The tendency in the
design of modern roofs is minimalism. It
works not only because of the construction costs and the appearance of the
house, but mainly because of the energy efficiency that it can provide during
the operation of the building.
Simplicity in the price
Roof shapes favoring
energy saving. Due to the shape,
the roofs can be flat, pitched, gable, hipped, multi-pitch, tent, pediment,
mansard. They differ not only in
appearance, but also in the cost of performance. Both in houses with an attic and a
non-usable attic, the most energy-efficient roofs are single-sided roofs (gable
roofs) and gable roofs, because the proportion of their surface to the home
volume is the smallest. This
means less energy needed to heat the building. The hoods of energy-saving roofs can
not be too wide, because then they shade the windows in the walls, through
which the warmth of the sun's rays reaches the interior. In addition, it is easy to install
solar collectors on large straight stretches of such roofs.
Specialized materials. Today, the roof construction is a very
complicated process, requiring not only
knowledge of the construction arts, but also currently used materials. Under similarly sounding names of
materials, there are products for various purposes, such as vapor barrier foil
and vapor-permeable pre-covering foil. Most
of them are special-purpose materials, confusing them can cause serious
consequences, so you should hire high-class specialists to build the roof.
Modern insulation and
system solutions cover. Roofing
system solutions are conducive to saving energy. In addition to the covering material,
manufacturers offer many accessories and elements that guarantee the tightness
and durability of the roof.Thanks to the system solutions of coatings and
modern insulating materials, the roof ceases to be one of the key barriers
exposed to heat loss.
Follow ecology. More and more attention is paid to the
fact that the materials used for the roof structure and its covering meet the
environmental criteria, i.e. the possibility of re-use, durability of coverage,
it is also important that they are made of renewable raw materials, and their
energy consumption in the process of creation as low as possible. An important environmental criterion
is also the health of residents - this condition is met by both the chemistry
used to build the roof and insulating materials.
Flat roofs - fashion and
economy. They have the smallest
ratio of roof area to home volume. Roofs
- regardless of whether they are ventilated or unventilated (full) - they must
be well insulated and carefully insulated against water and moisture, because
in comparison with sloping roofs, snow and ice are longer stored. More problems for the designer are
also created by the rainwater drainage solution from the roof. On a flat roof it is also possible to
place collectors without any problems, by adjusting the angle of inclination
and their orientation to the sun. The
surface of flat roofs is eagerly used as a terrace or planted with vegetation,
creating green roofs.
ROOF WIRE
The choice of the
structure and shape of the roof depends, among other things, on the building's
intended use (including the size and span of the roof) and climatic conditions
(such as wind strength, amount of rainfall and time of snow retention).
It is worth knowing
that, as a standard, such trusses are designed on which you can lay any cover,
from sheet metal to cement and ceramic tiles. The
basic mistake is to assume that the so-called light
covers (like sheet metal, roofing paper or shingles) need a much softer and
lighter truss. This is not true. The type of coverage only slightly
affects the construction of the truss. Much
more important is the sum of the roof's own loads, its insulation and finishing
as well as external atmospheric conditions. The
truss must withstand very strong gusts of wind and the weight of residual snow
worth 100-150 kg per square meter, and for mountainous
areas even above 200 kg .
The design process, the
selection of the appropriate construction and cross-sections takes place after
precise static and strength calculations, and the main parameters assumed for
calculations are: roof pitch angle, distance between walls, type of roofing,
support of the structure, wind zones regarding the location of the building.
In single-family and
multi-family houses, the most popular type of roof structure is a wooden truss. It is mainly made of pine or spruce
wood, whereas small elements (inserts, pegs etc.) from hard types: oak, acacia
or other with similar properties. Wood
should be properly dried (maximum may be 20% humidity), and protected against
biological agents and fire.
POPULAR ROOF
CONSTRUCTIONS
The rafter rafter is the
simplest construction used when the span of the external walls of the building
does not exceed 7 m , and the slope of the roof slope is
40-60 °. The basic supporting
element is a pair of rafters joined together in a ridge, spaced at intervals of
70-100 cm . Their
lower ends can be fastened to a horizontal pull beam which is also a
load-bearing structure of the ceiling or for roof slabs arranged on the ceiling
or on the top of the elbow walls. With
this solution, both rafter and murmur fixing for the building structure must be
very solid, because the stability and safety of the roof depends on it. Permissible length of a single rafter
is 6 m . The
advantages of this solution are ease and speed of execution and low cost. The disadvantages are: limited use, frequent
occurrence of curvature of the surface due to long sections (due to lack of
support) of the rafters and the action of forces pushing (outside) the walls.
