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Friday, 2017-08-18
Why are Scandinavian Homes houses built the way they are?

Hibernia 164 with nordic timber board exterior, behind trees

Nordica 135 with converted attic, 30 degree roof pitch and red plaster finish

Consider what you want from the perfect house. Make a list of your requirements! You might come up with things like:

Warm day and night - low maintenance and running costs
Durability in a maritime climate with driving rain
Healthy, dry indoor climate for inhabitants
Environmental considerations in the building process
Reasonable building costs and simple building process
Living-space that is compatible with your individual lifestyle.
Possible future enlargement at a reasonable cost.
We at Scandinavian Homes did a lot of thinking about such issues and researched the diverse techniques available. The building methods available can be divided into two groups - heavy and light. In places like Ireland and Britain the heavy methods have been totally dominant. This is also the case in hot countries like Spain and countries in South America. The light methods have been used in cold climates such as Scandinavia, North America but also in Japan, Australia and New Zealand. The reasons for this could be ascribed to climatic reasons, but also availability of building materials and cultural traditions. Generally, in Europe at least, timber has been used where it was available. In areas without local timber people have been forced to use other materials.

Historically, the Scandinavian settlers of islands like the Faroe Islands and Iceland built as much as possible of their houses of wood. The lack of forest forced them initially to build partly underground with only the top part of the walls, and of course the roof, being made of wood. All available timber was used, such as salvaged parts of boats and driftwood. Another example of the stone versus wood construction culture can be found in the forest-less southern Swedish province of Skåne and the neighbouring forested province of Småland. There are hardly any houses made of stone in Småland where timber is abundant. In Skåne timber had to be imported, so consequently the buildings economize with the amount of wood used. Most houses were made with a timber post-frame filled in with stones and mortar. Where timber was available it was always the preferred building material for the family home! - Today we have more choice than ever before, and we can use the materials best suited to the local climate.

We came to the conclusion that the two factors which are most essential to consider in achieving the goals stated above are:

1) The building's insulation levels.

2) The buildings capacity to withstand frequent driving rain.

In Ireland the average external temperature is around +10° and the lowest temperature is around -8° with relatively windy conditions. We estimate that we need a U-value of around 0,2 for the walls in order to minimize heatlosses to a tolerable level through the envelope of the house. This is provided that we use other energy saving components such as triple glazed windows and heat recovery to minimize the ventilation heat losses as well. Translated into insulation thickness this means that we need a minimum of around 150mm of some kind of carefully installed insulation in the external walls.

The external skin of the house must be capable of withstanding frequent wetting and sometimes driving rain conditions. For us this rules out the usage of external materials such as bricks or concrete block as they absorb moisture. There are modern methods that can easily meet our insulation design criteria such as blocks of expanded polystyrene, very much resembling large Lego building blocks, filled with pumped concrete. (We have used this method for the underground back wall of the garage at our show-house and it works very well!) It is however difficult to meet our other criteria about environmental concerns and low-cost with this method.

Super passive, plastered house, this house achieved a pressure rating of 0.28

If we consider that an external wall has three primary functions to fulfill we can gain a better understanding of how well different construction materials are suited to various tasks.

1) Structural function. The materials used must provide support for the roof and be structurally capable of withstanding all possible wind loads. Almost all commonly used building materials are acceptable from a structural point of view. The attachment of the roof to the walls is sometimes the most crucial detail. Materials that can be used in the construction of walls are:

Light methods:
  - timber-frame
  - steel-frame
  - post & beam
Heavy methods:
  - concrete blocks
  - stones
  - bricks
  - mass concrete
Other methods:
  - straw-bales
  - polystyrene blocks filled with concrete
2) Weather protection function. The external skin of the wall must protect against rain, snow, wind and sun
Timber panel. On a framed wall (our method)
Solid timber logs
Cement-based plaster applied on:
  - concrete blocks
  - mesh on timber wall
  - rigid insulation on any wall
Lime plaster applied on any heavy wall
Modern light plaster applied on:
  - fiber-cement sheet (our method)
  - rigid insulation on any wall
Sheetmetal, vinyl on framed wall
Bricks as outer wall in a double wall with concrete bricks
Stones as outer wall in a double wall with concrete bricks
3) Insulation function. The insulation must prevent heat from migrating through the wall.
Mineral wool: rolls, rigid sheets or blown in fiberglass or rock-wool,
Cellulose fiber: recycled newspaper, virgin wood fibers
Artificial materials: expanded polystyrene, extruded polyurethane
Natural materials: straw-bales, cork, sheep-wool

Our choice of optimal construction method is based on the belief that the primary technical challenge in the Irish climate is dampness and driving rain. The external skin of the wall in both the timber and plastered versions has to be ventilated. The roof construction has two ventilation gaps. In the foundation the edge to edge insulation provides a natural advantage as the moisture moves away from the warmer to the colder side of the insulation.

