14.Envelopes, Single-leaf and multi-leaf facades

Transcription

Pág. 1
Clave Máster y Curso
Sesión 1/4
Asignatura
LIGHTWEIGHT VENTILATED AND
EXTERNAL WALL INSULATION SYSTEM
FACADES
Construction II. Mineral Construction. 2nd year
Construction Area
Academic Year 2014-2015
Review 28/04/2015
Authors: Josep Olivé, Marta Adroer
Pàg. 2/78
Àrea de Construcció
Construcció II
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Index
1. Scope of study
2. Typologies
2.1. Lightweight ventilated facade
(cat. Façana ventilada lleugera)
Concept and basic features
Thermal performance scheme
Materials
Design determining factors
Singular points
Installation on site
Strategies: facade’s behavior
2.2. Facade with external insulation and without chamber (EWI System. External
Insulation Wall system)
(cat. Façana abrigada sense cambra (SATE- IDEA Vocabulari) )
Thermal performance scheme
Materials
Design determining factors
Singular points
Installation on site
Strategies: facade’s behavior
3. Information sources
Scheme of layers
HEAVY (cat. PESADA)
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Area of studies l Typologies - lightweight ventilated l Typologies - External ventilation l Information sources
SINGLE LEAF
(Cat.MONOFULLA)
MULTI LEAF
(cat.MULTIFULLA)
EXTERNAL WALL
INSULATION
EWI System (“coated”)
(cat. ABRIGADA)
WITHOUT
air chamber
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(cat SENSE
cambra d'aire)
WITH
Air chamber
(cat AMB
cambra d'aire)
LIGHTWEIGHT
VENTILATED
(cat. VENTILADA
LLEUGERA)
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Definition l Requirements l Typologies l Materialization I Controls I Information sources
Typologies and nomenclatures of the most common mineral origin facades in our
country
SINGLE LEAF
without a
specific
insulation layer
Using “traditional” materials
Single-leaf:
(cat. Monofulla)
(cat. amb materials “tradicionals”)
Using low transmittance materials
(cat. amb materials de baixa conductivitat)
(cat. MONOFULLA
sense capa
específica
d'aïllament)
without cavity
Conventional:
(cat. sense cambra)
(cat. Convencional)
with a non-ventilated
cavity
(cat. amb cambra
no ventilada)
heavy.
Precast:
(cat. Prefabricada)
MULTI-LEAF
with a specific
insulation layer
(cat. MULTIFULLA
amb capa
específica
d'aïllament)
(cat. Pesada)
not ventilated
lightweight.
(cat. no ventilades)
(cat. Lleugera)
cavity wall
heavy selfDouble-leaf:
supporting
(cat. Doble fulla)
exterior leaf
Lightweight
Lightweight ventilated not self(cat. Ventilada lleugera) supporting
exterior leaf
With external insulation
(EWI System)
(cat. Abrigada (SATE))
(cat. cavity wall
full exterior pesat
autoportant )
ventilated
(cat. Ventilada)
(cat. full exterior
lleuger no
autoportant )
very ventilated
(cat. molt ventilada)
not ventilated
(cat. no ventilada)
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LIGHTWEIGHT VENTILATED FACADE
(Cat. Façana ventilada lleugera)
DEFINITION: The principle of the facade is the same as with the double leaf
facade: a stable interior enclosure structure (wall) that works against
gravitational loads and horizontal forces. An insulating material covers the
external wall completely in order to avoid thermal bridges; an air cavity is left
in order to ventilate and then finishing the system, a second leaf is placed
giving the image of the building.
Unlike the double leaf facade, this second leaf is not self-supporting: it
transfers horizontal forces towards the interior leaf, as well as the
gravitational loads of its own weight (It has no foundation). The external
cladding is suspended.
IDEA:
evacuate water
evacuate hot air
reduce thermal bridges
create shade
BASIC FEATURES
complexity on its on site installation
good control of its insulation layer
good control of its water tightness and breathability
inertia on its interior
avoids thermal bridges completely
protection is necessary to ensure durability, on ground level
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Basic characteristics
Thermal performance scheme: warm climate
The solar radiation (light and short
wave infrared IR) affects the exterior
leaf. Part of the radiation is reflected
by the exterior leaf (depending on the
reflection index p[%] color and
brightness).
Part of the radiation is absorbed by the
exterior leaf, which warms and emits
energy (now as a form of long wave
Infrared IR) both inwards and
outwards.
The air in the ventilated chamber
gets warm, decreases its density and
rises up, starting a convection
movement inside the cavity. This warm
air, while it is moving, takes some of
the thermal load with it as well.
Thermal insulation makes it difficult
for the remaining energy to move
inwards, into the interior leaf.
The interior leaf, with its inertia, is
able to weaken temperature
oscillations.
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Thermal performance scheme: cold climate
The thermal energy from the
interior space warms up the
heavy interior leaf.
The interior leaf serves as an
energy accumulator using its own
inertia and is constantly radiating
its surroundings.
Thermal insulation placed on the
exterior face of the interior leaf
makes it difficult for the energy to
be transferred to the ventilated
cavity. This makes the energy
absorbed by the interior leaf
returns to the interior space.