A rafter-beam rafter - a
pair of rafters and a horizontal beam of a wooden ceiling together form a
three-piece girder based on the outer walls of the building. Beams that form this horizontal wooden
ceiling can be based directly on the masonry or on the masonry. This construction is used when the
span of the external walls of the building does not exceed 6-7 m . The
basic supporting element is a pair of rafters joined together in a ridge,
spaced at intervals of 80-120 cm . The
permitted length of a single rafter is 7
m . The rafter-collar beams - is used
where the span between the outer walls is 8-11
m , and the angle of the roof
slope closes in the range of 25-67 ° (in practice, structures with a slope of
at least 35 ° are recommended). With
such a large span, the use of rafter ceilings ceases to be economical (to
ensure proper stiffness of the construction rafters with very large
cross-sections should be used), often rafters are designed in which each pair
of rafters is more or less in the middle a horizontal element called a collar. This construction is a modification of
a typical rafter roof with the use of a horizontal bar for each pair of
rafters. It is designed most
often when the length of the collar does not exceed 3.5 m . Horizontal
vesicles are often used as an element of the attic ceiling structure. The recommended spacing of rafters with
this solution is 70- 100 cm . With
a roof span of 9-12 m , so-called rafter-collar beam rafter, which
consists of a pair of rafters with collar bolts based on an additional one or
two stool walls. These walls are
needed because of the long collarflies, which stiffens the entire roof
structure.
The purlin-pincage - it
is used when the wall span is over 11
m . The rafter supports are not only wall
coverings, but also intermediate purlins supporting rafters in the middle of
the span. The purlins are supported
by pillars standing on the so-calledpurlins (soles) or directly on the ceiling. The whole truss braces horizontally
stiffen the pliers - double beams binding the ends of poles with rafters
resting on them. Ticks are
mounted every third or every fourth pair of rafters. This roof construction evenly
transfers the pressure to the entire building and, due to the multiple rigid
supports, provides the most even roof slope. The
disadvantage is the partial restriction of the free use of the attic space.
ROOF INSULATION
The insulation layers of
the roof should be constructed in such a way that moisture can be drained from
the thermal insulation.Moisture in thermal insulation will drastically reduce
its thermal insulation parameters. Wind
insulation. In the case of
sloping roofs of houses with an attic, it should be remembered to allow the
removal of moisture, which may occur in the thermal insulation layer. This moisture is drained thanks to the
use of a ventilation gap between wind and thermal insulation or the use of a
vapor-permeable film laid directly on the thermal insulation. Roofing foils (pre-covering foils,
abbreviated as 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.
Low vapor permeable
foils - they are made of polyethylene film or 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 using a low-vapor-permeable film,
it is necessary to leave a ventilation gap between the foil and the insulation.
Highly vapor-permeable
foils (also known as roofing membranes) - are produced as single-layer, HDPE
polyethylene and as double-layer, polyethylene and polyester. They can be placed directly on the
insulation.
Thermal isolation. For insulation of pitched roofs,
mainly boards or - most often - mineral wool mats with high elasticity and low
volume weight (12-15 kg
/ m3) are used. Glass wool -
lighter than rock is particularly advantageous. To insulate pitched roofs, you can
also use elastic styrofoam boards. Thanks
to factory-made cuts, they spring and fill spaces between rafters. The rigid polystyrene boards of
extruded XPS or PIR polyurethane foam are also used for laying on rafters.
Vapor barrier. Vapor-tight foils protect thermal
insulation against penetration of water vapor during operation of the
house.They are produced as single-layer or multi-layered. 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 film there are
markings informing which side should be top.
Finishing the attic. The most popular is the attic finish
with plasterboard panels. They
are screwed to a rafter or 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.
ROOF COVERS
Ceramic roof tiles.
The basic raw material
for their production is clay. The
weight of the ceramic cover is 40-75
kg / m2. The
durability of this cover is even 100 years. Roof
tiles are resistant to weather conditions, including for acid rain and large temperature
differences.They are also less absorbent and frost-resistant. In addition, the coating is
non-flammable and suppresses noise very well. It
is easy to repair damaged parts of the cover, because only individual elements
are exchanged.
