• What is SPF

    What is SPF

    The product “RIGIFOAM Closed Cell Polyurethane Sprayfoam” which THERMAMASTA install,is a Closed-Cell, Rigid Polyurethane version of ‘SPF’, With superior Thermal Insulation performance, when compared to other ‘SPF’ formulations.

  • Building Professionals

    Building Professionals

    Closed-Cell SPF is especially suited to be applied externally, and due to its seamless nature, is unmatched for its ability to perform these duties. But even a roof insulated from underneath.

  • Building Managers and Owners

    Building Managers and Owners

    Closed-cell Spray Polyurethane Foam (SPF) systems deliver longer life expectancy and lower lifecycle costs over traditional systems, while affording superior protection to the building.

  • Before & After

    Before & After

    Photos of before & after the project started and finished.


What is “SPF” (Spray Polyurethane Foam)?


The product “RIGIFOAM Closed Cell Polyurethane Sprayfoam” which THERMAMASTA makes use of is a Closed-Cell, Rigid Polyurethane version of ‘SPF’. It offers superior Thermal Insulation performance, especially when compared to other formulations of SPF.
Applied directly to any surface with a foam spraying gun linked to a unique blending machine, the RIGIFOAM provides a smooth and effective waterproof thermal protective coating.











What is “Polyurethane (PU) Foam”?


PU is an organic foam product which is created when an exothermic reaction occurs between two chemical components. When the reaction is complete, the foam like substance starts to solidify and becomes an elastic but, firm product which is used for superior thermal insulation.

Many people are unwittingly familiar with the use spray polyurethane foam as it’s used to construct the inside of surfboards. Polyurethane foam has been used commercial as far back as the 1950’s.


How long does it take for the ‘SPF’ to form?

The two components which need to mix to form the SPF only come into contact as it leaves the spray gun. The reaction starts as soon as the liquid RIGIFOAM formulation hits the surface which requires insulation or thermal protection. The foam quickly begins to rise and soon reaches the required thickness for superior thermal protection.

Some of the factors which decide the final height and thickness include the temperature and the amount of moisture nearby. After being sprayed on a roof or floor, the foam coating can be walked upon after 20 minutes, although this may vary depending on the thickness of the foam sprayed. The foam spray reaches maximum strength within 24 hours.


How does ‘SPF’ Adhere to the Substrate?


The SPF polyurethane spray foam is self-adhesive and will stick to just about any clean surface. Although, there are a few surfaces which may require an adhesion primer.

While the polyurethane spray foam is still within its liquid state, it mechanically locks itself onto the surface at a molecular level which creates a very strong bond.

SPF is often recommended for structural enhancement projects because of its superior adhesion qualities. There have been studies conducted in the USA that have shown that the “racking strength” of light structures is improved by 300% when using spray polyurethane foam. SPF is often used to in the aircraft industry for strengthening the wings without adding extra weight to the aircraft.









What does “Closed-Cell” mean?

spfcellThe term Closed Cell refers to the foam’s internal structure. The gas which is created during the foaming process is permanently compressed within the tiny cells, the structure of which is closed. It is the gas strapped within these closed cells which makes gives its superior thermal insulation properties as well as making it resistant to water.






What does “Rigid PU-foam” mean?

This is a variant of polyurethane foam which hardens to form a rigid structure which still maintains a level of flexibility.


What is the Thermal Conductivity of ‘SPF’ material?

With a maximum aged Thermal Conductivity (‘Lambda’ ) of 0.028 W/(m•K), thin insulating layers can be produced with”RIGIFOAM” which THERMAMASTA install.


