It's a beautiful place to die. Cool and blustery, the wind whipping the lonely headland under a high sun as waves rub this raw stretch of the NSW Central Coast. Below is Broken Bay; beyond, the long, clean sands of Palm Beach. Sitting on the cliff top, Peter Bagnall looks down at the waves and rocks more than 100 metres below. He wonders whether the fall would kill him or just break all his bones. "If it doesn't work, what kind of mess am I going to leave?" he says, the wind stealing his words.

He sits there for hours, teetering on the edge. Tides ebb and flow. It took him a long time to find this spot, scrambling along dark paths that narrowed as they neared the cliffs. Stumbling over tree roots, ducking under banksia branches.

The hardest thing about a major construction site, where you have gas masks and goggles on, is that you can't look in someone's eyes and see they are struggling. 

He wonders how he got here. Saddled with a big house on a hill and a $510,000 mortgage that he signed the same day he was sacked from his job in the construction industry. Six months ago, his partner walked out, and since then he's been waking up in strange places. Each night is a murky lament of beer, wine and country music. On recycling day, he has the loudest bin on the street in the small waterfront community of Hardys Bay.

Peter Bagnall has loved this coast since he was a boy, staying with his grandmother in the holidays and surfing until his skin was scoured brown. He's past 50 now, a grandparent, too, and wondering whether his family would be better off with his life insurance money.

Harden up, he says to himself. You're a bloke. You ride motorbikes. You ride a surf boat. You work with 190-tonne trucks.

He feels like a failure. A fraud. He looks down and wonders whether the tide would take his body out to sea.

I STARTED WORKING for Wayne in the spring of 2005, starting from 7am as a labourer alongside one of his sons and a brother-in-law. He had an easy drawl, low-slung shorts and a laidback style that earned him the nickname "Zombie" as a teenager. He liked surfing and loved his family.

Wayne was in his early 50s and ran his own small building company. I remember how patient he was with my clear lack of building skills as we built a home on Sydney's lower north shore. The time I accidentally flooded the floor, he calmly turned off the water, shrugged his shoulders and showed me the broom.

He kept me on even though I suspect he didn't need to. It was good work and I enjoyed his company.

Summer came and I moved on. Years later, in 2013, I heard that Wayne had taken his own life. His business had gone into insolvency soon after. I believe he had legal troubles with an unhappy client. But I can only guess at why he might have killed himself. His family politely declined to be interviewed for this article.

Suicide in Australia is a dark plague, ravaging every age and occupation. Three-quarters of those deaths are men – more die by their own hand than from either skin cancer, liver disease, heart failure or car accidents.

The scourge is greater still within the building industry. Suicide among construction workers – who are almost exclusively men – aged 15 to 24 is more than twice as high as other young males, according to the Australian Institute for Suicide Research and Prevention.

Every two days in Australia, a construction worker kills himself. They're six times more likely to die from suicide than through a workplace accident. For those under the age of 24, the increased risk is 10 fold.

"We all know someone who has died by suicide or supported someone, or have been there ourselves and had our own struggles," says Jorgen Gullestrup, national chief executive of Mates in Construction, an independent suicide prevention charity set up in 2007.

The problem is greatest in NSW and WA: in each state, more than 40 workers kill themselves each year. "In the construction industry we have a male culture on steroids," says Gullestrup. "Suicide is so prevalent and it is such a tragedy that we try to keep it secret."

Typically, a worker who takes their own life might be separated, divorced or have relationship problems. They tend to be in debt or drink too much. The nature of the job – often involving long hours and commutes, poor job security and physically demanding work – makes social support more difficult. The stigma around mental health problems makes it difficult for these men to talk about their troubles. Bullying can also be a problem.

"It's a perfect storm," says Mates in Construction's NSW chief Peter McClelland. "You've got all these problems coming together at once. Even if there's a building boom, there are still gaps where workers fall through."

The rise of fly-in fly-out (FIFO) mining workers has worsened these issues. Reports that nine workers had suicided within a year in Western Australia prompted a 2015 state parliamentary report linking FIFO work with alcohol-related problems, widespread bullying, feelings of isolation, financial pressure and high levels of stress, anxiety, depression and fatigue. The downturn in the mining industry could further exacerbate job insecurity and the risk of suicide, the report warned.

McClelland invites me to a suicide awareness training session at a major building site in central Sydney. Nine workers gather in a grey room, resting their hard hats on tables. McClelland, lean and worn from years working as a glazier, stands out front in his wrinkled high-visibility shirt and faded blue jeans.

On the walls are multiple reminders to wear gloves, helmets, respirators or headphones. There's a single warning about mental health: "Suicide is everyone's business."

"I'm not going to try to turn you guys into psychologists or counsellors," McClelland says. "It's about mates helping mates." He compares suicidal thoughts to the red flashing light on a ute's dashboard. "I've known guys who have been on top of the world on Friday and by Monday their life has turned to crap," he says. "But men bottle it up, because we're supposed to have our shit together."

