1 by Universeal. Although give them a call as they may suggest their dedicated slate sealer seeing as it's an exterior.

      Universeal Website

      Oh one last thing! be sure to check the gloss value of any sealers, some will have a high gloss giving it that constant wet look or you many want a more subtle matt of satin finish. test on an off cut first to ensure it's the look you want.

      Good luck

    • PRO
      Rennew Traditional Building Materials
      6 years ago

      Hi Nicky,

      To reaffirm Floors of Stone and Kitchen Republic the stone should have been sealed once before laying and again once laid.

      As previous comments have suggested jet wash the stone (do not use any harsh chemicals or acid based cleaners as it can damage the stone), then proceed to use a reputable sealant brand to seal the stone. We recommend a brand called Resiblock who have a few options including a Colour Enhancer which may help to enhance your stone. Once sealed you will be able to use purpose made natural stone cleaners or mild soap and water to clean the stone. Generally the stone will need re-sealing every few years.

      If you do not feel confident to seal this yourself please use a professional.

      We do hope you get your stone looking as good as new soon!

    • pickbourne
      6 years ago

      Your not alone, We've got the same problem !


    • campo73
      6 years ago
      Nicky just out of interest where are your slabs from. Mine look the same and are marshalls casarta slate grey. In their installation instructions it only mentions sealing if used indoors. I'm just wondering if mine should be sealed too, I'd be concerned that the colour would darken though.
    • Nicky T
      Original Author
      6 years ago
      Hi, they're from BlueSky slate I think. BlueSky something. I'm just leaving them now til the works finished, then will jetwash them. I have absolutely no idea how we would seal them when there is only 1 way into the house (across them) & we have 2 cats and it might take 3 days to dry!!! So annoyed the fitter or supplier never said - we were on hol when they went down - the perfect opportunity
    • campo73
      6 years ago
      The poor cats, it'll be tricky keeping them off the patio! Have a read of this article before you seal them, just to arm yourself with all the information. http://www.pavingexpert.com/sealant_03.htm
      I don't think I'm going to seal mine at the minute although if I get a chance I will phone marshalls to double check their recommendation.
    • pickbourne
      6 years ago

      I am definatly not sealing , I think it's looking for trouble, just going to live with the patio, until I win the lottery, then redo the whole lot again!!!!!!

    • tabitha_smith40
      6 years ago

      Hi Nicky, please call Lithofin's Technical Line on 01962 732126 or email your picture to sales@lithofin.co.uk They will call you back and offer the correct product/technique and where to buy it from. Www.Lithofin.co.uk or see our products on Houzz, regards, Tabitha.

    • PRO
      Parmé Garden Design
      5 years ago

      I can recommend Lithofin. I have used it successfully on black slate outdoors with continual wear outside a front door.

    • PRO
      South Wales Garden Design
      5 years ago

      Are absolutely sure that it's slate. If it was a black slate it would never fade, limestone however is notorious for fading!

      Whether it's slate or limestone there are colour enhancers on the Lithofin site which will bring it back to life.

    • Resh
      5 years ago
      Guys - is it the same for limestone? Confusingly our supplier told us not to seal the patio, but to seal the indoor flagstones! Which seems like an odd approach...
    • PRO
      South Wales Garden Design
      5 years ago

      You can seal both but definitely indoors, particularly kitchen areas.

    • tamp75
      5 years ago
      Hi Nicky T, I've just looked on the Lithofin website as recommended on here & they do a product called Builders Clean for stone flooring / patios. Says it cleans cement film amongst other things. It's not a sealant but might help sort out your slate before you seal it.
    • tabitha_smith40
      5 years ago
      Hello Nikki,
      Test the Builders Clean in a small area first, then use on the whole area once you're happy it doesn't damage the surface. You cannot use this product on limestone as its acid based. If this gets rid of the "cloudiness" on the surface, you could use Lithofin Colour Intensifier or Lithofin Stainstop, these are designed to impregnate into the stone, not sit on the surface so you can walk in socked feet on the tiles after a couple of hours. Call Lithofin on 01962 732126 and they can talk you through the process.
    • PRO
      User
      5 years ago

      I would also recommend Lithofin for deep cleaning and sealing slate. When it comes to sealing, you can do half first and the other half later, so that you can continue to walk across whichever bit is dry. Just follow the lines of the grout rather than stopping half way across a tile. The cats would have to be kept in or temporarily relocated though!

    • lizziloumac
      2 years ago

      Hi Nicky - I was just wondering if you finally got your patio sorted as I have the same problem. Please can you tell me what you used in the end?

    • Alan Addis
      2 years ago

      hi

      did you find out as we have same problem too!

    • Alan Addis
      2 years ago

      Just checked mine is black limestone


    • lizziloumac
      2 years ago

      No we haven’t as yet - where did you get yours from?

    • Alan Addis
      2 years ago

      builders installed it as part of an extension so unsure

    • Tracy Cohen
      2 years ago

      I’d love to hear a reply as I have Casarta Slate Marshall’s , their site says no need to seal, but they scratch and hold dust and muck awful , I’ve only had them two weeks and already upset by the look

    • Sam Dix
      last year

      I would also love to know I feel like I’ve been ripped off a bit. I wanted a patio slab that looks nice but it seems like it’s just hassle

    • tamp75
      last year

      Our slate is also a mess. Gets dirty so quickly. Wouldn’t have it again.

    • campo73
      last year

      My patio was installed five years ago now and it looks great still, I really love it. It’s Marshall’s casarta slate which has only been power washed twice (including March this year) and cleaned once with lithofin. I never sealed it as I stated above Marshall’s did not recommend sealing outdoors.

