The present invention relates to a rectangular construction
panel having an upper edge, a lower edge which is situated opposite to the upper
edge, and two side edges which are opposite to one another, where the construction
panel comprises a sandwich structure having a first layer, a second layer and a
third layer, wherein the first and third layer comprise set mortar and the second
layer comprises hard foam.
Such a rectangular construction panel is known in the art,
for instance for partition walls. As hard foam, for instance polystyrene is applied.
For applications where the construction panel is loaded more heavily, construction
panels are known wherein the first and third layer are connected by reinforcement.
The present invention aims to provide an improved construction
To this end the present invention provides a rectangular
construction panel having an upper edge, a lower edge which is situated opposite
to the upper edge and two side edges which are opposite to one another, where the
construction panel comprises a sandwich structure having a first layer, a second
layer and a third layer, wherein the first and third layer comprise set mortar and
the second layer comprises hard foam, wherein
wherein in the second layer at least one duct is provided which extends from at
least 1 edge selected from the upper edge, lower edge and side edges, in the direction
of the opposite edge.
- the first layer has a thickness of 5 mm to 50 mm, the second layer has a thickness
of 80 mm to 400 mm and the third layer has a thickness of 5 mm to 50 mm, with the
provisio that the ratio R of the second layer to the total thickness of the first
and the third layer is at least 2, and
- the connection of the first layer with the second layer and the connection of
the third layer with the second layer are stronger than the second layer,
Such ducts offer two important possible uses, in particular
the drainage of moisture (such as rain water, condensation and the like), and the
possibility to lead through utility conduits. The presence of the ducts weakens
the construction panels somewhat, but the strength of the construction panels according
to the invention is such that this is nevertheless made possible. For the drainage
of moisture the ducts will generally have a diameter of 10 - 30 mm, and for pipes
generally a diameter of 15 - 25 mm, but for both applies that a wider, and optionally
a smaller diameter is also possible. The shape of the cross section of the duct
is selected depending on the intended application. Because of the reduced weight
of the first and the third layer in combination with the relatively great thickness
of the polystyrene layer at the specified adherence between the mortar of the first
and third layer with the second layer, surprisingly, such a construction panel,
despite the presence of one or more ducts, appears to be so strong that it can be
loaded relatively heavily but is nevertheless cheap in that reinforcement, which
connects the first and the third layer, can largely, and in most cases even entirely,
be omitted. The required adherence of the first layer and the third layer to the
second layer can be achieved in a manner known per se. This will be pursued later
in this application when a method for manufacturing the rectangular panels according
to the invention is discussed.
Hereinafter some embodiments will be described which are
preferred since construction panels which comply with one or more of these conditions
may be loaded even more heavily.
Preferably, the ratio R is at least 2.5 and more preferably
at least 4.
Preferably, the first layer has a thickness in the range
of 10 mm to 25 mm, and the third layer has a thickness in the range of 10 to 25
Preferably, the second layer has a thickness of at least
125 mm, more preferably a thickness of at least 180 mm.
Preferably, at least 1 of the first and the third layer
has reinforcement included in the layer in question and enclosed by the layer in
This reinforcement is, for instance, in the form of wire
mesh, fibre mats, such as a mat of glass fibres or plastic fibres, or loose fibres
mixed with the mortar. In the scope of the present application, the term "enclosed
reinforcement" means that this is essentially situated in the layer in question
and does not extend from the first layer to the third layer, or the other way around.
The term does not exclude that no single part of the reinforcement can be visible
at the surface of the layer in question.
The hard foam is preferably a thermoplastic polymer having
a softening point above 70°C.
Such thermoplastic polymers are generally cheap but nevertheless
afford favourable construction properties. According to an advantageous embodiment
the thermoplastic polymer is expanded polystyrene.
Preferably, the at least one duct extends from the upper
side in the direction of the lower edge.
