Download Rendering Thermal Performance

Rendering
Thermal
Performance
The
Specifiers
Guide to
Externally
Insulated
Facade
Systems
CI/SfB
Version 1 CAWS M21
(41)
Pq4
(M2)
Building with Conscience
The History of Externally Insulated Facade Systems
From Silo to Solar
Construction for the New Millennium
The first external insulation systems can be traced back to the late
1950’s in Germany where they were installed on sugar silos to prevent
condensation from sticking the sugar granules together. The first
domestic use of Externally Insulated Facade Systems (EIFS) was in the
beginning of the 1960’s in Germany, where the advantages of
improved thermal performance and crack bridging properties, made
them especially beneficial for over-cladding leaky panellised buildings.
Today in Germany where external wall insulation began, approximately
60% of all new constructions are built using external insulation systems.
To date over 400 million m2 have been installed, with StoTherm Systems
accounting for more than one quarter of this figure. But technology
does not stand still and now there is a unique insulation system available
which actually gives a net heat gain by using the pollution free energy
from the sun: StoTherm Solar.
It was at this time that Stotmeister KG developed a product which was
to revolutionise the renders industry. The material was Stolit, a cement
free acrylic, highly crack resistant render, with immense flexibility and
strength. These properties made it the ideal material for coping with
the thermal stresses encountered by Externally Insulated Facade
Systems (EIFS). The result? In1963 the first StoTherm Insulation System
was installed.
Since then, the use of externally insulated facade systems has spread rapidly across the globe with systems being installed in all climatic zones from
Siberia to Saudi Arabia. The oil crisis in the 1970’s underlined the need to
save energy through more efficient insulation and together
with increased awareness through the 1990’s of the environmental
implications of burning fossil fuels, this has spawned more stringent
legislation requiring better insulation values for all types of construction.
Building with Conscience - A Philosophy
for Building ‘Building with Conscience’ places emphasis on visible and invisible
quality in architecture and construction. It is about creating
buildings which are meaningful to use, but which recognise
ecological and social needs. It acknowledges the requirement for
durability and value in fulfilling ecological, functional and
aesthetical requirements at a realistic price. And it stands for an
attitude which critically examines that which has been achieved
and uses it as a basis for improvement and further innovation.
Building with Conscience - Bewußt Bauen
1
Why Insulate? - The Benefits
35% Energy Loss Through Walls
The benefits of insulating properly are numerous. For this reason
significant advances have been made through the years in insulating
different elements of the building to try to reduce energy loss: roof
insulation, double glazing and draught proofing to name but a few.
As up to 35% of heat is lost through the walls, these are the areas
where the greatest benefits can be achieved.
Saving Energy and Protecting the Environment;
That’s our mission...
By using thick layers of insulation (e.g.>100mm) heat loss through the
walls may be reduced by up to 80%, saving money which in some
instances amortises the cost of the external insulation system in as little
as 5 years. But it is not only money that is saved; The reduction in energy
consumption helps preserve precious natural resources and plays an
important part in decreasing CO2 and SO2 emissions.
A Flexible Protective Skin
By insulating externally, the structure of the building is protected from the
elements in a weather-proof yet vapour permeable layer. The Sto cement
free renders are designed to flex and absorb thermal movement and
impact. And there is also flexibility in the choice of finish, with 14
different textures and over 390 colours being available.
Improving the Comfort Factor
Externally insulating improves the comfort factor - and not just in terms
of warmer room temperatures: By keeping the external walls of the
structure warmer, the living climate is improved and condensation
eliminated, preventing damp and mould growth. In addition, warm walls
prevent the unpleasant draughts created by the combination of warm
air and cold surfaces; a feature of uninsulated walls.
2
Where should
It is now generally accepted, that some form of efficient in
be seen, the vari
Interior Insulation
General Attributes
Benefits
Drawbacks
1. Increased thermal
performance.
✗
1. Significant loss of space within
room.
✓
2. Rooms can be heated quickly
from cold.
✗
2. Installation is expensive and disruptive in refurbishment.
Occupants must be moved out.