The basic shapes of
ceramic tiles are: carp, monk-nun, esówka / holenderka, roman / marsylica. However, there are new models with
different shapes and colors, so that even the most demanding or eccentric
customers can choose something for themselves. In recent years, the so-called roofing tiles and large-surface roof
tiles, the use of which allows for maximum optimization of the roofing
execution time and has a positive effect on the tightness and aesthetics of the
roof.
The slope of the roof
tile for ceramic tiles is according to the Polish Standard from 11 ° to 50 °,
however, the recommended angle of inclination of the roof slope for the ceramic
cover is 35-50 °, where the values vary for different types of tiles. At the slope with a slope of more than
45 °, the tiles must be fastened with nails, wire or special fasteners (spins),
and at less than 20 ° they should be placed on a stiff plank made of boards or
wood-based boards protected with tar paper or insulating foil.
The overlapping lamellas
on the upper and side edges have factory-profiled overlaps that overlap each
other when laying the tiles, creating locks to facilitate the fit and increase
the tightness of the covering. Layered
roof tiles also have so-called bottom
locks for hooking them with roof rafter laths, which makes the skirt more
stable. In addition to
traditional roof tiles, so-calledLarge-format roof tiles - their consumption
per m2 of roof is smaller than in the case of standard roof tiles. The Polish market is dominated by roof
tiles resembling a wave in cross-section, but more and more boldly, clients
also reach for flat roof tiles.
The manufacturers offer
includes tiles with different surface textures. This is achieved due to diversified
production technology - so they can be natural, engobe and glazed tiles.
Natural roof tiles -
mostly have a characteristic brick-red color. However,
they are also available in various shades of red and brown. Their surface is not finished
anything.
Engraved roof tiles are
available in the largest number of colors. Before
firing they are covered with a thin layer of engobe, a special clay with
additions of oxides. This layer
protects the elements from adverse weather conditions and increases their
durability. This group also
includes shaded tiles, coated with two types of engobe. The most common colors are red, brown
and anthracite, moreover: green, blue and even black.
Glazed roof tiles, that
is glazed, after firing are covered with enamel and re-fired. The products have a smooth surface and
gloss, they are more resistant to moisture and dirt than natural or engobed
roof tiles. Also in this group of
tiles, the offer of colors is rich.
Cement tiles.
They are similar to
ceramic tiles. However, they are
made of cheaper materials and using simpler production technology. The basic raw material for production
is concrete. The weight of the
cement cover is 35-50 kg
/ m2.
To obtain a smooth and
non-absorbent surface, tiles usually overlap with two layers of acrylic paint:
the first is applied to the molded elements before the compound can bind and
the other to completely dry. In
addition to such a finish, cement tiles usually are colored in bulk. Cement tiles are non-flammable,
non-absorbable, frost-resistant - they withstand 100 freezing and thawing
cycles - and resistant to UV radiation. Their
durability is calculated for 70-100 years. The
offer of cement tile shapes is smaller than ceramic ones. Are produced, among others single and double e-pillars, double
Roman, Old German and roof tiles in the shape of a rectangle or carpenter's. The most common colors are various
shades of red and brown, gray, graphite and black.The surface can be matte,
semi-matt or glossy. Cement
roofing tiles are usually laid on roofs with an inclination angle of 22-60 °,
but they can also be covered with roofs with a smaller slope (even with an
inclination angle of 10 °), laying them on full boarding covered with tar paper
or foil, after applying an additional seal, and with a larger drop (even
vertical), attaching each tile to wooden patches.
Profiled sheet not only
as a tile, but also in the form of ready-made panels that look like a classic
flat sheet, joined on standing seam
Sheet metal and roofing
sheet.
Suitable for roofing
with inclination up to 90 °, except that flat sheets are used for large slopes
with a slight inclination. On
roofs with a lot of sunlight, tiles that do not fade for a long time are
better. On roofs of houses
located among trees, and therefore exposed to scratches by falling branches or
cones, it is better to choose a cover more resistant to damage. Contemporary plates are covered with
protective coatings that protect them from the harmful effects of weathering,
corrosion and scratches, which significantly prolongs their durability. They are sold in large sheets, so it's
easier and faster to put them together. The
roof with a complicated shape is no longer a problem. Many producers offer material
preparation to size, which significantly reduces the generation of waste.
