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Posted: Sun May 04, 2014 4:14 pm
by r4vvm
Just laid a pathway of natural limestone paving.
I did lightly clean the surface of the slabs after laying but they look like they need a thorough clean.
Could anyone help me with what i should use to clean the slabs assuming i should use a jet wash to clean it.
Also should i do this before i do the pointing?
I was going to use a dry mix of sharp sand and cement mixed with black powder dye for the pointing, is this ok or is there something specific i need to use?
Posted: Sun May 04, 2014 7:25 pm
by London Stone Paving
If it was me I would clean them first before pointing.
This type of limestone is VERY sensitive to any chemicals that have an acid content. So be really careful about using any patio cleaners. The best thing to do is to use a jet wash and plain water. This will remove most things.
Are you experienced in pointing?
The method you have suggested is not ideal. Firstly dry mix is no good. It will not be strong enough. It needs to be semi dry at minimum and well compacted to have any chance of lasting. Yuo simply will not get the required compaction with a dry mix.
Secondly pigments are crap (although there was one guy on here once who thought they were amazing. Does anyone remember that post???). They are very unreliable and rarely achieve the colour you want.
If you are experienced at pointing I would use something like easipoint which is a cement based product that's installed using a mortar gun.
This bit is VERY VERY important. Mortar stains from pointing are virtually impossible to remove from this type of limestone. This is because acid is usually whats used to remove mortar stains from paving and as I said at the beginning of the post you cant acid on this product. So if you do use a cement based product, make sure you have a bucket of water and sponge close to hand and immediately remove any mortar stains.
If you dont feel confident in your ability to do this I would use polymeric sweep in pointing product like Romex, Weather point or easijoint
steve
Posted: Sun May 04, 2014 9:26 pm
by RAPressureWashing
You most probably don't need to pressure wash this, just a decent alkaline cleaner and hose pipe will do prior to pointing.
The reason I say this is, if you are not carful with a pressure washer you will mark/etch the stone, and from the photos they are not that dirty/bad so don't need pressure to clean.
You could do no worse then use the mix I have on the stain's removal page on the main site for this, but please pre-wet first, and by pre-wet I mean soak the stone esp. Limestone, then follow the instructions to the letter.
Posted: Mon May 05, 2014 12:56 pm
by r4vvm
Thanks, i will just use a hose and stiff broom to clean these.
Is it the Sodium Hypochlorite Berry mix?
Where is the cheapest place to get Sodium Hypochlorite?
Posted: Mon May 05, 2014 1:37 pm
by r4vvm
London Stone Paving wrote:If it was me I would clean them first before pointing.
This type of limestone is VERY sensitive to any chemicals that have an acid content. So be really careful about using any patio cleaners. The best thing to do is to use a jet wash and plain water. This will remove most things.
Are you experienced in pointing?
The method you have suggested is not ideal. Firstly dry mix is no good. It will not be strong enough. It needs to be semi dry at minimum and well compacted to have any chance of lasting. Yuo simply will not get the required compaction with a dry mix.
Secondly pigments are crap (although there was one guy on here once who thought they were amazing. Does anyone remember that post???). They are very unreliable and rarely achieve the colour you want.
If you are experienced at pointing I would use something like easipoint which is a cement based product that's installed using a mortar gun.
This bit is VERY VERY important. Mortar stains from pointing are virtually impossible to remove from this type of limestone. This is because acid is usually whats used to remove mortar stains from paving and as I said at the beginning of the post you cant acid on this product. So if you do use a cement based product, make sure you have a bucket of water and sponge close to hand and immediately remove any mortar stains.
If you dont feel confident in your ability to do this I would use polymeric sweep in pointing product like Romex, Weather point or easijoint
steve
Thanks, I like the polymeric sweep in products but i am on a bit of a budget and they seem quite expensive.
Posted: Mon May 05, 2014 2:59 pm
by RAPressureWashing
r4vvm wrote:Thanks, i will just use a hose and stiff broom to clean these.
Is it the Sodium Hypochlorite Berry mix?
Where is the cheapest place to get Sodium Hypochlorite?
Yes it is the berry mix.
Can't really tell you the cheapest place as price does seem to differ around the country, just be careful buying on-line as it isn't always fresh, swimming pool out-lets will stock this though, you are wanting 13-14% which is the strongest you can buy.
Posted: Mon May 05, 2014 4:18 pm
by sy76uk
Judging by the photo's you've let the bedding push up into the joints whilst you've been laying. You need at least a 20mm depth to point properly. 25+ is better.
Posted: Wed May 07, 2014 12:56 pm
by Tony McC
I'd use Grundreiniger - always does a lovely job with dark limestone and is the ideal prep if you are planning to seal or colour enhance them.
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