Wool insulation

Last updated
A sample sheep wool insulation batt Woolpic.gif
A sample sheep wool insulation batt

Wool insulation is made from sheep wool fibres that are either mechanically held together or bonded using between 5% and 20% recycled polyester adhesive to form insulating batts, rolls and ropes. Some companies do not use any adhesives or bonding agents, but rather entangle the wool fibers into in high R-Value, air capturing knops (or balls) that hold themselves together. Natural wool insulation is effective for both thermal and acoustic insulation. The wool is often sourced from the less expensive black wools of the UK and Europe. [1] Batts are commonly used in the walls and ceilings of timber-frame buildings, rolls can be cut to size for lofts, and ropes can be used between the logs in log homes. Wool knops are installed loosely in attics or in walls as a blow-in-blanket system utilizing a fiber mesh to hold the wool in place during the blow in process.

Contents

Wool.Life Wool Knops A 2 Photo Knops-145.jpg
Wool.Life Wool Knops

Natural wool insulation should be distinguished from mineral wool insulation, also called slag wool or rock wool, which only resembles natural wool fibers. It is actually made from rock, blast furnace slag, and other raw materials which are melted and spun into fibers. [2]

Sheep wool is a natural, sustainable, recyclable material, which is biodegradable, and has low embodied energy. It does not endanger the health of people or the environment, and does not require protection to install, unlike fiberglass insulation. Wool is a highly effective insulating material which performs better than its rated R value because it can absorb and release moisture. [3] Mongolian nomads used felted and woven sheep wool pads as an insulating layer on the walls and floors of their dwellings, called ger or yurts. The use of wool for insulation is starting to rise in popularity. It is already popular in Australia, which produces 55% of the world's raw and processed wool, [4] as well as in Europe and Canada, and is gaining ground in the United States

Building considerations

Wool insulation commonly comes in rolls of batts or ropes with varied widths and thicknesses depending on the manufacturer. Generally, wool batts have thicknesses of 50 mm (2 in) to 100mm (4 in), with widths of 400 mm (16 in) and 600 mm (24 in), and lengths of 4000 mm (13 ft 4 in), 5000 mm (16 ft 8 in), 6000 mm (20 ft) and 7200 mm (24 ft). The widths of 16 in and 24 in are the standard measurements between studs in a stud frame wall. Most manufacturers provide custom sizes as well and batts and ropes are easy to cut once on site.

Wool insulation costs significantly more than conventional fiberglass insulation, but does not require the use of protective gloves, and may have significantly lower health risks to both the building occupants and the installation crew. It can be used in the roof, walls and floors of any building type as long as there are spaces to put the insulation in. Installing wool insulation is very similar to installing conventional insulation batts; it can be held into place with staples or it can be friction-fit, which involves cutting the insulation slightly bigger than the space it occupies, using friction to hold it in place.

Environmental considerations

Some wool used to manufacture insulation is the wool discarded as waste by other industries due to its colour or grade. As a controlled waste product it cannot be disposed of until it is cleaned. Hence the energy footprint of washing the wool is attributed to the livestock industry under PAS2050. There are some primary environmental factors that need to be considered when looking for a source of wool, such as the way the flock is treated for pesticides, the chemicals used in the treatment of the wool after shearing, and the distance from the source to its final destination. Sheep are often treated with insecticide and fungicide in a process called dipping. This leaves a residue on the fleece and can result in groundwater contamination if used improperly. [5] These residues are often washed off once the fleece is sheared, but this results in three byproducts: grease, liquor, and sludge. The first two can be safely disposed of, but the third contains remnants of the pesticides which cause a concern for disposal.

Sheep wool insulation is often treated with borax to enhance its fire retardant and pest repellent qualities. The level of Borax is relatively low only 4% dry weight although the scouring baths have a higher load of 8–9%. [6] Borax mining employs one of the cleanest mining techniques available [7] but borax is increasingly coming into focus as a suspected reproductive toxin having been considered relatively safe for many years; animal ingestion studies in several species, at high doses, indicate that borates cause reproductive and developmental effects. The most significant exposure route for humans is inhalation which raises questions over whether dust from wool insulation could lead to a significant exposure to humans, though this is probably unlikely for anyone except professional installers.