✗
3. Heat storing capabilities of substrate
not used - building will cool quickly
when not heated.
benefits
✓
✗
Technical Implications
inside
outside
✗
+20°C
✗
✗
0°C
-10°C
✗
✗
4. Cold bridging will occur between
rooms and floors
5. The load-bearing structure will
be in the frost zone; potential
freeze - thaw damage.
6. Interstitial condensation will occur in
the wall if a vapour barrier is not
installed.
7. Wall subject to high thermal stress
due to temperature fluctuation.
8. Neither weather protection nor aesthetics of outer leaf is improved by renovation.
9. Pipework in walls must be
protected from frost.
Summary:
Many technical drawbacks, system offers no protection for the substrate. Only suitable for buildings which are
infrequently used and need to be heated quickly.
3
For further technical information or queries, please contact Sto.
the Wall Insulation go? Internal Insulation v Cavity Insulation v Exter
nsulant must be used to obtain the required U - Value and desired levels of warmth. But does it matter where the insulation is situated? The three areas where insulation may be placed ar
ous options each have significant impact on the construction physics of the building and the general effect on the occupants. Below is a synopsis of the advantages and disadvantages of
Cavity Wall Insulation
General Attributes
Benefits
✓
✓
✓
✗
1. Increased thermal performance
( although limited by width of cavity ).
2. A cheap way of remedially
insulating a building.
✗
benefits
✓
Drawbacks
3. Little disturbance to occupants
during renovation.
1 Building process is slower and more
expensive with 2 leaves of block / brick.
2. New build cavity insulated walls tend
to be very thick, reducing available
space.
4. Heat storing properties of inner leaf
of wall are used.
✗
Technical Implications
inside
outside
✗
+20°C
✗
0°C
-10°C
✗
✗
✗
3. Due to the position of the insulation
between the 2 brick leaves, interstitial
condensation is likely.
4. The outer leaf of brick is in the
frost zone and may be subject to
freeze - thaw damage.
5. Wind driven rain absorbed by outer
leaf, may cross a completely filled cavity
(e.g. with remedial insulation ).
6. Wall subject to high thermal stress due
to temperature fluctuation.
7. Neither weather protection of outer
leaf nor aesthetics are improved by renovation.
8. Some thermal bridging will occur.
Summary:
A cheap way of renovating cavity wall constructions. Not the best solution for the construction due to a number of technical drawbacks. The
protection of the outer wall is not enhanced and may suffer in the long term from constant damp.
4
For further technical information or queries, please contact Sto.
rnal Insulation
re: inside the structure, in the cavity and externally. As can
the alternatives.
External Insulation
General Attributes
Benefits
✓
✓
✓
✓
✗
1 Increased thermal performance without
reducing internal space.
2. A cost effective way of renovating old
buildings.
3.Aesthetic improvement of facade through
colour fast, lime bloom free organic coatings.
4.Cost and space savings by using single
leaf construction for new build.
5. Design freedom from special recycled
profiles for creating cornices, features etc.
✓ 6. No additional expansion joints are
✓
✓
✓
✓
✓
✓
✓
required when cement free renders
are used.
7. Insulating externally precludes
cold bridging.
8. The wall acts as a thermal store,
minimising temperature fluctuation.
9. The wall is kept out of the frost
zone, there can be no freeze - thaw
damage.
10. There is no thermal stress in the
structure.
11. Condensation and mould will not
occur under normal conditions.
12. Dense construction materials may be
used giving improved sound insulation.
13. The entire structure is encapsulated in
a protective weatherproof envelope.
1. If cementitious renders are used these
can be more prone to cracking and efflorescence.
benefits
✓
Drawbacks
Technical Implications
✗
outside
inside
+20°C
2. Projections through the insulation system will have to be lengthened e.g. flue
pipes, vents, window sills
( refurbishment only ).
0°C
-10°C
Summary:
Highly cost effective method for new build construction and also refurbishment works. Very low energy buildings may be created. The building is protected from
the elements and the structure will not deteriorate over time.
For further technical information or queries, please contact Sto.
