Most heat escapes through
the roof, so it is necessary to attach a particularly large weight to its
insulation. The easiest way is,
of course, to insulate the roof while building a house. However, it is possible later.
Most heat escapes
through the roof, so it is necessary to attach a particularly large weight to
its insulation. The easiest way
is, of course, to insulate the roof while building a house. However, it is possible later.
Layers of insulated
roof: 1 - roofing, 2 - patches, 3 - windproofing, 4 - rafters, 5 - thermal
insulation, 6 - vapor barrier, 7 - wall-paper.
Isolation layers
Isolating the roof is
necessary. If the space under it
is unusable - just enough to protect it from moisture.
However, if it is to be
used as a residential one, it must be not only dry, but also warm. The insulated roof is a multilayer
structure, which consists - looking from the cover - windproof insulation (and
at the same time vapor permeable), thermal insulation and vapor barrier
insulation. Thermal insulation is
the middle layer, because it must be protected from outside water and steam
from the inside of the building. Suitable
materials are used for this.
In the case of
low-vapor-permeable film, two ventilation slots are necessary. 1 - roofing, 2 - patches, 3 -
ventilation slits, 4 - string, 5 - wind insulation film, 6 - thermal
insulation.
Wind insulation
Roofing foils
(pre-covering foils, FWK) protect against infiltration of rainwater and allow
evaporation of moisture from thermal insulation to the outside. Depending on the ability of water
vapor transmission, two types of film are distinguished. This factor also affects the scope of
the products listed below. Low
vapor permeable films are made of a polyethylene film or a polypropylene
membrane. Most often they are
reinforced with a net of polyethylene, HDPE polypropylene or fiberglass. Films with an anti-condensation layer
that absorb excess moisture from the air are also available. When laying the foil, it must be on
the inside of the house. When
using a low-vapor-permeable film, it is necessary to leave a ventilation gap
between the roofing and the foil, and between the foil and the insulation. Otherwise the water vapor escaping
from inside the house would remain in thermal insulation, causing it to become
damp.
In the case of a highly
vapor-permeable film, a
ventilation gap under the roof covering is
sufficient : 1 - roof covering, 2
- patches, 3 - gap, 4 - FWK foil, 5 - thermal insulation.
If building elements
protrude above the roof surface, the foil should be placed in such a way as to
prevent rain and snow from entering. The
low-vapor-permeable membrane can be installed without fear if the roof is not
insulated and the attic is unused.Highly vapor-permeable foils (also known as
roofing membranes) are produced as single-layer, made of HDPE polyethylene and
as double-layer, made of polyethylene and polyester. They should be placed with a colored
page or with inscriptions outside. The
membranes are reinforced with a polypropylene mesh, which makes them resistant
to tearing and other mechanical damage. The
higher the water vapor permeability, the better. This feature allows you to put them
directly on thermal insulation, without a ventilation gap. Highly vapor-permeable foils are used
instead of stiff plating and roofing paper, if the attic of the house is
insulated, and the roofing will be ceramic tiles, cement tiles or roof tiles
laid on patches and counter-battens. Some
foils may substitute for roofing paper, laid on a rigid planking or wood-based
boards.
Thermal isolation
For insulation of
pitched roofs, mainly mineral wool mats or boards with high elasticity and low
volumetric weight (12-15 kg
/ m3) are used. Glass wool is
particularly preferred as being lighter than rock. It is recommended to use a minimum
thickness of25 cm . It acquires a special meaning at the
moment when the so-called energy
passports of buildings. An object
that does not comply with the regulations is not energy-saving. Styrofoam panels can also be used to
insulate pitched roofs. It is
worth choosing those whose edges are contoured. When laying, they overlap, forming a
tight connection. Many
manufacturers offer styrofoam in varieties intended for roof insulation.
Vapor barrier
Vapor-tight foils
protect thermal insulation against penetration of water vapor during operation
of the house. They are produced
as single- or multi-layer. A
special feature is foil reinforced fibers, because they absorb moisture, and
then evaporate it at a higher temperature of air. Shoulder foils should be used, which have
a mesh of strong polypropylene between the plastic layers.They are resistant to
tearing and other mechanical damage. On
the surface of the foil there are markings informing which side should be top.
Cy rkulacja air under the roof covering 1
- vent Ridge, 2 - the ventilation opening in the gable wall, 3 - the flow of
air through the ventilation gap over the thermal insulation 4 - an inlet in the
roof eaves.
Ventilation of the roof
slope
Ventilation speeds up moisture removal from
insulation and protects the bottom surface of roofing against moisture. Leave ventilation space beneath poorly
permeable layers, such as full planks or roofing paper. It is not necessary to make a gap when
using FWK film with very high vapor permeability. The free air flow in the space under
the roofing is ensured by ventilation slits under the eaves and in the ridge,
or openings in the gable walls. Both
gaps and openings should be covered with a mesh to prevent insects and rodents
from getting under the roof cover. Many
manufacturers of roofing materials offer accessories for their systems,
including special plastic combs
that shield the ventilation gap in the roof ridge.
