Self-build timber frame - FAQ

We answer your questions about self-build

Would you like to build your own house quickly with a quality wooden structure? This is what Gablok concept is all about.

According to your needs and desires, Gablok comes up with a customized plan and then provides you with everything you need to build your timber frame yourself.

“What type of insulation do Gablok insulated wooden blocks use?”
“How do Gablok insulated blocks hold together?”

New concepts often raise a lot of questions, this is why Gablok team has listed for you the most frequently asked questions about our insulated blocks used for self-build.

Would you like to build your house yourself and learn more about our products? We will answer your questions!

Do you have a question that is not in our FAQ? Let us know!

In his early childhood, Gabriel was a fan of interlocking and construction games. He worked in the field of traditional construction for 25 years and developed an insulated wooden stacking block.

After many months of research and testing, the home self-construction system was validated by engineering offices specialized in structural analysis, energy efficiency and acoustic performance.


Frequently Asked Questions

FAQ & Guides

The jointing of the insulated blocks

No jointing system is required in the self-build process with Gablok.

The individual wooden blocks fit into each other, just like a construction set, to form the structure of the house.

The individual insulated wooden blocks from the outer walls are secured together by a vertical rafter system.

Once a floor is finished, these rafters – vertically fixed each 40 cm – joint, with the help of the screws provided, not only all the blocks forming the level but also the lower and upper embossed rails.

You can then apply the material of your choice for the finishes, such as Gyproc panels or any other material of your choice.

In more practical terms, the insulated wood blocks (on a threader or Insulated starter blocks) are nested on a starter. Once a wall is completed, a second rail (the embossed rail) is inserted into the last pile (block under ceiling or insulated belt blocks). It acts as a belt and support for the installation of the floor elements.

Your timber frame is then ready and stable. The same technique is used to fix the interior load-bearing walls.

Structural work and self-build techniques

Have you decided to cross the threshold and build your own timber frame house?

If Gablok insulated wooden blocks fit into each other to form the load-bearing walls of the house, you may need some advice concerning more technical issues.

Some issues include electricity, alarm and plumbing.

Don’t worry, Gablok has foreseen everything.

The distance between two rafters that hold the insulated wooden blocks together is referred as a “technical duct” and it is +- 40 cm. This distance allows you to easily install the various technical connections required for the smooth running of your house.

ll that is left for you to do is to close the technical ducts using finishing panels such as Gyproc panels.

The floor elements are also provided with a 10 cm space allowing the passage of your water piping system, sanitary facilities and electrical wiring.

Among all the insulators available, Gablok has made the choice of expanded polystyrene with graphite additive (EPS) for its building system.

Polystyrene and sustainable development

EPS is about 98 % air. The remaining 2 % is material derived from oil refining. EPS gives a second life to this material that could not have been used as a fuel.

The basic product has the form of styrene beads. The beads increase their volume by 40 times their size into contact with water vapour without solvents or other adhesives.

Contrary to what you may think, styrene monomer is a component that is naturally found in plants. It is not bad for health, it remains stable over time, it has no negative impact on the environment and it is neither toxic nor polluting.

In everyday life, we find EPS in some food packaging because it does not cause any allergies or illnesses.

Carbon impact and ecological footprint of the insulated formwork blocks

EPS is environmentally friendly. It also has the great advantage of being a high-performance insulation system.

The carbon footprint of a traditional house or timber frame insulated with EPS will be superior to that of a masonry construction.

EPS requires less transport given its small size and takes up less space.

Because of its expanding capacity, it does not use considerable amounts of water and energy to increase its shape. The company X-PACK conducts the expansion work in Verviers, than moulds the EPS into the insulating blocks we use.

EPS is a recycled and recyclable product.

An alloy of wood and EPS is manufactured for impressive performance.

The EPS insulation designed for Gablok insulated wooden blocks is combined with OSB formwork.

The blending of wood and EPS allows Gablok constructions to benefit from a very interesting insulating value and energy performance.

The thermal conductivity (“U” value) of a wall built in Gablok is 0.15 w/m²k. Our insulated wooden blocks will be able to meet the 2021 EPB requirements.

The thermal conductivity value (“λ” value) of the EPS is R=0.035w/mK.

Would you like to build your timber frame house by yourself in United Kingdom?


Gablok provides you with insulated wooden blocks for the structure of your house.

After drawing up the plans for your self-build project, we provide you with the guidelines to carry out your building.

We provide you with technical assistance during the time of your self-build project, if necessary

Impact of Gablok self-build structure


In addition to providing high-performance insulated wooden blocks for self-build projects, the Gablok concept is perfectly in tune with today’s concerns.

