Instead of sticking them in spaces no bigger than a cupboard, he plonked them in the middle of rooms larger than the average suburban semi. Despite his puritan streak - this was the man who made employees sign a pledge that they wouldn't drink alcohol, and had a piper walk round the house at dawn to make sure no one slept in - he placed two bathtubs next to each other in one of the rooms, a Victorian version of his and hers. Toilets and sinks were painted with garlands and the water, which came from the estate's private supply, rose through a peat bog and filled the baths with healthy brown water.
Edward VII came to stay (and so did the Rockefellers, Rudyard Kipling and Lloyd George), and rumour has it that he was keen to pinch some bath- time ideas for kitting out Buckingham Palace.
Today, Skibo is owned by another successful businessman, Peter de Savary, who has turned the castle into one of the UK's premier golfing holiday destinations. But those who care little for the passions of the putt can spend their weekends walking through 700 acres of grounds, getting their pimples squeezed at the Clarins Spa, doing laps in Carnegie's pool and easing away the aches and pains of life in one of those glorious baths.
Skibo is not a hotel but a club, and you have to fork out pounds 2,000 to join, plus pounds 350 plus VAT per couple a night. Non-members are allowed to visit just once, and pay pounds 485 plus VAT. Fees are set to rise on 1 May. Eeek. Apparently, these prices are modest if you happen to be a keen golfer or a glutton, as apart from champagne and cigars, everything is included in that nightly fee. You can stay in the castle, or in one of the cottages dotted across the estate: in a strange twist of snob appeal, stars after privacy often opt for a worker's cottage and avoid the house.
When I received an invitation to join a house party at Skibo, I was packing my bags within minutes, even though the only iron I intended to use all weekend would be the one that pressed my shirts.
To reach this fairy-tale castle (it has damsel-in-distress turrets and snarling-hound gargoyles), we flew to Inverness which had been camouflaged into the surrounding countryside by an overnight fall of snow. This was a rather unimpressive way of arriving, as a large number of Skibo's guests tend to pitch up in their private jets - some weekends there are half- a-dozen lined up on the apron - and although they mainly belong to faceless banking boys, their passengers have included Michael Douglas, Jack Nicholson and Sean Connery.
It's then about 45 minutes by car to the castle, which you approach down an avenue of ancient trees. Half-way along your car breaks a laser beam that alerts the staff to come running to the front door.
Andrew Carnegie's home remains largely intact since its construction in 1898, (the site has had a grand residence on it for over 1,000 years, but most of what you see today was put there by Carnegie) with the original wallpaper, much of the furniture still in place and some of the great man's personal belongings lying around the rooms.
The bedrooms are extraordinary. Each one contains something that makes it unique - some are panelled in fine wood imported from the US, others have miniature libraries, there's even a somewhat out-of-place art deco room - but all of them have glorious views across the countryside and landscaped gardens.
In all, we spent two days walking through frozen banks of bracken past iced-over lakes; strolling along the beach at Dornoch collecting pebbles and avoiding swarms of nasty flies; pretending to work out in the gym; sleeping an obscene amount of time; and eating. Each night, guests gather at the runway-length dining table, where before feasting commences, someone has to toast the memory of Andrew Carnegie and, if haggis is being served (don't worry, they have a vegetarian version available for the squeamish), Burns's Ode to the Haggis is recited.
Then of course there's always afternoon tea in the drawing room where James, a butler who could have featured in Remains of the Day, plies you with bite-sized cakes and lashings of pukka tea. And, of course, the giant breakfasts and lunches in the golf club house.
Apart from your girth, there's only one thing to worry about at Skibo and that's a stuffed lion called Clarence. He has been known to find his way into people's bedrooms and can give you a heart-stopping turn when you turn on the lights.
Skibo Castle, Dornoch, Scotland IV25 3RQ (01862 894600).Reuse content