Healthy home

Healthy home

We build or renovate our houses mainly because we want to create comfortable and healthy habitat for us and those close to us. To achieve this we need to

• use materials which have no negative impact on our health
• build our house in consideration of creating healthy enviroment

At the same time we are expecting low usage of energy for heating of the house together with longevity and quality of construction. Interior of the building is often being polluted with emissions of materials used to construct it. Volatile organic compounds (VOCs) in the indoor air are increasing with temperature and inadequate ventilation. That is the reason we need to replace those toxic materials with natural materials (what are they?) available. Hemp, earth, straw, wood are offering the healthy and ecological alternative and if there is no other option look for materials using minimum VOCs.

Natural Building is here since people started to build shelters. Thousands of years of building experience with Natural materials were pushed behind by portland cement together with construction companies. Let them build roads, factories, office and apartment blocks, but not our home. Natural Materials are the way…
The big question comes up, what natural materials should you use in your home. It depends mostly of the climate and location. Another factor is local availability of materials like wood, stone or earth (suitable for building) or chance to source materials which could be reused or recycled. For self builder it is necessary to consider which materials he can handle and visit workshops to acquire experience from experts. With unusual natural building materials it is good idea to contact local authorities in advance.

Load-bearing straw bale dome by Createrra

Great feature of natural materials that aids to create a healthy home is vapor permeability. It is the ability of material absorb and release moisture. This means lower risk of water condensation and mold growth and also better moisture levels inside.

On the other hand we have concrete shell houses and vapour barriers which dont let any moisture pass. It can work with good design and well executed work, but small leak can cause bad damage. Humidity can build up inside the wall and it takes long time before it will get noticed.

Geodesic Polydome and Spiral fields by Jan Slinsky

Sick Home

Many of us live in a Sick Home. Modern materials are slowly releasing chemicals and fumes into indoor environment. Sick building syndrome is the name given to a set of varied symptoms experienced predominately by people working and living in air conditioned buildings, although it has also been observed in naturally ventilated buildings. This syndrome along with Environmental illness and multiple chemical sensitivity are recent in the dictionary.
Until not so long ago our buildings have been free of man-made chemicals, but this started to change with the industrial revolution. Now there is more than 4 million registered chemicals and more than 70000 of them are used commonly. We don’t know much about their effects on our health and even less when they interact in a closed environment. Fact is that many chemicals once thought to be safe, are making us ill.
Postwar industrialization drastically changed fabric of our homes. Mass-produced building products were transported nationwide and replaced regionally sourced and manufactured materials.

Sick building syndrome (SBS) is a combination of ailments (a syndrome) associated with an individual’s place of work (office building) or residence. A 1984 World Health Organization report into the syndrome suggested up to 30% of new and remodeled buildings worldwide may be linked to symptoms of SBS. Most of the sick building syndrome is related to poor indoor air quality.

Sick building causes are frequently pinned down to flaws in the heating, ventilation, and air conditioning (HVAC) systems. Other causes have been attributed to contaminants produced by outgassing of some types of building materials, volatile organic compounds (VOC), molds, improper exhaust ventilation of ozone (byproduct of some office machinery), light industrial chemicals used within, or lack of adequate fresh-air intake/air filtration.

Symptoms are often dealt with after the fact by boosting the overall turn-over rate of fresh air exchange with the outside air, but the new green building design goal should be able to avoid most of the SBS problem sources in the first place, minimize the ongoing use of VOC cleaning compounds, and eliminate conditions that encourage allergenic mold growth.

source wikipedia.com

Sick building syndrome: Guidance for specialist inspectors

Materials

Adobe
Cob
Hemp
Cordwood
Earthbag
Rammed earth
Stone
Straw bale
Timber frame

The materials common to many types of natural building are clay and sand. When mixed with water and, usually, straw or another fiber, the mixture may form cob or adobe (clay blocks). Other materials commonly used in natural building are: earth (as rammed earth or earth bag), wood (cordwood or timber frame/post-and-beam), straw, rice-hulls, bamboo and rock. A wide variety of reused or recycled materials are common in natural building, including urbanite (salvaged chunks of used concrete), tires, tire bales, discarded bottles and other recycled glass.