5
Cost Effective Solutions for Modern Construction
Single Leaf Wall Construction
What is externally insulated single leaf wall construction?
It is a method of building, used predominantly on mainland Europe
since the 1950’s. There is no cavity, simply one externally insulated
monolithic wall.
Single skin wall externally insulated
with a StoTherm System.
1. Substrate
2. Sto Adhesive
3. Sto EPS Insulation
4. Sto Reinforcing Coat
5. Sto Glass Fibre Mesh
6. Decorative Finish Render
1 2
3 4 5 4
6
Why is the cavity no longer required?
What is the traditional purpose of the cavity? Firstly, the outer leaf
acts as a rain screen, preventing water reaching the inside of the
construction. Secondly, the shaft of still air in a sealed cavity acts as
an insulating layer. A modern single leaf construction utilises either
cast concrete or brick/block as the load bearing element and an
external insulation system to do the job of the cavity: A far more
efficient type of insulant replaces the still air as the thermal layer and
complete weather protection is provided by Sto Synthetic Resin
Renders which remain vapour permeable .
On a building of perimeter 100m, an extra 15m2 floor space can
be gained per storey simply by using single leaf construction and
external insulation.
Stud Wall Construction
What is Stud Wall Construction ?
Light-weight stud wall construction comprises of either metal or timber
studs, clad internally with plasterboard and externally with either plywood or external wall boards. Insulation is placed externally using a
StoTherm Insulation System to attain the desired U-Value and provide a
weatherproof finish, It is usually necessary for a vapour barrier to be
installed on the inside to prevent interstitial condensation.
Stud wall externally insulated
with StoTherm Classic
1. Structural framing
2. External Sheathing
3. Sto EPS Insulation
4. Sto Adhesive
5. Sto Reinforcing Coat
6. Sto Glass Fibre Mesh
7. Sto Decorative Finish Coat
Complete weather protection
is provided by Sto
Synthetic Resin Materials
1
What are the advantages of single leaf construction?
1. Reduced Costs: With only one wall to build, material costs are
reduced and construction is significantly faster than cavity wall, saving
time and money. In one recent project in London, the money saved by
the early off-hire of the tower crane virtually paid for the cost of the
insulation.
2.Better U-values can be achieved by single leaf construction for the
same space as a traditional cavity wall, saving money on heating bills.
3. Alternatively a better U value can be traded for more floor area
within the same ‘footprint’ of a building.
4. A significantly lighter structure is possible than that which can be
created with a cavity wall, providing the solution to difficult site
conditions.
5. Dense concrete blockwork may be used, which has excellent sound
insulating qualities. In addition, the dense blockwork also acts as a massive thermal store, keeping the building temperature constant i.e. cool
in summer and warm in winter.
6
2
3
4
5 6
7
What are the advantages of Stud Wall Construction?
1. Extremely fast construction times.
2. Very light-weight type of construction.
3. Good thermal properties can easily be achieved.
4. Durable, through coloured, low maintenance finish.
Externally insulated studwork infill panels were used to achieve good
U-values on the Piper Building in Fulham, London.
Cost Effectiveness and Durability
External Wall Insulation Systems Which Pay
Their Way
StoTherm insulation systems are cost effective in both new build projects,
and refurbishment schemes. Consider a traditional uninsulated cavity
wall; typically this may have a U-value of 1.19 W/m2K. By insulating
with a 100mm thick StoTherm Classic System, the U-value is reduced
to 0.29 W/m2K representing an energy saving of 76% or 84.08 KwH/m2.
Depending on the heating type, the StoTherm System will pay for
itself in approximately 9.25 years - or less if energy prices rise. If the
necessary maintenance costs of a rendered facade are taken into
account, the system will pay for itself in little over 6 3/4 years. From this
point onwards, the owner can expect to profit from his investment.
Durability from Exceptional Quality
Since its beginnings over 130 years ago, Sto has sought to
provide materials which offer good value for money. Value
comes not from cheap materials, but from using the best
quality raw materials and binders, to make products which
provide highly durable long-term solutions, out-lasting
cheaper alternatives and protecting the substrate for years to
come. And the result is a building which is energy efficient
and does not require over-painting to remain weather-proof,
saving money in the long term.
