Replacing windows? Choose the right scaffold.

Glazing work on a house needs a tower that gets past everything, and in the Altrex range that is the RS51 at 75 cm. The width matters, because you steer between a border and a fence, or along a narrow paved path to the back. Our hire builds for this one begin at 4.2 metres of working height and carry on up to 14.2, and upstairs windows sit in the 6 to 8 metre part of that span. Look over the whole range of mobile scaffolds for hire first.

Up on the deck that width matters less than you would expect. What counts is the platform length of 245 cm, because two people stand along it with a pane between them, plus a box of glazing beads, the packers and a sealant gun. You also work straight at the frame and hardly ever sideways, so you need length along the wall rather than depth. A narrow tower parks closer to the brickwork too, which makes settling a pane into the rebate easier to judge.

If you are swapping large units, or sending a complete casement with its ironmongery up, the wide RS52 at 135 cm deserves a serious look. On that floor you can set a unit down for a moment instead of holding it while the other person beds the packers. Weigh that against the access on your plot: if the wide tower will not pass the house, dismantling and rebuilding costs more time than you gain up top. Both widths sit side by side in the overview of scaffold dimensions.

The top point you have to reach is not the glass but the head of the frame, where the uppermost glazing bead sits. You want to stand square to it with both hands free to lever that bead out and press it back in later. With a window on the first or the second storey you land between 6 and 8 metres of reach. Such a build is the height your deck sits at, with something like 2 metres of arm reach on top, so the platform itself ends up between 4 and 6 metres.

Start your measurement where the castors will actually stand, not at the back door. If the lawn sits a step below the terrace, or the drive falls away towards the kerb, the whole build sinks with it, and that half metre is exactly what you would be short of. While you are measuring, check for a canopy, an extension roof or a run of awnings between you and the frame, because obstacles like that decide how close the tower can park to the window.

Booking too low is a bad idea when glass is involved. With the head of the frame at eye level you lift the new unit into the rebate with straight arms above your head, and that is exactly when a pane wants to slide out of a suction cup. You would rather have that top edge at chest height so you can steer it with bent elbows. Torn between two builds, take the taller one. What a build to eight metres of working height gives you in practice is set out per stage.

The tower goes directly under the window, and that is where the puzzle starts. Below upstairs windows you often find a planting bed, a sloping cellar hatch or a strip of paving that turns out just too narrow, while the four stabilisers need to swing out at an angle. So walk the elevation before you book and check per frame whether that spread has clear ground. A loose planter moves in five minutes, a built brick trough or a shed does not, and then the whole set-up shifts a window along.

There is a second piece of space here that other facade work does not need: somewhere for the glass to stand. New units go on edge against a wall or on trestles, out of the walking route and out of the wind, and the old pane has to wait there too until it goes in the skip. Pick a flat patch nobody has to pass with a barrow. If the garden falls away, get the tower level on uneven ground before you build any higher.

If the window faces the street, part of your build stands on the pavement. Leave a walking route past it, tape off the zone while a pane is out, and warn the neighbour who parks there. With a leg on public ground, ask the council which rules apply in your street. Sort that out well before the delivery date rather than on the morning the glass turns up, because a hire day lost to paperwork is a hire day you still pay for.

The hire period here is not set by the fitting but by the measuring. First the tower stands there so you can size up the openings, then the order goes off for made to measure glass, and only when that arrives can you strip the rebate and bed the new unit. So the waiting falls in the middle of your project rather than at the end. Sizing up a handful of frames takes half a day, including rolling the tower under each one.

From there you can go two ways. One is a short hire to measure, dismantle, and book again later for the fitting. The other is to leave the mobile scaffold standing until the glass lands. That second option sounds dearer than it is. Just the opening day and night is charged at the whole rental price, while every date you add behind it is billed with 95 per cent taken off. Building twice costs you two half days of labour instead. Work the sums through with the tariffs per model.

Fitting itself goes quickly as long as everything is right. Two people spend about an hour per window, plus the sealing and the clean up afterwards. What stretches the plan is weather, because sealant and glazing tape want a dry rebate and an open hole in the rain stops you dead. So set your collection date a day behind the last fitting day. If it rains that morning you move nothing in your schedule, work through the following day and still hand the set back on time.

With 245 cm of platform length you normally take one window per set-up, and that is exactly enough. The full width of the frame is in front of you, with a bit either side to put tools down. The order is fixed: beads off and numbered aside, old pane out of the rebate, rebate cleaned and dried, packers in place, and only then the new unit in. Anything you leave on the ground halfway through costs you a trip down the ladder.

This is precisely where the job differs from taking a window out as a job on its own. In that case the old pane or casement comes out and you board the opening up; when replacing windows something breakable and heavy has to go back into the same set-up. Small units go up the internal ladder with two people, but that stops with large panes, and then a glazier with lifting kit sets them. Your hired tower is for stripping and finishing.

The number of set-ups is usually underestimated. Eight upstairs windows across front and back means rolling eight times, brakes off and stabilisers in and out again each time. Never do that with glass or tools still on the deck. Work along one elevation in a line rather than room by room, so you are not walking a half loaded mobile scaffold round the house halfway through. On a long day that alone saves you an hour of shifting.

The mobile scaffold arrives at the house as a set of loose parts, counted through and left with you. Decide in advance where all that lands, because the strip under your frames stays reserved for the glass and for two people walking past with a unit in suction cups. A corner of the drive works better than the path you will be using. Reservations noted on a working day before 15:00 go into the van a working day later.

You pick the arrival date and the return date yourself, and with glazing you hang both on the glass order. Ask for the parts the day before your measuring round, so you can build in peace and start sizing rebates the next morning. Assembly is your side of it: a manual comes with the set and you watch the instruction video through once beforehand. With two of you that takes a couple of hours, which is why the parts want to be on site the evening before rather than on the morning itself.

When you have finished, we drive back out for the mobile scaffold. You dismantle it and bring everything complete to a point the van can reach, preferably not among the shards of the panes you took out. Count the braces and the decks as you break down and you have nothing to hunt for afterwards, and sweep any glass off the boards before they go back on the pallet. For what bringing and fetching costs, look at the rates per province, always including VAT.

A deck in load class 3, as EN 1004 sets it out, carries 200 kg per square metre. With glass that is anything but a theoretical figure: two adults plus a double glazed unit, a box of beads and a sealant case add up faster than they do on a painting job. So spread what you carry up across the whole floor and do not stack it all on the wall side. Do not leave an old pane waiting up there either.

The standing rules weigh heavier here than average. Brake the castors before the first person climbs, never roll it along while a person or a tool is still up top, and down tools the moment the wind gets up. That last one is not fussiness: a loose pane between two suction cups catches wind like a board and pulls you off balance the moment you turn it towards the rebate. The rest of the arrangements sit with the rules for working at height.

Then there is the glass itself. Close off the zone under your set-up while a pane is out, even in a back garden where you think nobody walks, and wear cut resistant gloves. Put removed beads in a tub rather than loose on the platform, because that is what you tread on stepping backwards. Take shards down straight away instead of collecting them up top. That keeps the floor you turn a heavy unit on clean and clear.