Washing a skylight? Choose the right scaffold.

Even for a light job like this the wide Altrex RS TOWER 52 of 135 cm is the logical choice. Not because of the weight you take up, but because of the way you work: you stand sideways along the roof edge with a bucket beside your feet and a long pole in your hands. On a narrow deck you kick that bucket over within the hour, and then you are ten metres up with nothing to wash with. Every build and width sits at the towers in the hire fleet.

The deck length of 245 cm plays a part here too. With two skylights side by side you often reach both from one position. If they sit further apart you move the tower once, and on this job that is quickly done because you have nothing heavy standing up top. So take the distance between the windows before you choose a build, and you will know whether one position is enough or whether you move halfway through the day.

The slim 75 cm version works here as well, and is sometimes handier: it passes a gate and squeezes along an extension where the wide one sticks. You give up some working room and your bucket then has to hang on a hook. If you are doing the glass and nothing else, that is a real trade off which spares you an awkward passage. Combine it with clearing out the gutter and the wide build is still the better one.

With a skylight you measure to the top edge of the glass and not to the sill. Your squeegee has to reach the upper corners, and that is the furthest point from your build. If the roof is shallow and the window leans far back into the slope, that distance counts double when you pick a build. Two storeys with a pitched roof over them put you at 8 to 12 metres, taken from the slabs your wheels rest on rather than from a doorstep or a raised terrace.

Then convert that figure into the build you order when you hire. Your working height is the deck you are standing on with roughly 2 metres of reach added to it. For a skylight whose top edge sits at eleven metres, you end up ordering a platform at around nine. Note both figures down before you settle the build in your booking. What that comes to in sections and guard rails is on the page about eleven metres of working height.

With washing, too high is more of a nuisance than with other work. With your deck above the window you push the dirt towards you and the water runs over the pane you have just done. You want to stand at roughly the middle of the glass, with the top edge just inside your reach and the bottom edge below your elbow. An adjustable pole gains you more than an extra section in your booking, and it fits in the back of the car as well.

The build goes square in front of the skylight, because reaching sideways with a wet pole is exactly what you want to avoid here. Look from the garden to see where the window sits in the slope and put the wheels precisely under it. If the window sits above an extension, a conservatory or an attached garage, the roof of that part decides how close you can get; sometimes you stand half a metre away and work with a longer pole than you expected.

The ground has nothing heavy to carry on this job, but flat and stable it has to be. Garden tiles, a laid terrace or a drive of block setts do nicely. Watch the spot for the four stabilisers above all, because behind a house that is where the water butt, the outside tap or a border full of planting stands. Clear that away in good time. On a terrace that falls away, the explanation of working on a slope takes you further.

Think about where your water comes from and where it goes afterwards. Filling a bucket five storeys up is not an option, so you want the outside tap or the loose end of the hose as close to the foot of the build as you can get it. The dirty water running down lands exactly where you climb on again, so do not lay cloths or cardboard boxes there, and keep the bottom rungs of the ladder dry.

The washing itself is a matter of hours. Two skylights at the back of the house are done in a morning with a good squeegee, including going over the frames and the seals. The problem is that building the tower comes before all that. With two people you are easily a couple of hours at it, and taking it down costs you time again at the end. Those hours belong to your hire day just as much as the cleaning does.

That is why most people take two hire days rather than one: build and wash on day one, and day two to dismantle calmly and take the rest of the elevation or the gutter with you. Certainly when the build is standing there for a whole day anyway it is a waste to do only the glass. See whether painting, an outside light or a blocked downpipe can join in, because all of it wants the same tower on the same spot.

That second day costs almost nothing. Only the first 24 hours are charged in full; every hire day after that carries 95 per cent off the rate. Taking an extra day for dismantling is therefore no real expense, while hurrying on a wet deck can be. A second day also gives you room to shift for rain. What a short period actually gains you is shown in hiring by the day compared with by the week.

Before you book anything, try whether the skylight pivots. Many models turn on a centre pivot, so you bring the outer pane inside and wash it standing in the loft. If there is a child lock on it, or the hinge has seized with old paint and years of dirt, that no longer works. A fixed light, a rooflight or a window high above a stairwell will not open either, and then a build in the garden is the only tidy way to reach the glass.

If you do work from the platform, keep everything you need within reach of the rail. The bottom of the glass is the easy part, and for the top corners you use a telescopic pole. Do not stand on the rail and do not lean over the edge with your upper body, because that is precisely where it goes wrong on work that is light in itself. Move the tower half a metre rather than stretching with a wet pole.

What people misjudge on this job is the dirt around the frame. The pane itself is soon clean, but the gutter of the skylight, the joint of the lead and the tiles around it are usually full of moss and old leaves. You want all of that taken while you are up there, because otherwise it washes straight over your clean glass at the first shower. Allow half an hour extra per window for it, and take a bucket for the leaves.

The mobile scaffold is dropped off in loose parts, counted and complete. If your reservation is in by three in the afternoon on a working day, the parts arrive the next working day; the date itself you choose from the calendar. For a short job it is handy to have delivery early on the morning you wash, so that you build, clean and are finished by late afternoon on the same day. The cost of bringing and collecting is listed per province.

Building is your work, even on a job of a few hours. The manual and the instruction video come with the set, and with two people you are up quickly. Do not underestimate that part: many people book one day for the washing and then find half the session gone before the first bucket is filled. So plan the build as a separate block in your day, and make sure somebody is there to pass parts up.

We come to collect the tower again on the date you chose and fixed at the moment of booking; all you have to see to is that it lies dismantled and complete. On this job that is soon done, because there is no building material or rubble standing in the way that has to be carted off first. Do let the deck panels dry before you stack them, and brush off the leaves and moss you have pushed down from the roof edge.

The decks answer to EN 1004 in load class 3, which puts 200 kg of capacity on every square metre. Washing a skylight comes nowhere near that, since a bucket of water and a pole weigh almost nothing together. It is still worth knowing why that class is stated: it holds for a build you put up yourself, and its strength depends on correctly placed rails, braces and closed deck hatches. So check while building that every hatch really drops shut.

The ordinary rules stand, however innocent the job looks. Lock the wheels before anyone climbs on, leave the deck empty as soon as you move, and simply come down in a stiff wind. Wind is more of a nuisance on wet work than you think, because with a long pole in your hands you lose your hold on the rail. Go over the stabilisers after each shift, even if you have only moved a metre to the next window.

The risk that really applies to washing is the water itself. A platform with a film of soapy water on it is treacherously slippery, and you only feel it when you step sideways without looking. So work with as little water at a time as you can, keep a dry cloth to hand for the deck itself and wear shoes with a coarse tread rather than smooth soles. The remaining rules sit at the guidelines for working at height.