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.


Newbyres castle conservation

Despite the bitter cold over 20 volunteers and archaeologists turned up this week to spend a day clearing vegetation around the little-known ruin of Newbryres castle in Gorebridge town centre.

Newbryres castle was ‘adopted’ by the Adopt-a-Monument Scheme run by Archaeology Scotland last Summer. Last week saw the first community volunteering day, led by myself on behalf of Gorebridge Community Development Trust  and Rebecca Barclay of Archaeology Scotland, to start conserving the remains of castle. The sun shone and we had a very enjoyable day, including a delicious home-made lunch served up by more volunteers in GCDT’s office down the road.

Newbyres castle conservation

Newbryres castle is 16th century L-plan, thee-storey tower house built by Michael Borthwick of Glengelt. He acquired the land from James, Abbot of Newbattle in 1543 with the consent of Mary Queen of Scots, patroness of the abbey. It was bought by Sir James Dundas of Arniston in 1624 whose family went on to use the castle as a dower house. In 1993 the ruins were classed as a scheduled ancient monument  by Historic Environment Scotland.

Adopt-a-Monument is a nationwide community archaeology scheme that provides practical advice, training and help raising funds.Newbyres castle conservation

The volunteers included archaeology students from Edinburgh University and a group from Midlothian YCAT (Youth Community Access Team). The task of the day was to remove all the vegetation from around the ruined keep without disturbing the stones themselves.

The next stage will be to have an archaeological survey done, clear away some of the rubble and consolidate the ruins that remain. This will be done in partnership with Archaeology Scotland and Historic
Environment Scotland as well as Midlothian Council, who own the land. Finally GCDT intend to landscape the area and hope to add two features – a small amphitheatre for groups such as local primary schools to use and a small timber tower relating to the original 16th century tower and built with the help of the community in a similar way to Wooploft, a large treehouNewbyres castle conservationse, built with Tynewater primary school pupils in 2013.

GCDT will be running further volunteering days that will have an educational aspect included such as conservation workshops and historical talks.


My new signboard

I never really took to the yellow RIAS architects signboard. So I designed my own. Here is the finished product on site at Happy Days nursery, Dalkeith.

Sick buildings

I organised an afternoon of CPD talks last week entitled ‘Breathability and low energy retrofit’. The session, organised for ECAN and a joint event with CIBSE, was held at the RIAS, in Rutland Square Edinburgh  and attended by about 30 architects, engineers and academics. It turned out to be a thought-provoking afternoon with some excellent speakers (see programme below).

For me, the strongest messages were that we don’t yet understand the complexities of the breathability of buildings – that is, how moisture moves through the fabric of the building and is absorbed and released into it. Valentina Marincioni  of University College London & Natural Building Technologies provided some examples of the factors that affect breathability and the dire consequences of not understanding it. Therefore one needs not only to consider the water vapour permeability, the hygroscopicity and the capillarity of each material in the build-up of the structure but also various other contributing factors such as the local climate, the use of the space and ventilation. I was surprised to learn that the sun also has an effect in that direct sunlight on a wet surface can draw water on the external surface into the building.

A more worrying theme that emerged was the lack of understanding and research into the inter-relationship between air-tightness and ventilation. Are our homes sick? asked Paul Paul Farren of the University of Strathclyde & ASSIST Design Ltd. Paul’s research has shown that the vast majority of Britain’s bedrooms have an indoor air-quality that’s below the acceptable limit for much of the night, with bedroom air regularly becoming so stale it’s damaging to people’s health and affecting their brains, largely as a result of high levels of CO2 caused by our breathing. Air-tightness in new buildings have reached levels that have left ventilation behind – how do we change the air in our rooms without loosing the heat that we have just managed to keep in? Again this is a complex area that requires a holistic approach to the indoor environment in order to solve the problem.

The insulation of new homes is now at pretty good levels, both for the environment and our wallets. However I believe it’s now high time that the government and the UK’s building industry funded some serious research into breathability and air-tightness in relation to ventilation so that we can deliver buildings capable of performing in a fit way for the twenty-first century. We need to learn how we can ventilate our buildings without compromising on the air-tightness.

You wouldn’t buy a car with such a lack of understanding by the designer.


Branched tree posts – first in Scotland?

Woodland, Abbey St Bathans

Woodland where oaks were sourced

Last week I spent another glorious day surveying trees in woodland near Abbey St. Bathans in the Scottish Borders.

