Sealing & pointing black limestone patio - Romex colour seal vs drytreat intensifia

[Xcalibur]

Hi

We had a Black Limestone patio laid in the Spring of 2015, which was pointed using Wickes brush in patio grout, but was never sealed.

Eighteen months later, the brush in grout - which we now know to be a very poor product - has discoloured badly and is already failing, so we have raked this out across the whole area in preparation for cleaning, sealing and re-pointing the patio.

As a complete novice I am a little unsure of how best to proceed and would really appreciate any advice about the following:

Sealant:

The Black Limestone has faded, so we plan to use a colour enhancing sealant and have narrowed the choice to either Dry Treat Intensifia or Romex Colour Seal, but are unsure about which to choose. Does anyone have any experience of which is the superior product?

I understand that Dry Treat Intensifia is both a colour enhancer and sealant combined, so we would not need to add an additional sealant product, but is this also the case with Romex?

Dry Treat seems much more expensive, but if the finish is as good as Romex, but lasts twice as long I would be willing to pay the extra.

Also I understand that with Dry Treat when the sealer needs to be re-applied (in 5 years?) this can be applied directly after cleaning the patio, is this also the case with Romex?

Is it best to apply either of these products with a brush, spray or roller?

Pointing:

I am unsure of which type of grout to use, but was considering Marshalls Weatherpoint 365 (or similar?) as this would be easier to apply, and if I understand correctly Black Limestone is unsuitable for a wet slurry due to the risk of staining the slabs. Additionally we also have patio steps with Black Limestone slabs which “overhang� the step risers, which would appear to be impossible to point with a wet slurry, if I am right about these points?

Does anyone have any experience about whether Marshalls Weatherpoint 365 is a quality product or are there better similar alternatives?

When to Point/Seal?:

Is it best to apply the two coats of the sealant first, and then point (and then apply some additional sealant to the pointing to protect this as well), or point first, then seal?

Sorry this is such a long list of questions!, but as this is completely new to me any advice would be very welcome!

[Tony McC]

Dry Treat was not a participant in the trials I ran for sealants and colour enhancers with black limestone, so we can't really compare and contrast. The Romex product fared really well (surprisingly well, if I'm being totally honest) and I still have the sample pieces which look almost as good now, 5 years later, as they did after 12 months.

Romex is also a colour enhancer but they don't really rate this feature in Germany (where it's manufactured) so it's barely mentioned in their literature.

Romex can also be 'topped-up' following a basic cleaning of the original sealed surface, apparently.

I reckon a fine pile roller is the best tool for applying sealants. I know some manufacturers extol the virtues of sprayers but they drift in the breeze and I'm not always convinced they give a truly even coverage. A roller lets you judge-as-you-roll just how much of the product is being applied.

I'm not sure where you got this notion about a slurry being unsuitable for black limestine: it would be my preference! And anyway, 365 is a slurry!

If you tape-up the nosings, it's not too difficult to point them using a slurry which has started to stiffen up. There's a picture of something similar being done here and LLL recently posted a pic of the same process.

365 is a 1-part polymeric. It's a very good 1-part polymeric but it's not in the same league as a 2-part resin product. My current top two are VDW800/850 or Romex D1. I've looked and looked and looked but still not found anything better.


Seal than joint or joint then seal? It's an ongoing debate but I still prefer to get the jointing done, allow the pavement to weather and lose any dust or efflorescence, allow time for any problems to appear, and then seal after, say, 3 months.

The only exception would be with the more delicate/sensitive/finicky stones that are best pre-sealed, that is, sealed before being laid.

I think that's all your questions addressed.

[Xcalibur]

Hi Tony

Thank you so much for your reply and help. As you can probably tell! I've never done this before so your advice really is appreciated.

With this in mind I plan to clean the patio with the Chlorine/Water/Baby Shampoo mixture Roger posted on here, allow to dry for 3 days then seal with 2 coats of Romex first as I'm really worried about pouring a liquid jointing product over un sealed Black Limestone and then not being able to clean all of the excess off of the slabs.

I will then use one of the jointing products you mention as I definitely don't want to end up with pointing which turns green again!, and as 365 is a 1 part it seems we would end up with the same problem again. We want a nice contrast between dark slabs and light pointing, which lasts.

If I do the job in this order would I be right in assuming I could then apply Romex with a small brush just to the jointing afterwards to seal it as well and stop it from discolouring?

Thanks again for your advice so far

Gary

[sy76uk]

Weatherpoint is a very good product for domestic use.
I can't compare it to wicks as i've never used it.
Another product that i've recently started using is called joint it.
It has a much finer grain than weatherpoint and comes in 20kg tubs.
It's a lot like symphony jointing compound.

[Tony McC]

No matter what jointing product you use, polymeric or 2-part, resin or cement mortar, it *will* discolour. It's just a matter of how soon it will discolour and what can be done when it does.

Generally speaking, the polymerics discolour quickest, attracting all sorts of algae (the red, green and black forms) and then mosses, lichens and other vegetation. The 2-parts resins and cement mortars take considerably longer (say 12-18 months rather than 12-18 days!) to be affected.

Of course, whatever you've used for the jointing can be cleaned, but the polymerics, in general, are not particularly good with power washers. The good ones can withstand a few cycles of cleaning, but the poor products often come out of the joint as soon as a jet of water gets anywhere near them. Cement mortars, assuming they are mixed well and properly done, will normally withstand a power washer for years, and the 2-parts resins mortars just laugh at your feeble attempts to dislodge them.

So, 2-parts are very easy to clean and are very rarely damaged by the process; cement mortars clean fairly easily and usually survive; polymerics need handling with care.

Finally, applying a sealant to a resin mortar is pointless. By definition, the resin mortar is already fully coated with a resin, so why apply another resin over the top of it?

[Xcalibur]

Hi Tony,

Thanks again for your advice.

I appreciate anything left open to the elements will discolour eventually, but we found that with the cheap Wickes brush in grout, when we tried to clean the pointing it had discoloured from the initial light grey to a dirty brown/green - which had penetrated through the entire depth of the jointing so there was no way we could clean it and had to rake it all out.

So if we use one of the resin products you recommended, would I be right in thinking that the inevitable accumulated dirt/discolouration would primarily remain on the surface (i.e. it wouldn’t penetrate right through the jointing as it did with the 1 part brush in stuff) and we could then clean this off with a pressure washer, say a couple of times a year, to maintain the contrast between the dark slabs and lighter jointing?

Or are we better off just accepting that discolouration is inevitable anyway, and use a dark jointing colour in the first place?

Regards

Gary

[Tony McC]

With 2-part resin mortars and cement mortar, any discolouration due to algae and its chums is typically restricted to the surface.

[Xcalibur]

Thanks Tony

Really appreciate all of your advice.

Gary