This document provides an overview of insulated concrete formwork (ICF). ICF uses rigid foam insulation such as expanded polystyrene to form the walls of a structure, with concrete poured into the cavities to form a continuous thermal mass. ICF walls provide high insulation, soundproofing, durability and resistance to natural disasters. While ICF has higher upfront costs than traditional construction, it lowers long-term energy costs and requires less maintenance. The document discusses the types of ICF blocks, specifications, advantages, disadvantages and applications of ICF in flooring, walls and other structures.

1. INSULATED
CONCRETE
FORMWORK
Presented by,
SAFA RIZWANULLA SHERIFF
DEPARTMENT OF CIVIL ENGINEERING
PRESIDENCY UNIVERSITY

2. CONTENTS
1. Introduction
2. Literature review
3. Types of forms
4. Specifications of ICF’s
5. Advantages
6. Disadvantages
7. Applications
8. Conclusion
9. References

3. Introduction
■ Insulating concrete Forms (ICF) System comprises of a
panel of two walls of Expandable Polystyrene (EPS)
separated by a nominal distance of 150mm by hard plastic
ties. These are assembled on site to hold reinforced concrete.
■ Upper and lower surfaces of the polystyrene panels are
castellated and the vertical mating surfaces are tongue-and-
groove to form a tight fit when joined together.
■ The forms are open ended hollow polystyrene blocks which
fit tightly together to form a shuttering system. Concrete
poured into the hollow space to form a continuous wall.
■ This wall supports the structural loads from floors and roofs,
and the shuttering provides thermal insulation.

4. INSULATED CONCRETE FORMWORK

5. Literature review
■ [1]Andreea-TereziaMircea(2010) carried his research on ICF wall with different parameters. The three various thickness of
shear wall was casted and tested for cyclic loading to find the seismic performance. It was concluded that, ICF wall provides,
energy efficient green building, high durable, increased strength, maximizes resistance to natural disasters and minimizes
temperature fluctuations by absorbing and storing heat.
■ [2]AfshinHatami (2011) studied the challenges in ICF system like high initial cost and difficulties of pouring concrete at higher
elevation. Final remarks made was, usages of flowable concrete (SCC) for walls upto 8ft height will reduce pouring difficulties
and reduce construction time.

6. Literature review
■ [3]Peter Dusicka (2010) studied the behavior of ICF wall under seismic loading. 4ft ,12ft ICF wall and conventional wall
are casted and tested under cyclic loading. It was concluded that, ICF grid wall system potential exists for the seismically
active regions
■ [4]W. Maref, M.M Amstrong and G. Ganapathy (2012) monitored two IFC wall specimen. ICF walls have the potential
to reduce the peak heating requirement of the furnace, and the peak cooling requirement of the air conditioning system.
This may have implications for the sizing and cost of mechanical equipment.
■ [5]Abdullah yildiz and GokhanGurlek (2008) presented a study on environmental analysis of thermal insulation in
buildings with different thickness. The result of this paper was increase of thermal insulation decreases the heat loss in
the building with increase in the cost of insulation material.

7. Types of forms
 Standard Forms – These form bulk of the forms and have 50mm
EPS panels on both sides with 8 hard plastic ties holding the panels.
Dimensions of these forms are 1000 x 250 x 250mm. (See Fig. 2)
 Lintel Forms – In combination with Half Height forms, these form
the top layer of all wall gaps and hold the concrete thus preventing
thermal leaks. Dimensions of these forms are 1000 x 125 x 250mm.
(See Fig. 3)
 Half Height Forms – Together with the lintel, these form the top
layer of all gaps in the wall and hold the required steel
reinforcement. Dimensions of these forms are 1000 x 150 x 250mm.
(See Fig. 4)