Durability - An Example from History
Immendingen, Black Forest, Germany (Project completed in 1976,
photographed in 1997)
For an EIFS System, Feldkirch in Austria has one of the harshest climates
in Europe. The harshness comes from the number of days per year when
a freeze - thaw cycle occurs. When the temperature drops below 0°C
any moisture present will freeze, causing damage to the substrate. In
1969 a StoTherm Classic external insulation system was installed on an
11 storey block of flats in Feldkirch. In 1991, the system was thoroughly
inspected by independant materials testing authority MA39 of Vienna.
The result? Fully functioning after 22 years. Now, nearly 30 years after
installation, the system is still performing as intended and looks set to
continue performing well into the new millenium.
Sto cement free decorative renders do not require over-painting
to maintain their weather-proof qualities. The environmental benefits
of reduced consumption of fossil fuels and CO2 emissions are
incalculable. It has been estimated that since 1973, the 400 million m2
of EIFS installed in Germany alone, has saved a quantity of energy
comparable with over 15 billion litres of heating oil.
Quality
“ There is hardly anything in the world that
some men cannot make a little worse and sell
a little cheaper, and the people who
consider price only are this man’s lawful prey.”
John Ruskin 1819 - 1900
Feldkirch, Austria (Project completed1969,
photographed in1991)
7
Designing for Lasting Performance
Detailing:
The Basis of Good Design
Poor detailing can be the downfall of even the
best system. For this reason, Sto has carefully
developed standard details and specialist
products to ensure maximum security and
provide a solution for every eventuality.
Typical details include:
Partially insulated reveal
Aluminium Window Sill
Sto Aluminium Starter Track
Unique Solutions to Construction
Problems
Fixing Systems for Uneven or Friable Substrates
Sto has the solution; its own unique track fixing system which
can be used to align uneven facades and safely fix to friable
substrates without the expensive preparation required by
adhesive fix systems.
Cement Free Reinforcing Coats for Maximum
Crack Resistance
Sto has the solution; when combined with Sto Glass Fibre
Mesh, the unique Sto-RFP cement free reinforcing plaster
provides more than double the crack resistancy of even a
modified conventional cementitious reinforcing coat. The
result? No extra joints and maximum security against
cracking.
Colour without Over-Painting Cement Free
Decorative Finishes
Sto has the solution; through coloured, cement free
decorative renders in a standard colour range of 390 shades
with UV resistance factor 8 on the International Wool Scale.
Stolit acrylic and StoSilco silicone resin renders are highly
flexible, weather proof yet remain vapour permeable.
Quick Set Materials - Winter Performance
without Solvents
Sto has the solution; its unique QS technology enables
the water based Sto-RFP QS and QS grade Sto decorative
renders to be applied in winter from +1°C without fear
of frost or rain damage after the initial curing
period of only 7 hrs.
Architectural Features - Changing the Face of
Buildings
Sto has the solution; StoDeco Profiles are made from a
unique recycled material, which is light-weight and
available in a standard range of profiles which are fixed to
StoTherm insulation systems to form string courses,
window surrounds etc. Special profiles can be made to order.
8
StoTherm Classic
StoTherm Classic, introduced in 1965 is proven as a tough and reliable system in extreme climates around the globe. Used in
locations as diverse as Siberia and Texas, the systems flexibility and weather proof capabilities have shown it to be the
durable long term answer for insulating and protecting buildings.
SYSTEM
Which
is d
StoTherm Classic is available with two types of fixing system:
Adhesive Fixing System
Suitable for:
Friable, non load-bearing substrates
Uneven / out of plumb substrates
Bridging different substrates
Suitable for:
New build constructions
‘fair-faced’ tolerance blockwork
Light-weight frame constructions
1
2
3
4
1
2
3
EPS ( Polystyrene )
CFC/HCFC free with Fire
Retardant Additive
INSULATION
Mechanical Fixing System
StoTherm Classic
( Class '0' Fire rating )
Is substrate
load-bearing &
level/even?
4
...
..
...
..