Inside the air cavity, although
there might be some sort of
ventilation, there is no wind like in
the exterior area  higher Re
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Area of studies l Typologies - lightweight ventilated l Typologies - External ventilation l Information
sources
Thermal performance scheme: thermal bridges
Thermal energy from the
interior area warms up
structural elements (such as
floors and columns
embedded in the facade),
which are normally higher
conductors than those in the
interior leaf of the facade.
If these conducting elements
are not thermally well
insulated from the exterior,
higher energy transfers will
take place at these points
(known as thermal
bridges). Condensation
might also occur.
This problem is solved by
placing thermal insulation
which completely surrounds
these elements
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INTERIOR
INTERIOR LEAF
INSULATION
VENTILATED CHAMBER
EXTERIOR LEAF
Materials: Interior Leaf
EXTERIOR
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Interior Leaf
The most common materials are masonry walls, made
up of ceramic pieces or concrete block, with
thicknesses between 10 and 15 cm.
On the most industrializes systems we might find
lightweight leafs (panels).
Usually the interior part has a finishing layer.
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PERFORATED BRICK (cat.MAÓ CALAT (gero))
Measurements from the Catalan format (h x L x e):
5x29x14 cm
7x29x14 cm
9x29x14 cm
CONCRETE BLOCK (or mortar blocs)
(cat BLOC DE FORMIGÓ (o de morter))
Common measurements (h x L x e):
20x40x15 cm
20x40x20 cm
The interior leaf’s constructive principles are those from the construction of
walls.
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Singular points: in relation to the structure
Without a secondary structure
- The interior leaf has to be stable against horizontal
thrusts, and it also has to stabilize and support weight
(gravity weight) of the exterior leaf, in order to transmit
loads further onto the principal structure.
- The exterior leaf is supported by the interior one in a
linear or in a point-based way (by a series of points),
through the means of fastening elements.
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With a secondary structure
- The interior leaf is not usually part of the
principal structure, although it can form part of
it. If it does, the interior leaf is always inserted
between structural elements, in a way that
always permits the pass of the insulation layer
in front of it.
- The interior leaf has to be stable against
horizontal thrusts, and it also has to stabilize
and support weight (gravity weight) of the
exterior leaf, in order to transmit loads further
on onto the principal structure.
- The exterior leaf is supported by the interior
one in a linear or in a point-based way (by a
series of points), through the means of
fastening elements
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INTERIOR
FULL INTERIOR
(cat. SISTEMA DE SUBJECCIÓ)
FASTENING SYSTEM
FULL EXTERIOR
Materials: support or fixing system: systems for transferring gravity loads and
horizontal forces
EXTERIOR
Depending on the type
of material, there are
many fixing systems for
the exterior leaf; always
using stainless
materials. Put into other
words, the finishing
material affects the type
of fixation.
In general we can
distinguish:
- Direct and individual
fixing (reserved almost
exclusively to stone
systems)
- Secondary structures
(supporting frames) with
more elements (struts,
crosspieces, etc.)
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Materials: Fixing framework requirements
The requirements that the fixing system
(and supporting frame) of the exterior leaf
must accomplish are:
It must effectively transmit the actions of
the outer leaf to the final support. Some of
these actions are the exterior leaf’s
weight and horizontal thrusts which
may be transferred to this element
(mainly wind).
The structure must adapt to the very likely
irregularity of the support, assuming
sufficient assembly tolerances (in the
three spatial directions). This will enable
the finishing pieces to be placed with the
dimensional accuracy that these pieces
demand.
It must allow free movements of the
external leaf pieces, which will be
subjected to major changes; both in
temperature and humidity.
It must not generate points where
rainwater can flow or pass into the interior
leaf. This water must be conducted out of
the building in a very controlled way.
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Materials: Fixing framework anchorage onto the support
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Materials: Thermal insulation
INTERIOR
INTERIOR LEAF
INSUALTION
VENTILATED CHAMBER
EXTERIOR LEAF
Adequate insulation:
EXTERIOR
Thermal insulating elements must be unchangeable in
front of moderate or intense humidity in relation to its
climate zone.
In order to choose the best insulating element, it is
important to analyze where the water tightness barrier is
placed as well as the risk of interstitial condensation.
These insulating elements must fulfill:
-It does not contribute to the creation of fire B-s3, d2 on
ground floor level and in most of the other cases.
-Blankets, projected, or rigid panels may be used
Most common materials
-Rockwool recommended from an environmental point of
view. (cat. Llana de roca)
-Extruded polystyrene as it maintains its properties in
the presence of water (cat. Poliestirè extrudit)
-Polyurethane projected foam: attention! when it is
burned, it generates hydrocyanic acid which is extremely
toxic to humans! In this case it is more dangerous
because the ventilation chamber disperses gases easily.
(cat. Escuma de poliuretà projectat )
-Can use alternative materials such as cellular glass or
natural wool.(cat. vidre cel·lular o la llana natural)
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INTERIOR
INTERIOR LEAF
INSULATION
VENTILATED CHAMBER
EXTERIOR LEAF
Materials: Air cavity
EXTERIOR
Purpose: do to the fact that it is placed on the insulation’s
exterior side, the cavity can be ventilated.
This way, it acts on two fronts:
- Evaporation of rainwater and condensed water that
comes from interior vapor.
-Evacuate, through means of convection, the radiation
emitted by the external leaf which has been heated up by
solar radiation.
