Installing a nest box? Choose the right scaffold.

The Altrex RS51 is the narrowest outdoor tower we hire out at 75 cm, and that makes it the obvious pick here. Not because of the deck, but because of everything you have to squeeze past before you stand at the right wall: a side gate, a wicket, a paved strip along the boundary. Boxes for swifts and house sparrows are hardly ever fitted on the street elevation. A narrow build gets through and can afterwards be nudged along on your own. The other sizes sit together in the overview of mobile scaffolds for hire.

Once you are up there the narrow footprint barely registers. A box, a mounting plate, a handful of stainless screws with plugs, a cordless drill and a spirit level together occupy half a square metre of deck. What does matter is the length: 245 cm gives you room to lay the box down flat while you measure and pilot drill, instead of holding it clamped against the masonry with one arm for all those minutes. For a single box two people work on that comfortably.

We also hire out the wider RS52 at 135 cm, but for this job that size is overdone. If you are going round fitting five or six boxes in one go, or a timber colony box close to a metre across is going on the wall, the roomier deck earns its keep. Working alone and staying under 6.2 metres, the MiTower is lighter: also 75 cm wide, but built for one person. The difference between those two models is set out separately.

The tallest point of this job is not the box itself but the upper hole you drill above it. Measure to that fixing and add the room you need to keep the machine straight. A tit box often hangs at two or three metres, but a swift box belongs under the roof edge or against the overhang, and on an ordinary terraced house that is already five to six metres above the path. A working height of 6 to 8 metres fits that.

Work the sum backwards and you see what you are actually booking. You stand on a deck at 4 to 6 metres, and to that you add roughly 2 metres of reach. The underside of the box wants to be at chest level once you are standing on the deck, not just above your cap, because you have to hold it level while the second person drives the screw. The page on working at eight metres shows which build goes with that.

Measure from the ground where the tower will actually stand, and with nest boxes that is more often grass or a border than flat paving. A garden that falls away towards the fence can easily cost you half a metre of height. Hire too low and the box ends up lower than you intended, or you are drilling with your arms stretched out and the thing wedged under your armpit. One build up costs a few tubes and buys you a calm working posture.

You do not really pick the wall yourself, the wind picks it. An entrance hole wants to be turned away from the prevailing south westerly and the driving rain that comes with it, and out of the full midday sun. In practice that lands you on the north or east side of the house, and that happens to be the side where the fence stands tight against the brickwork or where the deep border lies. So the standing place of your tower follows the box, not the other way round.

Walk that side before you commit to anything. Under the box you want a strip of flat, load bearing ground that is wider on every side than the footprint, because the stabilisers splay outwards at an angle. Loose garden soil, a freshly laid grass path or a bed of perennials do not qualify, so put sturdy boards under the castors if you must. What to do when the ground undulates or gives way is covered in this piece on uneven ground.

If the box goes in the overhang, one more thing comes into play. The roof projects and you have to get your upper body underneath it, so do not park the tower hard against the wall but at the distance where you can still stand upright at the fascia. Then look at what is drawn up along that side of the house: a downpipe, an outside tap, a bike rack, a shed or a hedge that has grown out. Together they decide whether the tower fits where you want it.

The fitting itself is small work. Building, measuring, drilling, screwing home and taking it down again fits comfortably inside a day for a single box, and you are often back on the ground by mid morning. Even so, reserving exactly one day is cutting it fine. The parts arrive on the agreed date, you put the tower together, and if it rains hard or blows that afternoon you want to be able to slide on without rearranging your whole weekend.

More important than the duration is the time of year. If there is an occupied nest in or right beside the spot you mean to work on, you stay away from it, tower and all, until the young have flown. Installing a nest box therefore happens outside the breeding season: between late August and February you have all the room you want, and very early in spring the box is up just in time for the first occupants. Here you choose your rental period in months first and in days second.

The way the tariff is built gives you a reason not to book tightly. Only that opening twenty four hours counts at the full rate; every day you tack onto it carries ninety five per cent off, which is why three days barely rises above one. In a changeable autumn, take a little margin rather than the shortest option. What the rental price for such a period comes to you can work out beforehand on the page with the rate per model.

With a deck 245 cm long, installing a nest box needs only one position. Stand the tower centrally in front of the spot where the thing is going, and you can then work half a metre to the left and to the right without wheeling. If you are hanging several on the same wall, space them so that two fall within arm's reach per position. Boxes for the same species should not sit right next to each other anyway, so that shifting is in your day regardless.

Collect your kit on the ground and only then climb. The box, the mounting plate, screws and plugs in a tub, the drill with the correct masonry bit, a level, a pencil and a cloth for the dust. Miss a single plug and you are back down again. A heavy colony box is better hauled up on a rope than carried up the build with one arm underneath it, because you climb with two free hands and nothing else.

What people misjudge is the fixing. In a brick wall you drill into the brick and not into the perp joint, and that asks for a hammer drill you keep straight with both hands. If the box is going into a timber overhang or against a fascia board, you have to hit a rafter and not just the boarding. Allow half an hour extra, which makes no difference to your rental days while it weighs heavily at the top of a ladder.

What arrives at your address is a counted set of separate components rather than a ready made tower. Agree beforehand where that pile ends up, because on this job the build nearly always goes behind the house. Ask for the tubes to be put down by the gate instead of at the front door, or you will carry every piece along the path one extra time. Place your booking on a working day and get it in ahead of 15:00, and the components are with you the following working day.

Which day the material arrives and which day it leaves again you state yourself when hiring, and with nest boxes you have a lot of latitude in that choice. Take a dry, still morning in autumn, because taking in loose tubes and levelling them while it blows is no fun at all. The assembly is your side of the arrangement: you follow the manual step by step, preferably with someone passing parts up. Six to eight metres costs you about an hour.

Once the box is hanging, you strike the build and stack the tubes, decks and guardrails back where they were dropped; we drive out on the day you picked to take it all away. Do not plan that dismantling for the last of the daylight on a short November afternoon, but simply for the next morning with a coffee beside you. One more night on hire costs you next to nothing and saves a quarter of an hour fiddling with a torch between your teeth.

These towers sit in load class 3, which puts the permitted load at 200 kg on each square metre of decking, and the method for establishing that is written into EN 1004. Installing a nest box, with a drill and two people up top, stays a long way below it, so on this job there is nothing to calculate. What counts more is that the figure only holds good for a build assembled in the prescribed sequence, with every guardrail fitted and the stabilisers wound properly down onto firm ground.

The standing rules apply just as much to a light little job. Put the castor brakes on before anyone climbs, keep the build empty of people and material whenever it is wheeled along, and get down once the wind gets up. That limit arrives sooner than expected here, because you are holding a sheet of plywood at roof edge height and it behaves in your hands like a sail. If it blows too hard, slide a day; the birds are not working to a diary.

Two risks genuinely belong to this job. First, tools fall: a cordless drill that slips off the edge of the deck lands exactly where the neighbours' children are standing and watching. Keep that strip empty and stow small items in a closed tub. Then there is the box itself. If a nest is already sitting in the overhang you postpone, because disturbing it is not allowed and you will get diving birds past your ears into the bargain.