An unusual idea with the Wood-Mizer band saw: pergola with green roof in the garden

Wood-Mizer ribbon saws can be useful not only in the woodworking business. People create a lot of interesting projects from wood, which they cut themselves on Wood-Mizer band saws.

For example, Jeremy Harper. This is a man who is used to making something out of nothing. For 20 years he has worked as an arborist, an occupation that has taken him all over the UK removing unwanted trees and hedges, often giving potential waste materials a new purpose and giving them a new lease of life.

But he even surprised himself with a project to build a pergola of greenery in the garden of his family home.

"The idea came to me from a trip to Norway and Iceland, where my wife and I saw quite a few green-roofed structures on sheds and commercial buildings," he said. "It gave me the idea that I wanted one at home."

Indeed green roofs are very popular in Northern Europe and Germany. Several research centres have been engaged in roof garden developments since the 1970s. Such designs have proven to have several environmental advantages, particularly important for cities. Green roofs accumulate clean rainwater, preventing it from mixing with sewage and reducing the demand on sewage systems. They protect against noise in the sense that the soil absorbs low-frequency noise, while plants - high-frequency noise. In addition, they clean the air and protect buildings from overheating, reducing air-conditioning costs. Finally, it simply looks beautiful!

Although green roofs are more expensive to build than normal roofs, these costs are fully offset over their useful life - much longer than normal roofs, as the gardens protect the roof structure from climatic influences.

There are intensive and extensive green roofs. Intensive ones are more like gardens, on which real trees grow, requiring a fairly deep layer of soil for roots. Usually these roofs are open to the public and are worked on by professional gardeners. And the extensive ones are very cheap in terms of running costs. The topsoil is thin, and the simplest plants are planted in it, such as chickweed or even grass. The only thing they need is to add special non-liquid fertilizers once a year to the soil. These roofs can be admired from a distance, they are not open for viewing.

Such an extensive roof Jeremy Harper set out to build. From idea to start of construction, it was a short journey.

"This was my first attempt at creating something like this in the garden and I made space by removing the grandchildren's play equipment, as they are now grown up, then I put some dimensions on paper, roughly. I thought about what size I wanted and decided on 8" x 8" (about 20 cm x 20 cm) uprights and 4" x 2" (about 10 cm x 5 cm) cross beams."

He was contracted on a demolished industrial site to clear and preserve the remaining trees and to remove any remaining woodland that was no longer needed. A hedge of Leylandii and, instead of cutting it as firewood, decided to process it to the size needed for the pergola.

"I wanted something for effect, so I went for the biggest possible prisms and everything was selected from the largest trunks. The beams we cut from what was left."

Above the structure is the green, wild plant roof that exploded in colour in a wet, warm English spring.

"The wife found a display stand in a garden centre and we went for plants like thyme, rosemary and even strawberries.

"We put wooden blocks around the roof to avoid stepping on the plants and then threw a mixture of wildflowers on the ground. I didn't expect it to over sprout but it produced a really colourful mix and so far it's worked with poppies, cornflowers and daisies mostly ."

Jeremy says he was lucky enough to have the materials at diposition and the right tools for the job. He regularly cuts wood for customers - creating bespoke sizes suitable for use in construction, furniture and lathe machining. He uses a Wood-Mizer LT40 mobile bandsaw that he bought second-hand almost five years ago.

"We felt the LT40 was about the biggest we could buy and afford for work," he said.

"We were able to cut massive pieces of wood with it - wood you never thought they could handle. We have jobs on a variety of scales, from small branch clearing jobs to clearing whole areas, so we bought the LT40 to provide a wood cutting service and be more proactive about the work we can do. It always seemed like the right model to choose and it didn't disappoint. We have some memorable woodcutting memories with him."

He now has a permanent structure in the garden to remind him of those times.

LT40 is housed in a barn across the street from Jeremy's house. His business owns five cranes for moving wood to sites, but he says this particular project hasn't made his job any easier.

"I moved everything by hand!" he said. "From the wood part of the work, the uprights were the heaviest, but the gravel we had to carry up the ladder to deposit on the roof was the most laborious part.

"Cutting all the wood didn't actually take too long because we knew what we wanted. The worst thing you can do when you're cutting is to sit and think; so you make your list of what you have to cut first and then you get on with your work."

"At first I wanted the uprights perfectly straight, but in the end I went with an unfinished edge so it wouldn't look too machined. The decision that took the longest was what shape to give the ends of the beams. We tried a lot of different options until we settled on the one we had."

The vertical posts are buried in the ground and secured in the soil. They carry the weight of the structure that comes crosswise with the beams.

One-inch planks are laid on the rafters forming the base of the green roof, waterproofed with pool lining material and then protected with a geotextile layer to keep the roof waterproof.

Jeremy then laid down heavy gravel - 30mm bags of engineered stone to improve drainage and then topped with a root barrier over which he laid a layer of groundcover to help retain moisture. The green roof physically grows in a mixture of wood chip compost and a layer of screened topsoil.

To improve drainage, drainage points for flat roofs are glued to the lining and the runoff is carried on chains and watered down to the ground level.

Instead of paving in backyard slabs, Jeremy again turned to the bandsaw and cut round sections of Leylandii to complement the natural appearance of the structure.

The end result is not only impressive, it's something the whole family can enjoy - whether relaxing below or gardening above.

"I'm not a gardener - the wife is very good at it - but I've become a bit of a gardener myself with my green roof and I can see that I've been successful. I usually spend a couple of hours up there on weekends, and I'm always trying to take pictures to see how it changes from season to season."

Having the main material available and the LT40 bandsaw for cutting wood allowed the project to be very cost effective.

Jeremy reports, "I calculated how much it would cost to build the structure out of green oak and came up with almost £3,000. All it cost us was a little fuel and time."

"I'm absolutely delighted that it's better than I thought it would be." Apparently the folks at Wood-Mizer felt the same way because Jeremy entered the pergola in the 2015 Wood-Mizer Customer Project Competition and won third place!

According to Ben Pike, Eve Communications