Our solution is a simple one. We use a timber-framed wall, a method well established for over 100 years, with 145mm insulation within the frame. Externally a rigid Masonite construction board is fixed directly to the frame. This gives a wall which is absolutely airtight, yet breathable, as the Masonite board is permeable but waterproof and structurally very strong. The external skin consists of either a timber-panel or a cement-fiber sheet with a lightweight plaster system, behind both of which there is a ventilation gap.

The roof from outside to inside: Tiles, battens and counter battens, mineral-felt, 17mm tongued and grooved solid timber sarking, air-gap for ventilation, 3.2mm Masonite, Warmcel cellulose insulation, Tenoarm vapor barrier, plasterboard/internal timber panel.

The floor from below to above: Quarry stones, single size clean stones, 120mm expanded polystyrene insulation, vapor/radon barrier, powerfloated concrete, foam, floating timber floor or timber floor on battens. Insulated base units are installed all around the circumference of the base.

Guidelines for how we work at Scandinavian Homes:
Present facts so our customers can make informed decisions.

Inform about the building methods used by our company  and the reasons why we use certain techniques.

Present the limitations of our modular building method and the drawbacks that can be encountered if we stray too far away from our standard methods.

Let the prospective buyer see and feel the end result by visiting the show-house, no one should be allowed to buy a house without first seeing the show-house. The best houses are usually built for/by people with a deep interest in their future home. Often they have been planning their house for years, made many simple sketches of their dream-house, before finally deciding on a certain plan.

Inform about how a standard Scandinavian Homes house could be improved even further.

Transparency and openness.
An open direct relationship between the customer and Scandinavian Homes should be established. The customer should be personally informed and involved in the following areas as far as possible:
The building- techniques, the drawings, the contract, the payments, the quality control, the checks to ensure all supplies are correct. The company will respond quickly to telephone calls, fax and e-mails and we expect our customer to do the same.

Relations with customers.
We like to have informed, demanding and enthusiastic customers. We also like to see our customers taking an interest in maintaining their houses in the future. We will be there with advice and spare parts whenever needed. We buy system-components from reliable companies with a long-term perspective on quality and spare-parts availability. A house built by us is not any timber-framed house - it is built by Scandinavian Homes Ltd. - an established brand name.

Avoid complex materials and substances.
In today's world we are all exposed to a multitude of new chemicals and materials almost everywhere. We believe it is beneficial to reduce the complexity and amount of chemicals that we expose ourselves to in the home. All materials emit particles to the surrounding air. What we can do as producers of houses is to use building materials that are un-complex, and to provide ventilation-systems to keep the particle-count in the air low. We use pure timber and plasterboards made of gypsum and paper, Masonite boards made of wood fibers and natural cellulose binders. The concrete in the foundation is separated from the livingspace with barriers of simple polyethylene film and foam. We strive to keep our customers informed about un-complex surface treatment methods and cleaning agents.

Keep It Simple.
We use simple constructions and systems that are easily understood and maintained in the future by whoever lives in the house. Our design philosophy entails investing more in passive structures than in complex systems. For example: We use triple glazed low emission shield, argon gas filled windows, that are located in the walls so that we maximize the passive solar heating in all houses. A more complex active solar heating system with special collectors, heat-storage and distribution system can be added if desired. We use a relatively simple ventilation / heat recovery system as opposed to a more complex heat-pump arrangement. Installation of solar collectors and/or a heat pump can be a very good addition to a Scandinavian Homes house, but we think that you must have the basic house right first.

In the forefront of sustainable design.
Scandinavian Homes Ltd. ensures it stays informed of the latest in energy-efficient and ecological design. For example: We offer a total "Passive house" upgrade, 2-4 liter flush water-saving WCs, biological toilets and urine/fecal separating WC systems. We monitor research and development, especially in the Nordic countries and take advice from other European experts. We are however interested in other methods as well, as we believe most of our customers are too. On this web page we would like to share some of this information with our existing customers as well as stray visitors. If you have information that you think could be of interest to others, please let us know.

Scandinavian Homes

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