MARK JACOBSEN SLEPT on his suicide note for two months, storing it in the dark rift between the base of the bed and the mattress. The letter was lined with apologies – to his girlfriend Alex, his parents and friends – before ending on a lighter note. "I will see you when I see you," he signed off. "Love ya."

Jacobsen had a plan. A car and a length of hose and a letter in a notepad, in which he wrote in 2013 that he didn't feel good enough for anyone, pressing so hard that the words left marks several pages deep. "I just said how I didn't feel worthwhile," he says now, his voice faltering. "I felt like I couldn't get out of the rut I was in. I couldn't see any ending."

He rubs at his blue eyes, hidden behind dark sunglasses. Jacobsen, now 27, has scruffy ginger hair, a sunburned neck and fingernails gnawed to the quick. He's wearing a high-vis shirt, the sleeves rolled up past the elbows, and a fleecy top he doesn't need as we sit in the sun outside an inner-city café.

He's still bemused by how rapidly a life can come undone. One morning in mid-March 2012, the Sydney Water hydrologist went to work but couldn't stand still. He smoked a packet of cigarettes while pacing about, his hands shaking.

His doctor diagnosed him with anxiety, which led to a panic attack. Jacobsen traces much of his stress to feelings that he wasn't performing well at work or fitting in, despite the support of his supervisor. He was drinking heavily after work, sometimes to the point of blacking out. But he felt too embarrassed to ask for help. "The stress leads to worry, the worry leads to anxiety," he says. "I was struggling to pick up a lot of requirements at work and felt that I was letting people down. I just went downhill so fast. I always considered myself a friendly, confident person but everything just went out the window."

One morning, waking from another sleepless night, he took out a notepad and started writing. "I was convinced that things were going to keep knocking me down. I messaged my girlfriend on Facebook and said, 'I don't think I can do this anymore.' "

Alex, his girlfriend, was overseas but happened to be online and they started to talk. That conversation was "like a weight off my shoulders", Jacobsen says. Soon, he was seeing a psychologist and taking antidepressants. Later, he tore the suicide note into tiny pieces, which he flushed down the toilet.

He's been back at work for more than a year and has started giving talks for Mates in Construction to help other workers in need. Tell people that you're struggling, he advises them. "It's like a dirty secret," he says, "but it feels so good to talk to someone about it."

There's an adage in mental health that men are more likely to end up in court (or worse) than a clinic. Dr Michael Dudley, until recently chairman of Suicide Prevention Australia, says that men are typically taught to fight, not conciliate. That problem is compounded within the construction industry. "These are tough blokes," notes Dudley. "They do hard physical work and there's an expectation that you hold feelings in."

A 2013 report from the University of Melbourne found people working in industry jobs such as construction and cleaning are at a greater risk of suicide than those in so-called "white collar" jobs in offices. The risk may be symptomatic of wider social and economic disadvantage, including lower education, income and access to health services, the research found. Work insecurity, low social support and high physical demands in such jobs may also play a role.

When days are spent digging a hole on a building site, your mind can fill with dark thoughts. Those extra beers last night. The fight with your wife. The time you're not spending with your children. The bills you can't pay.

Greg van Borssum, 45, was down that hole, shovelling mud on a major construction site in Sydney. He had been acting and choreographing fight scenes on the film Mad Max: Fury Road. But when the production was halted suddenly, in early 2013, he took a labouring job to pay the bills. "I went from working with Charlize Theron to being at the bottom of a lift shaft, shovelling mud for 10 hours a day," he says. "I felt I had let everybody [in my family] down. I started questioning whether I wanted to stick it out in life."

During a break one day, a co-worker came out of the hole, walked up many flights of stairs to the top of an unfinished building, and jumped off. "On a site that big a lot of guys had drug problems, financial problems, gambling problems, alcohol issues, broken families," van Borssum says. "But the hardest thing about a major construction site, where you have gas masks and goggles on, is that you can't look in someone's eyes and see they are struggling."

That death gave him a new inspiration for life – and to speak out on suicide prevention and overcoming adversity. A building site is a "rhino-skin place", he says. "A lot of guys are treated badly and made to feel unimportant. You get a kid out of school and he's treated like a dog. He's there for massive hours. He's got debts. He starts going out on the grog. And life can fall apart really quickly without him knowing it."

Some workers can't climb out of that hole. Alec Meikle was 17 when he killed himself in 2008, after allegedly being subjected to relentless, violent bullying at an office of engineering company Downer EDI, in the NSW Central West city of Bathurst. The young apprentice was regularly called a "f...ing useless c...". He was allegedly burnt with a welding torch, sprayed with adhesive and set on fire. Several of his colleagues allegedly threatened to anally rape him with a steel dildo.

