1. What are the various types of insulation?

There are many types of Insulation on the market. They are all effective if they are used for the correct application. Isotherm is considered a Flexible Polyester Blanket. Other types of insulation can include Cellulose Loose fill, Flexible Fiber Glass Blanket, Flexible Ceramic Fiber blanket, Rigid Polystyrene, to name but a few.

2. What exactly is R-value? Click here to read the answer

The R-value – Thermal Resistance is a direct indication of the performance of the product. The higher the R-value, the better the insulating effect of the insulation will be. R-value is determined in the following way:

R-value = Thickness (of the material) / Its Thermal Conductivity (or K-value)

The thickness is determined by the manufacturer – and will normally form part of the product range. The K-value is determined in an accredited laboratory. The manufacturer will produce a sample that is manufactured at a stated density (weight) and will submit to the laboratory for testing. The idea is to achieve an as low as possible K-value, in other words, a low thermal conductivity – put plainly, the product must be a bad conductor of heat flow.

Once the K-value is determined, the R-value can be calculated, for example:

For a 50mm thick blanket with tested K-value of 0.046:

0.05 (thickness) / 0.046 (k-value) = 1.08 (R-value)

As long as the manufacturer manufactures the other thicknesses in his range at the same density than the submitted sample, he can use the same formula and k-value to determine the R-values, eg:

For a 100mm thick blanket:

0.1 (thickness) / 0.046 (tested k-value)= 2.17 (R-value)

This is where the consumer must be vigilant – some dubious manufacturers may reduce the density or weight of their products to save on raw material. If they do this, they cannot use the tested k-value and thus cannot claim a good R-value. Always demand to see the test report and stated density that the manufacturer uses to determine R-values.

The R-value determined in the examples above is the so-called Product R-Value. The fact is however that the roof tiles and ceiling (as well as other roofing materials) also contribute to the insulating effect. In practice, the Total R-value of both roofing material and insulation material must thus be considered. So, if the insulation material’s R-value is 2.17, and the roof and ceiling materials have a R-value of 0.53, then the Total R-value will be 2.7. Refer to The Thermal Insulation Association of South Africa (TIASA) website for guidelines on Total R-values.

3. What else influences insulation choice?

The layout and pitch of the roof can also influence the insulation choice. Feel free to contact our professional sales staff for advice.

4. What raw materials is ISOTHERM made from?

ISOTHERM Thermal Insulation is made from the polyester of recycled PET bottles (“plastic” cooldrink bottles) that are heat bonded without any chemicals or added fire retardants.

Polyester is has natural fire-retardant properties and is non-toxic. It’s the same as the polyester used in pillows and duvets.

No one can say that he/she will never return into the ceiling after installing insulation. If the geyser bursts, an alarm get installed, the roof leaks, etc, it is comforting to know that there is a safe itch-free insulation material on the ceiling.

5. Is the stated R-value sustainable over time?

As mentioned in the discussion on R-value, it is obvious that the criteria for a sustainable R-value is a sustainable thickness and a constant K-value (density and weight).

If the product you choose cannot sustain its thickness in the ceiling over time, despite the fact that it was installed at a certain density, then the R-value will NOT be sustainable. Isotherm’s thickness is “locked in” as it is a bonded blanket – winds, leaking roofs, people moving around in the ceiling, etc, will not change the thickness. Should something disturb the blanket, the thickness will simply recover.

6. Do you have any product certification?

ISOTHERM Thermal Insulation carries the Agrément South Africa mark. This mark, although not as well known as the SAMS mark of approval, certifies that the product is fit for purpose and the certificate is recognised in the National Building Regulations.

But why do we not have the SABS mark?
The answer is simple – The SABS deals with products that can or have been standardised. When a new or relatively new product or innovation comes along, it falls outside the scope of existing SABS standards. Isotherm is a relatively new product and specific standards are only now being developed.

There is a SABS representative on the Board of Agrément South Africa, so this certification is a legitimate guarantee of fitness-for-purpose which allows for confident use.
ISOTHERM is a long standing member of TIASA and all required R-value and fire tests have been carried out.

7. Spare me the technical jargon; what must I really look out for when considering bulk insulation?

  • Go as thick and heavy as your budget will allow. The thicker and more dense (heavier) the product, the better the R-value.
  • If a manufacturer is shy to print the R-value on his packaging, it is probably because he is skimping on raw material and weight.
  • Either the SABS and/or Agrément South Africa mark. However – there is a difference between the SABS mark of approval and SABS ISO 9001:2000 certification. Some manufacturers are only ISO 9001 certified, but claims they have the SABS mark of approval.
  • Can the product sustain its thickness over time? If any movement in the ceiling has a chance of disturbing the installed thickness, then the R-value for that portion will not be the same.

8. Where can I buy ISOTHERM Thermal Insulation?

ISOTHERM is availalbe nationwide at most reputable hardware and building supply stores.