Ecological Building Systems has been at the forefront of airtight and wind tight building products and natural insulations for nearly a decade, based in County Meath in Ireland, the company has developed a complete range of environmental building solutions to meet the needs of energy efficient, low carbon builders. The range includes pro clima for air tightness and wind tightness, GUTEX soft boards, Calsitherm climate board, Thermo-Hemp insulation and many more.

Ecological Building Systems is about supporting and supplying the Irish and UK market with both the technical knowhow and quality tried and tested products for the sustainable building industry.

Why should I insulate?

The main benefits of insulating your home are reducing heat loss and saving money on your heating bills. Insulation will also provide a more comfortable climate for your home, by acting as a buffer between the cold damp weather on the exterior and the warm dry environment inside your home.

Why use natural insulation?

Thermo Hemp, HolzFlex natural wood fiber, Thermafleece sheep wool and natural insulation products provide effective thermal & sound insulation are easy to work with & can be readily cut to fit, but there are many other benefits, the most significant points being that natural insulation:

  • Improves the climate in your building because of its thermal & vapour diffusion capacity
  • Regulates temperature, absorbs moisture & gently releases it off again
  • Protects the structure by keeping it dry, prolonging the lifetime of the building fabric
  • Its' density provides outstanding protection against overheating in the summer
  • In the roof space it absorbs daytime heat from the sun & only releases it later when temperatures are lower
  • Ideal for use between rafters (Thermo Hemp, Thermafleece and HolzFlex only), joists with all our insulation products & timber studs (Thermo Hemp, Thermafleece and HolzFlex only)
  • Very effective fire resistance as they char rather than melt, self extinguishes and does not emit any noxious gases.

How does Thermo Hemp, Thermafleece and HolzFlex 040 wood fiber insulation products compare with alternative materials?

Thermo Hemp, HolzFlex040 wood fiber, Thermafleece insulation have a very low conductivity. The lower the thermal conductivity the more difficult it is for heat to pass from one side to the other. To compare these products with to other common insulators refer to the table below, here the conductivities are given in Watts per meter Kelvin (w/mK) – where the lower value is the better insulation value.

Insulation Material Conductivity (k Value)

Thermo Hemp 0.037 W/mK
HolzFlex 040 wood fiber insulation 0.038 W/mK
Thermafleece Premium sheep wool 0.038W/mK
Thermafleece PB20 Blend mix sheep wool 0.039 W/mK
Glass Wool 0.044 W/mK
Mineral (Rock) Wool 0.042 W/mK
Cork 0.040 W/mK

Natural products are a significantly more effective insulator once moisture is introduced into an environment, which typically occurs in everyday situations. Your attic may have over 60% humidity for example, which will adversely affect materials which can not absorb this moisture. Natural insulation materials such as Hemp, wood fiber, sheep wool and cellulose are hygroscopic, which means they can absorb moisture without becoming wet to the touch and without affecting its superior performance.

How much insulation do I need?

The amount of insulation that you need will depend on the type of house, where you are insulating and if you have existing insulation in place.

Ceiling Joists:

For attics in existing houses, regulations require a minimum of approximately 120mm of Thermo Hemp or HolzFlex040 wood fiber insulation or Thermafleece insulation. For attics in new houses, the regulations require a minimum of 240mm thick Thermo Hemp, HolzFlex040, Thermafleece.

External Walls:

For external walls in a timber frame home, the requirement is 140mm thickness of Thermo Hemp, Thermafleece or HolzFlex040, which is standard and up to 200mm thick (two layers of either product 100mm) for low energy homes. Thermo Hemp, Thermafleece and HolzFlex040 insulation is not suitable for use in the cavity of block cavity walls. Internally, Thermo Hemp and HolzFLez040 Insulation is usually installed from 40mm to over 100mm thick between studs and from 100mm thick upwards between the floors for thermal/acoustic purposes.

Insulated Pitched Roofs:

For roof-line installations (dormer/cathedral ceilings where the insulation follows the roof shape) the requirement is 200mm (two layers of 100mm) to achieve the desired performance and comfort in new buildings. There are numerous other construction types, which we can calculate the amount of insulation you need, please contact us for more information.

What if I have glass/mineral fiber insulation installed already?

Most existing houses have at least some level of insulation in the attic. Many houses over 15 years will find that the depth of existing insulation is usually quite small as old glass/mineral fiber may settle over time and will be much less effective. There are two choices here: the existing fiber glass can be removed or one of our natural Insulation can be rolled out or poured over existing insulation. If you remove the existing insulation, be sure to take all the proper precautions including gloves, protective clothing and dust masks. There may also be an issue regarding the disposal of such insulations, and the manufacturer should be contacted for guidance concerning this. If you decide to roll one of our Insulation products over the existing insulation you will improve the U-Value of your house and you will also reduce the old insulation fibers from blowing around the attic space. Please see our products section for more details.

What is embodied energy?

Embodied energy is the energy required to produce the material and manufacture it to a building-grade insulation standard. It is typically measured in kilowatt Hours per cubic meter (kWh/m3). Our natural insulation products contain, much less energy than synthetic insulation, meaning that in a very short time, it will save more energy than will have gone into its production. Most common insulation materials will take many years to achieve this break-even point and some will never reach it at all. As hemp and wood absorb Carbon over their life cycle this sequesters the carbon content of the construction even before the material is installed!