These are to be used as posts and beams in two new buildings that I am designing for Happy Days, a nursery in Dalkeith. But we’re not just looking for any old posts and beams – we’re looking for unmilled timber structures (and especially branching timbers). That means that the trunks are not machined, or regularised, but left in their original state, knots, bends, forks and all. This a good use of otherwise redundant or underused wood.
The woods belong to Willie Dobie of Abbey Timber, which is a small sawmill located at Abbey St Bathans.


Festival Foods, Madison, USA - over 5,000sq.m.

Festival Foods, Madison, USA

Underhill House, Wisconsin, USA

Underhill House, Wisconsin, USA

I was inspired by the website of Whole Trees Architecture and Structures, an American company that specialises in using raw trees in a range of projects including hypermarkets.

Little did I realise when embarking on this project how difficult it would be. The construction method is almost completely alien to the UK timber industry and specifiers. Whole trees are not recognised in design standards used by engineers.

So it was with great difficulty, and after an extraordinary wild goose chase the length and breadth of Scotland that I tracked down a ‘grader’ who is qualified to certify the whole trees that Willie Dobie and I had selected for possible structural use in the nursery. I discovered that there are only a handful of graders in the whole of UK capable of grading whole trees, and all of them based in England.

Iain measuring the oak's girth

Iain measuring the oak’s girth

Willie Dobie & 'tuning fork' larch to be used for our longest - 6.7m beam

Willie Dobie & ‘tuning fork’ larch to be used for our longest – 6.7m beam

Iain Thew of Dossor MCA, an engineering firm based in York, joined me and Willie in the woods last week to assess whole trees and identify 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.

Luckily the sun shone on us for both my visits and we found all the trees and round poles that we needed – 18 in total – a mixture of oak and larch. The UK hardwood grading rules 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 for strength.

I will be returning in the next few weeks to witness the trees being felled, and to choose which branches to keep. By the time the nursery is complete, I will have followed the journey of each tree from its original woodland setting to supporting the finished educational building – less than 40 miles away.

The building warrant application for the buildings has been submitted and we hope to start work in late Spring. The oak posts will be carved with some woodland motifs such as treecreepers’ foot prints spiralling around the trunk.

Iain Thew officially certifies some round pole larch with a pink spray can

Iain Thew officially certifies some round pole larch … with a pink spray can

Both Willie and I hope that we have somehow burst the logjam and that more people will consider using this cost-efficient and sustainable construction method – which permits the use of otherwise redundant trees – and that the UK’s constrictive regulations can be brought into line with those in the US and continental Europe.



Main image: Whole Trees Architecture and Structures



Huts planning guide celebrated

Last night the Thousand Huts campaign launched its ‘New hutting developments: Good practice guidance on the planning, development and management of huts and hut sites’ at the Scottish Parliament.

It is a comprehensive document with many seductive photos of huts, both old and new, to help planners and hut builders respond to the emerging opportunities for hut building in Scotland. It was produced by Reforesting Scotland’s Thousand Huts campaign, established in 2011 by Ninian Stuart, director of Falkland Centre for Stewardship. This is the first stepping stone for Thousand Huts campaign in its aim to get more Scots out in the forests and onto the mountains. Their next goal is to get a relaxation in the building standards for huts, which the campaign hopes to achieve by the end of the year.

I have already written about the campaign for The Magazine of the Architectural Heritage of Scotland. The article, Hutting in Scotland, was published in 2013.

The document’s launch is an exciting first step in getting Scots to reconnect with their landscape.

As I said at last night’s event the big challenge now is to make the cultural shift to get people away from their caravans or cheap package holidays and into the Scottish countryside. Being half Norwegian and having spent many a holiday in hytte (the Norwegian equivalent) I suggested that we need to think about encouraging organisations to build huts for the use of families and individuals.

Many people will not want to commit the time and money required to own their own hut but if they have access to a workplace provided one or a community-owned one that they could rent at a reasonable rate might well be tempted to go, whether for the weekend or longer. As a child I stayed in hytte with my father owned by the Royal Norwegian Air Force. Now when I go holidaying with cousins we often stay in huts owned by the energy company Statoil.

There is plenty of evidence around to suggest the benefits to health and wellbeing of time spent in the countryside. Norwegians recognise this and many organisations both state and private own hytte for use by their employees.

There is also the possibility of community-owned huts riding on the back of the many community buyouts around Scotland. It would be great if NGOs such as the National Trust for Scotland or the RSPB could also free up some of their land for hut building. Reforesting Scotland and Scottish Waterways Trust have already started to look at building huts on their land.

With the potential further changes to land reform after the next Scottish election this is the time to think seriously about growing the community of hutters in Scotland.