Replacing solar panels? Choose the right scaffold.

On a pitched roof a swap lands you at the Altrex RS TOWER 52, whose deck runs to a full 135 cm across. Width is not a luxury here, because two modules are in play the whole time: the failed one going down and its replacement waiting to go up. On a cramped floor that ends with a sheet of glass stood on edge against the guard rail, and from then on you are shuffling round it. The full range sits on the page of mobile scaffolds we hire out.

Alongside the width, the deck length of 245 cm does real work. A common module runs to roughly 170 by 110 cm, so the old sheet lies flat on the floor while the new one waits on its edge next to it. Nothing has to be held while you hunt for the right clamps. With two of you up there, that floor still leaves enough room to pass one another without catching an elbow on a panel frame or knocking a spanner over the edge of the deck.

Where it is one small module on a garage roof and the way through to the back is genuinely tight, the narrow RS51 at 75 cm will do. For a complete set it is punishing, and you lose time turning and lifting at every position along the row. Which model suits which roof is compared in the guide to towers for panel work, so you can settle that before you book. Count how many modules are due to come off in total as well.

Replacing solar panels starts at the bottom row, so your measuring point is not the ridge but that lowest line of modules. Stand with the deck level with the gutter and you look across the clamps and get a hand under the frame to reach the connectors. On a house of two storeys that puts you at 8 to 12 metres of working height. Work the figure back yourself if you like: the height of your platform plus roughly 2 metres of reach above it is the whole formula.

Which row has failed decides the rest of the choice. If the dead module sits in the second or third row up from the gutter, you can no longer touch it from deck level and have to build higher to reach over the row below it. So count the rows up from the gutter before you reserve anything at all. At a ten metre build you can see what that stage looks like on an average house, which tells you what to put on the booking form.

Lay your tape down on the exact spot where the castors will end up, not on the back door threshold. A garden sitting half a metre below the terrace counts towards your total just the same. Choose the build too low and you are hauling at twenty kilos of glass and aluminium with your arms straight above you, which goes wrong sooner or later. One extra stage costs a quarter of an hour while you assemble; a second delivery round costs a whole working day.

The pitch for replacing solar panels goes on the gutter side where the failed module lies, and that is often round the back of the house. So look first at how the parts get there. A gate of 80 cm, a path squeezed past the shed, or a rear garden reachable only through the sitting room decides whether the wide model can be used at all. Anyone meaning to hire a mobile scaffold for this work studies that route to the back as closely as the height of the roof.

Under the tower you want level ground with something in it. Each of the four stabilisers angles away from the base and wants something firm under its foot. Block paving or a drive is ideal, a freshly dug border is not. Where the ground falls away towards the boundary you take that up on the spindles, and how far that can go is set out in the advice on ground that is not level. Keep an inspection cover or a gravel strip out of your footprint entirely.

Point out a resting place for the modules as well. The failed sheet goes down flat on two battens or a piece of board, outside the walking route and out of full sun. The new one stands upright against the wall right beside the way up, so you can pass it along in a single movement. Think too about the hose reel, the bikes and the wheelie bins that always sit precisely where the tower has to go. Shift that lot the evening before it arrives.

Hiring a tower for replacing solar panels comes down in practice to two or three days. Unclamping one module and putting the next one back takes an hour, but that is not where your time goes. It goes on making the string dead, on hunting for the right clamps, on the build on the first morning and the strip down on the last. Where a complete set has to leave the roof, allow half a day per row and add the clearing up on top of it.

A period like that contains pauses you have no say in. The replacement module has to be there, and sometimes you only discover up top that it differs by a couple of centimetres and wants other clamps. The engineer who restarts the inverter turns up at a moment of their own choosing. Take that day into your hire period, or the tower will be gone exactly when you need it one last time. Panel suppliers keep to their own lead times whatever your diary says.

The way the tariff is built helps here. Only the opening 24 hours is charged at the standard rate, while each hire day that follows drops by a full 95 per cent, so a margin around an uncertain delivery costs almost nothing. Booking tight does cost you, because your array then lies half open while the van is already on its way. How long people keep a set on average is covered in the piece on the length of a hire.

Make the installation dead before anything else. Inverter off, the DC side isolated, and the module covered with a tarpaulin or a sheet of card before you touch a connector. Daylight alone is enough to put voltage on it, even on a grey afternoon in November. So bring that cover up in the same trip, because climbing down halfway through a module is precisely what you want to avoid at this height. Lay it ready beside the way up before you take the first rung.

Then mind the mid clamps. A clamp like that grips two modules at once, so the moment you back it off you have released the neighbouring panel as well. Secure that one first with a spare clamp, or have your mate hold it steady. Beyond that you work in bites: from 245 cm of deck you reach roughly two modules side by side, after which you shift the tower along the gutter and set the stabilisers out again. Work from the edge of the field inwards.

Reckon on a size difference while replacing solar panels. Modules from a newer series often run a few centimetres taller or thicker, which moves the clamping zone and means the rail has to follow. An odd one inside the same string also pulls the current down, since a series never delivers more than its weakest member. Ask for the outside dimensions and the frame thickness when you order. If the whole field is coming off, the page on stripping an array sets out the order of work.

The parts reach you counted and complete, and they stay where the driver puts them down. So point out that spot beforehand and keep it clear of the stretch where the old module will land. Get the order booked on a weekday before 15:00 appears on the clock, and the parts land at your address the following working day. Bear the date your installer can attend in mind while you pick. A drive or the grass beside the gate beats the pavement, where you leave pedestrians nowhere to walk.

Assembly falls inside your own hire period. A manual comes with the set and a film online runs through the order stage by stage. With two people you are busy for the best part of two hours before the top deck sits at height. When replacing solar panels, put delivery a day ahead of the module itself where you can, and count that morning as your first day of hire. Carriage out and back is a fixed sum for your province, set out at the delivery charges by province.

Taking it away again is our side of it, on the date you fixed at the start. You take the tower apart and pile the parts somewhere a driver with a sack barrow can get to them. Do that only once the scrap module has left the property, or your drive holds glass and aluminium at the same time. Count the braces and deck boards off as you take them down, so that nothing at all stays behind in the hedge or round the back of the shed.

Each square metre of the floor you stand on is rated at 200 kg, the ceiling EN 1004 puts on load class 3, and on a panel swap it fills up faster than you expect: two people, an old module laid flat, the replacement on its edge and a tool box beside it. Spread that weight down the length of the deck instead of piling it all by the ladder opening. What that class allows is set out in the note on the scaffold standard.

Brake the castors before the first person climbs and leave them braked for as long as anybody is up there. Moving the tower with a module lying on the deck is not done, not even for the single metre to the next bay. If it starts to blow, put the work down: a sheet of that size behaves like canvas and pulls itself straight out of your hands. Panels go up between two people and never over the top of a guard rail.

Finally, respect the current itself while replacing solar panels. Work in dry gloves, let no loose connector hang in a puddle on the floor, and measure that the string really is dead before you unplug anything. Let nobody walk underneath the deck while you are busy above, because a clamp or a screwdriver arrives hard from that height. Stand a wheelbarrow in that spot as a warning if it helps. The rest is gathered at the rules for work at height.