    • simon andrews
      last year

      Hi - there is website with a page called the “curse of black limestone”. Have a search and they do all sorts of tests on many different products.

      The top solution worked for mine and we had terrible problems. Also beware power washing, it can leave strike marks.

      Good luck

    • campo73
      last year

      As I understand it Simon limestone is a lot softer and very hard to keep as it marks easily. The Brazilian slate is harder, it does score with things like studs on football boots but was fine power washing.

    • rhamm20
      last year
      last modified: last year

      Hi folks,

      I just had a Marshalls Casarta slate in black patio installed 2 weeks ago, I too have got white deposits/marks all over it. I’ve scrubbed 3 times with a deck brush with soapy water and it’s not budged. I then went at it with the power washer (which I’d never used before) and it’s left squiggly lines all over it. My OH is now certain I have damaged the stone (is this true - I used a fan stream; not narrowed further, I think it’s 110 bar?) Is there a way to get rid of these lines? I’ve emailed Marshalls to ask how to get rid of what I assume is the mineral deposits.

    • rhamm20
      last year

      Trying to upload a photo here...


    • campo73
      last year

      Have you tried going over one slab methodically to see if it blends. It looks like the squiggly lines are the cleaned parts with the residue left where you haven’t power washed? Try the Lithofin product as well-there may be one specifically for patios I’m not sure, I diluted it down a lot, threw buckets of it over the patio in sections so it didn’t dry out, gave a light to medium scrub with a yard brush and then hosed down.

    • rhamm20
      last year

      I’ve not had the washer out since - too worried I had damaged it but that’s going to be my next attempt. Marshalls said I should sweep it would be alright if I sweep diagonally at low pressure. They recommend Lithofin as well and I’m just waiting on them recommending the right product. I think it will either be the builders clean or the power clean which has been suggested here also.

    • campo73
      last year

      Rhamm20 that’s what I used on my Marshall’s casarta slate, lithofin power clean and it was absolutely fine. From memory it left a slight sheen on the slate but that wore off after a few days. Hope you get it sorted.

    • rhamm20
      last year
      last modified: last year

      Campo73 - do you know what dilution you used? I tried it this morning with a 1:10, did a small pitch test, left it on for 15 minutes and scrubbed with a deck brush and then hose it off. It didn’t make any difference, I repeated with a stronger dilution on to the worst areas and still no difference. The photo here is after 2 attempts


    • rhamm20
      last year



    • campo73
      last year

      I honestly couldn’t say what ratio I used but it was definitely very weak because I was cautious about using it. I actually bought it to clean some encaustic tiles indoors originally. Have just checked the bottle there and I’ve used approx 750ml in total. May be half of that was on the patio which is 100 sq metres. I seem to remember adding water to stop it drying out and scrubbing each tile very methodically. I did the patio in sections to stop it drying out. I would try leaving it for 15 mins then adding a little more water and then scrubbing. Try not to go over the grout lines just the surface of the slab.

    • Hasher Peekpower
      last year
      last modified: last year

      I have Brazilian slate. I had same issue when installed. So i used brick and slab cleaner from screw fix if i recall. Will add a photo of each i used in a bit. I then sealed them using a cheap slab sealer. Perfect, nothing wrong. cost about 20 quid for botha and 5 litre cans. They are now water proof, but slippery when wet especially with flip flops. opps.. Remember, if you need to allow soak away, you may not be able to use sealer as it creates a water barrier. but if its just in the garden on level ground sloping away form house you should be fine to go. As soon as dry, they are as good to go as before, but clean remember to let completely dry and needs 24 hours of good weather to dry. Use at least 2 coats. works a treat.!!!

    • rhamm20
      last year

      Thanks! I went to back to Lithofin and explained what I had done and that the power clean didn’t touch the marks. They suggested I use the Builders Clean so I’m waiting on that getting delivered. Fingers crossed this works as I’m at my wits end up with now. Very disappointed.

    • Hasher Peekpower
      last year

      I know what you mean and if its a brick cleaner they are sending you. then yes it will work like a dream. But will still get dirty if walking over them with dusty shoes. This is why i used a sealer. amazing, holds colour 99% of the time. can still get dirty, but doesn't fade when cleaned.

    • Andrew Backhouse
      last year

      As a fellow Casarta grey owner I'm very impressed with campo73 pictures and thanks for the cleaning tips. Mine shows dust and dirt but after a shower or two it's mostly clean. Who do you keep it from showing scratches from patio furniture/everything else.

    • campo73
      last year

      Hi Andrew I haven’t noticed any scratches from patio furniture but I’ll be going out now and inspecting tomorrow in the daylight! The only scratches I’ve had are from football boot studs and dragging the basketball hoop across the ground. To be honest I don’t do anything, they just wear away on their own. I even had a piece of heavy machinery trample over it a couple of weeks ago and it didn’t leave any marks!

    • catherine Phillips
      last year

      rhamm30 did you manage to sort the issue with the lines on the patio? We have just power washed a new Brazilian slate patio and have the same issue! so disappointed!



    • catherine Phillips
      last year

      Sorry rhamm20 !

    • rhamm20
      last year

      Catherine Phillips - yeah. I went back over it taking more care, going slow and overlapping slightly to avoid the lines. I also spoke to Marshalls about power washer if slate and they recommended to go in a diagonal motion. Hope this helps!

    • Craig Rae
      7 months ago

      The circles/marks you are seeing in the photos is just poor installation, not laid on a full bed of cement and a primer slurry applied to the paving before being laid. Brazilian slate is a high end quality stone and is not very porous so I doubt any of the marks are caused anything you guys have done. You don't need to seal slate either, or any other quality stone

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