There are some companies that use DE (Diatomaceous Earth) as pesticide. DE is believed to be harmless and is used in feed and animals to stave off parasites. DE has the drawback of having to be applied in two steps to be effective and the wool having to be installed loose. [8]

Some companies use Thorlan IW (Kaliumfluorotitanat), which repels moths. It is a titanium based treatment which remains with the fiber during its entire period of use. Thorlan IW is in the European Union chemical law register of certified products. A rubber solution is applied hot and allows a coating of Thorlan to stay with the product for its lifetime. [9]

Related Research Articles

<span class="mw-page-title-main">Wool</span> Textile fibre from the hair of sheep or other mammals

Wool is the textile fibre obtained from sheep and other mammals, especially goats, rabbits, and camelids. The term may also refer to inorganic materials, such as mineral wool and glass wool, that have properties similar to animal wool.

<span class="mw-page-title-main">Thermal insulation</span> Minimization of heat transfer

Thermal insulation is the reduction of heat transfer between objects in thermal contact or in range of radiative influence. Thermal insulation can be achieved with specially engineered methods or processes, as well as with suitable object shapes and materials.

Fiberglass or fibreglass is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass cloth. The plastic matrix may be a thermoset polymer matrix—most often based on thermosetting polymers such as epoxy, polyester resin, or vinyl ester resin—or a thermoplastic.

<span class="mw-page-title-main">Mineral wool</span> Fiber made from spun molten minerals

Mineral wool is any fibrous material formed by spinning or drawing molten mineral or rock materials such as slag and ceramics.

<span class="mw-page-title-main">Wool classing</span> Examination of the characteristics of the wool in its raw state

Wool classing is the production of uniform, predictable, low-risk lines of wool, carried out by examining the characteristics of the wool in its raw state and classing (grading) it accordingly. Wool classing is done by a wool classer.

<span class="mw-page-title-main">R-value (insulation)</span> Measure of how well an object, per unit of area, resists conductive flow of heat

In the context of construction, the R-value is a measure of how well a two-dimensional barrier, such as a layer of insulation, a window or a complete wall or ceiling, resists the conductive flow of heat. R-value is the temperature difference per unit of heat flux needed to sustain one unit of heat flux between the warmer surface and colder surface of a barrier under steady-state conditions. The measure is therefore equally relevant for lowering energy bills for heating in the winter, for cooling in the summer, and for general comfort.

<span class="mw-page-title-main">Drywall</span> Panel made of gypsum, used in interior construction

Drywall is a panel made of calcium sulfate dihydrate (gypsum), with or without additives, typically extruded between thick sheets of facer and backer paper, used in the construction of interior walls and ceilings. The plaster is mixed with fiber ; plasticizer, foaming agent; and additives that can reduce mildew, flammability, and water absorption.

<span class="mw-page-title-main">Soundproofing</span> Methods to reduce sound pressure

Soundproofing is any means of impeding sound propagation. There are several basic ways to reduce sound: increasing the distance between source and receiver, decoupling, using noise barriers to reflect or absorb the energy of the sound waves, using damping structures such as sound baffles for absorption, or using active antinoise sound generators.

<span class="mw-page-title-main">Extreme cold weather clothing</span> Clothing for arctic or high altitude conditions

Extreme cold weather clothing refers to clothing for arctic or mountainous areas. Its primary function is to trap air as an insulator to prevent heat loss from the wearer's body. Secondary and necessary is to conduct water vapor away from the body to keep the insulating layers dry. A shell keeps the wind from disturbing the still air in the insulating layers. In warmer conditions, the shell protects from water intrusion.

<span class="mw-page-title-main">Structural insulated panel</span>

A structural insulated panel, or structural insulating panel, (SIP), is a form of sandwich panel used in the construction industry.

Wool is the textile fibre obtained from sheep.

<span class="mw-page-title-main">Glass wool</span> Insulating material made from fibers of glass

Glass wool is an insulating material made from glass fiber arranged using a binder into a texture similar to wool. The process traps many small pockets of air between the glass, and these small air pockets result in high thermal insulation properties. Glass wool is produced in rolls or in slabs, with different thermal and mechanical properties. It may also be produced as a material that can be sprayed or applied in place, on the surface to be insulated. The modern method for producing glass wool was invented by Games Slayter while he was working at the Owens-Illinois Glass Co.. He first applied for a patent for a new process to make glass wool in 1933.

