Replacing ridge tiles? Choose the right scaffold.

Take the RS52 here, which means the wide size at 135 cm. Replacing ridge tiles brings bulky company with it: a mortar tub, water in a jerrycan, a stack of new tiles at a few kilos apiece and the old ones to dispose of. Every one of those ends up in your walking line on a narrow deck, when what you need is to pass a second person carrying something heavy. The extra width serves as bench and store. The full choice sits in the overview of towers we hire out.

That 135 cm size has a price attached: you need a clear route of a good metre and a half. If the only way through to the back runs past an eighty centimetre gate, this model drops out and you end up with the RS51 at 75 cm, with the caveat that you walk up and down more often and carry less each trip. So pace out that route with a tape measure in your hand before you commit. A wide build parked on the drive while the work is round the back helps nobody.

Room scaffolds and the MiTower fall outside this job. A MiTower is meant for one person and stops just past six metres, which simply does not reach the roof edge of a house with a pitched roof. The RS52 runs on to 14.2 metres as a model, so a three storey property with a steep pitch also comes within reach. Which build belongs at which floor level is set out on the page about the second storey and higher.

Do not measure to the ridge but to the place where you step off the tower onto the roof. That is the roof edge or the gutter, and on an average house with a pitch above two storeys it usually hangs at six to seven metres. You want to come out above it with your hips, so your platform sits half a metre under that edge or level with it. Add roughly two metres of reach and you land on the 8 to 12 metres of working height this work asks for.

The upper part of that range is reserved for tall buildings. A townhouse with three floors, or a barn with a heavy overhang, puts the gutter at nine metres soon enough, and then you simply reserve the next build up when you hire. The page about working at twelve metres shows how many components that takes. Count on such a tall arrangement needing a good deal more levelling, and on the number of parts landing on your pavement growing to match.

Hiring short is no small matter when replacing ridge tiles. If you stand with your chest under the roof edge you have to pull yourself up over the gutter with a ridge tile in your hand, and that is exactly what you want to avoid. Half a metre too much is never a problem: you simply step off one deck lower. So take the taller variant when in doubt, certainly if you do not yet know precisely how far the gutter hangs above ground level.

The tower belongs along the elevation where the gutter runs closest to the ridge, which is usually the long side of the house. You are looking for flat ground with enough bearing: slabs, block paving or a drive are ideal, and grass after a wet week a good deal less so. The wide version covers a bigger area than the narrow one, and the four stabilisers still have to go around that. So check whether you can genuinely clear that strip before you fix a date.

On this kind of property the obstacles usually sit in exactly the wrong place. An extension or a conservatory under the gutter forces you further sideways, a dormer decides where you can get onto the roof at all, and a shed against the boundary swallows precisely the space you wanted for the stabilisers. Walk a circuit of the house with the layout of your roof in mind. If the terrace slopes or the paving has settled, look first at the approach in this article on levelling on uneven ground.

Think as well about what comes down from above. Old ridge tiles, lumps of mortar and moss drop straight past the tower onto the strip of path you kept clear. Fence that strip off with cones or tape, certainly where the wall borders a pavement or a shared rear alley. Give the neighbours warning before the job starts, because a day of chiselling on the ridge deserves an announcement on their side of the fence too.

A ridge of eight to ten metres is not something you count off in hours. Chiselling goes slowly because old mortar bites into the tiles underneath, and every tile you tap free has to be checked, cleaned and laid ready. Then comes the lining: the first and the last tile set the run, and everything between them has to sit true. In practice you land on two to four days, depending on the length of the ridge and on what appears once the tiles are off.

In between sit waiting periods that no amount of effort will shorten. Fresh mortar has to take up before you walk over it, and a shower passing right after you lay it washes your work straight out again. Work on a ridge also stops earlier than work ten metres up along a wall, because on top of the roof you catch every bit of wind. So put your rental days around a dry spell and count on losing one of them.

The way the tariff is put together makes booking generously cheap. Only the first twenty four hours are billed in full; from the second day onward ninety five per cent comes off the tariff, so four days stay close to the price of one. That suits ridge work, because beforehand you do not know whether the ridge board and the battens under it are still sound. What a longer period does to the rental price you can work out on the page with rates per model and height.

Be straight about this: you hire a tall build, but you do not work on the ridge from the scaffold. A mobile tower stands on the ground beside the house, and the ridge lies metres into the roof slope. Even a build that rises higher than the ridge will not put you there, because the pitched roof sits in between. What the tower does do is bring you safely to the roof edge and keep your material up at working height. The last stretch you cover across the tiles.

For that last stretch you need equipment of your own: a roof ladder or a tile hook, and boots that hold on wet moss. We do not hire those out, so arrange them separately. The 245 cm deck serves as your transfer point. That is where the tub, the new ridge tiles and the bucket for rubble stand, and from there the second person walks to and from the roof. Nobody then has to climb over the tiles with full hands.

In practice this means you move the tower several times. You keep the walking distance across the roof slope short, so after every two to three metres of ridge you shift the build along the wall. On an average house reckon on three or four positions before the whole ridge has had its turn. Moving happens with an empty platform and nobody on board, so clear the tub and the tiles first. Replacing ridge tiles therefore includes that shifting time, and it belongs to your rental period.

You get no assembled tower but a complete, counted set of components out of the van. On a build of ten or twelve metres that is a considerable pile, so work out in advance where it may lie. The drive or the path beside the house works better than the front garden, since you have to keep windows and planting clear and the parts stay there for days. Working days count: an order with us before 15:00 goes into the van on the next working day.

The date we bring it and the date we fetch it you enter yourself in the reservation, and there is more strategy in that than you would think. With ridge work you want the delivery to line up with the first day of a dry run, so that assembly and roof work follow on smoothly. Stacking it is your job, with the manual open on the deck and the instruction film within reach. For twelve metres two people are busy a good part of the morning, so allow for that.

Once the ridge is finished you strike the build and lay the parts back where they were unloaded; on the day you pinned down we come to take them away. Wipe the decks and tubes over with water before you set them down, because dried mortar barely comes off afterwards. Clear away the rubble and the old ridge tiles first, so the stack lies free and loading does not stall on a wheelbarrow standing half across it.

The decks are built to carry 200 kg on every square metre. That figure is the load class 3 requirement, and EN 1004 is the standard it is written into. On ridge work you genuinely come near it. A full mortar tub, a stack of tiles at five to eight kilos each, tools and two people add up faster than you expect, and that weight lands on one square metre. So spread the load across the whole length of the deck and do not put everything down right beside the climbing hatch.

The remaining rules you already know, and at this height they weigh more heavily. The castors are braked the moment somebody starts to climb, moving never happens with material or people on the build, and in strong wind you come off the roof first and off the deck second. After every move, walk round the stabilisers, the diagonals and the guardrails, even if you only shifted the thing a short way. There is more on that in the safety rules for work at height.

The particular hazard of this job sits in the transition between roof and deck. That is where you step across with full hands, and that is the moment things go wrong. Pass material rather than carrying it, and use a bucket on a rope for rubble and mortar. Keep the strip directly under the build empty, because a ridge tile falling ten metres does serious damage below. Wet moss on the tiles also makes that last step unpredictably slippery.