Construction Systems
Building a wooden house
Wood is a material that has been used throughout history in the world of construction.
While it is not a construction system deeply rooted in our climate and environment, it has received a very strong boost in recent years, and more and more companies and clients are using wood to build houses and even residential buildings.
On the Slow Studio blog, we often talk about wood because it is a resistant material, easily accessible if we have nearby forests, organic, natural, and sustainable.
You will find other articles related to passive wooden construction, but first of all, it is interesting to be clear about certain basic aspects.
That is why today we bring you this article with keys to building a wooden house, focused on better understanding this material in order to use it in construction while making the most of all its qualities and benefits.
Wood as a raw material in construction
Before starting with the keys to building a wooden house, we will talk about the material itself: wood as a raw material.
Wood is one of the oldest materials used in construction. In antiquity, Egyptians and Greeks covered their houses with roofs featuring wooden structures. Medieval and Roman cities, despite being mostly built of stone or brick, also had many dwellings made of natural wood. Unfortunately, due to cooking with fire and recurring wars, fires were a very common occurrence.
Consequently, and for it to be a profitable material, the cost of obtaining it had to be low. This is also true today. The first thing we must consider when working with wood as a construction material is its origin. In Spain, for example, wood usually comes from the forests of the Pyrenees.
Generally, wood from the Pyrenees is characterized by being homogeneous and slow-growing. The result is a resistant, flexible, and versatile wood with an excellent strength-to-weight ratio and countless construction benefits.
Furthermore, it is a fairly abundant material of organic origin, which is why we consider it a renewable, ecological, and sustainable resource. It is a true commitment to the future in addressing climate change.
Once these characteristics are known, let’s address a question that has surely crossed your mind.
Is wood a safe material for the construction of houses or residential buildings?
First of all, it must be remembered that wood is a very resistant and durable material. In the Spanish context, there are PEFC or FSC certificates that ensure that the wood used comes from local forests, and that it is a legalized material with its corresponding sustainability certificate.
In fact, in recent years, there has been a move toward producing wooden elements of greater strength and length. We can cover spans of up to 12 meters with solid or laminated wood beams.
Finally, other qualities should be highlighted before moving on to the keys to building a wooden house.
It is a material with great flexibility and versatility, which is ideal in the world of construction, architecture, and interior design.
Precisely because of its flexibility, wood is a material with high anti-seismic properties.
It is ideal for generating light structures such as Balloon frame (light timber framing) or the CLT system of load-bearing panels.
It is an abundant and renewable resource—a commitment to addressing climate change.
It is a porous material, helping indoor environments by being a good humidity regulator.
Wooden houses or structures are quick to assemble and can be a system that saves both time and money.
As long as it is treated and protected from the weather, insects, or rodents, wood is a material with high durability.
Although it may seem contradictory, it has good fire resistance.
The Keys to Building a Wooden House
Let us now develop the keys to building a wooden house.
1. Local sourcing
We have already discussed this topic, but it is worth emphasizing that for wood to truly be an economical and sustainable material, we must consider the energy invested from its extraction until it reaches the construction site.
The shorter this time, the lower the investment in energy and transformation from raw material to construction material, and therefore it will be more economical and sustainable.
Choosing local wood is a good way to save energy while promoting the local economy.
2. Construction possibilities
However, we must not forget that within the world of wood there are many types and systems, some of which are not very suitable for construction.
Therefore, and in relation to the previous point, we must assess what local vegetation we have and see if it is wood that can be used for structures, enclosures, finishes, etc., according to its properties.
Today, there are countless products for building a wooden house. We have pillars, beams, fiber or cross-laminated panels, flooring, cellulose insulation, cork, etc.
But if we are looking for the keys to building a natural wooden house, we must be careful to choose organic and sustainable materials that have not been treated or contain toxic products.
One should not be extremist and discard all wood products and derivatives that have been treated, but one should be careful with products that are in contact with the indoor environment of our home—that is, with the air we breathe or the surfaces we touch.
