Renewable energies CPD

Earlier this month I organised a CPD to unravel the complexities – claims and counterclaims – around the renewable energy sector. Several independent experts gave their views on how to sort through the issues and provided us with much food for thought. Thank you to all who contributed to an enlightening afternoon.

100 Sustainable Scottish Buildings

I recently attended the book launch of “100 Sustainable Scottish Buildings” by SEDA (Scottish Ecological Design Association). I strongly recommend it to everyone.

As Robin Harper (SEDA’s patron) said “It is a celebration of new ideas, of ingenuity, imagination, philosophy and art, a tribute to creativity, joyfulness, human scale design, an expression of our dedication to live with nature and the ow of life, to be genuinely sustainable in every possible way.”

Woodland to playground

Halvorsen Architects have just completed phase I of a new playground at Happy Days’ Eskbank nursery school. All the oak and larch trees were sourced from nearby woodland – trees that otherwise have no commercial value and were due for clearance. A tree lorry carrying all the wood just sneezed through the nursery gates and the on-board crane manoeuvred the trees seamlessly into place.

It remarkably only took three days for Leslie Winthrop’s team to position all the trees – either in meter deep holes in the ground or laid above ground – and build the structure to carry the various decks. All is now ready for phase II – decking and balustrades.

The play pieces follow a path from one end of the playground to the other, with several choices of route, and integrating some of the existing structures along the way. My favourite piece is ‘Nessie’ – the bendy oak surfacing from the ground.



Slovenian wood

Last week I was in Slovenia for a tour of Riko’s timber factory in Ribnica, about an hour’s drive south of the capital Ljubljiana. I was invited there to look at their facilities as I am intending to make the Woodland Nursery out of timber, or — more specifically — out of cross-laminated timber panels (CLT).

Five layered CLT panel

Cross-laminated timber is large-format, innovative, engineered timber that is manufactured off-site. It was first developed in the sawmills of Austria and Germany in the early 1990s there are now CLT factories right across Europe, but not yet in the UK.

Although wood has been used in buildings for centuries, the development and production of large format CLT panels was the first time a wood product had been produced that matched the structural qualities of concrete, whilst being sustainable. It has one of the lowest energy consumptions of any building material across its lifecycle.

CLT panels are used for walls, floors and roofs of a building’s superstructure. It is produced from small softwood sections that would otherwise be of no great value, made up in layers at right angles and glued together under pressure using a polyurethane adhesive (with no formaldehyde or toxic emissions) – or laminated. These panels are light, stable and very strong.

Forests around Ribnica

Slovenia is one of the most densely forested countries in Europe, with forest and woodland covering 58 per cent of its surface area. Beech, spruce, fir and oak are the most common species. I was impressed by the seemingly endless mountains of unspoilt forest. Where are the scars associated with tree felling that we see so often in Scotland, I wondered? Slovenia has a principle of what the Ministry of Agriculture, Forestry and Food calls “close- to-nature forest management”, but it is no doubt helped both by the large number of small forest owners with small and fragmented tenure and that 50 per cent of forests are situated inside the EU Natura 2000 ecological network. The amount of felling lags behind the allowable cut determined in the forest management plans.

The barn at Škrabec Homestead were I stayed, used as a cultural venue, has a state-of-the-art CLT panel structure hidden behind a traditional exterior.

As far back as 1492, the Austro-Hungarian emperor granted an imperial patent to the people of Ribnica for their wooden products after which they sold them all over the world. Sadly now, Slovenia exports much of its unprocessed timber to be processed in Austria and then buys back CLT panels.

Riko Hiše
, a subsidiary of Riko, was founded by Ribnica born, Janez Škrabec in the 1990s, and specialises in tailor-made prefabricated buildings. It manufactures a patented system incorporating structural panels, insulation (wood fibre), doors, windows, blinds, services, internal and external finishes. Riko’s team assembles the building on site, the panels being hoisted into position by crane and bolted together.

The advantages of prefabricated CLT panels include strength, speed and efficiency, as well as a light environmental footprint. They also produces less waste, improved thermal performance and design versatility.