The bullying turned him into "a hollow boy", the NSW Coroner's Court heard in 2013. Meikle was admitted to hospital with severe anxiety and depression. He later moved to New Zealand, where he hanged himself from a staircase in his aunt's home. (The coroner said in his report that it would be speculation to conclude the events at Downer EDI precipitated Meikle's suicide.)

The WA parliamentary report into FIFO workers found bullying was widespread and often unreported. Mates in Construction's Jorgen Gullestrup says bullying was once "almost a rite of passage", particularly for young workers. "But I think that is changing and I think that's a good thing," he says.

A SMALL BIRD WHACKS into Donna Shanahan's kitchen window, making the glass shake, but she doesn't stir. She has seen too many broken things before.

She lives in a brown-brick home with a high grey fence in Frankston in Melbourne's south-east. Shanahan, 39, is wearing a red dress with black sneakers and uses her left hand to wipe away tears with a paper serviette as we sit at her dining table drinking tea. Her right hand is curled over from cerebral palsy and has limited function.

Her husband, Brett, used to plait her long hair, she says: "He was a fabulous bloke to be with." When he wasn't away working as an apprentice for a roof plumbing company, across Victoria, they'd sit in the backyard and chat for hours.

Shanahan can't remember what they talked about now. Some memories stick, some fade. You don't get to choose which. "Your life becomes divided into two," she says. "You've got your life and then you've got this strange reality that you walk. You're like a fish flapping around in no water. That's the thing with suicide. They do it and you never have those answers. I will never know why. It was so well-hidden."

She grasps at reasons why Brett drove into the bush one morning in 2011 and hanged himself from a tree. He was stressed about changes at work, which meant he'd go from being an employee to a sub-contractor, with less job security. He drank heavily and gambled: feeding $75,000 into poker machines over eight months.

He was also facing child pornography charges, about which he felt great shame, Shanahan says. Brett was accused of taking photos of a teenage girl in a bathroom. He and Shanahan almost divorced as a result, but somehow found a way through. Brett was more troubled by his shift to sub-contracting than his impending court case, she says.

Studies suggest that each suicide directly affects at least six other people – including family, friends, co-workers and medical staff. Shanahan has lost chunks of her life, consumed by confusion and sorrow. "Widows need a blueprint of how to get through it: how to shut down bank accounts, what you dress them in when they're dead, who talks at the funeral," she says.

"There's that perception in construction that 'If I can build a house then I can get through my marriage breaking up, or I can get through a problem with the law, or I can get through spending $75,000 on the pokies.' But everything becomes a chasm and they can't cope with it."

PETER BAGNALL LEADS THE WAY down the twisting bush track to the sea. He's walked this rough path many times but usually alone, past fire-scorched eucalypts and bull ants scampering in the scrub.

His partner, Lisa, 33, a naturopath and wellbeing mentor, points to the flannel flowers lining the way. They grow in harsh conditions and are used in bush medicine, she says.

Bagnall, 56, looks like a weathered surfer, with tanned skin, a shaved head and curls of grey hair climbing from his T-shirt. He's still fit from a career spent working with earth-moving machinery, including FIFO work in the gold mines of WA and laying pipes across Sydney.

In 2009, he joined a construction company selling drill rigs and generators, and was eventually promoted to national service manager. He bought a big house in Hardys Bay and planned to live there with his then partner. She left him six weeks later. He was under growing pressure at work and started drinking heavily. "I felt myself going down," he says. "Everybody thinks a construction worker is a big tough bloke but we're no different from anybody else – everyone has issues."

In the months before he was sacked in February 2013, he started taking long walks down this path. We walk it again now, quiet but for the waves below and the sound of shoes slipping on the rocks. So many twists and turns, and then, suddenly, we reach the cliff top.

Bagnall hops to his rock, overlooking the ocean, and calls above the wind: "Picture it. You're in a bad spot and you're going to end up down there and get washed out. You're going to be free." Why end your life here? I ask. "I love the ocean," he says.

Fortunately for Bagnall, a week after losing his job, his brother found him work at southern Sydney's Kurnell oil refinery, which has since closed. He cut back his drinking. One day, he met Lisa at his local surf club.

They now live together, along with her two young sons, in a friend's wood-panelled home near the water. The kitchen window looks up the hill to the house that Bagnall still owns but has rented out. He sees it each morning before going to his current job, driving trucks for a skip-bin company.

It's hard work and he doesn't love it. He won't let Lisa hug him until he has changed out of the high-vis shirt he hates wearing. But every day he gets to live is a good one. He volunteers for Lifeline Australia in his spare time. He hopes to move back into his own home soon, with Lisa and her kids. "I repainted the whole place inside and out," he says. "It's where I'm meant to be one day."

He looks out across the sea and smiles. "Who knows, my ashes might get thrown over here one day and that's okay. But I'm not going to jump anymore. And that's what I want people to know. That it is only a dark spot you are in for a little time. And that it gets easier."

He watches the waves below, then turns towards the rough bush track and steps back from the edge.

Mates in Construction: 1300 642 111

Lifeline: 13 11 14