Entertaining season is here and that means your outdoor spaces are under the spotlight. Your guests see the grease-stained concrete by the grill, the slippery dark patches on the patio and the chalky white residue leaching across pavers. Doing it right before the first party means hustling through the steps in order, not running outside and blasting everything with the hose.
First, get everything out of the way. Then dry-sweep the whole area. This important step gets overlooked more often than not. If you don’t dry sweep, wet debris turns into abrasive mud that will scratch surfaces and block drain points. A good dry sweep takes ten minutes and saves you time later on.
Next, you can properly assess the situation if you’ve removed everything and given the space a good sweep.
Pre-Treat Stains Before You Wash Anything
This is the step that many DIY cleans skip. They fire up the pressure washer and can’t understand why the grease marks are still there.
The fact is, oil and barbecue grease do not react to pressure. They react to chemistry. Spray a degreaser directly onto any staining under or around the barbeque, brush it in with a stiff brush, then let it dwell for the prescribed amount of time. Rust spots from metal furniture feet require a different treatment: Oxalic acid-based rust treatments, available at most hardware stores, work best here. They are safe to use on concrete and most pavers when you follow instructions and dilute properly.
Efflorescence – that white, powdery salt residue that sometimes leeches out of concrete and pavers needs to be treated directly before washing, as it doesn’t come clean with pressure and just spreads out wet. Scrub it dry first, then lance it wet.
Pressure Washing Without Damaging The Surface
There’s more skill involved here than you might think. Concrete seems solid, but the cream coat – that thin, smooth, harder layer at the top – can be inadvertently washed away with too much pressure, exposing a rougher, more porous layer that takes up stain like nobody’s business.
Keep PSI under 3,000 for residential concrete. The easiest way to do this is keep a 25 or 40-degree nozzle tip on the end of your wand, don’t swap it out for a zero-degree ‘blast’ tip. Keep at least 12 inches between the nozzle and concrete, and, if you’ve rented or bought one, fire up your surface cleaner attachment. This rotating dual-nozzle disc spreads the water and pressure in a consistent, zebra-stripe free swath.
For paved areas, be especially wary around the joints. With pavers, polymeric sand often does double duty as a jointing compound, and it won’t take much fast jetting of high-pressure water to blow it right out of there. Work across the joints, don’t lance them, and check how many eroded out and needs topping up before applying a fresh coat of sealer.
If all that looks and reads a bit like much, maybe just let the pros take care of it. Homeowners who want to skip the equipment hire and avoid the risk of surface damage should look into professional Paving and Concrete Cleaning services – they will bring commercial gear that’s right up to the task and they can often save you a careless weekend of teaching yourself how easy it is to etch the side of the barbecue into a faded tombstone.
Dealing With Algae And Mold Properly
Dark, shaded areas of patios and paths can be a breeding ground for algae, mold, and lichen. While it may not look overly dramatic until it’s too late and someone slips during wet weather, it can be a serious safety hazard at a hosted event when guests are walking with drinks and plates.
Pressure washing will shift the surface growth but often it will return. You simply can’t eradicate it until you kill the spores. Apply a purpose-made outdoor fungicidal cleaner or a diluted bleach solution before or after washing. Leave it to act for 20 minutes before rinsing with clean water. This will knock the growth on the head rather than just removing it from the surface.
Once the area has dried properly, check dark shaded patches – if the growth was heavy, apply another dose and repeat the process the next day.
Seal The Surface After Cleaning
Unsealed outdoor concrete is a bit like a sponge as it gets cleaner, as well as after a good deep cleaning. Spills are absorbed right away and repeat spills very soon after. Red wine, cooking oil, a dropped spoonful of sauce, they’re all soaking into your beautiful concrete and paver surfaces within minutes.
That’s certainly not the best start to an outdoor meal. Plus, deep cleaning these outdoor surfaces makes the problem worse as cleaner, brighter concrete/pavers also means more open surface pores to absorb stray food and drink.
The answer is to apply an appropriate sealing product after the surface has fully dried out (which can be a day or two after you wash outdoor areas – in good weather). A good sealant will fill the microscopic pores and help prevent future ingress of water and staining materials. It will also make cleaning between parties much quicker and easier.
For pavers, in particular, choose the right type of sealer for the type of pavers and follow the manufacturer’s guidance to the letter. A good-quality preapplication sealer will extend the paver’s life as well as prevent staining.