Each CLT panel manufactured is cut and processed using state of the art CNC (Computer Numerical Control) technology. The precise tolerances achieved result in high levels of airtightness. This leads to benefits to health and well being, contributing to improved internal air quality. Studies in Norway indicate children who are taught in solid wood classrooms have heart beats that are 6 beats per minute slower than those taught in non-wooden classrooms.

It also has a surprisingly excellent performance in fire.

After the tour of the factory we went for a walk on some of the many paths through the forests around Ribnica. I was relieved not to encounter either a brown bear or a wolf, although at least I now know what to do if I do – play dead!

Traditional Slovenian timber barn

Tree columns bring wildlife into nursery

Tree columns bring wildlife into nursery

Horntails, or wood wasps, have made their nests in the internal oak trees supporting the roof of Halvorsen Architects’ recently completed Happy Days nursery extension, along with several other species of insect! Rather than be alarmed at their new, uninvited guests, the creative and environmentally-friendly nursery has embraced the chance to study wildlife indoors and set their under fives a project on these mean-looking but quite harmless beasts!

(See blog for more information on this project)



Beauty and elegance

At last a skyscraper that is not yet another phallic symbol.  Herzog & de Meuron, architects of Tate Modern, have designed Beirut Terraces, a residential tower in the Lebanese capital. This beautifully elegant building is made of staggered floor plates with large overhangs breaking the relentless pursuit for the sleekest vertical tower. How refreshing to have a tower that both grounds one with its horizontals but with such a lightness of touch. Read more in Dezeen.


Whole tree structure – first in UK?

This is an abridged version of an article for the next issue of Association of Scottish Hardwood Sawmillers.

If I had known how difficult this project was going to be, would I have still done it in the way I did? – absolutely!

Genesis (J&T) Ltd., owner of a successful pre-school nursery chain in Midlothian asked me to design an extension to their Dalkeith branch. They chose my practice, Halvorsen Architects, having seen a timber treehouse we designed and built with a local P7 class.

Genesis is run by a delightful and energetic family of Greek descent who I find easy to engage with due to our mutual love of the outdoors and aspirations for the children. Genesis have won many awards for sustainable learning and outdoor activities. They asked for a dining room, craft room and performing arts room. The first phase – the dining room and craft room – is now complete.

Halvorsen Architects tries to design ‘honest’ buildings that reveal their structure, and so for these young children I wanted the structure to be not only obvious but also fun. I had seen some branched whole tree constructions in American publications, most notably some of the astonishing structures designed by the Wisconsin-based Whole Trees Architecture and Structures and wanted to design something similar here. The client embraced the concept immediately and I set to work, blissfully unaware of the problems ahead.

The main obstacle I faced, was that unlike in America, British buildings do not use ‘natural’ whole trees and they are not even recognised in design standards used by British engineers. There is no regulation governing their use and and there is a distinct shortage of people qualified to visually grade living whole trees for structural use.

I then embarked on an extensive search which was initially something of a wild goose chase. It involved following leads from experts in, amongst other fields, academia, the Forestry Commission and saw mill owners, up and down the land. The difficulty was finding anyone in the UK who was able to grade living trees with their branch structures still intact. My big breakthrough came when I tracked down James Coulson who has taught timber grading for over 40 years and set up TFT Woodexperts Limited, North Yorkshire, in 1991 to teach both Wood Science and Timber Technology. Jim put me in touch with one of his ex students, Iain Thew of Structural and Civil Consultants, based in Northallerton, but then based in York. Iain was trained by Jim and the two seem to be the only people in the UK able to grade live trees.

I then discovered that the UK hardwood grading rules, BS 5756, only cover a very limited number of tree species – oak and chestnut – while larch is the only UK grown species that can be visually graded to the strength class C24. We were lucky enough to have some natural, branched beech growing in one of my clients nursery grounds that needed to be felled, which we had hoped to use but because they are not covered by the UK regulations we will have to use them internally in the performing arts room for non-structural partitions.