The principle features which have made StoTherm Classic popular over the years with Architects and Clients
alike can be summarised as:
Highly flexible anti-crack coatings
Wide colour choice
Class ‘0’ fire rating
Curves, features and ashlar grooves possible
Vapour permeable coatings
Proven reliability over 30 years
Completely weather proof system
Low maintenance, painting is unnecessary
Special details solve difficult design problems
Light-weight system 10-12kg/m2 compared to 20-22kg/m2
for traditional heavy-weight systems
No
Adhesive
Fix
Mechanical
Fix
Sto-RFP and
Sto Glass
Fibre Mesh
INTERMEDIATE COAT
1. Adhesively fixed EPS board with secondary fixings if required
2. Sto Glass Fibre Mesh embedded in
3. Cement free Sto-RFP reinforcing plaster
4. Cement free decorative render - see below
Brick/Tile
Finishes
Stolit K/R
&
Sto-Rustic
FINISHES
1. Mechanically fixed, track system EPS board
2. Sto Glass Fibre Mesh embedded in
3. Cement free Sto-RFP reinforcing plaster
4. Cement free decorative render - see below
REINFORCING COAT
FIXING
Yes
StoSuperlit
StoSilco
K/R/MP
Sto Decorative Renders
Stolit: Through coloured, ready to use, acrylic, cement free render. Completely impervious to driving rain
yet remains vapour permeable. Immensely tough, and highly flexible. Available in range of 390 colours.
Over 400 million m2 applied world-wide since 1955. Stolit is available in Quick Set (QS) winter grades.
StoSilco: Through coloured ready to use, silicone resin, cement free render.
Special properties include excellent vapour per-
Stolit and StoSilco
are available in a variety
of textures including:
A traditional style of finish is provided
by Sto-Rustic or StoSilco MP with a
fine grain and gently undulating texture.
9
smooth
rilled
coarse
StoTherm Mineral
StoTherm Mineral is the alternative for those who wish to use a mineral based insulation system. The insulation boards formed
from basalt stone are slightly heavier than the EPS boards used in the Classic system, but have outstanding fire resistant properties and are used where a non-combustible insulant is preferred. The system shares the same finishes as StoTherm Classic
and has proven to be tough and reliable over many decades of use.
SELECTION
Insulation
desired?
StoTherm Mineral is available with two types of fixing system
Mineral Fibre Insulation
StoTherm Mineral
( Class '0' Fire rating )
Mechanical Fixing System
Lamella Adhesive Fixing System
Suitable for:
Friable, non load-bearing substrates
Uneven / out of plumb substrates
Bridging different substrates
Suitable for:
New build constructions
‘fair-faced’ tolerance blockwork
Light-weight frame constructions
Is substrate
load-bearing &
level/even?
1
2
3
4
2
1
3
4
No
Yes
Adhesive
and Dowel
Fix
Mechanical
Fix
Sto Mineral
Plaster and Sto
Glass Fibre Mesh
Sto
Primer
1. Mechanically fixed, track system mineral fibre board
2. Sto Glass Fibre Mesh embedded in
3. Sto mineral reinforcing plaster
4. Cement free decorative render - see below
1. Adhesively fixed mineral lamella board
2. Sto Glass Fibre Mesh embedded in
3. Sto mineral reinforcing plaster
4. Cement free decorative render - see below
Special features in addition to the shared advantages of StoTherm Classic which have made StoTherm Mineral
popular over the years with Architects and Clients include:
...
.
Class ‘0’ non-combustible system
Lamella board easy to install around curves
Highly vapour permeable
Completely weather-proof system
...
Flexible render finishes
Proven reliability over 30 years
Low maintenance, painting is unnecessary
Sto-Superlit: exposed aggregate style, through coloured acrylic render. Available in 24 colours and 2 aggregate
sizes. Using variegated stone, Sto-Superlit is tough, flexible and especially suitable for use in plinth area’s.
Sto-Superlit is available
in 24 colours and 2
aggregate sizes.
Sto-Superlit gives
buildings a distinctive
appearance.