Gablok has been designed and studied to have a less negative impact on environment.

The insulated wooden blocks are designed in Belgium with recyclable materials. Gablok works with local companies: X-PACK in Verviers and l’atelier Les Gaillettes in Battice.

The wood to make our self-build blocks is OSB. This wood product consist of compressed wood slats, which makes it 100 % recyclable.

Our blocks include EPS (expanded polystyrene) for insulation. EPS is a material that requires little energy for its manufacturing and little water, since it takes up 40 times its size in contact with heat alone, while retaining formidable insulating capacities. It is a 100 % recyclable material.

Thanks to it expansion capability, EPS is easily transportable.

In order to keep a clean environment even on the building site, the self-construction blocks are delivered to you on bonded pallets with the necessary equipment to place your possible waste.

The blocks fit together without the need to use a toxic joint.

You will get the number of blocks necessary for your project after a self-build plan is completed.

The Gablok self-build system of timber frame was designed for the building of one-storey house.

However, it is possible to consider the building of a two-storey house depending on the stability study to be carried out.

If the starter is correctly level, the assembly of insulated wooden blocks will therefore be perfectly vertical up to the first floor.

The calibration of our self-build blocks has a tolerance of 0.5 mm. Up to now, no correction has been made to our projects.

How is the self-build structure fixed to the floor?

The wooden structure of the self-build house is fixed to the floor with anti-wrench angle plates. The concrete slab is built as for a traditional house.

What about the quality of the wood used for insulating blocks?

The wood used for Gablok’s building elements is 18 mm thick OSB: a blend of natural resin and wood slats (chips). What makes OSB special is the fact that wood used for its manufacturing is highly compressed. It remains stable over time since it no longer works.

Your home will therefore remain level with Gablok.

Gablok self-build system has been studied for almost any cases relating to structural work.

Our insulated wooden blocks are designed to build up the shell of a construction. Gablok offers the possibility to build on any surface area.

When drawing up your plans, we try to closely fit your needs so that your self-build project remains faithful to your wish, while staying simple to carry out.

As far as the finishes are concerned, we can also adapt the construction according to the type of coating you want.

Dimensions of the finishes of a wooden kit house

Do you want to install 2 m long window frames? Wooden blocks are presented in multiples of 30 cm, therefore the total planned length will be 2.10 m. Insulated wood cut-outs will be placed at 5 cm on both side of the window to obtain the desired 2 m.

All these options will be requested in advance so that you will only find what you need on your building site, therefore avoiding superfluous waste. If you want to build your house yourself with Gablok, you can contact the different trades for the finishing touches as soon as you get your building permit.

By anticipating all the technical aspects you will save a lot of time! As an example, you will save between six and eight weeks when ordering your exterior joinery.

The construction of a floor with insulated wooden blocks

Gablok system was updated to meet the requirements of two storey house projects. We can still consider the possibility of the building of a three storey house after stability study.

The fact that Gablok self-build blocks are entirely designed in Belgium is what brings an added value to our products.

We wanted to collaborate with local companies on the production of our self-build blocks used for timber frame.

It is a privilege for us to work with qualified teams from Verviers and Battice: X-PACK for the production of blocks with EPS insulation and added graphite, and ASBL Les Gaillettes for the production of structures using OSB panels.

Each of them creates a part of the blocks which are then assembled to form Gablok insulated wooden blocks.

X-PACK and moulded expanded products

The insulated part of our insulated blocks is made of EPS with added graphite.

The basic product is in the form of styrene beads. The beads increase their volume by 40 times their size into the contact of water vapour, without solvents or other adhesives. The next stage is their placing in moulds and their compression operated by X-PACK. The obtained product forms the insulation of Gablok® wooden blocks.

Thanks to this technique, EPS becomes a hyper-insulating material composed of 2 % material and 98 % of the best existing insulator: air!

L’atelier Les Gaillettes and insulated wooden blocks

It is up to ASBL Les Gaillettes to manufacture the different wooden building elements. They include wooden blocks that include an EPS insulation.

OSB panels consists of a mixture of wooden slats and natural resin. Wood chips (thin slats) are compressed to form a 18 mm OSB panel. OSB/3 and OSB/4 that make up our blocks does not contain formaldehyde.

The big advantage of this type of wood is that it does not work anymore. There is no risk that its shape will be changed over time. Your house will keep the same level.

After they are assembled, Gablok self-build blocks are delivered on bonded pallets, this to avoid any waste on the building site.

