Insulating a roof? Choose the right scaffold.

For roof insulation you pick the wide frame. With 135 cm between the uprights you lay a board flat down instead of leaning it against the rail, and across the 245 cm of platform length several fit behind one another. That sounds like a detail, but it decides whether you carry one board per climb or three. On a roof surface of dozens of square metres that difference mounts up fast in the number of trips up the ladder.

The slim 75 cm version is an emergency measure here. A board will go on it, but no walking room is left, and that is precisely what you need when there is wind and you are holding a panel with two hands. If you truly cannot reach the back any other way, work with smaller sizes and accept climbing up and down more often. Both widths and their reach sit beside one another in the hire range of mobile scaffolds.

On this job also choose deliberately for one set up that you move, rather than a series of separate places. You build the tower, insulate the strip you can reach, and then wheel it further along the roof. What you get in outside dimension and stabiliser spread is shown in the survey of scaffold measurements, which is handy when you check the route past the house for gates, garden walls and other places where you get stuck.

The point you have to reach is the roof edge the panels go over, so run your tape to the top of the gutter or to the fascia board above it. On a house of two storeys that lies somewhere around 6 to 8 metres, which lands you squarely in the 8 to 12 metre bracket that most people hire for this work. Your platform height plus a reach of roughly 2 metres together make up the working height you enter when you hire.

Always measure from the level where the castors will rest. If the back garden lies lower than street level, your whole build shifts upwards with it. Look as well at whether an overhang or a projecting roof edge sticks out past the wall, because you have to get the panel past that and it costs you height. The page about a reach of 10 metres shows what such a build looks like and how many platforms it takes.

Underestimating is nastier on insulation work than on other maintenance. Stand below the roof edge and you have to lift every panel above your head and hold it straight in the wind at the same time, and one day that goes wrong. Stand with your hip above the edge and you slide it across calmly. Working on a house with the gutter at second storey level, take the generous reach and not the tight variant.

On this job you need two places: one for the tower and one for the stack of panels. You want that stack near the access point, but not so near that you trip over it while climbing. Lay it to one side, flat on the ground and with some weight on top, because a loose pile of insulation blows through the whole garden at the first solid gust. A carport or a garage is better still for that stock.

Under the scaffold itself the stabilisers have to rest on firm ground, and that asks more width on each side than the frame has. Watch the surface with extra care here, because you are busy for days and the terrain changes with the weather. What is a solid grass path on Monday has gone soft after two days of rain. The approach for a sinking or crooked base is described in the guidance on uneven ground, including what to put under the stabilisers.

Look at the wind direction on the spot where you stand as well. Between two houses or along an open back there is often far more draught than you judge from the street, and that is exactly where you walk with large panels. So set the tower on the sheltered side of the house if the layout of your roof allows it. Keep the walking route clear of garden furniture, because you carry material back and forth here for days.

Insulating is not a spot job. You replace no single tile and you repair no piece of gutter, you treat a complete surface, which means the size of your roof sets your rental period. For a terraced house with one roof surface you are quickly at four to seven days, and on a house where you take in two surfaces and the roof edge it runs up further. Work out in advance how many square metres you realistically manage per day.

That planning includes the days on which you can do nothing. Wind is the chief spoiler: with large panels above your head you stop sooner than on other work, and a day of stiff gusts you simply write off. Rain matters as soon as you have taken tiles away and the boarding lies open, because then you want to be certain you are closed again the same day. So plan with margin and not with your sharpest estimate, especially in autumn.

Financially that margin is modest. After the first 24 hours, which you pay in full, the meter runs on slowly: every following rental day comes with 95 per cent off. Two spare days therefore cost you less than one repeat delivery because you booked too tight. How to build up such a period for a larger job is explained in the piece on the number of rental days, with worked examples for work running over several days.

A platform length of 245 cm tells you two things: how much roof edge you serve per set up and how much material you can keep up there. In practice you lay a few boards flat, slide them over the edge one by one and finish the strip before you move. What you should not do is stack the deck full until you cannot stand anywhere; you need walking room to turn a panel and that will not happen between two piles.

The real work sits in the hand over at the roof edge. A board a metre wide catches the full wind there and wants to twist out of your hands the moment you let go at the top. So work with two people: one below or on the platform passing up, one above taking it. Never alone, and never with a panel larger than you can still control at arm's length while the wind blows.

When estimating your set ups, count on a good two metres of roof edge each time. For eight metres of wall that means three to four standing places, and before each move you take everything off the deck first. If you also take on insulating the roof edge, extra time comes with every position, because you are then busy both on top and at the side of the edge and the scaffold has to stand a good deal more precisely.

The scaffold turns up as a complete set of loose parts, counted, on the place you point out beforehand. Choose that place with the rest of your job in mind, because with roof insulation a pallet of material also lands in your garden or on your drive. So do not put the parts where the insulation supplier has to leave his pallet. Reservations in before 15:00 on a working day travel out with the van the next working day.

You fix both the delivery day and the collection day yourself, so you can make the scaffold match the arrival of your insulation material. Have it come a day before the panels and the set up is standing before your garden fills up. On a job of a week that is the difference between starting calmly and being behind from the first morning. The survey of delivery rates per province shows that item before you book.

Once the roof is closed we come and fetch the scaffold again. Dismantling is yours, after which all parts lie complete on the agreed spot. Sweep the insulation dust and the sawn offcuts off the deck boards before you stack, because it gets in everywhere. Do that on a still day, or keep an open bin bag to hand while you work, otherwise the cuttings end up in the neighbours' garden or down in the gutter after all.

The platform is approved to load class 3 under EN 1004, meaning 200 kg per square metre. With insulation material you do not reach that ceiling quickly, but that is precisely the trap of this job: because the panels are light, people stack far more on than there is room for and start climbing over it. The weight is not the problem, the volume is. Keep the deck free enough to put your feet down anywhere.

The basic rules stand. Castors go on the brake as soon as anybody climbs up, the set up is never wheeled with material or people aboard, and when the wind gets up you stop this work sooner than any other. An insulation panel acts as a sail: it pulls you off balance before the scaffold itself notices anything. Tie loose boards down up there or lay them flat the moment you go down, even for a few minutes.

Then there is the offcut material. Scraps of board, membrane and bits of tape make the deck slippery and blow across the boundary, so sweep up as you go and keep a closed bag to hand. Watch your knife too: cutting often happens on the deck and then the blade sits close to your own knees and your power lead. All further agreements are found in the rules that hold at height and in the notes on this standard.