Width:
Requirements: the width of the air chamber must be
between 2 and 10 cm. In order to have enough movement
to cool the cavity during summer, it is considered to need
to be at least 5 cm wide.
Diaphragms are needed in order to prevent undesirable
sucking and / or maintain fire building sectors
Ventilation:
It is important to foresee where ventilation will happen
(ventilation lines or joints) as well as water evacuation
systems in the exterior leaf.
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INTERIOR
INTERIOR LEAF
INSULATIONG
FASTENING SYSTEM
(cat. SISTEMA DE SUBJECCIÓ)
EXTERIOR LEAF
Materials: Exterior Leaf
EXTERIOR
Requirements:
- Homogeneity and continuity of the pieces
- Porosity (does not absorb water by capillarity)
- Hardness
- Mechanical properties: strength against tensile forces,
compression and bending (impact resistance)
- Durability of these properties after being exposed to the
environment (sun, rain).
Usually, the material is the one that defines the system:
- Natural stone slabs (cat. pedra natural en plaques)
- Mortar pieces, artificial stone, or ceramic pieces
(cat. peces de morter, pedra artificial o ceràmica)
- Composite panels (cellulose-cement, cement-wood ..)
(cat. Plafons composites (ciment-cel·lulosa, cimentfusta)
- Metal panels ( sandwich panels, thin composite panels,
folded sheets) (cat. Plafons metal·lis (sandvitxos,
compòsits prims, xapes plegades))
- Solid wood or plywood
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Materials: different positions of the exterior leaf’s fixing system
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Materials: exterior leaf made of stone (cat. Pedra)
Natural stone
Natural stones' characteristics mainly depend on the type of
stone. This type of stone must have enough strength to be able
to be mechanized and supported by points. Its most common
thickness varies between 2 and 5 cm.
Limestone and marbles
Sandstones
Granites
Phyllites
Slates
Quartzite
(cat. Calcària i marbres)
(cat. Sorrenques)
(cat. Granits)
(cat. Fil·lites)
(cat. Pissarres)
(cat. Quarsites)
Fixing elements:
- Fixing elements must be unalterable by water: oxidation
would create an increase of the piece’s volume that could
destroy the area of the fixing element and would cause a
decrease on the fixing element’s section; and therefore,
creating a possible release of the piece (stainless steel).
- Strength to hold the piece’s weight on suspended claddings,
which will determine the fixing element’s dimensions.
-Resistance against both the panel detachment and tipping
over
-Mechanical resistance against wind forces
- Adaptability to the support from where the piece is held, in
order to correct errors such as the lack of flatness.
- Facility to maintain and to change a piece if it has a broken
item.
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Materials: exterior leaf made of stone, fixing elements
(cat. Ceràmica plana)
Fixing elements by pieces made of stone can be
classified in two types:
Fixing elements screwed directly onto the
interior leaf:
This type of fixing element joins the closing
elements using screws.
- These elements can directly enter in a loading
situation
- Due to the piece’s design, different “free”
degrees can be achieved between the point from
where the fixing element is supported onto the
enclosure wall, and the hole made in the stone
finishing.
Fixing elements supported by a supporting
framework:
This is a much more sophisticated system that
incorporates a substructure (struts and
crosspieces, cat.muntants i travessers); which is
fixed onto the interior enclosure and is in charge
of transmitting the loads onto the structure.
There are some anchorage elements designed to
support the piece’s weight (support elements)
and other elements which only prevent the piece
from tipping over (retaining elements). Some
anchorage elements can fulfill the two conditions.
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Materials: exterior leaf made of stone, individual fixing elements
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Materials: exterior leaf made of flat ceramic pieces (cat. Ceràmica plana)
Characteristics of a flat ceramic piece:
Dimensional accuracy
Homogeneity
Reduced coefficient of dilation
Resistance against corrosion
Resistance against acids
Resistance against solar radiation
Resistance against frosting
High durability
Very sophisticated and delicate fastening elements are needed due to the fact that
ceramic can not be formed on site.
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Materials: exterior leaf made of flat ceramic pieces, fixing elements
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Ceramic tiles: supports
(cat. Ceràmica en rajola: suports)
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Ceramic tiles: fixing elements
(cat. Ceràmica en rajola: fixacions)
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Flat ceramic pieces: anchorage
onto the ceramic piece
(cat. Ceràmica plana:
ancoratge a la peça ceràmica)
Materials: exterior leaf made of flat ceramic pieces
Ceramic tiles: example
Image source: “Tectónica” Magazine
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New Art Gallery in Walsall, United Kingdom. Caruso & St John
Materials: exterior leaf made of extruded ceramic pieces
(cat. Ceràmica extrudida)
Extruded ceramic pieces
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Not flat ceramic pieces
Material’s characteristics:
Homogeneity
Reduced coefficient of dilation
Resistance against corrosion
Resistance against solar radiation
Resistance against frosting
High durability
Limited colors to clay colors
Ability to mold the piece in order
to facilitate its anchorage.
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Extruded ceramic pieces
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Fixing systems for ceramic elements, using
individual fixing elements for each piece or
using a support guide for various adjacent
pieces.
Must ensure the vertical continuity of the air
chamber.
