FAQ: Natural Insulation

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.

Thermo Hemp, Gutex woodfibre boards, Thermafleece sheep wool, and Warmcel 100 cellulose 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.

Thermo Hemp, Gutex wood fibre, HolzFlex040 woodfibre, Thermafleece and Warmcel 100 cellulose 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 0.038 W/mK

HolzFlex 040 woodfibre insulation 0.038 W/mK

Thermafleece sheep wool 0.039W/mK

Warmcel 100 Cellulose insulation 0.035 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, woodfibre, sheep wool and cellulose are hygroscopic, which means they can absorb moisture without becoming wet to the touch and without affecting its superior performance.

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.

We would be more than happy to run specific U value calculations and advise for your particular construction,however the following is a guideline.

Ceiling Joists:

For attics in existing houses, regulations require a minimum of approximately 100mm thickness of Warmcel 100 cellulose Insulation (this is 1 bag of Warmcel 100 per m2), or 120mm of Thermo Hemp or HolzFlex040 woodfibre insulation or Thermafleece insulation. For attics in new houses, the regulations require a minimum of 240mm thick Thermo Hemp, HolzFlex040, Thermafleece or Warmcel 100 cellulose insulation.

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 roofline 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. Warmcel 100 can only be used across and in between horizontal ceiling joists.

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 fibre may settle over time and will be much less effective. There are two choices here: the existing fibre 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 fibres from blowing around the attic space. Warmcel 100 can easily be poured over existing insulation. Please see our products section for more details.

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 metre (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 fibres are not harmful in any way. No protective clothing or equipment is required to handle or install our natural insulation products. However we would recommend a dust mask if you are working in a confined dusty area, such as a loft.

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.

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.

Yes. Depending on the quantity and products ordered, we deliver with our own vehicles directly to your door or we use couriers. Delivery charges are minimal, and generally delivery within 4 to 5 working days from receipt of payment. Express deliveries can be arranged which may incur an additional charge.

No! The climate board is made out of lime, sand, and 0.6 vol.-% cellulose. It is non combustible and in the case of a fire there are no toxic fumes.

Before the climate board was introduced in 2000 by Calsitherm they took part in a research project from the EU. Various buildings were equipped with the climate board. Sensors measured the temperature and condensation levels in the climate board for 5 years. The outcome was so convincing that the system thereafter was introduced to the market.

Yes. The insulating properties of the climate board are very good. The energy saving level depends also on existing structure and its properties. The costs of energy with a 24 cm Brickwork wall can be reduced by appoximately 50% with a 30 mm climate board.

Yes. However we recommend tiling only two thirds of the wall area where the climate board is to be applied.

One should apply the climate board only on smooth surfaces according the manufacturers specification. Valid surfaces are lime or lime cement plasters. Gypsum must be avoided.

Items up to 5 kg can be mounted with the help of Fischer: plasterboard fixing GK. Loads above 5 kg have to be bolted through the climate board into the load bearing wall.

Yes. We have wall ceiling joint panels which reduce thermal bridges in ceilings as well as thermal bridges through internal walls connecting to external walls.

We recommend two kinds of finishes. The first option is a smooth lime plaster applied in two layers (app. 1-2 mm each layer). The second option is a lime plaster with a grain to obtain a rough texture. In both events the paint used should be a diffusion open mineral paint like silicate paint or lime paint.