Chimney maintenance? Choose the right scaffold.

For a round on the stack you take the RS52, the wide 135 cm model that the hire fleet can build as high as 14.2 metres. For this work it stops at 8 to 12 metres. You need that width because so much goes up with you and stays lying while you work: a wire brush, a sealant gun, a roll of mesh, a screwdriver set and a small bucket of pointing mortar. Which versions are otherwise ready is on the page with mobile scaffolds from the hire fleet.

The 245 cm of deck that comes with it gets used differently here than on flat work. You do not shuffle along a wall with it; inside that length you look for the spot with the best view of one face of the stack. Working with two of you it pays off: one holds the new mesh in place while the other drives the screws, without anybody having to stand on the edge of the platform. You pick the tools up in turn, so everything must stay within arm's reach.

If the route to the right elevation runs through an alley or along a narrow path, you end up with the RS51 and its 75 cm. The same work goes perfectly well from it, only you lay less down beside you and climb down more often for something you forgot. Weigh that against how many times a round makes you change position, because those climbs add up. Indoor models are a different matter; for a stack on the roof this is the lower limit.

On chimney maintenance your highest point lies above the roof edge: the top course of bricks or the rim of the cowl, because that is where a brush and a screwdriver have to reach. So it is higher than the gutter, where most other roof jobs stop, and that easily makes a whole build's difference in what you reserve. On two storeys it comes to a reach between 8 and 12 metres. Which builds belong to that is shown at ten metres of reach.

The platform sits about two metres under the working height figure, but bear in mind that you do not work straight up at a stack. You stand to one side of it and reach forward at an angle, which takes you less far than the sum suggests. So prefer a build where the top bricks come out around chest height to one where you can only just touch them. That half metre decides whether you work comfortably for an hour or spend an hour stretching.

Hiring too low takes its revenge on precisely this work. Running over joints with your arms above your head goes well for a quarter of an hour, after which you look sloppily and fill sloppily; the spots you skip come back in three years. So take the tape from the ground beneath your wheels up to the top of the cowl, and count in a sloping path or a sunken slab. For a roof that starts above the second floor hire a build more generous than you would guess from the street.

This is the hardest question on chimney maintenance, because a stack has four faces and your build stands against one. Walk round the house before you reserve and work out which elevations lie close enough to the stack to work from. On a mid terrace with the stack on the party wall that is usually two: the front and the back. The flanks of the stack you then reach at an angle, or not at all. The tower cannot stand where there is no ground for it.

Per standing position the usual story applies afterwards: level ground under the wheels, room for the stabilisers that stand out, and no bin or shed exactly where you need to be. Behind the house that ground is more often soft than at the street, so keep base plates or sound boards to hand. A wheel that sinks a centimetre after a wet night puts your whole build out of true. How to get a build solid on ground that gives is set out in the explanation of bracing and tying in.

Count on changing sides costing time. Rolling along the same elevation goes quickly, but front to back means dismantling, carrying and rebuilding at most houses. That is half a day each time, and it is the main reason this round asks for more hire days than the work itself would suggest. Skip it in your planning and you are rushing on the last day or leaving a face untouched. So decide beforehand which sides really need doing. Two faces means building the tower twice, and that is the honest sum.

The work on one face is done in a few hours: brushing down, running over the joints, making good a worn stretch, checking the cowl and mesh and fixing them. Add building, changing to the next side and striking, and you are quickly at three to four hire days. Checking only the front and nothing else gets by on two. So it is not the size of the work that sets your period but the number of faces you want to tackle. The tower stands idle for much of each of those days.

There are waiting moments inside that period. Fresh pointing mortar or a bead of sealant wants to cure quietly before rain falls on it, and in frost you do not start at all. A sweep coming the same week can also cost you half a day in which you cannot go up. So plan this round for autumn or early spring, and allow for a day when the weather stops you. That is not a lost day as long as you booked it in advance. A hired tower waiting out a frosty morning costs little.

Booking wide is cheap on this job. The opening date is charged at the ordinary rate and everything after it drops away by ninety five per cent, so the day you do nothing because of rain costs you little. What does work out dear is a second transport run because you had to stop halfway, since you then pay for bringing and fetching twice and build everything again. Put your end date behind the face you mean to do last. Estimating a period like that is covered in the piece on hire days.

Start every standing position by looking and only then by working. Run a screwdriver along the joints: where the tip sinks straight in, the joint is due for making good. Brush the stack down so you can see what is under the moss, and watch for bricks discolouring because they take up water. What you leave today you note for the next round, with a photograph, so that in three years you know where to look first.

The cowl and the bird mesh then ask their own attention. Check whether the cowl still sits firm and level on the stack, whether the fixing has not rusted through and whether the mesh is still closed; a hole a bird can pass means a nest in your flue. Take new mesh, stainless screws and sealant up in a bucket and hang it on the guardrail, so your platform floor stays clear to stand on and nothing rolls about.

What you do not do from a hired tower is step onto the roof slope to reach the far side. If the angle will not give it to you, move the build or leave that face until another time. A tower is a working place at the edge of the roof, not a way onto it. When the pointing needs a chisel and a hammer it is no longer maintenance, and your hire period changes with it. What that involves is at chimney repair work from a tower.

The parts come to you loose, counted and complete, and on this job they do not stay in one place. Because you move to another elevation partway through, pick a gathering spot where the stack of frames can stand in between without blocking the way to the back. Confirm the order on a working day ahead of three in the afternoon and the set arrives the following working day. That helps when you want to plan a round as soon as the week looks settled.

When you book you say which day the parts should come and which day they should go, and you choose them with the forecast beside you. For chimney maintenance have the parts arrive a day ahead of your first working day, because a tall build takes two people half a day. The scaffold goes up in the manual's order, not yours. That building, the changing to each next face and the striking are yours; manual and video show the way. How the order runs is in the step plan for building up.

With the last face finished you take the build apart and we put it back on the van. Wait until your fresh joints and sealant have had a night, so you do not scrape past them with a frame. Count the parts while you stack and nothing stays lying among the shrubs at the back. That count is what the yard checks the returned scaffold against. Transport there and back has a fixed rate per province, which you can read at the cost of bringing and collecting.

A hired platform under EN 1004 load class 3 will take 200 kg spread over a square metre. On this round you come closer to that than you would think once two people stand up there with a water bucket, a mortar bucket and a tool box. Water in a bucket weighs more than anything else you take up. Spread that weight out. A hired tower is not a shelf for buckets you are not using. More about what the class means is at the note explaining the load classes.

Above the ridge there is nearly always more wind than down at the wall, and you feel that with a sheet of mesh in your hands. Stop in hard gusts and do not carry on with wet gloves on a cowl you have to hold. The fixed rules hold entirely: wheels locked first and only then up, never anybody or anything aboard while you roll, and at every new standing position the stabilisers set again. On this job you change often, so that check keeps returning.

Finally, think about what can fall. Work on a stack loosens grit, moss and old mesh, and it lands at the foot of the tower or where somebody walks past. Lay a sheet, close off the way underneath and throw nothing down, not even a loose lump of mortar. Lower the waste bucket on a rope instead. Nobody should be under the tower while a face is being brushed. Which further agreements apply you will find in the article on safe work at height.