3. Budget
The issue of the budget is something we must always establish and respect, whether we build in wood or not.
It is essential that, as a client investing in a house project, the price to be paid for a home is clear from the start. This figure will determine the criteria for choosing materials and organizing construction priorities in all phases of construction.
One of the keys to building a wooden house is that we should not sacrifice the quality of materials and construction elements just to respect the budget, as investing in this means investing in safety and durability. It is a long-term saving; a commitment to the future.
Furthermore, it is important that the choice of construction system, enclosures, and finishes responds to good energy efficiency. A wooden house does not accumulate heat from the sun, and this is very important in a passive house, so we must always combine wood with other systems that allow us to accumulate heat.
4. Defining the structural system
Defining the structure is perhaps one of the most important keys to building a wooden house.
Firstly, wood is a very light structural material but with excellent mechanical properties, as its fibers provide resistance to tension and compression.
Its average weight, 400 kg/m3, which in comparison with concrete (2,500 kg/m3) or steel (7,000 kg/m3) allows for a reduction in the total weight of the structure. This fact reduces the load that the foundation must support and, consequently, its volume is also reduced, allowing us to save on construction costs.
Another design aspect we must consider is the choice of the type of structure that best suits our home.
While there are many structural systems using wood, the most used and safest today are usually the Balloon Frame (light timber framing) or the CLT system (cross-laminated timber load-bearing walls).
Balloon Frame
This wooden construction system using light framing, originating from Anglo-Saxon countries, consists of a structure of solid pillars with a reduced section that are stabilized with each other by forming a kind of box at distances of around 1 meter.
The Balloon Frame is an economical and resistant system that reduces assembly and construction time. Being based on a natural raw material, wood, it is considered an ecological, renewable, and easily recyclable system.
With the light framing system, we can carry out custom projects according to the needs of each client.
CLT System
The second system, which uses CLT panels, works differently.
CLT panels are cross-laminated panels made by gluing a succession of layers of wooden boards, which often come from northern European woods such as Norway spruce.
Thanks to the wide variety of formats, CLT panels adapt to any architectural design.
Their assembly is simple and can be done dry, which enormously reduces construction time.
Furthermore, structurally they are very resistant, static, and self-supporting elements.
They allow for deformations due to settling and possible modifications after installation.
Finally, it should be mentioned that these panels have the PEFC certificate, which guarantees that the raw material used comes from ecological and socially responsible forest operations.
5. Exterior enclosure – Facade
Another key to building a wooden house will be determining whether we also use this material in the exterior enclosures, that is, in the facade.
Currently, the market offer is very wide, so it will be the client who must choose, taking into account the exterior aesthetics they want for their house and the energy benefits that one enclosure or another can provide.
Therefore, it is important to consider that the sheets or surfaces exposed to the elements have a waterproofing layer, a windproof sheet, and a protection system to prevent water and humidity from rising through capillarity in contact with the ground.
Protecting the facade is vital to ensure the durability of the home.
To this end, we recommend annual maintenance, treating the wood with oils and varnishes of natural origin. There are products, such as larch resin, which, despite giving a gray tone to the wood, are very resistant and durable, thus avoiding the need for maintenance tasks for a long time.
6. Interior enclosures – Partitioning
Likewise, the partitions inside the home (walls) can also be made of wood.
In this case, it is a simple system, similar to drywall or plasterboard, but using wood as both a structural and finishing element.
First, a structure of wooden studs is placed.
Secondly, one side of the enclosure is fixed—usually with plywood boards—to then install the necessary electrical, water, heating, etc. systems, as well as acoustic and/or thermal insulation.
Finally, the partition is finished by fixing the other plywood board to the studs using screws.
There is also the possibility of making the partitioning with solid wood panels, but in these cases, the installations must pass through other points, and these solid walls could be used as the structure of the house.
Regarding finishes, we recommend sanding the surfaces and edges of the wood or plywood boards so that they are smooth and without splinters that could cause injury. In the sanding process, it is very important to use masks and have good ventilation to protect the respiratory tract from the dust produced during the wood sanding process.