Calculation of R Value

grm/m³ grm/m³
k- Value 0.024 0.03 0.04 0.032 0.032 0.039 0.045 0.04 0.04 0.04
Thickness R-Value R-Value R-Value R-Value R-Value R-Value R-Value R-Value R-Value R-Value
(mm) (Km2/W (Km2/W (Km2/W (Km2/W (Km2/W (Km2/W (Km2/W (Km2/W (Km2/W (Km2/W
10 0.42 0.33 0.25 0.31 0.31 0.26 0.22 0.25 0.25 0.25
20 0.83 0.67 0.50 0.63 0.63 0.51 0.44 0.50 0.50 0.50
25 1.04 0.83 0.63 0.78 0.78 0.64 0.56 0.06 0.63 0.03
30 1.25 1.00 0.75 0.94 0.94 0.77 0.67 0.75 0.75 0.75
35 1.46 1.17
40 1.67 1.33 1.00 1.25 1.25 1.03 0.89 1.00 1.00 1.00
50 2.08 1.67 1.25 1.56 1.56 1.28 1.11 1.25 1.25 1.25
55 2.29 1.83 1.38 1.72 1.72 1.41 2.29 1.38 1.38 1.38
60 2.50 2.00 1.50 1.88 1.88 1.54 1.33 1.50 1.50 1.50
65 2.71
70 2.92 2.33 1.75 2.19 2.19 1.79 1.56 1.75 1.75 1.75
75 3.13 2.50 1.88 2.34 2.34 1.92 1.67 1.88 1.88 1.88
80 3.33 2.67 2.00 2.50 2.50 2.05 1.78 2.00 2.00 2.00
90 3.75 3.00 2.25 2.81 2.81 2.31 2.00 2.25 2.25 2.25
100 4.17 3.33 2.50 3.13 3.13 2.56 2.22 2.50 2.50 2.50
110 4.58 3.67 2.75 3.44 3.44 2.82 2.44 2.75 2.75 2.75
120 5.00 4.00 3.00 3.75 3.75 3.08 2.67 3.00 3.00 3.00


What is the WEIGHT of ‘SPF’?

The product RIGIFOAM, which THERMAMASTA installs, has a density of about 45 kg/m3.

(Upon request, we can provide products with a higher density)It is very light weight for the strength it offers, e.g. 1m2 installed at 25mm thick weighs only 1,125 kg.


Can ‘SPF’ be installed onto substrates of any shape?


When it’s sprayed on, the SPF is in a liquid form and will take on the shape of the surface it’s applied to. The only limitation would be the accessibility of the surface to the operator using the polyurethane foamsprayequipment.


Can ‘SPF’ easily be shaped after it has formed?

spfformedOnce the foam has hardened, it can easily be sculpted using simple tools. For example, if it is used on a roof, it can easily be trimmed on the edges.










Can you walk on it after installation?


Yes, you can. The Density (45 – 60 kg/m3) and Compression Strength (0, 20 – 0, 40 N/mm2) of RIGIFOAM, is designed for it to be installed on roofs and floors. It is designed with foot traffic in mind.

Only if you anticipate much heavier traffic, such as regular maintenance of roof equipment with heavy tools etc., do we suggest bonding an additional walkway mat (there are various options available) on top of the foam, to protect it from excessive impact.


Is ‘SPF’ affected by Moisture?

No, it isn’t. The closed-cell structure of the foam offers it water resistant properties. Spray polyurethane foam is the only insulation material which has been approved as flood resistant.

You’ll often find that closed cell SPF is used in the hulls of boats and ships to prevent sinking.


Can ‘SPF’ be used as a Vapour Barrier?

Yes, it can. Closed cell SPF has been approved in the USA and Canada as a vapour barrier.


Will ‘SPF’ help to waterproof a Masonry Wall from Driving Rain? 


Yes, it definitely can. Closed cell SPF tested according to EN 12865 (a largescale test which simulates real exposure) is water resistant up to 1800Pa, which resembles a wind speed of 197 km/h. Following the new Spanish regulation rigid polyurethane foam is the only insulation material which can attain the best water resistance level on masonry façades without any other requirement.


Can ‘SPF’ be used underground?


Yes it is. Studies carried out over the long term have shown that closed cell SPF is quite effective for the insulation and enhanced waterproofing for basements.


What happens if the ‘SPF’ is damaged?

It’s highly unlikely that the SPF could be damaged. If it does get damaged, because of the structure of the closed cell foam it is easy to repair.


What Temperatures can ‘SPF’ tolerate?

THERMAMASTA installs RIGIFOAM Closed Cell Polyurethane Sprayfoam which is both frost and heat resistant. It can withstand temperatures anywhere between -50°C to +100°C.


Can ‘SPF’ be installed on the Outside of Building Envelopes?


