Many women spend their leisure time flexing their credit cards at shopping centres or catching up over a coffee.

Some prefer to get their hair and nails done or indulge in some other form of pampering. But there is a growing band of women who like nothing better than to spend their weekend building walls - yes, building walls.

Tracey Blackwell is probably one of the very few women in the UK who has turned walling into a profession.

But this type of walling doesn't involve a trowel. It doesn't even rely on cement sticking the stones together. This is dry stone walling, which relies on skill, technique and, according to Tracey, a good eye for the right stone.

The methods Tracey and her female walling counterparts use is based on a bygone tradition. Unlike modern-day walling, dry stone walling is complex. "Like putting together a jigsaw I suppose?" I ask.

I am genuinely interested - something I suspect Tracey finds fascinating. "I bore some people to death," she laughs. "I'm just an anorak. Me and the guys I work with spend our lunch breaks talking about walls!"

Walling is an expansion of her outdoor career. Before spotting an advertisement for people to learn dry stone walling in a supermarket in her home town of Otley seven years ago, Tracey was running her own gardening business.

The 47-year-old has been involved ever since attending the inaugural meeting of the Otley and Yorkshire Dales Dry Stone Walling Association.

"I like being outside. I was into gardening, I walk and it was one more thing to try," she says.

Through practice sessions, she learned the skills and techniques needed to do her exams. "You don't just know how to wall'," says Tracey. "You have to have an eye for which stone to pick up and practice over a period of time.

"Three years ago I got the chance to do two paid days' dry stone walling a week. I was gardening then but then the dry stone walling picked up. I started working with the guys I'm with now and I do it full-time."

Tracey is working towards her advanced certificate, with the intention of eventually achieving her master craftsman - or craftswoman - qualification. "I know a few women who have got their advanced certificate but it's quite hard," she says. "A lot of our work is rebuilding and sometimes building new walls."

It's obviously a skill but I question whether there's a knack to it too. "The trick is to build lengthways into the wall rather than along it. That makes it stronger," says Tracey.

One of her current projects is creating a lunky' - a passage through a wall for sheep to pass through - for one of her exam pieces. She was involved in some exhibition pieces at Shibden Hall in Halifax and she has even done some walling in the South of France, but her regular patch tends to be North Yorkshire.

"It dovetailed with what I was already doing but this is a bigger sense of satisfaction because you know the wall is going to be there for 150 to 200 years, whereas you do a garden again. You get a tangible result.

"It is a very different discipline to gardening. Gardening is an all-over workout, whereas walling is physically demanding on joints, wrists and elbows and you need to be careful with your back, and lift properly.

"Often it is hard in the winter but I would rather be walling than anything."

At one time lady wallers were few and far between. Tracey tells me that many more women are now taking it up. For the majority it is a hobby, but a few take it up professionally.

Tracey believes it is too physical for some. "I am fairly strong but I built up my stamina with gardening. I am also very determined!" she laughs. "A lot of women enjoy walling but won't go to the same level. Some want to do it day in and day out - they're as capable and they're not frightened to try new things."

Next year the Dry Stone Walling Association celebrates its 40th anniversary. Tracey and her fellow wallers are keen to raise awareness about walling as a pastime or profession.

Doctors and lawyers are among those who have taken it up. Tracey believes many people seize the opportunity to work outdoors.

Volunteering with Grass Woods in Grassington, close to her Threshfield home, introduced Enid Borthwick to walling.

The 66-year-old retired nurse spent her early years tending the sick before becoming a full-time mum. She spent her latter working years running cookery sessions, but volunteering work in the woods where she used to walk her dog introduced her to a pastime she's pursuing with passion.

It started when she met a professional waller. "He's a guru of limestone walling but he often needed a volunteer to help him, so one day I was assigned to him and he said I had a natural eye for it," says Enid.

She enrolled on a training course through the National Parks and was asked if she'd like to join the local Dry Stone Walling Association. She joined the Otley and Yorkshire Dales branch six years ago.

"It is such an ancient craft and you don't want it to disappear," she says. "One of my hobbies is bobbin lace and to me this is like the weaving of a wall. People say How do you compare lumps of rock with fine pieces of thread?' It's the satisfaction, it's like putting it back in order."

Enid prefers working with natural stone rather than grit stone. She says when she joined the Otley branch she couldn't understand why they were talking about hammers and chisels. The limestone she was used to working with can't be cut, whereas the grit stone found in other areas can be cut to fit.

I soon learn that dry stone walling is more complex than simply piling stones on top of one another. "It's a bit like a jigsaw, but it never goes back the same," says Enid. "Some people think you can strip a wall out and put it back as it was but you set yourself new problems and you read it differently. It's order out of chaos I suppose!"

I dare to ask whether women are better wallers than men. "I think women make a neater wall - it was my examiner who said that!" smiles Enid.

"And it's keeping the history of the landscape going," says Tracey.

Adds Enid: "You're building something, making your mark. Some of the walls in Grass Woods have been there for nearly 2,000 years. The majority of walls are 200 or 400 years old, so it is history.

"You're putting something back, repairing what has lasted all that time and it should last another 200 years."

Terry Bollen, chairman of the Otley and Yorkshire Dales branch of the Dry Stone Walling Association, says that while professional female dry stone wallers are still few and far between, an influx of females joining the national body - the Dry Stone Walling Association - shows that more women want to learn.

"I suspect there are very few female wallers whose work is represented in the surviving, historical walls which define our upland landscape," says Terry. "Recently, especially in the last decade, the association has seen an extraordinary increase in lady membership. If our branch in Otley is representative of a national trend, at least 20 per cent of the association's registered membership will be women."

For those who may think walling isn't for women, Terry's response is: "There is no reason whatsoever why women should not be able to build in dry stone to the highest level. It has just taken them many millenniums to be motivated to do it!"

  • For more information visit www.dswa.org.uk or ring (01539) 567953. The Dry Stone Walling Association is a charitable organisation committed to the preservation of dry stone walls throughout Britain and to the training of people in the ancient craft.