Several other materials are increasingly avoided by many practitioners of this building approach, due to their major negative environmental or health impacts. These include unsustainably harvested wood, toxic wood-preservatives, portland cement-based mixes, paints and other coatings that off-gas volatile organic compounds (VOCs), and some plastics, particularly polyvinyl chloride (PVC or “vinyl”) and those containing harmful plasticizers or hormone-mimicking formulations.

Techniques

Many traditional methods, techniques, and materials, are now experiencing a resurgence of popularity, however the relative popularity of these techniques differs around the World.

Adobe

One of the oldest building methods, adobe is simply clay and sand mixed with water. Sometimes chopped straw or other fibers are added for strength. The mixture is then allowed to dry in the desired shape. Usually adobe is shaped into bricks that can be stacked to form walls.[citation needed]

Various claims are made about the optimal proportions of clay and sand (or larger aggregate). Some say that the best adobe soil contains 15% – 30% clay to bind the material together. Others say equal proportions of clay and sand are best to prevent cracking or fragmenting of the bricks. Sometimes adobe is stabilized with a small amount of cement or asphalt emulsion to provide better weatherproofing. The blocks can either be poured into molds and dried, or pressed into blocks. Adobe colored with clay and polished with natural oil makes an attractive and resilient floor.

o protect the walls and reduce maintenance, adobe buildings usually have large overhanging eaves and sizeable foundations. Adobe can be plastered over with cob or lime-based mixes for both appearance and protection. Adobe has good thermal mass, meaning that it is slow to transmit heat or cold. It is not a good insulator, however, so insulation can be added (preferably on the outside), or a double wall built with airspace or insulation in between. The traditional thick, un-insulated adobe has proven to perform best in regions without harsh winters or where daily sun is predictably available during those cold periods.

Cob

The term cob is used to describe a monolithic building system based on a mixture of clay, sand and straw. The construction uses no forms, bricks or wooden framework; it is built from the ground up. Various forms of “mud” building have been used in many parts of the world for centuries, under a variety of names, and date from at least 10,000 years ago. Cob building began use in England prior to the 13th century, and fell out of favor after World War I, although it is seeing a resurgence today. Cob is one of the simplest and least expensive building techniques available, though it is typically very labor-intensive. Cob’s other great advantage is versatility; It can easily be shaped into any form. While cob building was falling out of favor in England by the late 19th century, thousands of cob structures have endured to the present (20,000 in Devon, England alone).[2] It is estimated that from one third to one half of the world’s population lives in earthen dwellings today. Although typically associated with “low-rise” structures, in Yemen and other Middle-Eastern countries, it has, for centuries, been used in “apartment” buildings of eight stories and more.

Cob-like mixes are also used as plaster or filler in several methods of natural building, such as adobe, earth bags, timber frames, cordwood, and straw bales. Earth is thus a primary ingredient of natural building.[citation needed]

Hemp

Hemp is a very special plant and it can be used for food, textile, paper, plastic, fuel. For construction purposes the inner celulose part (hurds) is used. We mix hemp hurds with lime and water to create Hemcrete. It can be poured into shuttering or make prefabricated pricks or panels. It is not load bearing and a supporting frame needs to be used. Once dry, hempcrete makes an impressive insulator – tests at the UK’s National Physical Laboratory indicate a U-value of 0.23 W/m2K derived from their research. While this figure isn’t ground-breaking, the thermal performance of hempcrete can’t be measured by U-value alone. The thermal mass of the material – its ability to absorb, store and release heat – means it can naturally balance out temperature fluctuations and maintain a comfortable indoor temperature. A study by the BRE also found that hempcrete performs better than its calculated U-value.

Cordwood

Cordwood construction is a term used for a natural building method in which “cordwood” or short lengths pieces of debarked tree are laid up crosswise with masonry or cob mixtures to build a wall. The cordwood, thus, becomes infill for the walls, usually between posts in a timber frame structure. Cordwood masonry can be combined with other methods (e.g., rammed earth, cob or light clay) to produce attractive combinations. Cordwood masonry construction provides a relatively high thermal mass, which helps to minimise fluctuations in temperature.

Earthbag

Earth is the most typical fill material used in bag-wall construction techniques. This building method utilizes stacked polypropylene or natural-fiber (burlap) bags filled with earth or other mixes, with or without a stabilizer such as portland cement, to form footings, foundations, walls and even vaulted or domed roofs. In recent years, building with earth bags has become one of the increasingly practiced techniques in natural building. It facilitates self-contained, often free-form rammed-earth structures. Its growing popularity relates to its use of an abundant and readily available often site-available material (earth) in a potentially inexpensive building technique that is flexible, and easy to learn and use. However, because earth is a poor insulator, in more extreme climates other filler variations are now being explored, substituting pumice, rice-hulls or another material with better insulating value for all or part of the earth (see also Rice-hull bagwall construction).