Extruded ceramic
pieces
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Materials: exterior leaf made of wood and wood-based materials
(cat. Fusta i derivats)
Timber boards (cat. taulers de fusta)
Wooden boards must be protected on all
sides (edges, exterior and interior sides)
because the air cavity provides suitable
conditions for insects to make their dens,
and if we do not take this fact into
consideration, insects can end up
damaging the wood.
The best protective treatment for
ventilated facades is the autoclave (cat.
autoclau) for a deep penetration (risk 3)
and possible solar radiation filter.
Its durability is no more than ten years
long because sun rays deteriorate wood
causing it to lose and damage its color
and this can not be repaired using any
treatment.
Image source: “Quaderns. COAC” Magazines
Timber larch boards or battens: (cat.
llates de fusta)
This cladding product made out of
wood is attached to the interior leaf
using a supporting framework made
out of vertical battens or horizontal
crosspieces. (cat. mitjançant rastells
verticals o travessers horitzontals). Boards
or planks (cat. llistons or plafons) are
normally screwed on to these vertical
and horizontal elements.
Must have the same precautions as
the ones used for timber boards.
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Housing in Borneo Docks. Amsterdam. Netherlands. 1999. MAP arquitectes
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The most suitable boards used for exteriors are
phenolic laminated boards (cat. Taulers
estratificats fenòlics) bakelite board (cat. baquelitzats)
and coated boards (cat. revestits) (HPL).
We can also find high density plywood boards
(cat. taulers contraxapats d'alta densitat), which use
phenolic adhesive material to completely
impregnate the wooden board. However, these
boards are not recommended for use in exterior
areas because they are easily damaged by
humidity on their edges.
These boards are heavy, hard, and therefore,
require their own fixing system. The fixing
method uses metallic profiles placed on its backside.
Despite its popularity and usage in facades, the
only technical literature available is the one
given by the manufactures themselves.
Therefore, although it has a good durable life,
we do not have precise knowledge about its
service life nor its possible pathologies. So far,
we have only found specific problems with the
board’s hardware chemical compatibilities.
Font imatge : revista Quaderns
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Materials: exterior leaf made of Cement fiberboards (Cat. fibrociment)
Cement Bonded Particle Board
VIROC ®
Composite material, composed of a
compressed dry mixture of wooden
fibers and cement, which acts as a
binder.
The finished material is sterilized by a
process where the mixture (between
wood and cement) is exposed to high
vapor pressure, increasing the
cohesion and that gives the finishing
appearance.
This process gives the material:
-Resistance and durability
-Flexibility
-Protection against fire and humidity
-Good acoustic characteristics
Materials: exterior leaf made of phenolic resin panels
(cat. plafons de resines fenòliques)
TRESPA ® and other companies
Construcció II
Product that comes from an industrial
process, which consists of a
combination of heat and high pressures
onto synthetic and phenolic resins
which are then reinforced with wooden
fibers.
In general, the thickness of the panels
can vary between 6 mm and 13 mm,
and we can also apply some curvature
on the panels.
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These panels have lots of variations in
colors and textures for its finishing
layer.
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Materials: exterior leaf made of panels: exposed mechanical fastening system
(cat. pannells, fixació mecànica vista)
This type of system is valid for all
types of materials which can be
fixed by screws and can be drilled:
phenolic panels, made out of wood,
plywood, made out of wood chips
(cat. encenalls, cast. virutas),
agglomerates, etc.
Nevertheless, each material will
have a specific screw or adhesive
materials and the distances and
fastening systems used will have to
be adequate for each product.
Image examples from the Prodema
company. Fixing system using
screws or rivets. (Cat. Cargols o
reblons)
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Materials: exterior leaf made of panels: hidden mechanical fastening system
(cat. pannells, fixació mecànica oculta)
This type of system is valid for
all types of materials which can
be fixed by screws and can be
drilled: phenolic panels, made
out of wood, plywood, wood
chips (cat. encenalls, cast. virutas),
agglomerates, etc.
Nevertheless, each material will
have a specific screw or
adhesive materials and the
distances and fastening
systems used will have to be
adequate for each product.
Image examples from the
Prodema company. Fixing
system using hidden screws
and guides (Cat. cargols ocults i
guies)
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Materials: exterior leaf made of panels: attached fastening systems
(cat. panells, fixació adherida)
This type of system is valid for all
types of materials which can be
fixed by screws and can be
drilled: phenolic panels, made out
of wood, plywood, wood chips
(cat. encenalls, cast. virutas),
agglomerates, etc. Nevertheless,
each material will have a specific
screw or adhesive materials and
the distances and fastening
systems used will have to be
adequate for each product.
Image examples from the
Prodema company.
Fixing system using adhesive
tapes Cat. cintes adhesives)
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Materials: exterior leaf made of metal trays
(cat. safates metàl·liques)
Metallic plates
- The finishing elements made
out of metallic sheets stand out
for
their
lightness,
total
absence of water absorption,
and no gas emission in case of
fire.
- On the other hand, metallic
plates present condensation
problems and loss of flatness
caused by dilatations.
- The first of these problems
can be solved by creating a
ventilated facade, and the
second one is solved by using
small pieces to separate them
from each other.
- As in the case of ceramic
elements, metallic plates have
a wide variety of finishes (form,
texture, and color)
Materials: exterior leaf made of metal trays, fastening system
(cat. safates metàl·liques, fixacions)
Fastening system
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Vertical section
Horizontal section
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Materials: exterior leaf made of metal trays, fixing system
(cat. safates metàl·liques, fixacions)
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Determining factors of a project: constructive characteristics:
Design and modulation
In vertical and horizontal directions. It is
absolutely essential for all elements
(windows, sills, heights between ceilings,
…) which will have to be modulated
according to the exterior layer’s finishing.
