House style

25 June 2018

Family houses are much the same the world over, but the cranes used to construct them vary widely. Julian Champkin reports.

After the great crash of 2008, housebuilding declined dramatically. Eurostat’s construction product (volume) index is measured against a 2015 baseline of 100%. From 2008 (122% against the baseline), to 2013 (92%), it fell 30 percentage points, the great majority of the loss being in the housebuilding sector. Since then recovery has been relatively steady and has now reached 90% of its former peak level.

A similar story can be told of North America. In the US, too, single-family starts are over the recession: in January this year the three-month moving average for single-family starts remained near a post-recession high of 890,000 units.

All of which means that there is demand for the cranes that are commonly used in house-building. Curiously, national practice varies considerably in exactly which types of cranes these are. The fundamental requirements for building single-family dwellings of one or two stories, or low-rise apartments of not much more than that, are similar everywhere: a modest lift capacity—typical loads would be a pallet of bricks or roof tiles, weighing perhaps 0.5t; a height and boom reach adequate to deliver over the ridge of a roof construction to both sides of the building; a small footprint; and ease and speed of set-up.

Self-erectors, truck-mounted knucklebooms, truck-mounted straight-booms and aluminium boomed cranes all have their adherents in different regions and a strange lack of popularity in others.

Knucklebooms get focused

Marcel Boxem is director of heavy cranes for Hiab. Based in the Netherlands he sells globally, and finds distinct regional variations, not just in equipment that is used but in the way that it is used. “You find differences between countries and regions that are sometimes only a few kilometres apart,” he says.

“To a large extent the differences are in what people have grown accustomed to, and in practices that have evolved over time. That seems to be the main driver, rather than any particular benefit of one piece of equipment or way of using it over another.

“Even for lifting the same materials for the same application, neighbouring countries can be totally different in their approaches.”

And this is true even within the specialised market of truck-mounted knuckleboom cranes. “Take as an example moving pallets of brick and blocks: in the Netherlands and the UK, people use rolling-based cranes with short booms, to drive right up to the load. Germans use rear mounted knucklebooms. In Belgium they will use a crane with a fly-jib for the same application and materials.

Move just 200km and you find complete substitutions of method. “And at the site, in the UK people like small knucklebooms with small outreaches; and deliverers will just dump the load on-site. In Germany the rear-mounted knucklebooms with more outreach will place the load further from the vehicle to a place that suits the convenience of the customer. In Belgium, they will deliver a pallet of brick or tiles all the way up the scaffolding!

“Demand for both types is definitely improving after the housing bubble burst in 2008. In the wake of that crisis the industry realised that there was far too much equipment around to be sustainable, and that much of that equipment was relatively new. So when house building started to pick up again, a few years ago, there was a large reservoir of available machines, and that delayed the recovery of crane sales for a while. But for the past two years the industry has been back at full swing,” he says.

“A big change we have seen is in forms of ownership. Leasing and long-term rental are definitely becoming increasingly popular, together with service contracts that secure uptime. In the old days people bought a crane or vehicle, privately funded, and operated it for a very long time, ten years or more.

It was common to move the crane to a new vehicle when the old one was disposed of. Now financing is standard; it is generally over five to eight years, depending on the country, and the financing, rather than the longevity of the equipment, is the biggest driver for renewal.

“Because of this, and because of the greater intensity and dedication of use that they receive now, cranes are required to be more optimal for the jobs that they do. Twenty years ago, they were generic: a knuckleboom would carry out all kinds of functions. Now they are more dedicated to a single application: one crane may be just for deliveries, one will be dedicated solely to wall panels, a third to roof tiles and shingles. Now vehicles spend all day running from one site to the next doing exactly the same thing at each.

“And because of this dedication of application, more and more accessories have been developed. In the past a load would be suspended from a sling or chain. Now we have clams and grabs and special attachments for lifting pallets and other attachments for bags of sand.

“Ever more important to-building customers is how quickly the house can be built,” he says. “Off-site building—pre-fabrication—may become more common, and that will require different below-the-hook appliances, for example for lifting wall panels. Really you are looking at maximising the use of equipment, and that is the demand-led driver of change. Emission controls are another example. And that is emission not just of diesel exhausts but of noise and that is becoming an increasing issue. Housebuilding takes place in residential areas.

Electrically-powered cranes are much quiet quieter and offer the prospect of night-time deliveries which the industry would love to do. Similarly, in residential areas as in inner cities work areas are becoming more and more restricted and permits to block traffic are expensive. These are reasons why among house-builders truck-mounted knucklebooms are picking up more and more of the market from conventional cranes.”

Across the Atlantic

Fixed boom truck cranes are another option, more favoured in the US than in Europe. “Generally speaking, home construction only requires a crane for certain portions of the work,” says Dan Brock, market manager for Altec, who make as well as hire boom trucks to the US house-building market. “Therefore, the crane needs to be able to quickly get in and off the jobsite to stay busy. Having a boom truck crane on a conventional chassis enables this speed. Furthermore, the inherit advantages of having a boom truck for duty-cycle type applications, such as hanging rafters, makes the overall home construction that much faster.”

And, as with knucklebooms, there is variety within the crane type: “Depending on the type of construction and the geography, the type of boom truck required can vary greatly. Assuming a modest two-story home where the ground surrounding the foundation allows for the unit to park with relative proximity, the boom truck can be used for a variety of tasks. It can do everything from delivering dimensional lumber to installing the rafters and to positioning bundles of felt and other roofing material,” he says.

