Darker days may be driving us indoors, but it's just the right time to think of giving outdoor spaces a bit of TLC, and that means cleaning.
At London Stone we've carefully chosen the cleaning products we recommend and we know that some seem to overlap in purpose, so we thought we'd take you through how to choose the best one for the job.
Autumn: Anti-algae Treatment
Leaf fall is the main headache at this time of year and leaves carry a lot of tannins. One of the simplest things to combat problems is occasionally to use a stiff brush to keep paving clear and remove dirt and debris. “The main problem is when leaves mulch down,” says Antony Pasquini, our North-East London Showroom Manager who, like so many of our staff, has had long experience of working with stone. “Leave them for four or five months and you'll get stubborn vegetation stains.”
This is also the time of year when damp, dark days encourage algae to take hold. “Right now, it's worth using Algex. It's a maintenance cleaner that breaks down algae and lichens. Sweep, Jetwash and then follow-up with Algex.”
What we like about this product is that it stays on the stone, almost as a barrier, and every time it rains, it dilutes again and penetrates the stone a little more, which means it continues to work at reducing the algae's ability to get a foothold over the winter season.
An alternative to Algex is Brintons MMC-PRO Moss Killer, which goes a long way. You get a lot of product for your money, but it's better to use it quarterly. “If you had something like a large, north-facing patio that was going slightly green – that would be a good time to use it.”
You can use a watering-can to apply these products, but a low-pressure sprayer is preferable to allow for better coverage and penetration.
Spring: General Cleaning
Looking forward to spring, Lithofin Outdoor Cleaner is probably all you'll need to bring a patio up to summer party standard.
“It's an intensive cleaner for natural vegetation, leaf marks, mould, and where leaves have mulched,” explains Antony. “It is very intensive and the results are literally like magic. It is fantastic stuff.”
The ideal is to use Outdoor Cleaner once a year to get really thorough deep clean, so your clients can enjoy their outdoor space through to the autumn, when a re-application of Algex will protect it from the worst of the winter. The only caveat we need to offer is that Outdoor Cleaner shouldn't be used on stone which has been sealed with Dry Treat Intensifia, as it can sometimes lead to bleaching.
Of course, not all stains are vegetal, which is where Hanafinn Oxy-klenza comes into its own. Doing very much the same job as Outdoor Cleaner, it's the product of choice for stains resulting from food spills, drinks (the dreaded red wine spill!), oil, and anything that contains grease - even old, dried-in stains. A combination of oxygen, alkaline and detergent, it pulls different stains out of stone, depending on the concentration used.
With the increasing popularity of using Natural Stone and Porcelain to unite indoor and outdoor spaces, we've found Hanafinn Rejuvenator is the answer for indoor use, both for light, regular mop-downs and where oil and grease need removing. Its sister product, Hanafinn Rejuvenata Spray, is formulated for daily cleaning of Natural Stone and Porcelain worktops, and would also be our recommendation for outdoor kitchen surfaces.
Lithofin Bero isn't a cleaner you'll need unless you encounter rust, the orangey-brown marks that result from iron content oxidising near the surface in natural stone. This happens naturally as a result of rain or sometimes through cleaning. Bero chemically changes the rust particles in the stone, so removing the marks and keeping further occurrences under control.
Lithofin Builders Clean will also clean rust and can be used for light rust discolouration. However, it's more squarely aimed at cementitious residues where, for example, pointing has spilled over and been left too long to clean off completely.
It's important to follow instructions. “With Builders Clean, you must apply water before using it,” says Antony. “Get the stone saturated, then do it again twenty minutes later.” This gets as much water into the stone as possible, which is what you want to ensure that the cleaner stays on the surface. “When people only dilute the cleaner and put it on to dry stone it gets drawn into the stone where it can oxidise iron deposits causing rust marks to appear.”
Hanafinn Eff-Erayza is formulated to remove efflorescence, while also working on rust stains, timber tannings, grout haze and mortar stains. It's worth noting that Eff-Erayza has a gentler acid content than our other cleaners and brief contact does not burn the skin. It can be used indoors and out as it produces no toxic fumes.
Now that you've got a good understanding of the products, we should also mention sealing. While it doesn't prevent the need for cleaning, it does considerably reduce the attention that natural stone requires. Un-sealed stone absorbs dyes and stains more readily, whereas sealed stone prevents the transport of dyes and marks repels them so that they lie more on the surface, making them easier to remove. If you've got stone that hasn't been sealed, it's worth considering that as an alternative to a more rigorous cleaning regime.
A Word On Limestone
“It's a common problem,” says Antony. “Too common.” What is? The misuse of acid cleaners on limestone. The problem, of course, is that technically there aren't any products available to clean cementitious residues from limestone. The good news is that limestone, being generally dense, seldom needs cleaning, but what can you do if it does?
Well, you could call in the experts. Here at London Stone we offer advice on the best way to use the products on offer. We'll talk you through all the options available.
And that applies if you need advice on any of our products. And on any particular stains. Just pick up the phone, visit one of our showrooms (we'll give you a coffee, too!), or click on Live Chat at the top of the page.