Water control
Sills and lintels are designed in order to
evacuate the water inside the façade.
The shape of the fixing elements have to
permit the flow of water and ventilation.
Effective ventilation
Continuity of the chamber.
Movements
Due to the fact that the exterior leaf is
exposed to outside conditions, it is very
suitable to thermal movements;
therefore, we must foresee sufficient
joints between pieces in order to
withstand these movements (the joints
will depend on pieces’ material)
Fixing elements, durability
A study about the cost-benefit
relationship of the different fixing
systems will be needed. In particular,
the possibility that some systems have
to replace parts without having to
dissemble the facade.
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Determining factors of the project. Reflection.
Industry – systems relation versus designer-opinion leader
(Relació indústria- sistemes versus dissenyador- prescriptor.)
[...] Evolution takes place in a very biased way. A material is introduced in the exterior layer without knowing how it affects
the movement of air inside the ventilated chamber, the interior layer is lightened without thinking about the acoustic or air
tightness consequences, solid is optimized without thinking about void, carpentry is worked without thinking about solar
protection, etc.
Many reasons explain the combination of good intentions with an incomplete understanding of problems. The most important
reason affects industries and very diverse material suppliers. What would the man in charge of hanging the stone know about
what plasterboards can (Pladur) offer? How can the Alucobond manufacturer deal with the window frame designed nowadays
by architects? Who has to explain to the big semi-products manufacturers the necessity of design and how to introduce a
new material into the market that can solve potentially interesting middle leaf? What does a porcelain tile company know
about the function of a drain cavity?
In past years, there has been proposed and tested a series of construction techniques, each of which can provide solutions
to partial aspects of lightweight facades. The wise combination of theses proposals, already proven, could put us in a
position of collective design, as a collage, that new facades need nowadays, using the best and most experienced of each
proposal, benefiting from the success and good perspective of each of them.
[…]La evolución sucede de una manera absolutamente parcializada. Se introduce un material en la hoja exterior sin saber cómo afecta a los
movimientos de aire en la cámara ventilada, se aligera la hoja interior sin pensar en las consecuencias acústicas o de estanqueidad al aire, se
optimiza el macizo sin pensar en el hueco, se trabaja en la carpintería sin pensar en la protección solar, etc.
Muchas razones explican esa combinación de buenas intenciones con una visión parcial del problema. La más importante afecta a industrias y
proveedores de materiales muy diversos. ¿Qué sabe el que cuelga la piedra de lo que ofrece el Pladur, cómo puede el fabricante de Alucobond
afrontar su relación con el premarco telar que hoy diseñan los arquitectos? ¿Quién debe explicar a los grandes fabricantes de semiproductos la
necesidad del diseño y puesta en el mercado de un nuevo material para resolver la potencialmente interesantísima hoja central? ¿Qué sabe una
empresa de gres porcelánico del funcionamiento de una cámara drenante?
En los últimos años se han propuesto y ensayado una serie de técnicas constructivas, cada una de las cuales puede aportar soluciones a aspectos
parciales de la fachada ligera. La sabia combinación de esas propuestas, ya comprobadas, podría ponernos en situación de diseñar colectivamente,
como un collage, esa nueva fachada que hoy necesitamos, que aproveche lo mejor y más experimentado de cada propuesta y que se beneficie del
éxito y las buenas perspectivas de algunas de ellas.
“La fachada. Ventilada y Ligera”. Cristina Pardal – Ignacio Paricio. Ed. Bisagra
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Singular points: in contact with the ground
1. Take into consideration to respect bottom ventilation
2. In areas exposed to impacts (public spaces, schools,
etc…) protect ground floor level areas in order for the
exterior leaf not to be damaged (since it is usually a
very thin layer):
- Change material or thickness
- Fill in the air cavity (so, it doesn’t ventilate in this area)
(cat. Full interior
Full exterior (termoarcilla)
Aplacat full exterior
Massissat de morter
Solera
Barrera capil·laritat
Vorera)
Interior leaf
Exterior leaf (aerated clay bricks)
Exterior leaf cladding
Mortar infilling
Slab on grade
Capillarity barrier
Sidewalk/pavement
Llar d’avis. Campdevànol. 1997. MAP arquitectes i J. Avellaneda
AR012
Construcció II
Singular points: corners
Recommendations:
- Reconsider or replan
the modules on the
exterior layer.
- Choose the geometry
of the joint between the
two pieces at the
angle.
Each type of material
allows a certain
number of geometries
and some others are
not possible.
- Reinforce the corners
if the fixing elements
are far away from the
corners or if it is an
Example of the image: possible solutions for phenolic panels
exposed point.
Singular points: openings
Lintels: The interior has a lintel unless
its blind/shutter box or its own opening Exterior panel (cat. plafó exterior)
arrives to the structural floor.
Partition frame (cat. Bastiment)
A piece can be placed in order to
Insulation (cat. Aïllament)
visually close the air cavity on its top
Window Blind (cat. Persiana
replegable)
part. This piece is also used to
evacuate water out of the cavity, far
Window blind track (cat. guia
away from the opening.
persiana)
On the exterior leaf there is no lintel.