7. Low thermal inertia
The topic of the thermal inertia of wood requires a brief introduction.
Thermal inertia is a property that indicates the amount of heat a body or material can conserve and the speed with which it releases or absorbs it. It depends mainly on the thermal mass, specific heat, and conductivity of each material.
Due to its properties, wood does not have much thermal inertia, so temperature gains and losses occur almost instantly.
For this reason, we consider that wooden houses can be very efficient in specific cases such as weekend homes, as they need to heat up and cool down in a short time.
Another aspect related to thermal inertia would be the case of wanting to have radiant walls. This is a very healthy heating system, but it requires the incorporation of panels with greater thermal inertia than conventional ones to maintain the heat generated by the heating pipes.
8. Natural insulation
For both conventional houses and wooden houses, conserving the heat captured from solar radiation or heating is vital.
To do this, we must install an appropriate thickness of thermal insulation, which will depend mainly on the climate of the area where we are located. Generally, we use a minimum thickness of between 15 and 20 cm, although in conventional homes, between 8 and 12 cm of insulation is placed.
In this regard, one of the keys to building a wooden house will be avoiding thermal bridges—those points in the envelope where the continuity of the insulation is lost and a considerable loss of heat is generated.
There are wooden construction systems that achieve complete airtightness by sealing the walls against the passage of air (both incoming and outgoing). Thanks to this, heating and cooling needs are minimized, but on the other hand, we must consider forced ventilation systems to renew the stale air from the interior.
9. Maintenance (Protection from insects and rodents / waterproofing)
The correct maintenance of the wood in our house is something we must seriously consider and is within our top 10 keys to building a wooden house.
As an organic material, it deteriorates with sun, water, and also from attacks by insects and rodents.
We have already mentioned how to care for and protect facades exposed to solar radiation using natural varnishes and paints.
Conversely, emphasizing strategies to waterproof these surfaces exposed to the elements can help prevent their contact with the outside from making them vulnerable to humidity and water.
Resins and other treatments can be applied to protect the wood, preventing its deterioration and extending its life and effectiveness. We can also think of architectural systems such as pergolas, porches, or simple eaves that cover the wooden facades from rainwater.
In the interior, we will only waterproof those areas that, due to their contact with water, are more susceptible to the consequences of humidity (bathrooms, kitchen, laundry room, etc.).
The use of a breathable membrane is recommended to allow humidity to dry, as waterproofing the wood can act as a vapor barrier and cause condensation inside the home.
Finally, we cannot forget to talk about insects/rodents, as they are the main enemy of wood.
The most harmless protection to avoid chemical treatment of the wood involves a good cutting and drying process of the wood at the sawmill; with this, we ensure that insects and termites discard our wood as a primary food source.
It is a very effective, safe, and healthy treatment for people and the environment, as it does not use any type of chemical or toxic protection.
10. Its enemy, fire
To conclude, we reach the last of the keys to building a wooden house.
It is none other than the dreaded fire.
The truth is that many of our clients come to Slow Studio concerned about safety regarding the fire risk of a wooden house. Rest assured!
Thanks to technological advances and knowledge about fire behavior, today we can build with wood without suffering from the risk of fire.
Basically, it must be understood that wood burns easily but only on the surface, and for this reason, it is easy to increase its fire resistance by increasing its section.
Furthermore, wood is a material with low thermal conductivity, so in the event of a fire, the temperature would not be easily transmitted to other rooms and would take time to affect the structure and the rest of the materials in the house.
Fire prevention regulations are very demanding in our country. Therefore, the wood sector industry has gotten to work and offers products with certified guarantees that ensure the wood we use, whether in the structure or in other construction elements, meets the fire resistance requirements demanded by regulations.
As always, and to close this article with the keys to building a wooden house, just a reminder that if you are thinking of building houses or residential buildings of this type, you can contact us.
At Slow Studio, we work on wooden house projects in Catalonia and throughout Spain, carrying out custom projects for all types of families and budgets.