Repairing pointing? Choose the right scaffold.

For local repair work on the joints of a two storey house the model to hire is the Altrex RS51, the version that measures only 75 cm across the base. A generous deck is not the point here. What you want is a frame you can park on one precise spot, and that spot turns out more often than people expect to be the corner behind the shed, the strip between two dwellings or the passage running past the garage. The range of mobile scaffolds kept for hire lists what is in stock.

Everything that travels up with you sits happily on a slim platform: a grinder wearing a thin raking disc, the suction nozzle and its hose, a small tub of made up mortar and the iron you finish with. The vacuum cleaner itself stays down at the foot, because a machine that size is not something you carry up a ladder. Platform length of 245 cm counts for more here, since it settles how many courses of joints you can open, clean out and close again inside one day.

The wide RS52 makes sense only where two people work the same run together, one raking out while a second comes behind with the mortar, or where a full bucket of mix plus a heap of tools has to travel up. On repairing pointing across a few square metres that extra width mainly costs you time carrying parts through the garden. Weigh that against how often you would actually be working in pairs. Both widths sit side by side in the table of mobile scaffold dimensions.

Your top limit here is set not by the damp patch but by the highest joint under suspicion. Water that tracks through an open joint runs down behind the brick and shows up half a metre lower, sometimes a whole storey further down. So keep looking above the stain, right up to the junction with the window head or the soldier course sitting over it, and take your reach from there. Across two storeys that quickly brings you out at 6 to 8 metres.

You then translate that figure into the build you reserve. It puts your platform somewhere around four to six metres, since on top of the deck you count roughly another 2 metres of arm reach before your hands run out. Measure up from the ground the castors will end up standing on, not from the threshold of your back door. A sunken terrace or a garden falling away from the house can easily swallow half a metre of build, and on the topmost course of joints you feel that straight away.

Pick a build that is too short and you repair the wrong stretch. You rake out what you can get at, fill it neatly, and leave the joint the water genuinely runs through standing wide open, so the stain indoors returns quietly after the first autumn downpour. Taking a little extra height when you hire a mobile scaffold costs very little, while starting over costs a full week. The page on a seven metre working height shows what such a build involves.

Here the damage sets the standing position. If the leak sits above the utility room, behind the bay window or hard beside the dormer, that is where the build has to go, and a beautifully flat driveway ten metres away is worth nothing to you. Look first at where the patch actually is, and only then at what lies underneath it: a border of wet soil, a terrace of loose slabs, an inspection chamber or the sloping strip beside the extension where the ground runs off towards the boundary.

Count on power and on somewhere to park the vacuum. The extension lead runs from the meter cupboard or the shed to the foot of the tower, the machine stands beside the build and the hose travels up with you. That strip has to stay clear, and so does the ground where the stabilisers splay outwards. Run the cable along the wall rather than straight across the path, so that nobody catches a foot in it at the moment you are working the grinder overhead.

Then think about everything parked or hanging below the patch. Raking out throws a fine, stubborn cloud of dust that settles on a car, a shed door and a set of garden furniture alike, so sheet those things over or move them a few metres clear. Shut the windows on that side of the house and give the neighbours notice if you are working tight against the boundary. Fixing the build down is covered in the guidance on stabilising a mobile scaffold.

Allow two to four hire days for a repair covering a few square metres. Much of the first day tends to go on tracing: you play a garden hose over one strip of wall at a time from the bottom up while somebody indoors watches for the moment the stain darkens. That search costs half a day and saves you a repair in the wrong place, which is to say it saves you a second booking. Only once you know which joints let water through do you pick up the grinder.

After that come the waits you cannot hurry along. Fresh pointing mortar wants leaving alone rather than being reworked the same afternoon, and your test patch has to dry right through before its colour tells you anything true. If there is frost overnight or full sun on the wall, the filling shifts to a kinder part of the day. Moments like that never appear in your programme, yet they fall squarely inside your hire period, so give them a place there in advance.

Happily the later days are cheap. The full amount is settled over the opening 24 hours, and every day beyond that comes with 95 per cent knocked off, which makes an extra day of breathing space cost you almost nothing. Booking tight does cost something: a half opened wall waiting while the collection van pulls up outside. Reckon a day long rather than a day short. What a period runs to is set out on the page of hire rates.

A deck of 245 cm lets you work off a strip a good two metres wide, and on this job that is usually exactly enough. Rake the joint back until you meet mortar that is still holding fast; as a rule of thumb take roughly twice the joint width as your depth. Do not go deeper than you need to and keep the disc away from the brick, because a nick in the face never comes out again and that nick will draw damp in all over again later.

Vacuum the grit away afterwards, right into the corners of the opened joint. Leave dust behind and your fresh mortar beds down on a layer of powder, then lets go again within a couple of winters, precisely the way the old joint did. Damp the brick lightly next and use a mix no harder than the masonry itself: with soft old brick you want a lime rich blend, or the new joint will break the arrises off the face of the brick.

Always put a test patch somewhere out of the direct line of sight, and judge it only once it has dried right through. Wet mortar sits several shades darker than the same mortar a week on, so anyone who judges colour on the day gets it wrong as a matter of course. If the tone and the hardness both look right, fill the rest of that panel from the same position and only then move the build along.

The delivery day and the collection day are both yours to name when you book. Get an order in ahead of 15:00 on a weekday and the components are on their way for the following working day. On a pointing repair that suits people well, because most only want to fix a date once they have seen indoors how far the stain is spreading. Rain in the days beforehand is no disaster either, since a thoroughly soaked wall actually helps you find where the leak begins.

What turns up is a full set of loose components, counted through and checked, which you raise into a scaffold yourself. A manual sits with the bundles and there is a film showing which part goes on next, so nobody needs experience beforehand, and at this height two people have it standing quickly. Agree beforehand where the bundles may go: on a repair that is best close to the damaged patch, so you are not walking tube and deck boards across the whole garden.

Once the filling is done you take the build apart and stack the components back on that same spot. On the date you picked we come and take them away again, and nothing further is asked of you. Anyone close by with a van of their own may pick the parts up at no charge, by arrangement, at Zeeburgerpad 89, 1019 AD Amsterdam, though over a job of several days that is rarely the calmest way to organise things.

EN 1004 puts builds of this kind in load class 3, and that class stands for 200 kg on every square metre of deck. Repairing pointing rarely comes near that figure, since you work with small tools and small quantities of mortar at a time. Do keep an eye on it if a bag of sand, a bucket of water and a second person all go up together, because those three add up faster than you expect, so spread them out instead of stacking them in one corner.

Put the castors on the brake the moment the build is standing and leave them braked until everybody is back on the ground. Moving the tower along with tools or a person aboard is not on, even for the single metre to the next course of joints. In a stiff wind you stop grinding, because the dust then blows straight back at you and nobody has proper control of the disc. Wear eye protection, ear defenders and a mask rated for fine dust.

The real risk on this job points downwards. Raked out mortar drops as sharp grit and the grinder hangs on a lead that can chafe over an edge, so lay that lead over the guard rail rather than across the lip of the deck. Cordon off the ground beneath you while the disc is running and let nobody wander underneath for a look. Sweep the dust off at the end of the day, because it makes the boards slippery underfoot.