Thus, particularly for applications involving a lowered
ceiling, where utility conduits are fitted in the lowered ceiling, a utility conduit
can readily be introduced into the duct in order to achieve that it can be made
accessible at a lower location in the space that is defined at at least one location
by a construction panel according to the invention, by making a hole in the construction
panel. For applications with moisture drainage, the at least one duct will extend
as far as the lower edge, where the moisture can be discharged in a manner known
Particularly, for wall panels and outer wall panels it
applies that preferably within a distance of 1 m from a side edge at least 2 ducts
Especially at this location, in practice there is a demand
for utility conduits such as electricity and data conduits (such as for Internet).
Especially for moisture drainage, it is preferred that
ducts are present distributed over the entire construction panel, said ducts being
situated a) at the interface between the first layer and the second layer; and/or
b) between the centre of the second layer and the interface between the first layer
and the second layer.
After placement these run from the top down.
According to an important embodiment the construction panel
is an outer wall panel having a width of at least 4 m.
Outer wall panels will more usually have a width of at
least 5 m, more in particular at least 6 m.
The invention also relates to a method for manufacturing
a rectangular construction panel according to the invention, wherein a first mortar
is applied on a mould, a plate of hard foam is applied on the first mortar before
the first mortar is set, and a second mortar is applied on the hard foam, producing
the rectangular construction panel after setting of the first and the second mortar,
wherein the composition of the first and the second mortar is such that they are
low-shrinkage mortars and present a shrinking or swelling of no more than 1% when
setting, and wherein the first layer has a thickness of 5 mm to 50 mm after the
setting, the second layer has a thickness of 80 mm to 400 mm and the third layer
has a thickness of 5 mm to 50 mm after setting, provided that the ratio R of the
second layer to the total thickness of the first and the third layer is at least
2.5, and the composition of the first mortar and the second mortar is selected such
that in the set state of the first and the second mortar, the connection of the
first layer with the second layer and the connection of the third layer with the
second layer are stronger than the second layer.
Low-shrinkage mortars are generally known in the art and
need no further explanation. As a result of setting of the mortar such mortars preferably
shrink or swell no more than 0,5%, more preferably no more than 0,2%. In order to
ensure that a mortar presents the adherence to the second layer as required according
to the invention, the person skilled in the art has a wide range of options at his
disposal. Firstly, the person skilled in the art can provide the plate applied with
an enlarged surface, for instance by coarsening it or by providing it with a profile.
Secondly, as a low-shrinkage mortar, a mortar of low viscosity can be selected,
which penetrates further into the surface cavities of the hard foam. Finally, it
is also possible to adjust the composition of the mortar by using additives. For
instance, a glue is contemplated, such as Beamix Primer 780 (Beamix, Eindhoven,
Most advantageously, the hard foam is a thermoplastic polymer,
and the at least one duct is provided in the hard foam by means of a hot heating
It has been found that particularly with polystyrene, it
is possible to provide ducts very easily.
According to a preferred embodiment a connecting split
that is formed by the hot heating element between the duct and a surface of the
hard foam is filled using a kit or foam.
Thus, an optional loss in strength of the construction
panel formed therewith can be limited. Advantageously, in particular if the hard
foam is polystyrene, polyurethane foam can be used as a foam, which presents a proper
adherence and has in addition filling properties.
In an alternative embodiment, the at least one duct is
formed by gluing together two hard foam parts of which at least 1 has a groove,
and the groove is formed into a duct which is defined by both hard foam parts.
Finally, the invention relates to a method for laying utility
conduits, which is characterized in that in a dwelling provided with a rectangular
construction panel producible according to the invention, a place is selected at
a location along the at least one duct where a utility connection has to be fitted,
at that location a through-hole is formed, through the second layer of mortar, which
connects to the duct, and from an end of the duct selected from the through-hole
and an edge of the rectangular duct a utility conduit is introduced into the duct,
wherein the hard foam prior to or after the application is provided with at least
Thus, it can be achieved that the utility conduits, such
as a water conduit, are out of sight, without slotting of the first or third layer
or the like. When more ducts are present, it is also very well possible, should
there be a need to change, to provide a utility conduit of the same or a different
type at another location.
