Parts can be connected with coupling plates, with connecting or linking beams and - simply - with screws, bolts and nuts.

To make parts of the building portable, walls and floors must be made out of small pieces of no more than 100 kg, each with fire protection all around so that they can be linked together. This means we get horizontal and vertical seams.

We could screw all the walls and floors together tightly. But in order to prevent sound propagation, we better rely flexible, fire-resistant foam tape, rubber or compressed rock wool and connect floors and walls with a little bit of slack. When bolting or screwing, a large ring can be used as a spacer for noise reduction.

A coupling plate typically connects four units at their corners a few millimetres apart.

A coupling plate does not give much strength when it is only attached to one side of the wall, as can happen in case of a fire, but it can suffice in the building as a whole.

A horizontal beam does the same thing, but in multiples, depending on its length. The beam gives extra strength both in terms of stiffness and tensile strength.

Especially at the bottom a connecting beam can be useful because there will lots of "holes" in the construction, being doors. A floor can also fulfil this additional strengthening function, but must be linked to the wall for instance using the beam at the bottom. In terms of construction, it will be easiest to first lay the floor with a connecting beam on top of it. The wall sections can then be placed against this.

Coupling beams can be connected with coupling coupling-beams, but they can also be connected by the components that link them.

Wood is up to 20 times stronger in the direction of the grain, but the surface area is many times larger in the longitudinal direction.

If components are storey-high, a horizontal beam at the top and bottom can be sufficient, which can be aesthetically pleasing.

In the drawing, the horizontal beams are mounted directly on the fire-resistant plate and must therefore be constructively secured to the middle skeleton. This can lead to problems in terms of fire and vapour. The coupling beams are best placed on the outer and inner skeleton.

On the inside of the building, vertical beams may be more aesthetically pleasing. If they are attached to the ends of inwardly sticking plates (e.g. of cabinets), the sound transmission will be low, but the strength of the joint may be low in the horizontal direction, so this type of joint will be most useful in terms of aesthetics. It can be combined with coupling bolts closer to the wall.

Linking beams ultimately form part of the inner and outer skeleton. Maybe an inner or outer skeleton even consists entirely of linking beams.

Linking beams can also be fitted in between building elements. In that case, insulation and fire-protection must also be provided in between there. This can have an advantage with high-rise buildings because you can add extra strength. Furthermore, for floors and roofs, it is an option to place linking beams between boards, and then it might be useful to do the same in the walls. Blokiwood® does this in the roof by using I-beams with insulation.

A recessed connecting beam sits both on and between building elements. It can also merge with the interior skeleton (or the technical cavity).

A flush mounted connecting beam can be covered for fire resistance. The cover then (typically) belongs to the linking beam.

If the horizontal beam is recessed, a vertical, not recessed beam can pass over it.

With modern, sleek fashion, many people will find (semi) recessed linking beams most beautiful. It also has technical advantages as you don't have to take into account protrusions. But it is at the expense of the simplicity of the construction. So it would be nice if both systems could be used interchangeably.

If you don't want to mount linking beams directly on a fire resistant plate, but on an inner or outer skeleton, then the whole thing will come out or in. It can be difficult to make this beautiful. You could countersink the inner or outer skeleton to the height of the linking beams.

Countersunk or semi-sunk linking beams are fixed on beams that are "around" or "between" the building elements. They could be in the middle skeleton and between the fire resistant plates, but that's not necessary. You can also see it as an inner or outer skeleton that sits at the top, bottom and sides of a building element. I suggest we call this a sunken skeleton. Typically this is an inner and outer skeleton. In the drawing above, this is even one whole. It can also be more inside the fire protection of the central skeleton. Then you can call it "a sunken part in the middle skeleton", perhaps (but perhaps confusingly) abbreviated to "sunken middle skeleton". The point is, from the outside, it is a recession in the wall.

Coupling plate and linking beam can be used with normal, non inverted walls.

Coupling bolts or screws can be used for inverted walls.

You can place a small beam on an ordinary wall to be able to use coupling screws, as long as you couple in a fireproof way, so both inside and outside of the building - or only on the outside but behind a fire-resistant (curtain) wall.

Coupling plates and linking beams must be fixed and this will be done most cheaply with bolts or screws. For structures that have to be disassembled often, screws may be less desirable because they will eventually damage the wood. This damage can be reduced when coupling plates and beams are positioned tightly so that the screw always falls into the same hole.

Forms of positioning will often go hand in hand with things that stick out, which is vulnerable in transport. The protruding parts are preferably mounted on linking beams and plates and not on building elements. Semi-countersunk coupling nuts on countersunk threads, for example, can be removed, but this can be difficult from a fire technical point of view because they will then be recessed into a fire protection board.

Screws and bolts may pass through the fire protection. Heat can enter through the metal into the underlying skeleton or can leak along the screws or bolts. Stainless steel conducts less heat and is therefore preferable. The metal should preferably be thin in relation to the thickness of the fire resistance. So staples are preferable, but they can't be disassembled.

Without special couplings, the linking bolts seem to win out over linking beams and coupling plates.

However, linking beams and plates can be mounted outside the fire protection on the external or internal skeleton. You can let this sink into the wall so that the linking beam looks like a plinth.

 

Linking skeleton

One of the complications with linking beams is that, especially if you want to use them both inside and outside, the thickness of the wall sections comes quite precise. However, if, instead of a complete inner or outer frame, you only mount the horizontal or vertical beams, then you can lay the linking beams on these. This comes much less tight than mounting them on the outside.

If you only mount the horizontal or vertical beams, then you can also easily connect without link beams. The skeleton itself becomes sort of a link beam. So you get a kind of Linking skeleton.

Take a horizontal beam at the bottom of a wall section. You can now screw it to a floor box at the ends. This is not possible if there is an equally thick vertical beam above it. A thinner vertical beam would be fine. The horizontal beam can then look like a skirting board. The difference with a link beam is that it does not connect multiple wall elements itself.

Take only vertical beams - a vertical linking skeleton. Now you connect the wall element to the floor with a small link beam or connecting plate.

Along the outer wall of the building there are many possibilities to connect. Along the inner wall that can be more difficult when all kinds of things are built in there or when different types of walls are mixed. We leave this to the creativity of the builders and designers.

The inner skeleton may be visible on the inner wall. That can be eliminated, but I think that this is precisely the charm and should be turned on and used.

A horizontal beam on the wall at the height of a tabletop or window sill seems handy to me. For example, if you put a 160mm beam against the wall at 750mm, you can attach a table or desk to the bottom, and a worktop at the top at about 910mm for standing at. Now, these aren't handy sizes, but with a small spacer you can also attach a tabletop to a beam that is slightly higher on the wall.

Bags of fire-resistant, vapour-proof material, such as "Stamisol Safe One" by Serge Ferrari, can be mounted on the outside of the building elements and filled with soft insulation materials such as flax. Stamisol Safe One has a fire class of A2-s1,d0 and is heat resistant up to 800 degrees.

Insulation material can also be placed in containers made of fire-resistant panels. Then it is easiest to connect with linking bolts. But coupling plates and linking beams are also possible because the sides and top of the bins can be partially open, as long as the whole thing is closed after coupling.

We prefer to make special corner sections for the corners of a building. The bottom line is that you have to connect the edges or linking beams of two walls and that you have to connect air- and fireproof by means of side plates that will now be at an angle to each other.

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