Repairing a chimney? Choose the right scaffold.

Repairing a chimney is haulage work in miniature. Up go a bolster chisel, a breaker or a club hammer, a tub of mixed mortar, a pointing iron and an empty bucket for everything you rake out. All of that suits the wide Altrex RS52, which measures 135 cm between the standards. Hiring a tower for chimney repointing is therefore mainly a question of deck area: it should all sit beside you without you stepping over it every few minutes. The full range of mobile towers for hire sets the widths out side by side.

The narrow RS51 at 75 cm reaches the same heights, but it forces a choice on you: either the mortar tub stands next to you or the rubble bucket does. Pointing has you reaching for both in turn, and every time something has to go, that costs a trip down. Take the narrow build only where the passage to the back of the house lets nothing wider through. Measure that gate or that garden path before you commit, because a 135 cm set will not squeeze along it.

The remaining models are out of the running for this. The RS44 room scaffold stops at 3 to 4 metres and is meant for indoor jobs, where it rolls through an interior door from about 70 cm. The MiTower carries one person and reaches 6.2 metres, which covers a light fitting or a canopy but not a head standing above the ridge. The RS52 can be built on as far as 14.2 metres, comfortably clear of the roof of an ordinary terraced house.

The measuring point on this job sits higher than on any other job against a wall: not the gutter and not the ridge, but the topmost brick of the head. That is where the last joint gets raked out, so that is where you want your shoulders to clear. Two storeys plus a head give a band running from 8 to 12 metres working height, depending on how far the chimney rises above the tiles. The deck then hangs at 6 to 10 metres.

Those two bands differ for one reason: working height is reckoned as platform height with some 2 metres of reach added. Start the tape on the ground where the castors will stand, and that surface almost never lines up with your doorstep. Back gardens frequently sit half a metre below the pavement, while a raised terrace works in your favour. If you want a worked reference, look at a ten metre build for chimney work and read off the platform height.

Booking too low shows in your shoulders within the hour. If your head only just clears the top edge, you swing the bolster above eye level, the grit lands in your collar and the top row of joints stays uneven. That top row has taken the most weather and deserves you standing square to it. One extra lift costs half an hour of assembly; having to book again because you could not reach the head costs a week of planning. Judge the rise against a window on the second floor.

The head sits on the roof and the tower stands on the ground, and those two seldom line up. Put the build along the elevation where the chimney breaks out nearest to the roof edge: on a gable end house that is the side, on many mid terraces the back. If the head stands squarely in the middle of a pitched slope, no mobile scaffold gets near it sensibly and you need other equipment. Establish that first, with a photograph taken from the far pavement if need be.

Under the four legs belongs flat, load bearing ground, with more room around it than the build itself takes up, since the stabilisers splay outwards. In a back garden that usually means laying a couple of slabs first or sliding a stout board under one foot. Then look at what stands along that elevation: a shed, a water butt, a rear extension, or a conifer that has grown just a little too wide. Working out over the top of a lean-to roof is not on.

Last of all, keep the strip beneath your deck clear. Raking out produces falling grit however carefully you go about it, and a brick you take hold of wrongly arrives below at speed. Park no bicycles, garden chairs or cars there, and warn the neighbours where you share a path or a communal garden. Should a leg or two finish up on the footway or inside a parking bay, check with the council beforehand what your street permits.

For an ordinary head on a terraced house, three to four hire days is a fair reckoning. The first half day disappears into assembly and into studying the head from close to, because only from a metre away do you see which joints are genuinely loose and which bricks move. Then comes the raking out, dusty work that runs slower than you expect, and only on clean, dampened joints do you start filling. If bricks have to go back in, everything slides another half day.

Hire a mobile scaffold for four days and there are still waiting moments in the job that working harder will not claw back. Mortar wants neither blazing sun nor steady rain, and once filled, the head has to cure quietly before you finish or cover it. If it freezes, or a stiff wind gets up at ten metres, you shift a half day and lose nothing but the date. Set your end date on the moment you are certainly done, then, rather than on the moment the job could theoretically be finished.

The shape of the tariff works for you here, and it is worth understanding before you pick dates. Your first twenty four hours stand at the whole tariff, and each further date on the booking is reduced by 95 per cent. A curing day therefore barely registers on the bill, whereas a booking cut too fine has the van arriving while the top joints are still open. What each model and build height comes to, VAT included, sits with the rental prices for every tower.

With 245 cm of platform length you have more deck than head alongside a chimney, which means one position lets you finish two faces completely. Rake both of them out first, brush them clean and damp them down, then fill them in a single round. That way no mortar is stiffening while you are still chiselling. For the two remaining faces you move the tower, ideally at the start of a half day rather than in the middle of fresh mortar.

Take up in one trip what is needed above: bolster, hammer, brush, water and a modest quantity of mixed mortar. Small batches beat a full tub here, because that tub gets no lighter upstairs and has to come down again eventually. The raked out grit goes into a bucket you lower down the standard on a rope. Tipping it over the edge looks faster right up to the point where you are picking grit out of the gravel.

What nearly everyone underestimates is the number of ladder trips. A forgotten trowel, topping up water, a brick that turns out to need replacing after all: on this job you go up and down ten times. So lay out a fixed corner below with everything you might want, and hang your buckets ready before you climb. If you are taking in the roof abutment on the same visit, check what renewing the lead flashings asks of your build.

The tower turns up in pieces, counted and complete, with nothing bolted together yet. Say in advance where that pile of components may land, because on this job the strip along the elevation is already claimed by your tub, your bags of mortar and the rubble buckets. A driveway, or a slice of front garden nobody walks along, beats the route you will tread ten times an hour. Order it before 15:00 and, provided that day is one we work, the parts arrive on the next.

Two dates you enter yourself when booking: the one for delivery and the one for collection. On masonry you consult the rain radar before you pick them. Ask for the components a day ahead of the first chopping day, which lets the tower go up unhurried and lets you begin the moment it stays dry. Assembly is your side of the arrangement: you do it with the manual open beside you and the build video on your phone. Two people are occupied with that for a half day.

Once the work is done you unbolt the build and stack tubes and decks tidily on the drive, and we come past to load it all again. Rinse decks and tubes before spilt mortar turns rock hard, because chipping dried mortar off costs more effort than the pointing itself did. Tally the components while you dismantle, which is how you spot a brace still lying in the grass. What the run comes to where you live sits under delivery charges per province.

Load class 3 applies to this decking, an EN 1004 classification that permits 200 kg for each square metre of platform. Chimney repair creeps nearer that ceiling than painting does, because two people together with a tub of mortar, a bucket of soaked grit and an opened bag of cement mount up fast. Spread the weight over the deck rather than piling it against one guardrail, and lower full buckets down as soon as they become heavy.

A chimney changes nothing about the ordinary rules. Lock the castor brakes before you take the first rung, only push the tower along when the deck is entirely empty, and come down as soon as it genuinely starts to blow. Above the roof edge there is more wind than there is down in the street, which you notice at once with a bucket hanging off your forearm. After every move, check that all four stabilisers are out again and truly bearing on the ground.

One hazard belongs to this job alone: the chimney itself is not sound. You are up there precisely because bricks are loose and the pointing is falling apart, so never treat the head as a handhold, as a support or as an anchor for a line. Nor should you step off the deck onto the tiled slope to reach that last bit, because roof tiles are not made to carry you. The wider picture sits with the rules that govern work at height.