8. Types of forms
 Floor Edge Forms – These form the top most layer, where the wall
ends and floor begins. This envelopes the floor slab and thus prevents
thermal bridging. Dimensions of these forms are 1000 x 375/125 x
250mm. (See Fig. 5)
 Corner Forms – These constitute 90º corner of the building. The two
sides are 50mm EPS panels held together with 8 hard ties.
Dimensions of these forms are 750/500 x 250 x 250mm. (See Fig. 6)
 End Forms – These create wall ending by fitting in inside the
Standard or Corner form and provide a smooth and thermal bridge
ending to the wall. Dimensions of these forms are 150 x 125 x
50mm. (See Fig. 7)

9. Specifications of ICFs
(i) Expanded Polystyrene (EPS): Self-extinguishing type EPS shall conform to IS 4671: 1984 having density
not less than 25 kg/m3 and valid Restriction of Hazardous Substance (ROHS) test certification.
(ii) Polyurethane (PU): Foam Adhesive Shall have Skin Formation of 8 min, Density 25 kg/m³, Sound
insulation 58 dB, Insulation factor 35 mW/mK, Shrinkage< 2%, Insulation factor 35 mW/m.K and Water
absorption of 1 % volume.
(iii) Plasticizer: Slump retaining super plasticizer for self-compacting plastic concrete shall conform to IS
9103:1999.
(iv) Hard Plastic Tie: Shall be made with HDPE (High density polyethylene)
(v) Cast-in-place concrete: The ingredients, grade of concrete & slump for walls, floors and roofs shall be used
as per IS 456:2000.

10. Advantages
1. Insulation: ICFs provide very good insulation. The R-value (a measure of effectiveness as an insulator) of ICFs is
typically rated R-18 to R-35, depending on the thickness of the wall. In comparison, traditional brick walls are usually
rated R-10 to R-12.
2. Thermal Mass Effect: The mass of the concrete core of ICFs adds significantly to the thermal efficiency of the
structure. The concrete acts as an energy reservoir and EPS sheet act as a energy barrier reducing temperature changes
from day to night.
3. Energy Efficiency: Homes built with ICFs typically require less energy to heat and cool than typical wood framed
homes.
4. Sound Proofing: Concrete is a material that tends to reflect noise, while foam insulation absorbs sound. The
combination of foam and concrete creates a thick wall that serves as an excellent sound barrier.

11. Advantages
5. Disaster Resistance: ICF walls provide good resistance to storms, strong winds and seismic effects. According to tests
performed at Texas Tech University, ICF walls were less likely to suffer damage in high winds than conventional houses..
6. Less Maintenance: ICFs are resistant to rot and termite infestation, problems that is common in wood homes and costly to
repair.
7. Simplicity: ICF homes combine framing, installation of insulation, and sheathing into one step. An experienced contractor
can construct an ICF home in less time than it would take to construct a wood conventional brick house, thus creating labor cost
savings.
8. Flexibility: ICFs can be used with most conventional finishes or designs. Moreover, ICFs can easily be cut with a saw, so
curves and odd angles are usually not a problem.

12. Disadvantages
 Cost
One major disadvantage to insulated concrete forms is the cost. You should expect to pay 5 to 10 percent more in
construction costs than you would for a traditional wood-frame house.
 Difficult Remodeling
Another problem with ICF homes is that they are difficult to remodel. We must think carefully about the design and
anticipate changes that we might want to make in the future. It is also important to account for all of the electrical and
plumbing chases that are required, because adding them after construction may require cutting into concrete.

13. Disadvantages
 Takes up Floor Space
ICF walls consist of several inches of rigid foam insulation and reinforced concrete, which means they take up more space
than traditional wood frame walls.
 Insect and Water Problems
If polystyrene forms are used for ICF construction, that exterior foam insulation may actually provide a route for insects
and groundwater to enter the walls. To address this problem, we can choose foam blocks that are treated with an insecticide
and designed to be waterproof. However, these blocks are usually more costly than untreated options, which may drive
construction costs a bit higher.
 Humidity
Immediately following construction, an ICF home may experience problems with humidity. The rise in interior humidity
occurs because the concrete is still in the process of curing. Once it is fully cured, the air's moisture level should return to
normal.

