Note: Descriptions are shown in the official language in which they were submitted.
.~ -
- 2070~6
This invention is directed toward an improved, electrically
he~ted floor area. The invention is also directed toward a method
for constructing the electrically heated floor area.
Electrically heated floor areas are known. They normally
comprise floors having panels, with electric heating resistance
wires in them, sandwiched between the sub-floor and the finish
floor. The heating panels are usually constructed separately, off-
site, and then sent to the site for installation on top of the sub-
floor, After installation, the heating panels are covered with an
adhesive, or similar adherent material, and the finish floor is laid
- onto the adhesive adhering it to the heating panels.
- Variations of the above heating panels are known. The panel
may be provided with a finish floor surface during its manufacture.
Then no finish floor is required on-site once the panels are
installed. An example of this type of panel is shown in U.S. Patent
t 2,889,439. The panel may also be provided with an electrically
conductive layer in place of the resistance wire. An example of
this type of heating panel is shown in U.S. Patent 3,973,103.
All installations that require separate panels are expensive
however since the panels, and the floors incorporating the panels,~
must be separately constructed. In addition, floors incorporating
separate electrical heating panels are relatively heavy and thick.
It is the purpose of the present invention to provide a~
simplified electrically heated floor that is relatively inexpensive~
to construct and that is lighter and thinner than known floors~
employing separate electrical heating panels. It is also the~
purpose of th~ present invention to provide a method for simply and~
inexpensively constructing such a 100r.
In accordance with the present invention, the improved
electrically heated floor is constructed by laying the electric
~ heating resistance wire directly onto the sub-floor. The wire i8;
- laid down on the sub-floor in a pattern to provide optimum heating
~ over the heated floor area. The entire sub-floor is then covered
20704~6
with a layer of adherent material, such as an adhesive, to a
thickness at least equal to, or slightly greater than the thickness
of the wire. ~he adherent material covers the wire. In one
embodiment of the invention, the adherent material used is selected
to be compatible with the finish floor that is used. The finish
floor is laid onto this adherent material before it sets to adhere
the finish floor to the sub-floor with the wire sandwiched between.
In another embodiment of the invention, a first layer of adherent
material can be used to at least partially cover the wire. This
layer is allowed to set to fix the wire in place. A second layer of
adherent material, compatible with the finish floor that is used, is
then laid on the first layer. The thickness of the two layers is at
least equal to, or slightly greater than, the thickness of the wire.
The finish floor i~ laid onto the second layer of adherent material
r~ before it sets.
~ The completed floor comprises a sub-floor; at least one layer
of hardened adherent material on the sub-floor with the heating
, wire, laid on the sub-floor, embedded in it; and a finish floor. No
separate heating panels are employed in the floor construction. The
improved heated floor differs from a normal unheated floor that
employs adherent material only by adding the heating wire and
employing a slightly thicker layer or layers of adherent material so
as to completely cover the wire. The only extra step required in
constructing the heated floor, over constructing a normal unheated
floor, is in laying down the wire. This single step makes the floor
much cheaper to construct than a floor that employs separate heating
panels that must be constructed separately off-site, transported to
- the site, and then installed.
The adherent ~aterial used is the same as that used to
construct a normal floor that is not heated. If for example an~
-~ epoxy based glue is used to bond finish wood flooring to a wood or~
concrete sub-floor, then the same glue is used in making a heated~
-~ floor of the same sub-floor and finish floor materials, the only~
2070456
difference being that more glue is used to provide a thick
enough layer to embed the heating wire.
More particularly, the invention as claimed is
directed toward an electrically heated floor having-
a sub-floor defining a floor area, said sub-floor
being made of combustible material;
an electric heating resistance wire resting directly
on the top of the sub-floor said wire having a double
insulated resistance core covered with stainless steel braid
lo and being secured onto the sub-floor in a pattern having long
parallel length`s that are no more than two inches apart so as
to heat substantially all of the floor area;
at least one layer of hardened adherent material on
the sub-floor, said at least one layer embedding the heating
wire and having a thickness at least equal to the thickness
of the wire;
a finish floor on top of the layer of adherent
material; and
an electrical connexion box to which the heating
20 wire is connected, said box supplying a current of no more
than 2 watts/linear foot in said heating wire.
