Cleaning screens? Choose the right scaffold.

For cleaning screens one or two storeys up, the RS51 is the sensible answer: the Altrex RS TOWER 51 on a 75 cm chassis, a type that reaches 14.2 metres but which you put together far lower for this. Narrow pays you back here, because you shift the tower along one window at a time and a footway often leaves nothing more than a strip between the wall and the parked cars. The rest of the fleet appears on the page about mobile scaffolds available to hire.

Let down, the fabric hangs a little proud of the wall, held in the channels beside the reveal. Your set-up therefore belongs just in front of that, never up against it. On a narrow deck you watch that gap almost automatically, whereas a wide platform quietly invites you to step backwards without looking first. Put your bucket down on the wall side of the deck so that you do not knock it over while edging sideways along a wet panel. A bucket going over at four metres costs more than the suds.

Taking a whole elevation of four or five panels with two people is the case for the broad RS52 at 135 cm. Two buckets, two brushes and two people fit onto that deck without any negotiation over elbow room. Against that it swallows more footway and it shifts less willingly from window to window, and shifting is exactly what this job asks for again and again. For a single opening, it can still pay to hire a mobile scaffold with the slim chassis and simply move it more often.

When cleaning screens, measure to the top of the headbox, because the box itself is part of the wash. Dust settles on it, cobwebs gather inside it, and the top edge of the fabric vanishes underneath, so you want a brush in there and a clear line of sight along the whole run. Take the reading from the paving your castors will actually sit on, and not from a raised terrace that happens to lie alongside the wall. In practice that difference alone is worth half a metre of build.

From there the deck height follows, and the working height you book is that deck with something like two metres of reach standing above it. For panels on a two storey elevation that comes out at six to eight metres, with the platform itself stopping somewhere between four and six metres. You state the reach at the booking stage, along with how many openings you intend to get through in the period. What a build of that order delivers is shown at seven metres of reach, deck height included.

Take the higher stage rather than the lower one whenever you hire. With your head stuck under the box you end up washing by touch, and you miss precisely the sort of dirt that hides up there. You also want to wet the fabric from the top and work down; start halfway and streaks run through the part you had already finished. For a panel at second floor level that means the roomier build, never the tight one.

For cleaning screens the set-up goes in front of the hanging fabric, centred on the opening, with roughly a hand's width between guardrail and panel. Catch it with a castor or a brace and you push the fabric out of its channels, which will cost you far longer than the wash itself. So look beforehand at where the channels run and how far the panel stands off the brickwork, and keep that clearance over the entire height of the opening rather than only at deck level.

Water ends up underneath you, and that changes the ground. Suds run down the wall, across the paving and into the border, so any surface that was already slippery becomes considerably more so. Set the legs down on dry slabs or lay boards beneath them, and empty your bucket somewhere other than the route you will walk along carrying a full one. On grass or on bare soil a set-up can lean noticeably within an hour of wetting the wall down, long before you have finished.

Look too at whatever is standing beneath the opening before the tower goes there. With this sort of fabric it is usually a terrace set, a barbecue, an awning at ground level, or a ventilation grille low in the wall. Cover those over or move them well away first, because suds and loosened grime will otherwise land on every one of them. Keeping a tower steady on a slope or on loose ground is covered in the notes on ground that will not lie level.

Cleaning screens runs at roughly an hour a panel: wetting down, soaping, letting it work, brushing, rinsing off, and then the box and the channels. Drying takes a great deal longer. Fabric rolled up too soon goes damp into the box and comes out marked, or spotted with mould, so you wait until it feels dry everywhere you touch. On a sunny day with a breeze that is two to three hours; under cloud or in damp air it stretches out considerably.

Your hire period therefore follows the drying rather than your working hours. In practice: wash through the morning, go back and check during the afternoon, and only then roll anything up. Four panels are manageable inside two days, but only where the weather plays along from start to finish. Put one grey, damp afternoon in the middle and the fabric stays hanging out while rolling up slides to the next morning, with your hired tower standing exactly where it was.

So reserve on the generous side rather than to the day. That opening 24 hours carries the whole amount, and anything you stick to the back of it comes in with 95 per cent taken off, which makes one spare drying day cost next to nothing on the rental price. What the tower does per model and per build is on the page listing every rate, with transport shown separately and VAT included. Booking too tight means rolling up damp fabric and doing the lot again next season.

At 245 cm the deck matches the width of an average panel fairly closely. Usually that works out at one panel per pitch of the tower, working left to right and always from the top downwards. Begin up at the box and drop down from there, so that dirty water always runs over a stretch you have not yet washed. Rinse each section off before the suds dry on it, because dried soap leaves edges along the fabric that are a real nuisance to lift out afterwards.

Suds without pressure is the rule when cleaning screens. Lukewarm water, a mild detergent and a soft brush or sponge take most of it off; a pressure washer drives water behind the coating, damages the seams and blows the fabric clean out of its channels. Rinse afterwards with a hose on low pressure, once again working downwards. Carry the water up in a bucket, or run the hose up alongside an upright of the tower so that it reaches the deck.

The zip and the channels want separate attention. Sand, moss and leaf litter collect inside the channel, and that is exactly what makes a zip skip later on. Run a narrow brush down the groove over its whole length, rinse it through and then wipe the channel dry. Then go along the underside of the box, checking for leaves and cobwebs as you pass. Only when the whole panel feels dry to the hand does the fabric go back into the box, and not one minute earlier.

The mobile scaffold travels to you in loose parts, counted and bundled, and you are the one who stands it up. Reserve somewhere for that pile in advance, since the strip directly beneath the opening is wanted for your buckets, your brushes and your hose. A drive, or a patch of grass a little further along the road, suits the pile far better than the footway right under the wall. Book on a weekday while the clock is short of 15:00, and the van reaches you on the working day that follows.

Delivery date and collection date are both yours to mark out, and on this job the forecast ought to have the deciding vote on each of them. What you want for cleaning screens is a dry and breezy run of days, because your drying time depends on nothing else. Standing the thing up is part of your own day, working from the booklet and the film that comes with it; at this height a pair of you is busy for roughly an hour. Follow the order in the steps for putting one up.

Once the last panel is dry and rolled safely away, unbolt everything and set the parts out bundled together; on the collection day you chose, we take them off your hands. Rinse the uprights down if suds have run over them, so that no white streaks are left behind to raise questions at the check. Collecting yourself is equally possible: by arrangement and free of charge in Amsterdam, at Zeeburgerpad 89. The charges for bringing and fetching are listed per province.

Every tower on our hire list is manufactured under EN 1004 in load class 3, a grading that allows 200 kg of carrying capacity for each square metre of decking. On washing work you fill that up faster than you would think: a ten litre bucket weighs ten kilos, you often have two of them with you, and then there is your own weight, your brushes and the hose as well. More about how that grading works appears at the standard all of these towers meet.

The ordinary rules still stand. Brakes locked before you climb. Nothing and nobody riding the deck while it rolls. And straight down the moment it starts blowing hard. Wind matters more here than it usually does, because a wet panel hanging out acts as a sail and loads both the channels and the box heavily. If the wind gets up, roll the fabric away as soon as it feels dry enough, and never leave it out flapping through a whole night.

The hazard when cleaning screens is simple enough: everything gets wet. A deck carrying suds is treacherous underfoot, so wipe between panels, wear boots with a decent tread, and place your bucket where you will not step over it as you turn. Keep the area below clear, because a falling bucket brings its contents down with it. Do not work on your own above four metres on a wet day like that. There is more at the rules for work at height.