Preferably, the utility conduit is selected from a flexible
water conduit, an optical fiber cable, an electric cord and a cable for transision
of electronic data.
Generally, these can readily be bent and fed through the
The present invention will now be illustrated by the following
working examples with reference to the drawing, in which
- fig. 1 shows a front view of a construction panel;
- fig. 2 shows a cross-section according to line II-II through the construction
panel of fig. 1;
- fig. 3 corresponds with fig. 2, but here the construction panel, according to
the invention, has ducts for the drainage of moisture;
- fig. 4 corresponds with fig. 3, but here the construction panel according to
the invention has ducts for a utility conduit;
- fig. 5 shows a longitudinal cross section through the construction panel via
line V-V of fig. 4;
- fig. 6a and 6b show, respectively, a front view and a perspective front view
of a wire loop suitable for forming ducts in a thermoplastic polymer; and
- fig. 7 shows a detail of a plate of thermoplastic polymer provided with a duct.
The figures are schematic and not to scale, wherein particularly
the thickness of the construction panel is shown exaggeratedly.
A construction panel was manufactured for testing purposes
having a width of 50 cm and having a length, representative of a construction panel,
of 3 m. To this end, a boundary casing having the aforesaid dimensions was placed
on a mould. A low-shrinkage mortar composition was prepared using casting mortar
TM5203 (Tillman, Megchelen, The Netherlands) prepared according to the instructions
of the manufacturer. A layer of this mortar composition having a thickness of 2
cm (first layer) was cast and spread on the mould. The layer of mortar was then
immediately covered with a polystyrene plate having a thickness of 20 cm (second
layer; EPS foam, Firma Unidek B.V., Gemert, The Netherlands). When doing so, the
plate was put into the mortar with one edge first and was subsequently positioned
horizontally in order to prevent air from getting trapped under the plate. The plate
was pressed down by walking over it. Subsequently, a finishing mortar was made using
the fibre reinforced casting mortar ABS340 of Beamix prepared according to the instructions
of the manufacturer. The finishing mortar was applied onto the plate of polystyrene
(in a thickness of 2 cm). This layer of finishing mortar (third layer) was levelled
using a spatula. After 16 hours of setting at 20°C the construction panel 1
thus formed could be taken from the mould, and was allowed an additional setting
of 7 days.
To remove air bubbles captured under the polystyrene, an
underpressure can be applied. This is, for instance, possible by covering the totality
of the mould and panel with a PVC foil, and subjecting the space under the foil
to an underpressure. For that matter, it is noted that, although the presence of
bubbles may not be desirable, especially the large bubbles are disadvantageous,
and especially the large bubbles, should they even occur, can be removed properly
with the underpressure technique described above. The air can escape between adjacent
polystyrene plates or via holes that have been provided in the polystyrene plates
for this purpose. These holes can be made, for instance, by using, optionally hot,
needles. Another advantageous method to prevent air from getting trapped under the
hard foam in the method according to the invention, is using strips of hard foam
having a width of 50 cm or less, such as 40 cm or less. Advantageously, plates are
cut to strips and the strips are placed with a cut face (thus, transverse to the
original surface of the plate) on the first mortar.
Once it is taken out of the mould and placed upright, the
construction panel 1 as obtained above has an upper edge 2, a lower edge 3 and side
edges 4 and 5 (fig. 1). Fig. 2 shows a cross section along line II-II of fig. 1.
Here, the first layer of set mortar 6, the second layer 7 consisting of polystyrene,
and the third layer of set finishing mortar 8 can be seen.