Hemp, wood, wool and cellulose fibers are not harmful in any way. No protective clothing or equipment is required to handle or install our natural insulation products. As is the case with synthetic insulation materials, electric wiring in the attic is best left on top of the insulation. This will allow easy access for electricians in the future and can avoid heavily loaded wires from overheating.

Can I use natural insulation as a hot water tank jacket?

Yes. Our natural insulation products can be placed beneath the existing lagging jacket or can be held in place with a layer of old blankets.


Thermo-Hemp is a natural insulation material manufactured from hemp by Hock in Bavaria, Germany.

Hemp grows up to a height of nearly 4 meters within a period of 100-120 days. Because the plants shade the soil, no chemical protection or toxic additives are required for hemp cultivation. As well as having low embodied energy during manufacture, hemp is carbon negative as it locks in carbon during its growth.

Hemp is one of the oldest cultivated plants on earth, hemp is not only used as an excellent insulating material, but also for clothing, paper, oil, fuel, food and other construction materials.

With a thermal conductivity of 0.038W/(m.k), a density of 38kg/M3 and thicknesses ranging from 40mm to 200mm, Thermo-Hemp is the perfect solution for wall, floor and roof applications in both and new and old buildings.

• Healthier for you - made from natural hemp plant fibers grown without any chemicals or toxic additives. Thermo-Hemp is totally safe and easy for you to install.

• Healthier for your home - its hygroscopic properties hemp regulate humidity offsetting condensation risk. What’s more it’s naturally resistant to mold growth and insect attack and has outstanding fire resistance.

• Healthier for the environment - as well as having low embodied energy during manufacture, hemp is carbon negative as it locks in carbon during it’s growth.


HolzFlex from Homatherm is a unique semi-rigid wood fiber insulation in slab form. The main raw material used to produce HolzFlex is wood chippings. HolzFlex can simply be friction fitted between rafters, joists or studs and wedges itself in the studs almost independently because of its elasticity. Because there is no requirement for wearing awkward protective clothing when fitting and also because the product is easy to cut it can be installed effortlessly with no concern for harmful fibers. Even hard to reach hollow spaces can now be insulated thoroughly and effectively.

HolzFlex is ideally suited for timber constructions but it is also very suitable in traditional masonry constructions as dry lining insulation. In timber frame constructions HolzFlex is ideal as both the insulation slab and the timber frame compliment each other. With a thermal conductivity of 0.038W/mK HolzFlex acts as a very effective thermal insulation layer. High elasticity and excellent drought proofing properties compliment each other superbly with HolzFlex. HolzFlex is not restricted by the width of the studs as each slab may be cut easily using a knife or handsaw.

Buildings constructed from natural building materials offer a hitherto unachievable level of comfort, safety and energy efficiency. Similar materials complement each other in a construction. When HolzFlex is used as an insulating material the result is a thoroughly homogeneous healthy construction.

• HolzFlex also offers superior heat protection to buildings in comparison to conventional insulation materials. This is particularly critical in timber frame buildings and dormer houses which suffer from intense overheating in the summer months.

• HolzFlex also offers outstanding acoustic airborne sound reduction due to its density and natural flexibility. Whether installed in stud partitions between rooms or in ceiling joists between floors, HolzFlex offers an incredibly effective, simple, natural acoustic solution to match the home owner’s needs.

• The hygroscopic nature of HolzFlex wood fiber insulation allows for the rapid absorption of moisture when internal humidity is high. The moisture can in turn be released quickly when internal conditions are too dry. This feature is important in order to improve the health and comfort of the inhabitants and prevents the growth of molds, fungi and dust mites.

• HolzFlex has outstanding fire resistance properties. HolzFlex does not emit noxious gases when exposed to a naked flame, nor does it degrade rapidly. HolzFlex chars when exposed to a flame


Premium Thermafleece

Thermafleece is a high density, wool rich insulation that is the first choice when maximum thermal and acoustic performance and breath-ability are required or in space limited situations.

Manufactured to meet the highest quality and performance standards and using British sheep’s wool, Thermafleece is the only wool based insulation to hold BBA certification.

Thermafleece has a thermal conductivity of 0.038W/mK and is available in a variety of dimensions suitable for all your application needs. Thermafleece is supplied in slab form with standard lengths of 1200mm with three thickness, 50mm,75mm and 100mm and two widths, 400mm as standard stock size and 600mm upon request.

Thermafleece PB20

Thermafleece PB20 is as a lower density, compressed roll insulation that is easy to handle and install in confined spaces such as lofts. Thermafleece PB20 contains a lower quantity of wool than Thermafleece (60% compared to 85%). Because Thermafleece PB20 is compress packed, it is necessary to incorporate a proportion of recycled polyester fibers to ensure the insulation regains its full thickness when un-rolled.

Compressing the rolls by approximately 60% significantly reduces the impact of transporting the finished product and nearly halves the required storage space for the same volume of insulation.

Thermafleece PB20 has a thermal conductivity of 0.039 W/mK and is available in roll forms in widths of 370mm to enable quick and easy installation. Each roll contains a single 5.3m length of insulation and is available in a thickness of 100mm.