<span class="mw-page-title-main">Cavity wall</span> Type of wall with a hollow center

A cavity wall is a type of wall that has a hollow center. They can be described as consisting of two "skins" separated by a hollow space (cavity). The skins typically are masonry, such as brick or cinder block. Masonry is an absorbent material that can slowly draw rainwater or even humidity into the wall. One function of the cavity is to drain water through weep holes at the base of the wall system or above windows. The weep holes allow wind to create an air stream through the cavity that exports evaporated water from the cavity to the outside. Usually, weep holes are created by separating several vertical joints approximately two meters apart at the base of each story. Weep holes are also placed above windows to prevent dry rot of wooden window frames. A cavity wall with masonry as both inner and outer skins is more commonly referred to as a double wythe masonry wall.

<span class="mw-page-title-main">Duct (flow)</span> Conduit used in heating, ventilation, and air conditioning

Ducts are conduits or passages used in heating, ventilation, and air conditioning (HVAC) to deliver and remove air. The needed airflows include, for example, supply air, return air, and exhaust air. Ducts commonly also deliver ventilation air as part of the supply air. As such, air ducts are one method of ensuring acceptable indoor air quality as well as thermal comfort.

<span class="mw-page-title-main">Building insulation</span> Material to reduce heat transfer in structures

Building insulation is material used in a building to reduce the flow of thermal energy. While the majority of insulation in buildings is for thermal purposes, the term also applies to acoustic insulation, fire insulation, and impact insulation. Often an insulation material will be chosen for its ability to perform several of these functions at once.

<span class="mw-page-title-main">Building insulation material</span>

Building insulation materials are the building materials that form the thermal envelope of a building or otherwise reduce heat transfer.

<span class="mw-page-title-main">Cellulose insulation</span>

Cellulose insulation is plant fiber used in wall and roof cavities to insulate, draught proof and reduce noise. Building insulation in general is low-thermal-conductivity material used to reduce building heat loss and gain and reduce noise transmission.

<span class="mw-page-title-main">Rigid panel</span>

Rigid panel insulation, also referred to as continuous insulation, can be made from foam plastics such as polyurethane (PUR), polyisocyanurate (PIR), and polystyrene, or from fibrous materials such as fiberglass, rock and slag wool. Rigid panel continuous insulation is often used to provide a thermal break in the building envelope, thus reducing thermal bridging.

<span class="mw-page-title-main">Alpaca fiber</span>

Alpaca fleece is the natural fiber harvested from an alpaca. There are two different types of alpaca fleece. The most common fleece type comes from a Huacaya. Huacaya fiber grows and looks similar to sheep wool in that the animal looks "fluffy". The second type of alpaca is Suri and makes up less than 10% of the South American alpaca population. Suri fiber is more similar to natural silk and hangs off the body in locks that have a dreadlock appearance. While both fibers can be used in the worsted milling process using light weight yarn or thread, Huacaya fiber can also be used in a woolen process and spun into various weight yarns. It is a soft, durable, luxurious and silky natural fiber.

References

  1. "Sheep Wool Insulation". Archived from the original on 4 June 2018. Retrieved 17 January 2017.
  2. "Understanding different insulation materials" . Retrieved 16 January 2017.
  3. "Sheeps Wool Insulation". Archived from the original on 29 September 2018. Retrieved 17 January 2017.
  4. "Global Wool Production". Archived from the original on 12 March 2015. Retrieved 16 January 2017.
  5. Cypermethrin sheep dip to be scrapped Archived 2013-12-05 at the Wayback Machine . environment-agency.gov.uk. 3 March 2010
  6. Mike Madon – British Wool Textiles research undertaken 2007 [ full citation needed ]
  7. Tom Laichas, A Conversation with Jared Diamond Archived 2008-12-08 at the Wayback Machine . worldhistoryconnected.press.uiuc.edu
  8. "Wool Insulation". Archived from the original on 2016-03-04. Retrieved 2013-05-05.
  9. "Sheep Wool Insulation/ technical specifications". Archived from the original on 4 June 2018. Retrieved 17 January 2017.