The construction panel 1 as manufactured hereinabove was
subjected to loading tests. Here, the construction panel 1 was supported at the
long ends 2, 3, and across the length of the construction panel 1, weights in the
form of bags of cement (25 kg each) were put onto the construction panel 1. Starting
from the middle, the bags were put on the construction panel 1 in pairs, flat (and
longitudinally transverse to the longitudinal direction of the construction panel
1). When the ends 2, 3 of the construction panel 1 were reached, a new layer was
begun starting from the middle again. After every pair of bags, the deflection was
measured and was checked for formation of cracks. Once the construction panel 1
was loaded with 550 kg, during which no formation of cracks was observed, an endurance
test of 28 days was performed. Regular checks were made to find whether the degree
of deflection had altered and whether formation of cracks had occurred. This appeared
not to be the case. Thus, it can be concluded that with using the method an extremely
strong and light (90 kg/m2) construction panel 1 can be obtained.
Fig. 3 corresponds with fig. 2, except that as a second
layer 7 a polystyrene plate is used which is provided with ducts 9. The ducts 9
serve for draining moisture, particularly moisture accumulated near the first layer
6 (which, when used as an outer wall panel, functions as the side that is exposed
to the atmosphere) as a result of cold (condensation), rain etc. According to the
invention these ducts 9 in the second layer 7 will preferably be situated between
the centre of the second layer 7 and the first layer 6 (fig. 5). Usually the distances
between the ducts 9 will be smaller than the thickness of the second layer 7. It
has been found that despite the presence of ducts, the strength of such a construction
panel is more than sufficient.
According to the invention, the second layer 7 can be used
for laying a utility conduit in a duct 10 (fig. 4, 5). In practice, such a utility
conduit will most often be an electric cord or power cable, but may also be, for
instance, glass fiber for an optical data network. After placement of the construction
panel 1 and particularly when there is more than 1 duct 10, this allows the laying
of a connecting socket or a connection for telephone, Internet etc. in a desired
location. According to the invention, these ducts 10 in the second layer 7 will
preferably be situated between the centre of the second layer 7 and the third layer
Using this method according to the invention and using
a panel according to the invention, a bendable utility conduit can be laid in a
concealed fashion, without a great deal of work. For instance, when using a lowered
ceiling, the utility conduit (not shown) can be hidden in the lowered ceiling, and
can be introduced into the duct 10 by means of a hole 11, to be made in the third
layer 8 at the location of a duct 10. At the location in the room where the connection
for the utility conduit has to be provided, also a hole 12 is made in the third
layer 8. As shown in fig. 5, at the location of a hole 11, 12, excess material of
the second layer 7 can be removed to facilitate connecting.
For laying the ducts 9, 10 in the second layer 7, in particular
for thermoplastic polymers such as polystyrene advantageously a copper wire loop
13 can be used (fig. 6). The wire loop has two ends 14, 15 which connect a loop
part 16. The two ends 14, 15 may be connected to a low-voltage supply (eg. 20 V).
The current that runs through the loop part 16 is such that it reaches a temperature
at which polystyrene melts. For manufacturing a duct 9 or 10 situated in the second
layer 7, the ends 14, 15 are designed flat (fig. 6b) and are placed in line with
each other, substantially transverse to the intended direction of movement of the
wire loop 13, which defines the cross section of the duct to be made using the wire
loop 13. A hot wire loop 13 is passed through the polystyrene plate from the upper
edge 2 or lower edge 3 of a plate polystyrene. Although for forming a duct 10, this
may take place after the plate polystyrene has been applied onto the first layer
6, forming ducts 9, 10 will usually take place prior to applying the second layer
7 onto the first layer 6. Usually the hot wire loop will be passed along the entire
distance between the upper edge 2 and the lower edge 3. A residual core of polystyrene
formed in the duct 9, 10 during this process can be readily pushed or blown out
of the duct 9, 10.
By forming the wire ends 14, 15 as described above, a duct
9 or 10 can be formed, which along its length is connected with the surface of the
plate polystyrene 7 only by means of a narrow gap 17 (fig. 7). Particularly, in
case of duct 10, and when using a relatively thin or little thixotropic mortar,
but also more generally in order not to unnecessarily affect the properties of strength
of the second layer 7, it may be recommended to fill the gap 17, for instance using