14. Case study
■ It was selected for the building of cottage to Passive house
standards in an Area of Outstanding Natural Beauty with
additional planning development restrictions in West Sussex.
■ The Curly House a home designed and build to minimise energy
consumption and carbon footprint.
■ It is designedto be an affordable and very low energy building
on a highly exposed site that is subjected to bitingly cold
winters and very hot summers.
■ ICF (insulated concrete formwork) for the walls and OP-Deck
(thermally broken super insulated deck system) for the floors
and roof.
■ ICFs are highly suited for ease of build for both complex and
curved structures, and the same system can be used for below
and above grade walls.

15. Case study
■ In total, 340m3of concrete was required to complete the project.
■ The Op-Deck was specified to take a load of 5kN/m2 .
■ The heavier construction option was chosen to provide thermal
mass in order to balance the heating gains and losses due to the
large areas of glazing.
■ The insulating element of ICF acts as a buffer to the thermal mass
allowing the slow release of heat into the building to ensure a
constant internal temperature throughout the year.
■ The semi subterranean nature of the design also meant that
materials susceptible to damp could not be considered, so no
timber was used in the construction of the building envelope.

16. Applications
 Floors and Foundations
■ ICF walls are conventionally placed on a monolithic slab with
embedded rebar dowels connecting the walls to the foundation.
■ ICF decking is becoming an increasingly popular addition to
general ICF wall construction.
■ ICF decking weighs up to 40% less than standard concrete
flooring and provides superior insulation.
■ ICF decking can also be designed in conjunction with ICF walls to
form a continuous monolithic structure joined together by rebar.

17. Applications
 Walls
■ ICF walls are constructed one row at a time, usually starting at the
corners and working toward the middle of the walls.
■ End blocks are then cut to fit so as to waste the least material
possible.
■ Interior and exterior finishes and facades are affixed directly to the
ICF surface or tie ends, depending on the type of ICF.

18. Applications
 Plumbing and Electrical
■ Plumbing and electrical conduit can be placed inside the forms
and poured into place, though settling problems could cause
pipes to break, creating costly repairs.
■ A hot knife or electric chainsaw is commonly used to create
openings in the foam to lay piping and cabling.
■ Electrical cables are inserted into the ICF using a Cable Punch.

19. Conclusion
■ Concrete specimen with EPS sheets exhibit, no cracking or zero disintegration of EPS sheets
even after complete failure of concrete core
■ When compared to normal plain concrete and ICF model there is no much change in the load
carrying capacity, but after attaining peak load sudden failure occur in the plain concrete but
ICF shows ductile failure.
■ Curing process is not required, since the concrete is covered by EPS sheets.
■ Due to the ductile behaviour its use may protect the structure from natural disasters like
earthquake.
■ From the analytical and experimental investigation it concluded that thickness of 75mm EPS
sheet with concrete core gives maximum strength & ductility.

20. REFERENCES
[1]Andreea-TereziaMircea and RuxandraCrutescu (2010), Research Contributions to the Seismic Performance of ICF
Technology Wall Systems, WSEAS Transactions on Information Science and Applications, pp 1240-1250.
[2]AfshinHatami and George Morcous (2011), Job-Built Insulated Concrete Forms (ICF) for Building Construction, 47th
ASC Annual International Conference Proceedings.
[3]Peter Dusicka, Thomas Kay, Carl Werner and Max Stephens (2010), Seismic Evaluation of Green Building Structural
System: ICF Grid Walls, IStar Laboratory infrastructure Testing and Applied Research.
[4]W. Maref, M. M. Armstrong, H. Saber, M. Rousseau, G. Ganapathy, M. Nicholls and M.C. Swinton, (2012), “Field Energy
Performance of an Insulating Concrete Form (ICF) Wall”, National Research Council, Canada.
[5]Abdullah Yildiz, GolahanGurlek, Mehmet Erkek, (2008), “Economic and environmental analysis of thermal insulation
thickness in buildings”, Journal of thermal science and technology, Turkey.

21. Thank you