How to warm
During roof insulation,
it is not necessary to remove the cover. The
work is carried out from the attic side.
Fixing of wind
insulation: 1 - edges of foil belts curled on the rafter, 2 - metal staples.
Stages of implementation
Wind insulation
The first layer,
performed during thermal insulation, is the pre-covering foil. Currently, low-vapor permeable foils
are being used less and less often, because a ventilation gap between the foil
and the thermal insulation layer must be made. Otherwise, there is a risk of
insufficient evaporation of moisture from the insulation and, consequently, its
destruction. In the case of
membranes, i.e. high-vapor-permeable foils, this gap is unnecessary. However, it is always necessary to
leave a gap between the windproofing and the roofing. This enables proper ventilation of the
roof slope. In order to attach
the foil, wooden strips with a thickness of approx. 2 cm should
be nailed between rafters . It is only to them that the wind
insulation is fixed, secured with a special stapler.The edges of the foil must
be wrapped on the sides of the rafters. When
fixing the windproof foil, special attention should be paid to its arrangement. The subtitles page must be on top. This is why it is so important because
the foil has microscopic funnel-shaped openings. Thanks to this, they allow the removal
of steam, but at the same time do not allow water to enter the thermal
insulation layer. It is a
frequent mistake made by the contractors not to care about the correct
positioning of the film.
Fixing of thermal
insulation: 1 - wind insulation, 2 - string, 3 - mineral wool, 4 - system
hangers, 5 - system profiles.
Fixing of thermal
insulation: 1 - wind insulation, 2 - string, 3 - mineral wool, 4 - system
hangers, 5 - system profiles.
Thermal isolation
If mineral wool mats are
used for insulation of the roof surface, unpack them beforehand and tap to
allow the material to expand. Warming
will be most effective if the insulation is placed in two layers: the first one
between the rafters and the other under them. Wool
straps in the first layer must be cut on both sides about 2 cm wider
than the distance between the rafters.Then press them between the rafters. To protect the material against
falling out, it should be supported from the bottom with a string fastened to
the sides of the rafters. The
next step is to fasten the metal system frame. First screwed to the rafters,
so-called hangers, and then put
on a second layer of thermal insulation. Also
in this case, the wool must be cut so that it fits between the profiles. After laying the wool, C profiles are
screwed to hangers; they must be
arranged perpendicular to the rafters. These
profiles support thermal insulation and at the same time constitute a grate for
fastening gypsum boards, which are usually finished with attic.
Fixing of vapor barrier
and finishing: 1 - windproofing, 2 - mineral wool, 3 - self-adhesive tape, 4 -
plasterboard, 5 - screws fixing boards to profiles, 6 - vapor barrier, 7 -
system profiles.
Installation of a vapor
barrier
The foil is laid with
stripes, parallel to the floor, starting from the highest attic space. The foil should be laid evenly,
without corrugation. It should be
slightly stretched, but only enough to level the surface without permanently
deforming the material. The foil
is attached to the frame with double-sided self-adhesive tape. It is necessary to ensure that the
vapor barrier is sealed. Its
individual belts are connected to bets about 10
cm . Joints should fall on the frame slats. The foil joints must necessarily be
sealed with self-adhesive tape, as well as staple driving areas - in the case
of windproofing.
Finishing plasterboard:
1 - the place where the plates meet, 2 - reinforcing tape, 3 - putty.
Finish. The most popular is the attic finish
with plasterboard panels. They
are screwed to a frame supporting the second layer of insulation. By mounting the panels to the frame,
the possibility of cracks caused by the work of the truss is minimized. Gypsum plasterboards should be laid in
two layers. This provides much
better fire protection of the truss than the standard single boards.The boards
of the first layer are fastened vertically, while the other is horizontally,
with the longer side perpendicular to the floor.The bonding points of the
panels must not fall out in both layers in the same place (they are laid on the
pass). The boards are screwed
with screws intended for this material. After
attaching them, the joints should be stitched. It is good to strengthen the joints
with reinforcing tape. Then,
cracks will not appear on the finished surface. Discs prepared in this way are usually
painted, but you can also glue wallpaper on them.
What you need to know
The most advantageous is
the installation of thermal insulation in two layers. Only then is it possible to eliminate
thermal bridges.It is also important that the insulation is sealed. If the insulation is to be directly in
contact with the wind insulation, do not press it too much, as this may cause
it to bulge and contact the roofing. This
will disable the ventilation process, and in the case of, for example, sheet metal
coating, it may damage the foil due to overheating. It is necessary to maintain at least a
2.5-centimeter ventilation gap between the wool and the roofing. The actual size depends on from the rafter length: the longer the
rafter, the larger the gap.
In order to ensure
proper ventilation of the space above the membrane, inlet and outlet openings
should be made. The inlets should
be in the eaves and have a combined cross-section of min. 2% of the roof area. You can make a gap instead of a hole. It must then be 5-