Rammed earth

Rammed earth is an earth-based wall system made of compacted gravel, sand, and clay; that is extremely strong and durable. Quality rammed earth walls are dense, solid, and stone-like with great environmental benefits and superior low maintenance characteristics.[citation needed] As an option depending on climate or seismic concerns rigid insulation can be placed inside the wall as well as steel reinforcement. Rammed earth has been used for around 10,000 years in all types of buildings from low rise to high-rise and from small huts to palaces.

Rammed earth walls are formed in place by pounding damp sub-soil (gravel, sand, and clay) into movable, reusable forms with manual or machine-powered tampers. A mixture of around 70% aggregate (gravel,sand) and 30% clay is optimal. Cement may be added if the mix requires it or pigmentation to achieve the desired color. Around 5-10 inches of mixed damp sub-soil are placed inside the forms and pounded to total compaction and the process is repeated until the desired height is achieved. What is left after the forms are removed is a wall that is structural and can last over 1000 years.[citation needed]

Stone, granite, and concrete

The model fireproof farm house built by engineer A. L. A. Himmelwright in 1907 and presently used as a residence and overnight rental facility at Rock Lodge Club, a nudist resort in Stockholm, New Jersey, USA.

Locally obtained stone has been used as natural construction material for centuries. Combined with modern engineering and materials such as concrete and steel, a durable, low-impact building can be constructed.

Straw bale

Although grasses and straw have been in use in a range of ways in building since pre-history around the world, their incorporation in machine-manufactured modular bales seems to date back to the early 20th century in the midwestern United States, particularly the sand-hills of Nebraska, where grass was plentiful and other building materials (even quality sods) were not. Straw bale building typically consists of stacking a series of rows of bales (often in running-bond) on a raised footing or foundation, with a moisture barrier between. Bale walls are often tied together with pins of bamboo, rebar, or wood (internal to the bales or on their faces), or with surface wire meshes, and then stuccoed or plastered, either with cementaceous mixes, lime-based formulations or earth/clay renders. Bale buildings can either have a structural frame of other materials, with bales between (simply serving as insulation and stucco substrate), referred to as “infill”,or the bales may actually provide the support for openings and roof, referred to as “load-bearing” or “Nebraska-style”, or a combination of framing and load-bearing may be employed, referred to a “hybrid” straw bale.

Typically, bales created on farms with mobile machinery have been used (“field-bales”), but recently higher-density “recompressed” bales (or “straw-blocks”) are increasing the loads that may be supported; where field bales might support around 600 pounds per linear foot of wall, the high density bales bear up to 4,000 lb./lin.ft. and more. And the basic bale-building method is now increasingly being extended to bound modules of other often-recycled materials, including tire-bales, as well as those of cardboard, paper, plastics and used carpeting, and to bag-contained “bales” of wood-chips, rice-hulls, etc.

Timber frame

The basic elements of timber frame building—joined timbers, clay walls and thatch roofs were in place in Europe and Asia by the 9th century. It remained the common mode of house construction in northern cultures until the 19th century. Craftsmanship was, and is, an important value in timber frame building. The oldest timber frame structures (for example, the timber framed stave churches of Scandinavia) show both craftsmanship and a strong grasp of the technical aspects of structural design, as do such structures in Japan.

Timber framing typically uses a “bent.” A bent is a structural support, like a truss, consisting of two posts, a tie beam and two rafters. These are connected into a framework through joinery. To practice the craft, one must understand the basic structural aspects of the bent. This, along with a knowledge of joinery, are the basis of timber frame building.

Timber framing is now a modern method of construction, Ideally suited to mass house building as well as public buildings. In conjunction with a number of natural insulations and timber cladding or modern lime renders, it is possible to quickly construct a high performance, sustainable building, using completely natural products. The benefits are many—the building performs better over its lifespan, waste is reduced (much can be re-cycled, composted or used as fuel). Timber frame structures are frequently used in combination with other natural building techniques, such as cob, straw bale, or cordwood/masonry

source wikipedia.com