The invention is also directed toward a method of
constructing an electrically heated floor area comprising the
steps of:
laying down a sub-floor made of combustible
material;
securing an electric heating resistance wire having
a double insulated resistance core covered with stainless
steel braid on a selected area of the sub-floor in a pattern
30 having long, parallel lengths that are no more than two inches
apart so as to heat substantially all of the floor area;
covering the sub-floor, including the wire on it,
completely with at least one layer of adherent material, said
at least one layer having a thickness at least equal to, the
thickness of the wire;
2070456
setting a finish floor on top of the adherent
material before it sets to adhere the finish floor to the sub-
floor with the heating wire, set in the adherent layer,
located be~tween them; and
connecting said heating wire to an electrical
connexion box so that a current of no more than two
watts/linear foot circulates in said heating wire.
The invention will now be described in detail having
reference to the accompanying drawings in which:
Fig. 1 is a perspective view of the sub-floor with
the heating wire on it;
Fig. 2 is a broken-away perspective view of the
heated floor;
- Fig. 3 iæ a cros6-section view taken along line 3-3
of Fig. 2;
Fig. 4 is a detail top view of a wire support;
Fig. 5 is a broken-away perspective view of another
embodiment of the heated floor; and
Fig. 6 is a cross-section view taken along line 6-6
20 of Fig. 5.
The invention is directed toward an electrically
heated floor 1 as shown in Figs. 1 to 3. The floor has a sub-
floor 3. The ub-
./
/
A
2070456
floor 3 can be made from wood, such as plywood sheets, or concrete.
The sub-floor 3 can be carried on supports 5 such as wood joists, if
wood is used, or metal channels or beams.
An electric heating resistance wire 7 is laid down directly on
top of a selected area of the sub-floor 3. The wire could cover the
ent-ire sub-floor area, or just a part of it. The wiré 7 is laid
down in a pattern to ensure that substantially all of the selected
floor area is uniformly heated. Patterns are used that ensure that
the variation in temperature over the selected ~loor area will be no
~0 greater than about 2 P. Preferably the wire 7 is arranged in long,
parallel lengths 9 on the sub-floor 3 with each length 9 joined at
its ends to an adjacent long len~th with short transverse lengths
11. The wire 7 provides a serpentine current path. The wire 7
preferably has a double insulated resistance core of copper-nickel
alloy wire ranging in size from 32 A~G to 20 AWG depending on the
inætallation. The insulated core is covered with stainless steel
braid. The maximum operating temperature of the wire is about
ninety degrees centigrade and its power rating is a m~ of 12-
watts / 40 BTU per square foot.
The wire 7 is held in its serpentine pattern on the sub-floor
3 with wire supports 13. The wire supports 13 can be made from
plastic or sheet metal, or other sultable material. The wire
supports 13 can be arranged in straight lines 15 at opposite sides
17 of the floor area to be heated by the wire 7, if the floor àrea
is regular in shape. If the floor area to be heated is irregular in
shape the supports 13 are arranged accordingly to heat the irregular
shape. Th~ supports 13 in ea~h line 15 are spaced apart a distance
generally equal to the desired spacing "A" between the long wire
lengths g. Each support 13, as shown in Fig. 4, has a hook 19, 19'
at each end 21, 21' on its upper surface around which the wire 7 is
passed. A long wire length 9' of the wire 7 leads to one end 21 of
the support 13 from a support on the opposite side of the- floor
area, passes around hook 19 at that end, and goes to hook 19' at the
:
20't04~6
other end 21' of the support 13 as a transverse length 11'. From
hook 19', the wire 7 goes across the floor area to another support
as a long length 9". The supports 13 are fastened to the sub-floor
3 with nails 23 or similar fastening means.
The far end 25 of the heating wire i is brought back to the
initial end 2~ of the wire as shown in Fig. 1, and both ends as, 27
run along the sub-floor 3 and up a wall 29 to an electrical
connection box 31 in the wall. A connector 33 connects the wire
ends 25, 27 to the box 31. The heating wire 7 is connected to the
building wiring 37 in the box 31 by suitable-means (not shown) and
a thermostat 39, connected to box 31, controls the current in the
wire 7.
After the heating wire 7 is laid down directly onto the sub-
floor 3 in the desired pattern, it is covered with a layer 41 of
adherent material. The layer 41 of adherent material is at least
equal to, or slightly thicker than, the thickness of the wire 7, or
the thickness of the wire supports 13 as shown in Fig. 3, so that
the layer 41 completely covers them, embedding them in the layer.