10
StoTherm Solar
Insulation for the New Millenium
StoTherm Solar System Construction
Reduce heat loss and gain free energy - these are the principles behind
StoTherm Solar, the only external insulation system to make active use
of solar energy. The theory is very simple: A transparent insulating layer
lets solar rays pass through to a black solar absorber which also acts as
an adhesive. The 95% efficient solar absorber then converts the solar rays
to heat. After 6-8 hours, the heat energy permeates through the solid wall
construction to the inside. The result? A net gain of up to 120KwH/m2
per annum for south facing facades. The transparent insulation layer, then
effectively reduces heat loss at night.
1. Single leaf dense brick/blockwork
2. StoSolar Absorber
3. StoSolar Panel
4. Conventional adhesively
fixed StoTherm EIFS
1 2
StoTherm Solar
integrated in a
conventional
StoTherm EIFS.
3
4
Temperature Flow
In winter, with an outside
temperature of -10°C,
temperatures of up to +60°C
can be reached in the absorber
StoTherm Solar: Temperature Change
in Wall over Time
70
StoSolar Absorber
50
Middle of wall
30
Inner wall behind
StoTherm Solar System
Interior wall behind
conventional EIFS
10
°C
Time
7.00
1000
13.00
16.00
19.00
22.00
1.00
4.00
Data: Detached house,
Bonndorf, Germany 1995
The wall heats up slowly during the course of the day and discharges
the heat into the room after 6-8 hrs. Source: Test house in Germany,
Winter 1995
Selective Solar Energy
StoTherm Solar works selectively:
In summer, when the sun is at its
highest in the sky, the majority
of the solar rays are reflected.
By contrast, in winter when the sun is at
its lowest in the sky, the majority of the
solar rays are absorbed and turned into
heat. The result? A self regulating
system which does not require expensive
shading systems to prevent over-heating.
11
..
.
..
..
Technical Summary
Substrate: Single leaf blockwork.
Min.density 1200kg/m3
Not suitable for use on cavity wall
constructions.
Potential Energy Gain /m2/yr:
South Facade: 120KwH
West / East Facade: 80KwH
North Facade: 30-40 KwH
Insulation Thicknesses in mm:
80/100/120/140
Min / Max installation area’s: 10% 30% of facade
StoTherm Solar standard panel formats: 7 no.
The system does not require shading
in summer.
Sto Reference Projects
1
4
2
5
6
7
3
1
Project: Planet Hollywood, Chessy, France
Architect: Rockwell Group, New York
Products / Description: StoTherm Insulation System, StoSilco MP
5
Project: Premier Place, Isle of Dogs, London
Architect: Chassay + Last Architects
Products / Description: StoTherm Insulation System, (EWIA Award winner)
2
Project: Mercedes Benz U.S.A.
Architect: Gresham, Smith and Partners
Products / Description: StoTherm Insulation System
6
Project: Charlesworth House, Stanhope Gardens, London
Architect: Chassay + Last Architects
Products / Description: StoTherm Insulation System, StoDeco Profile 2001, StoSilco MP
3
Project: Feder Lechner, Germany
Architect: Winkler and Bahm
Products / Description: StoTherm Solar
7
Project: Rotel Inn, Passau, Germany
Architect: Hans Hoffer, Austria
Products / Description: StoTherm Insulation System, StoSilco Color
4
Project: Crescent House, Wiltshire
Architect: Sir Norman Foster & Partners
Products / Description: StoTherm Insulation System, StoDeco Profile 2000
12
.
.
.
.
.
.
High Performance Render Systems
Externally Insulated Facade Systems
Silicone Resin Paints
Architectural Profiles
Acoustic Ceilings
Concrete Restoration
Head Office:
Sto Ltd
Unit 3
Lyon Rd
Linwood Industrial Estate
Paisley
Scotland
PA3 3BQ
Sto Ltd
Unit 4
The Ringway Centre
Edison Rd
Basingstoke
Hampshire
RG21 6YH
Tel: 01505 324262
Fax: 01505 323618
E-mail: [email protected]
Tel: 01256 332770
Fax: 01256 810887
E-mail: [email protected]