Self erectors are another area of regional variation. In the US, they are rarely used in housebuilding; in the Netherlands they are common. Montarent is a Dutch company that has specialised in mounting small self-erectors onto its own self-propelled chassis that can drive around a site even with the jib fully mounted and in position. Their current offering is a Potain MA21— renamed M21, since the assemblage is no longer an entirely Potain product—on a small-sized electromechanical four-wheel-drive chassis.

The outriggers can be retracted with the crane still fully assembled, in which condition the operator can drive the chassis around the site walking beside it and using a cable remote control. The only other requirement is to insert a locking pin against luffing while in motion.

The result, says Cor Koopmans, sales manager, is ideal for small housebuilding. “Delivered on a low-loader, it takes 15 minutes to unload and 15 more to be fully operational. It can lift 700kg to 19m height at the full extent of its 26m jib, or 1.8t at 12.8m radius.

When work needs to be done on the other side of the building, the crane can be moved there in a matter of minutes,” he says. “Instead of a larger tower crane, or two smaller ones, this can do all the work on a site.

“Clients come to me saying, ‘We need a crane with a longer jib for our project’. I tell them, ‘No, you need a crane with a shorter jib and mobility.’

“Added to which, it can be unloaded and operated by one man, which saves labour costs. There is no cost of mounting or de-mounting; for every job that lasts less than four weeks it will work out cheaper; and you have the advantage of mobility on site,” he says.

“The footprint is tiny, so it can get into narrow spaces and work there: and it can be electrically operated via a plug-in cable.”

Montarent’s concept has been popular for some years in Europe but so far has made little impact elsewhere—which may be about to change. Montarent has just made its third sale in North America, to Stephenson Equipment.

All-in on aluminium

Truck-mounted aluminium boom cranes are another regional variation. Well used in Germany for many years, they were not seen in the UK until 2013, when Kranlyft became pioneer importers. In January Kranlyft became UK distributors for Klaas cranes of this type.

“Aluminium boom truck cranes have been in the UK for about five years,” says Andy Crane, sales executive for Kranlyft. “It was a slow start, but numbers have rapidly increased.

“The concept behind aluminium boom truck cranes is not that they are massive lifters—our largest has a 6t capacity—but that they lift far. With these cranes it is all about reach—and the reach is phenomenal. A typical size for a small builder would be the Klaas K750 RF, which has a capacity of 1t at 14m radius and 0.5t at 21m. Unlike some of our competitors’ they have continuous 360° slewing. Several different carrier trucks are available.

We have just sold a K900RSX on a Mitsubishi Fuso, which is a very compact carrier compared to the size of the crane. With a luffing jib these are superbly fitted for roofing. And, being truck mounted, they are really economical to run.”

Aluminium boom truck cranes are speedy to set up on-site, he says —they can be at work five minutes after arriving. The point ground loading on the outriggers is low, and their positioning is fully variable as long as each is at a minimum extension of 0.3m.

“They are speedy on the road as well—they all do 56mph in the UK— and that does make a big difference to users and to how quickly the job gets done.

“These cranes are becoming more and more popular in the UK,” says Crane, “as they have been for many years on the continent.” Böcker on 2nd January this year opened its new UK subsidiary Böcker UK to sell, among other things, aluminium boom cranes into the UK market. Böcker also believes that vehicle-mounted cranes represent the ideal solution on construction sites, where static construction cranes lack versatility. They promote their truck-mounted aluminium-boom cranes for roofing, carpentry, building construction, façade construction, metal construction or any type of installation work.

‘The aluminium boom cranes sell like hot cakes,” says Alan Peck, manager of Böcker UK. “The AK52, with 12t lift capacity at 34m radius, and 500kg at 41m radius, is particularly suited to house-building.

The AK 37/4000 is our top seller in the 7.49t weight class and is a real friend to roofers and carpenters who need safe and easy access to the back of a roof or building.”

And he too emphasises the economies involved: “These truck cranes have the capacities of a much larger traditional mobile crane at a fraction of the cost. They are much cheaper to buy and run. On Mercedes carriers they are very fuel-efficient— they give 12 miles per gallon on a 26t carrier—and you don’t need an HGV licence to drive it. Being truckmounted, they need in the UK only a £165 road-fund licence. Things like tyres are far cheaper than for a traditional mobile crane and the axle loadings are really light. That of course is mainly down to the aluminium boom. The AK52, the newest and biggest in the range, has a 55m boom option. Position that onsite and you have a huge reach. Where other cranes need to move about and reposition, this can do it in one.

“There are 145 of them now in the UK, and we have a healthy order book. Just as an example, Wales Timber Solutions of Ffestiniog, who specialise in timber-frame houses, have just bought one from us.”

Different philosophies bring different solutions to the same set of challenges; but all have their advantages and disadvantages.

It will be interesting to see if one solution comes to dominate overall and homogenisation takes over. Until then, we should celebrate variety.

A Montarent mobile self-erector being prepared on a Dutch housing project
Truck-mounted straightbooms are common in North American housebuilding
A Klaas aluminium boom demonstrates its length of reach
A Hiab knuckleboom delivers to waiting roofers