AR012
Construcció II
Jamb (Cat. Brancal)
Jambs: When the window has an
interior position, it is recommended to Glass with a cavity (cat. vidre amb
cambra)
use isolated jambs in order to
guarantee the envelope’s thermal
Window pane (cat. Fulla)
continuity.
Window sill: weathering (cat escopidors)
must be fixed on to the interior leaf and
Window frame (cat. marc)
must overhang the air cavity thickness
without breaking. When the window
has an interior position, it is
Window sub-frame(cat premarc)
recommended to guarantee the
Weathering with drip
envelope’s thermal continuity
(cat. Escopidor
amb trenca aigües)
AR012
Construcció II
Precipitations:
Although the exterior leaf takes
over most of the raindrops’
impacts and conducts most of it,
it is possible that some of the
drops enter the air cavity due to
the big amount of open joints.
(remember that ventilation is
very important for most of the
cases.)
The window puts in contact the
exterior leaf with the interior one,
and therefore, generates a path
for the entrance of water.
Depending on the opening’s
position in relation to the
enclosure, it will need waterproof
sealing bands/strips. (cat. bandes
impermeables)
Source: http://www.mecanofas.com/docs/DIT%20353-R.pdf
AR012
Construcció II
Interior position of a window in a ventilated facade
(cat. Finestra en tancament de façana ventilada en posició interior)
AR012
Construcció II
Middle position of a window in a ventilated facade
(cat. Finestra en tancament de façana ventilada en posició intermitja)
AR012
Construcció II
Exterior position of a window in a ventilated facade
(cat. Finestra en tancament de façana ventilada en posició exterior)
AR012
Construcció II
Singular points: facade capping
Ensure ventilation:
In order to allow air movements, openings on the air cavity’s top part are needed
Ensure thermal insulation continuity on the last structural floor.
Thermal insulation can end up being continuous over the roof (it is not the case
from the details below).
Construcció II
On site installation
On site installation process
Font de la imatge: l'Informatiu del CAATB
1.
2.
3.
AR012
4.
5.
6.
Construction and plumbing of the
interior leaf.
Setting-out and fixing of the
substructure(support framework) or of
individual elements on the interior leaf
in order to subsequently receive the
exterior leaf.
Thermal insulation placing fixed on to
the interior leaf using adhesive
elements and/or mechanical fixing,
without thermal bridges.
Setting-out and fastening of the fixing
elements and accessories that
support the exterior leaf.
Placement of the exterior leaf.
Placement of the finishing/flashing
pieces (cat. peces de remat) if these
pieces are needed.
AR012
Construcció II
Strategies of the facade’s behavior
l1
l2
e1
e2
INTERIOR
INTERIORLEAF
INSULATION
VENTILATED CHAMBER
EXTERIOR LEAF
Thermal insulation
EXTERIOR
The strategies depend on the addition of the different
thermal insulation layers and the ventilation degree of
the cavity. Nevertheless, the essential factor is the
specific insulation layer (l1 and e1), and the interior leaf,
which also collaborates (l2 and e2).
AR012
Construcció II
INTERIOR
INTERIOR LEAF
INSULATION
VENTILATED CHAMBER
EXTERIOR LEAF
Thermal inertia
EXTERIOR
Thermal inertia is exclusively provided by the interior
leaf. Thermal inertia depends on the material’s
specific heat Ce and the enclosure's mass, which
depends on the density and thickness e, and on the
l which will have influence on the heat flow’s velocity
through the mass.
AR012
Construcció II
INTERIOR
INTERIOR LEAF
INSULATION
VENTILATED CHAMBER
EXTERIOR LEAF
Solar protection
EXTERIOR
The exterior leaf works as a shade, protecting the
interior layers from sunlight’s direct incidence.
Solar radiation protection depends on the exterior
leaf’s characteristics: opacity, absorption, reflection
(color), control customizability (movable slats…).
It is very important to guarantee an intense
ventilation of the air chamber in order to reduce the
heat gains from radiation and heat transfer to the
inside by convection.
AR012
Construcció II
INTERIOR
INTERIOR LEAF
INSULATION
CAMBRA VENTILADA
EXTERIOR LEAF
Water exchange
EXTERIOR
Precipitations
The exterior leaf takes over most of the raindrops’
impacts and conducts most of it, it is possible that some
of the drops enter the air cavity, depending on the
amount of open joints proposed by the system. We
must analyze and recognize until what point the water
will flow inside. (remember that ventilation is very
important for most of the cases.)
The ventilated cavity has to permit a good drain. We
must foresee drainage systems, specially on window
sills and lintels on openings and in contact with the
ground.
If thermal insulation is not well protected, it has to
withstand the presence of liquid water, can not loose its
insulating ability, nor undertake degradation. In very
ventilated facades, in which water can flow until the
interior leaf, a waterproof coating against rain must
be foreseen. As a consequence of this, we must
analyze the facade’s hydro-thermal behavior.
AR012
Construcció II
INTERIOR LEAF
INSULATION
VENTILATED CHAMBER
EXTERIOR LEAF
Breathability
EXTERIOR
See higroterm
The outcome of water vapor has to be permitted by
the interior leaf’s materials. Once the water vapor is
inside the cavity, it will have to be evacuated by the
airflow. This vapor can also condensate and then be
evacuated as the water that comes from rain.