Local and social companies working together to offer high-performance self-build product.

Details on insulated blocks

The EPB is studied on a case-by-case basis, depending on each building site. The energy performance of buildings (EPB) is evaluated based on a number of precise criteria whose value differs depending on the type of dwelling. These criteria correspond to the characteristics that define a dwelling.

For instance: the different types of insulation (roof, exterior walls, interior walls, …) used, the type of frame and window surfaces, the orientation of the house or the heating system.

In a self-build project using Gablok, as for any other building, it is impossible to give a precise value of the EPB without knowing the other data (heating system, ventilation system, degree of insulation of the windows and so on).

Nevertheless, we can assert that the thermal conductivity (“U” value) of a Gablok wall is U=0.15 w/m²k. Our insulated wooden blocks will be able to meet 2021 EPB requirements.

Today, the thermal conductivity required by the EPB for a wall is U=0.24 w/m²k

The thermal conductivity of a passive house wall is U=0.10 w/m²k.

Note that it is always possible to increase the insulating value of our Gablok walls by applying additional external insulation.

The insulated wooden blocks have been designed to meet the requirements of a self-build project.

Gablok OSB wood blocks fit together to form the structure of the future house.

Thanks to the lightness and ease of use of Gablok wooden house kit, building your own house in Belgium can be done quickly and in anticipation.

The self-build project can be done in anticipation because all measures and finishes are planned in advance. Your individual wooden blocks are delivered to you on a bonded pallet. These earlier stages are time-savers, which is very important in construction field.

Planning your self-build project in depth also allows you to have no waste on the building site.

What about renovation with insulated formwork blocks?

Gablok system can be perfectly integrated for the construction of your extensions. A simple sketch will allow us to check its feasibility and give you a personalized quotation.

Build you house by yourself in United Kingdom

With Gablok, all self-build projects use the same insulated wooden elements.

Among these, we have our own flooring system. It is not necessary to cover it with a concrete screed. We provide all the beams and lintels required to make the floor.

The Gablok self-build kit consist of wooden beams that could support very long span

Wooden house kit

The self-build kit for timber frame houses proposed by Gablok includes all the insulated elements of the shell.

Gablok allows you to build the loadbearing interior walls and the exterior structure of your home.

Insulated wooden blocks used for your self build project are delivered to your building site on bonded pallets. This saves you the waste associated with on-site processing. Building is done quickly and your environment remains clean during the entire self-build process.

When the timber frame shell of your house is completed all you have is the finishing of the entire roofing system and general finishing works (finishes, special facilities, and so on).

Self-build using Gablok elements does not require drying time. With Gablok, the assembly of blocks becomes a simple and quick process. The entire building process is explained on a plan supplied together with the blocks. Gablok team will still provide you with technical support throughout the entire self-build process.

An intuitive but planned construction technique.

The dimensions of the openings (doors, windows and others) are established in advance, as soon as the building permit is received. Therefore, you can order the required equipment that will be installed directly after the construction of the shell.


The weight of a block used in a timber frame


Gabloks are available in 3 different lengths: 30 cm, 60 cm and 90 cm.

The height and depth of the individual blocks are always. They are 30 cm.

The 60 cm insulated wooden block weighs only 7.5 kg, which makes it very easy to handle.

The full span of a structure built in Gablok is equal to that of a traditional house.

Walls with insulated wooden blocks

The compressive strength of a wall with insulated wooden block is 150 kN/m.

Lintels, beams and floor elements

The lintels are the closing elements above the doors and frames.

Our longest lintels are 240 cm long. The beams have a very important span and they fit within the project.

The floor elements have a full span of 4.80 m. However, it is possible to increase this span by interposing a beam.

In terms of payload, the floor elements allow a load of 250 kg/m².

Insulated wooden blocks used for self-build projects are composed of OSB as wooden component and EPS as insulation component.

OSB: insulated wooden blocks

OSB is a type of wood composed of wooden slats and natural resin. It does not contain formaldehyde.

The wooden chips and slats are compressed to form a 18 mm thick OSB panel.

One of the most striking features of OSB is its stability. OSB panels used are classes 3 and 4. The wood used in this process no longer works. The timber frame construction will therefore not work over time.

EPS: insulator in wooden blocks

EPS stands for expanded polystyrene. The polystyrene beads are placed in an oven. They increase their size and volume by 40 times into contact with heat.

The obtained product is then poured into moulds before being compressed to form EPS.

The insulation is composed of 2 % material and 98 % air. EPS offers hyper energy efficient insulation.

The association of wood and EPS gives the self-build blocks a perfect insulation.