Woodland, Abbey St Bathans

Woodland, Abbey St Bathans

Iain measuring the oak's girth

Iain measuring the oak’s girth

Then the fun part came – sourcing the trees. I contacted several ASHS members and the first to respond positively was Willie Dobie owner and managing director of Abbey Timber. On a glorious sunny day, I set off with Willie around his beautiful woods on a bank overlooking Whiteadder Water near Abbey St Bathans, about a 45-minute drive away in the Scottish Borders. We narrowed our search to forked oak trees that could be used as posts and straight larch that could be used as roof beams for the nursery extension. We were looking for lengths of 3.5 metres for the branched oaks and up to 6.7 metres for the larch, and we wanted 18 in total. Willie was delighted as I was going to be making use of trees that were otherwise redundant due to their bends and branches.

Once the trees had been identified, qualified grader Iain Thew joined us for another glorious day in Spring, armed with a long measuring stick, a tape measure and a pink spray can. He assessed the growing trees and identified which ones had the right load-bearing capacity. This was done visually by assessing the position of the branches – and therefore the knots – and carefully measuring limbs and trunks. A couple were deemed to be too thin but the remainder were approved and given the official pink spray of approval.

Abbey Timber  

The trees were driven to Leslie Winthrop’s builder’s yard in Dewartown, Midlothian and tooled with oversized tongue and groove joints. The entire structure was placed upside down in the workshop with the oak columns hanging from the gantry to check that all the joints fitted. Getting the trees to the site was not easy as all the materials had to be manhandled up and over scaffolding straddling a single story building, as the back garden of the original Georgian house could not be accessed any other way. It took eight men to carry each tree up the ramp and then lowered them by winch onto the site. They weighed approximately half a tonne each.

I also had some fun with smaller, forked parts of the oaks. Two of these were used for the intermediary supports required in a long feature window at low level for the children while one massive one was used as a support the pizza oven.

The trees currently still have their bark and lichen on. Some of the larch beams that had been sitting in the yard for a while have started to shed their bark but most of it is likely to stay on for a while. Again, this was relished by the client. Once all the bark comes off, we intend to get a woodworker to carve some nature-related features such as a tree creeper with its footprints spiralling up the trunk.

 Happy Days DalkeithHappy Days Dalkeith Happy Days Dalkeith

Having spoken to many people involved with trees along my journey I have been surprised at how little knowledge there is of the strength of living and, especially, forked trees. In fact it seems that this building may be the first in the UK to use “natural” or “forked/branched” trees. Dan Ridley-Ellis, head of the Centre for Wood Science and Technology, Edinburgh Napier University said “globally we do not understand how to grade round wood as well as we should, making better use of its intrinsic strength, particularly for forked timbers”.

The second phase of the building – a performing arts room – is due to start in July. This will also use whole tree structure and include a roof garden and a small outdoor amphitheatre.

It has been a real pleasure and very satisfying following the trees from woodland source to in-situ column and beam, less than 40 miles away. So far the response has been extremely positive – everyone I have shown around loves the raw trees, especially the children.


Woodland nursery

Planning permission has now been granted for a new nursery building that we have designed for Happy Days, in Eskbank, Midlothian. Midlothian Council planners refused to give consent last December, but the Local Review Body (comprised of Midlothian councillors) overturned their decision earlier this week.

Woodland NurseryHappy Days moved in to Hardengreen House – a large Georgian house originally built in 1796 – a couple of years ago but have already outgrown the premises. The house has extensive grounds, with fields in front and woodland behind. The client asked Halvorsen Architects to design a new building at the edge of the wooded area directly behind the house.

The proposed building has two-storeys and a floor space of 130 sq. m. It features three gable ends facing south-west, and will have room for approximately 40 children aged 0-5 years and 16 staff.

Three sides of the new building are of solid wood. The relatively plain timber facades are deliberately simple, as the adjacent trees and their shadows will bring the elevations to life. The feature windows enable the children to rediscover and sit amongst the trees. These include several large bays with window seats. The south-west elevation is fully glazed with French doors opening outside from every room – onto large balconies at first floor level. This elevation also has the best view of the garden.

Woodland Nursery The design is a response to the ethos of the client. Happy Days believes that children should spend as much time as they can out of doors, where activities include Forest Families and bush craft.

The construction will be of “solid wood” – a relatively new cross-laminated timber panel system that is fabricated off-site to high standards and assembled on site in a matter of days. It gives excellent air-tightness, acts structurally and therefore makes unusual opening patterns easier to achieve. The whole building, including the roof, will be clad in timber, giving it a uniform appearance.