Condensation
In the case of interstitial condensations, a water
vapor barrier can be placed on the exterior face of
the interior leaf.
FACADE WITH EXTERNAL INSULATION AND WITHOUT AIR
CHAMBER OR EWI SYSTEM (EXTERNAL INSULATION SYSTEM)
(cat. Façana abrigada sense cambra o bé SATE (Sistema aïllant tèrmic per l’exterior))
DEFINITION: Thermal insulation is supported directly on the interior
leaf and finished with a render layer, specially
designed to ensure the adherence with the insulation.
AR012
Construcció II
CONCEPT:
Avoid thermal bridges
Reduce thickness
Possibility of an easy final application
BASIC FEATURES:
Not easy to install, needs means on its exterior.
Good control of its insulation layer
Needs protection to ensure durability, on ground floor
level
Suitable for remodeling facades
Avoids thermal bridges completely
AR012
Construcció II
The most common materials are masonry walls (cat.
Obres de fàbrica). But it can also be any stable
support. Usually it has an interior finishing treatment.
INTERIOR
INTERIOR LEAF
INSULATION
EXTERIOR
AR012
Construcció II
PERFORATED BRICK (cat.MAÓ CALAT (gero))
Catalan format dimensions (h x L x e):
5x29x14 cm
7x29x14 cm
9x29x14 cm
The interior leaf’s constructive
characteristics are those from the
construction of walls.
CONCRETE BLOCK (OR MORTAR)
Dimensions (h x L x e):
20x40x15 cm
20x40x20 cm
- The interior leaf can be a
bearing or a simple enclosure,
but has to be inserted in
between the structural
elements. In the case of
remodeling, if it has various
planes, we can place different
insulation thicknesses in order
to give the facade’s surface a
flat finishing, just like the image
on the right.
.
AR012
Construcció II
Housing building. Montbau. Barcelona. 1961. J. Soteras i L. Garcia-Barbón. Rehabillitation: Josep Olivé
AR012
Construcció II
INTERIOR
INTERIOR LEAF
INSULATION
Materials: thermal insulation
EXTERIOR
Thermal insulation has to be a rigid panel, they can not be
“blankets”.
Usually, the most common material is expanded
polystyrene, because we do not need an inalterable material
in front of humidity; the exterior finishing layer is the one in
charge of giving water tightness to the envelope.
Most common insulations:
Expanded polystyrene EPS (cat. Poliestirè expandit)
- Medium thermal resistant values
- Low water absorption
- Water vapor diffusion possible
- Good mechanical features
Extruded polystyrene XPS (cat. Poliestirè extrudit)
- Very high thermal resistant values.
- Very low water absorption
- Very high mechanical features
In all cases, most common thicknesses from cm to cm: are
from 1 cm until 20 cm
AR012
Construcció II
Regarding the finishing layers, we must distinguish
the exterior, which is the one in charge of water
tightness and solar radiation control, from the
interior, which is only a finishing.
INTERIOR
INTERIOR LEAF
INSULATION
Materials: finishing layer
EXTERIOR
The exterior coating has two layers: the finishing
layer and the insulation’s adherence layer
The exterior coating’s conditions are:
1.Mechanical resistance
2.Stability against UV rays
3.Water tightness
4.Water vapor permeability (breathability *)
5.Adherence to thermal insulation
Can be used:
1.Mortars made out of resins (guaranteed by the
manufacturer *)
The interior coatings must have:
1. Mechanical resistance
2. Water vapor permeability (breathability *)
Construcció II
Materials: adherence layer between thermal insulation and exterior finishing
layer
1. Interior leaf (cat. full interior)
2. Thermal insulation (cat. Aïllament tèrmic)
3. Insulation’s fastening System avoiding thermal bridges (cat. Subjecció aïllament)
4 i 6. Resin layer which works as an adherence bridge between thermal insulation and
exterior finishing layer (cat. capa de resina)
5. Reinforced plastic mesh which holds together all the coatings. Avoids marks from the
thermal insulation panels onto the exterior coating. It also avoids cracking on the exterior
layer. (cat. malla plàstica d'armat del conjunt dels revestiments)
A,B,C. Different finishing types according to the commercial company
FINISHING RENDERS
COTETERM
INSULATION
Panels and suitable
fixings
AR012
1st LAYER
COTETERM M
MESHCLOTH
COTETERM
2nd LAYER
COTETERM M
STOP BEAD
SUPPORT
AR012
Construcció II
Materialization: exterior finishing layer
Single layer renders:
Single layer stuccos specially formulated to adhere to the resin support.
The pigment is in the mass.
Must require that the render must be waterproof against rainwater but
permeable to water vapor.
Renders have an excellent adherence to the support, rationed for a mechanical
application although it is difficult to be corrected or reviewed in case of
deterioration.
There is a wide range of colors coordinated with the same pigments used in the
paintings said on color-charts of each company.
There are various finishing textures:
AR012
Construcció II
Singular points: in contact with the ground
- It is indispensable a horizontal
waterproof barrier in order to avoid
humidity on the interior leaf.
- Placement of the bottom profile,
separated minimum 15 cm from
the ground.
- Placement of a double layer
made up of a plastic mesh or
fiberglass used for the
reinforcement of the initial meters.