The adherent material is selected to be compatible with the f inish
floor that is to be laid on the adherent layer. The adherent layer
41 is applied in sections on the sub-floor 3 and is trowelled to
spread and level it in a direction generally parallel to the heatin~
wire lengths 9 as shown in Fig. 2 so as not to disturb the wire
lengths. Before the adherent layer 41 sets, elements 43 of the
finish floor 45 are laid on the adherent material to adhere them to
the sub-floor 3 as the adherent material sets. The finish floor 45
can be made from wood, ceramic tiles or squares, natural or
artificial s.one squares or slabs, concrete squares or slabs, or
similar material.
The adherent material employed, is that normally employed with
the particular finish floor material selected. The adherent
-~ material can be an epoxy or latex based adhesive, or a masonry
grout-type cement. The adherent material layer 41 is normally about
2~70~56
one-quarter of an inch thick, but the thickness can be varied so
lon~ as the layer is thick enough to cover both the wire 7 and the
wire supports 13.
The long lengths 9 of the heating wire pattern are spaced apart
a distance "A" that preferably is no greater than 2" when the floor
employs combustible material such as wood. This close spacing
' permits less current to be used in the heating wire to heat the
floor thus minimi7ing the risk of fire. While current to provide a
power output of up to 5-6 wattsJlinear foot can be used in the wire
on combustible floors, with a wire spacing of 2", it is preferred
that current providing a power output of no more than 2 watts/linear
foot be employed. When the floor employs non-combustible materials,
the heating wire 7 can carry more current and thus the long len~ths
9 of the wire can be spaced farther apart. The long lengths 9 could
be spaced apart between 1" and 12". For non-combustible floors,
current providing a power output of up to 40 watts/linear foot could
be used. It is preferred however to space the long lengths of wire
4" apart and to use a current providing a power output of between 2
and 6 watts/linear foot on non-co`mbustible floors. The heated
floor, when completed, has a sub-floor and a finish floor joined by
a thick, hardened, adherent material layer in which layer is
; embedded a heating wire.
The heated floor described above employs a single layer of
~ adherent material. However, heate~ floors can be constructed using
- two different adherent material layers. As shown in Figs. 5 and~`6,
the heating wire 107 is laid on a suitable sub-floor 103 as before
with the aid of wire supports 113. ~he sub-floor 103 is then
covered with a bottom layer 141 of suitable adherent material which
is thick e~u~h to cover, or almost cover, the heating wire 107 and
the wire supports 113. This bottom layer 141 is allowed to set,
fixing the heating wire 107 in place. A top layer 142 of suitable
adherent materi~l, preferably one that can be levelled, is next
a~plied onto the bottom layer 141, completely covering the heating
2070456
wire 107 and wire supports 113 if they are still exposed.
- This top layer 142 can be applied immediately after the bottom
layer 141 6ets, or several days later. This top layer 142 can
be spread,and levelled with curved strokes as shown in Fig.
! 5. After the top layer 142 is levelled, and before it sets,
the finish floor 143 is applied to the top layer 142 adhere
it to the sub-floor. The two-layered adherent material layer
is normally employed with masonry floor construction with the
top layer being a cementious adherent material such as grout
10 that can be spread to level the floor.
By way of example, a heated floor can be made using
a sub-floor of plywood with a heating wire laid on top of the
sub-floor with the long lengths at 2" spacing. The sub-floor
and heating wire are covered with a 1/4" thick layer of
adhesive having a polymer base sold under the trademark
"Keralastic" by Mapei. Before the adhesive layer sets, it iæ
covered with a finish floor made up of ceramic tiles having
a thickness of 3/8".
As another example, a heated floor can be made using
20 a sub-floor of concrete with a heating wire laid on top of the
sub-floor with the long lengths at 4" spacing. The sub-floor
and heating wire are covered with a 1/4" thick bottom layer
of adhesive having a polymer base sold under the trademark
"Grani/Rapid" by Mapei. This bottom layer is allowed to set.
It is then is covered either immediately after setting, or
sometime latter, with a 1/4" thick top layer of grouting
,
cement that is levelled. Before the top layer sets, it is
covered with granite sl~b6 having a thiFknes6
~ ,
~ ,