SPF is often used on the exterior layers of building envelopes. To achieve the best energy efficiency, it’s best to have the insulation on the exterior of the building. The building is then shielded from extreme heat or frost before it can have any consequence on the other components, which also improves the sturdiness of the building envelope.

More material weight is obtainable behind the insulation, where it can act as insulated thermal mass, to inactively aid in the regulation of internal temperatures, further increasing energy efficiency.






How Durable is ‘SPF’?


Roofs insulated with SPF have lasted longer than 30 years in places where the technology was initially used. In theory, it should last as long as the building does. Buildings with SPF insulated roofs, can better withstand severe weather, as can be seen during hurricanes or tornadoes. Not only is SPF itself enormouslyrobust, but it also protects and preserves the structure it covers.






Is ‘SPF’ affected by Sunlight?

Yes it is. If the SPF is used on a surface which is exposed to sunlight it should be covered with a coat of good quality paint to ensure superior thermal insulation.  The protective coating of paint should be regularly maintained.

Time intervals between re-coating on a roof may vary depending on the specific product. We suggest about 8 years for quality Acrylic Roof Paint, to almost 30 years for a good quality Polyurea coating.

Lighter coloured coatings will generally last longer than the same in a coloured version, but it has no effect on the spray polyurethane foam beneath it.


Is ‘SPF’ a good Soundproofing Material?

Closed cell SPF can used effectively to reduce noise by sealing gaps and cracks which would usually allow sound to travel through the walls, ceilings or floors of a building. To a degree,it’s effective against noise caused by vibration, but this is where the density of thepolyurethane foam plays a larger role.

Closed cell SPFusually absorbs sound from the lower frequencies. An open cell SPFvariety is available for special order. It’s suited toabsorb a wider range of sound frequencies, but this can only be applied internally.


Is ‘SPF’ a “GREEN” product?

Yes, it has been thoroughly evaluated by a number of Sustainability Rating Systems overseas (e.g. “LEEDS” in the US) and found to be one of the most Sustainable Insulation Systems to specify today.

Some of the attributes which gives it this excellent rating includes:

  • Excellent thermal efficiency– leading to optimumenergy savings and reduced CO2 emissions.
  • Relatively low environmental impact at the building level – the product saves more than 100 times more energy than is used in its manufacture.
  • Durability – leading to long term performance and reducing the need for replacement, thereby saving resources and energy over time. It helps to preserve the building components as well, leading to further long-term savings on resources and energy.
  • Minimal thickness – minimizing building footprint and land use.
  • Additional Benefits – apart from the superior Thermal Insulation, it offers additional benefits which adds value and eliminates need for additional measures e.g. Self-Adhesive; Self-Flashing; Seals Airtight; Vapour Barrier; Enhances Waterproofing; Enhances Structural Strength; etc.
  • Transportation – large volumes of material is formed in-situ from compact liquid raw materials, which means no multiple deliveries of bulky materials, or large space for site-storage, required.

Example: ‘SPF’ as Sustainable Roofing Solution is unequalledCriteria SPF Qualifications

Criteria SPF Qualifications
Weather Protection

  • Water cannot migrate through Closed-Cell SPF
  • Seals all gaps, laps and holes
  • High wind uplift resistance
  • No deck penetration
  • Seamless protection
  • 30+ years experience

Energy Efficiency

  • Highest R-value Insulation
  • Zero air leakage
  • No thermal bridging
  • Optimal savings on energy
  • Reduced CO2 emissions
  • Improved occupant comfort


  • Fast Installation
  • Lower transport and storage costs
  • Performs multiple functions
  • Fully self-adheres to most substrates
  • Virtually no waste
  • Conforms to any shape
  • Minimal thickness required
  • Simplified detailing
  • Self-flashing

Maintenance and Repair

  • Minimal maintenance
  • Very easy and economical to repair, if necessary


  • Very long service lifetime
  • No need for replacement
  • Preserves building components
  • Saves resources over time

Impact on Enviroment

  • Low impact at building level
  • SPF saves more than 100 times more energy than is used to manufacture


What Support can I expect with THERMAMASTA and RIGIFOAM?

With over 25 years of experience in the Building Industry (as Architects and Project Managers) combined with direct access to our international associates at RIGIFOAM, we offer our Clients well-proven technology and support, to develop their Individual Solutions