Actual wall
Expanded polyestyrene
1st and 2nd
COTETERM layer
Mesh (fiberglass)
Mesh COTETERM
Finishing
COTETERM finishing
Plinth’s profile
New plinth
A. Stop Bead
(cat. Perfil d’arrencada)
Actual wall
Thermal envelope continuity:
We must ensure its continuity
Mesh (fiberglass)
Finishing
COTETERM finishing
COTETERM Mesh
1st COTETERM layer
Protective angle
2nd COTETERM layer
AR012
Construcció II
New weathering
In relation to single-leaf
facades, it avoids
thermal bridges.
If the system is used
until the opening, it
guarantees a water
tightness continuity.
If the system overlaps
with the opening’s subframe, it reduces the
risk of air filtrations.
Brick
Expanded polystyrene
Thermal envelope continuity:
We must ensure its continuity
Elastic waterproofing joint
Filling mortar
New rain gutter
Lacquered aluminum
Profile
Anchorage
Link with an existent weathering
Finishing
COTETERM finishing
Mesh (fiberglass)
COTETERM Mesh
1stCOTETERM layer
2ndCOTETERM layer
AR012
Construcció II
Expanded polyethylene
Sto rain gutter
AR012
Construcció II
Singular points: facade capping
Ensure protection against water
over all the facade, and especially
for insulation. It is achieved with a
waterproof finishing element (cat.
remat impermeable). If we do not want
this finishing to get dirty, we must
incorporate a drip (cat.goteró) to this
finishing element.
Ensure thermal insulation
continuity on the last structural
floor.
Thermal insulation can end up being
continuous over the roof (it is not the
case of the detail).
AR012
Construcció II
On site installation
1. Base bead (starter profile): metallic
profile with a “U” perforated form and a 1
drip. It is placed at a minimum height of
15cm from the ground and it is
subjected with screws and dowels
every 30cm. It needs a previous
horizontal levelling
2. Expanded polystyrene thermal
2
insulation, EPS: EPS panel placement
onto the starter metallic profile, they
must be attached with the company‘s
recommended product.
3. Fixing for insulation: fasten the
insulation panel onto the interior leaf (a 3
polypropylene dowel and washer in
order to avoid thermal bridges)
4. Corner profiles
5. Surface protection for EPS panels
with a Coteterm metallic mesh adhered
with resin.
4
6. Resin priming (in function of the type
of finishing)
7. Applying of the finishing render layer
8. Final texture
We must avoid placing it under rainy
conditions or extreme temperature..
5
Coteterm system start up
6
Distribution of Coteterm M on panel
7
Perforation of plate on 5 points
COTESPIGA placement
Embedding of the Coteterm mesh
Application of Coteterm base coat
Application of decorative finishes
8 with trowel
Application of decorative finishes with gun
Example of “Parex” from Coteterm company
AR012
Construcció II
l1
l2
e1
e2
INTERIOR
INTERIOR LEAF
INSULATION
Insulation
EXTERIOR
Insulation depends on the addition of the thermal
insulation layers. The essential factor is the specific
insulation layer (l1 and e1), and occasionally, can also
collaborate with the interior leaf (l2 and e2).
AR012
Construcció II
INTERIOR
INTERIOR LEAF
INSULATION
Thermal inertia
EXTERIOR
Thermal inertia depends on the material’s specific
heat Ce and the interior leaf’s mass t. The l of the
insulation layer will affect on the loss of heat towards
the exterior.
AR012
Construcció II
Precipitations
Water tightness envelope is given by the exterior coating
layer
INTERIOR
INTERIOR LEAF
INSULATION
Water exchange
EXTERIOR
Capillarity
Inner leaf: protection against the rising water depends
on the porosity of the material and the continued
existence of water in the soil. Protection systems include
the placement of barriers against the ascent of capillary
water
Insulation: should never get to the soil
AR012
Construcció II
veure higroterm
Breathable facade. The materials do not deteriorate
under moderate humidity.
INTERIOR
INTERIOR LEAF
INSULATION
Breathability
EXTERIOR
Condensation
In case of existing interstitial condensations, a water
vapor barrier can be placed on the exterior face of the
interior leaf. (warm side of the insulation)
Stolite (resin coating from the STO company)  =150
Information sources
Class bibliography:
Facade Construction Manual. Ed Birkhäuser. Edition Detail. Herzog Krippner Lang.
Complementary bibliography. RECOMMENDED
- La fachada. Ventilada y Ligera. Cristina Pardal – Ignacio Paricio. Ed. Bisagra
AR012
Construcció II
-Revista Tectónica. nº1 i nº 2
- La Arquitectura como técnica (1). Ramón Araujo. A.T.C. Ediciones S.L. caps. 2, 3 i 4
WEBSITES OF INTEREST
- Prodema: www.prodema.com/
- STO ibérica: www.sto.es/
- Wall Term: www.wall-term.com/
- Coteterm Parex: www.parex.es/
Bibliography for INTERIOR FINISHING LAYERS
http://www.salleurl.edu/tecnologia/pdf/teoria/segon/22.pdf > 2nd year class about FINISHING LAYERS,
Nº561 notes about “Finishing layers (cat. Acabats)" sale on “Publicacions”

14.Envelopes, Single-leaf and multi-leaf facades

Transcription

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