Steel - covering
materials are made of sheet metal protected with protective layers that
increase its durability. The most
popular solution is the cover made of galvanized steel sheet additionally
coated with a layer of varnish, where the durability of the covering material
is determined by its type and quantity (thickness of the lacquer layer on the
sheet). They are mainly flat
sheets and extruded in a shape imitating tile cover. Also made of Aluzinc plated steel
sheets (aluminum, zinc and silicon alloys).Another type of finish is a mineral
topping made of fine-grained rock aggregate covered with acrylic resin with the
addition of fungicides. Thanks to
this layer, the sheet muffles the sound of rain drops well, does not heat up
too much and is resistant to growing over with moss and algae. The durability of steel sheet
coverings is set at 30-50 years, depending on the type of finish.
Modern roofing tiles are
protected with polyester coatings that provide resistance to corrosion. The underside layer is protected by
epoxy varnish
Modern roofing tiles are
protected with polyester coatings that provide resistance to corrosion. The underside layer is protected by
epoxy varnish
Copper - this is the
most durable of the known roofing materials; can
last up to 300 years. However,
due to the high price in single-family homes is not popular. Copper sheet under the influence of
atmospheric factors is coated with a patina in a characteristic - first brown,
then black, and finally green - color. Patina
is a protective layer that significantly increases the durability of the material. Plaster-patinated sheets are also
produced, so that the roof does not change its appearance over time.
Aluminum - covers made
of this metal are lightweight, easy to process and resistant to corrosion. The aluminum is coated with a
protective passivation layer, and then from the bottom with an epoxy varnish,
on the other hand with a colored polyester coating resistant to UV radiation.
Zinc - the durability of
these coatings is estimated at 30 years. Also
in this case, protective coatings are used to increase the durability of the
sheet. In single-family houses,
they are not used anymore. Titanium-zinc
sheets are available - much more durable (100-120 years), but much more
expensive. Titanium-zinc sheets,
like copper, over time cover with a protective layer - patina. On the market there are available
titanium-zinc sheets, natural or pre-patinated, giving the metal sheet a
characteristic noble appearance. A
typical feature of titanium-zinc sheets is the reaction with impregnating
salts, which should be soaked in their wooden foundation. Failure to apply a special separation
membrane, especially on horizontal elements, will lead to rapid corrosion of
such sheet.
Many colors and the
possibility to match the roofing sheet to different surfaces, allows the roof
to fit the facade and the environment
Many colors and the
possibility to match the roofing sheet to different surfaces, allows the roof
to fit the facade and the environment
Bituminous materials.
This group of roofing
materials includes bituminous roof tiles (also called shingles), corrugated
bituminous boards and roofing felt. For
their production, organic material is used - bituminous mass. It provides a damp insulation - the
thicker the layer, the more tight the coating. These covers are light, durable, easy
to assemble and resistant to damage. They
are cheap. 1 m2 of roofing with bituminous roof tiles
is 8-13 kg . The
thickness of welded roofs is 4- 5
mm , and 1 m2 of cover weighs 4-6 kg .Bituminous roofs can cover roofs with
a 12-90 ° angle of inclination. The
corrugated bituminous plates can cover roofs with a slope of 5-90 ° and arches
with a radius of curvature of 5-9 m .
Bituminous roofing tiles
- called bituminous shingles - are rectangular belts of about 1 m long and 30-35 cm
wide . The lower edges of the belts are cut
into various shapes, for example a triangle, a rectangle, a trapezium or a
scales. The cutouts determine the
appearance of the finished roof.
The core of bituminous
shingles (bituminous shingles) is a glass nonwoven or a mixture of glass
nonwoven and plastic - fireproof and resistant to stretching. The fleece on both sides is covered
with bituminous mass, which prevents the roof from penetrating moisture. The top layer is formed by a mineral
topping - from crushed basalt granules or stone shale. The topping gives the tile color and
texture and protects it from UV rays. From
the bottom the tile is protected with sand or special foil. There are also tiles covered with
copper.
Bituminous roofing tiles
are resistant to atmospheric, non-absorbent, flexible, flexible and dampen the
sound of rain drops.Coverage durability is calculated for 30-50 years. It is worth buying self-vulcanizing
tiles, which after sealing, under the influence of high temperatures, will also
seal. Roof tiles from the bottom
are covered with bitumen glue, shielded for the time of foil transport. Before laying the cover, the
protection is removed, and the glue under the influence of heating from the
sun's rays dissolves and glues tiles together. Bituminous shingles are great for both
roofs and roofs of small garden arbors. A
wide range of colors and shapes is an additional advantage of these roofing
materials.
Bituminous corrugated
boards - they are resistant to harmful weather conditions, including UV
radiation, do not discolour, crumble and have high acoustic insulation, and
their durability is determined to be about 20-25 years. The plates are colored in the mass and
hardened with resin, thanks to which they do not peel and do not fade. They differ in height as well as the
width of the wave. The most
common colors are: brown, green, red, black. Manufacturers
offer complementary elements and accessories to facilitate the implementation
of the cover and improve its aesthetics: glasses, ventilators, eaves bars, etc.
You can also buy a transparent polycarbonate plate with identical embossing as
bituminous board that allows daylight to enter rooms in the attic.
Welded roofing paper -
the middle layer (carcass) is made of polyester or glass fabric that does not
absorb moisture and resists rotting on both sides covered with bitumen. Some manufacturers combine polyester
fabric with a glass fiber veil. The
matrix is the bearing layer of the
cover. It is combined with a
bituminous material, which prevents changes in the shape of the roofing under
the influence of temperature and humidity, it also provides mechanical
resistance of the roofing paper, prevents it from tearing during laying and
under the influence of ground movements. The
surface of the roofing paper is covered with a coarse sprinkle that protects
against solar radiation, wind, rain, temperature fluctuations and softening. An important parameter is the weight
of the roofing felt, which determines the weight of the used carcass per 1 m² of product. The higher the weight, the better. Papa after heating the bottom layer
with a gas burner easily sticks to the substrate. Also important is the method of
welding the roofing paper: overheating of the material, as well as insufficient
heating, will result in the loss of the assumed insulation properties. There are also self-adhesive papers on
the market that stick to the substrate under their own weight. Of the mentioned coverings, roofing
felt has the widest application. In
addition to the so-called pap. the
top covering, which can be the finishing layer of the roof, are also undercoats
used for other types of coverings.
Fiber-cement tiles.
They do not contain asbestos,
they are durable, resistant to changing weather conditions, UV radiation,
moisture and decay and biological corrosion. They
have a thickness of 4-6 mm . The
surface of the tiles is coated with acrylic, acrylic-silicone paint and even
copper. The tiles can be square
with bevelled opposite corners, rectangular full, with bevelled or rounded
corners and the appearance resembling flat ceramic roof tiles. Coating from fiber-cement tiles can be
laid on roofs with an angle of inclination greater than 20 °.
WATER TREATMENT FROM THE
ROOF
The basic elements of
the gutter system are gutters and downpipes. Special
accessories are used to fix them. Pipes
that will drain rainwater outside the building are also necessary. Internal or external corners are used to
change the direction of the course. Sometimes,
instead of downpipes, chains are installed. In
places where the downpipes can not be fastened, in the outflows of gutters,
so-called gargoyles. The drainage project must be prepared
for a specific building.
Materials.
Galvanized steel sheet
is most often used for production - in order to increase durability and give
color, the elements are covered with decorative and protective coatings from
varnish, plastisol or polyester. There
are still cheap galvanized gutters produced. The
material is dimensionally stable in variable atmospheric conditions, but not
very resistant to mechanical damage.The durability of steel systems is
estimated at 30-50 years, but it is largely influenced by atmospheric
conditions and air pollution. Copper
and titanium-zinc - these are the most expensive gutter systems, but also the
most durable. Copper durability
is estimated at about 150 years. The
surface of this material can be factory patinated, galvanized or coated with
acrylic. When using copper
guttering, its direct contact with steel and aluminum should be avoided.
Aluminum - the elements
are covered with anti-corrosion coating and acrylic, varnish or polyester. They are connected to rivets and seals
the connections with silicone. Some
manufacturers offer gutters of any length, formed directly on the construction
site.The durability of aluminum guttering is calculated at 70 years and is
resistant to salt contained in the air and acid rain.
PVC - for the production
of gutter elements, unplasticized polyvinyl chloride is used, resistant to
mechanical damage and colored in bulk in various colors. These gutters do not require
maintenance. They work well in
coastal regions. The durability
of PVC systems is calculated at approx. 50 years.
