Construction Techniques &Technology
Light-Frame Construction
Light-frame construction can be categorized mainly into 2 sub-categories: Platform Framing and Balloon Framing.
On top of this is placed a second floor or the roof. The roof is formed of rafters (sloping joists) or wood trusses. The standard interior wall sheathing is gypsum board (drywall), which provides fire-resistance, stability, and a surface ready for finishing. Framed structures traditionally were constructed individually at each house site; today many of the framing elements are mass-produced elsewhere and assembled on-site.
It is thought that the name “balloon framing” was derived from a criticism that this sort of construction would be no more substantial than a balloon – and even though this proved untrue, the name stuck.
- Platform Framing
On top of this is placed a second floor or the roof. The roof is formed of rafters (sloping joists) or wood trusses. The standard interior wall sheathing is gypsum board (drywall), which provides fire-resistance, stability, and a surface ready for finishing. Framed structures traditionally were constructed individually at each house site; today many of the framing elements are mass-produced elsewhere and assembled on-site.
- Balloon Framing
It is thought that the name “balloon framing” was derived from a criticism that this sort of construction would be no more substantial than a balloon – and even though this proved untrue, the name stuck.
Prefabrication
Prefabrication is another way of constructing shelter. Instead of the conventional practice of transporting raw building materials to the site of construction, sections of walls, floors and roof are prefabricated in a factory and transported to the construction site, where it will then be bolted together. Only the foundations of the shelter will be constructed the traditional way.
Currently, prefabrication is mostly used by civil engineers because most buildings use repeating units of concrete and steel sections – and it makes economic sense to prefabricate these units, cutting labour costs as well as on-site work hazards (e.g. unpredictable weather conditions, overcrowding of labour).
The main downside to prefabrication would be that extra attention has to be given to the joining of the prefabricated sections; if not joined well, the structure may be subject to corrosion and leaks, and its strength may be compromised.
Currently, prefabrication is mostly used by civil engineers because most buildings use repeating units of concrete and steel sections – and it makes economic sense to prefabricate these units, cutting labour costs as well as on-site work hazards (e.g. unpredictable weather conditions, overcrowding of labour).
The main downside to prefabrication would be that extra attention has to be given to the joining of the prefabricated sections; if not joined well, the structure may be subject to corrosion and leaks, and its strength may be compromised.
Cordwood Construction
Constructing with cordwood (short pieces of debarked tree) is a type of natural building method in which pieces of cordwood are laid up crosswise with masonry or cob mixtures to build a wall. It can be sustainable depending on the design and process.
Homes constructed with cordwood maximize interior space, are visually appealing and also easy to construct. Wood usually accounts for about 40- 60% of the wall system and the remaining portion consists of a mortar mix and insulating fill.
Homes constructed with cordwood maximize interior space, are visually appealing and also easy to construct. Wood usually accounts for about 40- 60% of the wall system and the remaining portion consists of a mortar mix and insulating fill.
Straw-bale Construction
As the name implies, this building method uses bales of straw (e.g. wheat, rice, rye and oats straw) as structural elements, building insulation or both.
Straw bale building typically consists of stacking rows of bales (often in running-bond) on a raised footing or foundation, with a moisture barrier or capillary break between the bales and their supporting platform. Bale walls can be tied together with pins of bamboo, rebar, or wood , or with surface wire meshes, and then stuccoed or plastered, either with a cement-based mix, lime-based formulation, or earth/clay render.
Alternatively, bale buildings can have a structural frame of other materials, usually lumber or timber-frame, with bales simply serving as insulation and plaster substrate.
There are advantages to such a method – including the low cost, easy availability, high insulation value and renewable nature of straw, but also disadvantages such as large space requirements for the straw itself as well as the straw’s susceptibility to rot.
Straw bale building typically consists of stacking rows of bales (often in running-bond) on a raised footing or foundation, with a moisture barrier or capillary break between the bales and their supporting platform. Bale walls can be tied together with pins of bamboo, rebar, or wood , or with surface wire meshes, and then stuccoed or plastered, either with a cement-based mix, lime-based formulation, or earth/clay render.
Alternatively, bale buildings can have a structural frame of other materials, usually lumber or timber-frame, with bales simply serving as insulation and plaster substrate.
There are advantages to such a method – including the low cost, easy availability, high insulation value and renewable nature of straw, but also disadvantages such as large space requirements for the straw itself as well as the straw’s susceptibility to rot.
Wattle-and-daub Construction
This method of construction is becoming popular again in more developed areas as a low-impact sustainable building technique. Wattle-and-daub is a building material used for making walls, in which a woven lattice of wooden strips called wattle is daubed with a sticky material usually made of some combination of wet soil, clay, sand, animal dung and straw.
The wattle is made by weaving thin branches (either whole, or more usually split) or slats between upright stakes. The wattle may be made as loose panels, slotted between timber framing to make infill panels, or it may be made in place to form the whole of a wall.
Daub is generally created from a mixture of certain ingredients from three categories: binders, aggregates and reinforcement. Binders hold the mix together and can include clay, lime, chalk dust and limestone dust. Aggregates give the mix its bulk and dimensional stability through materials such as earth, sand, crushed chalk and crushed stone. Reinforcement is provided by straw, hair, hay or other fibrous materials, and helps to hold the mix together as well as to control shrinkage and provide flexibility. The daub may be mixed by hand, or by treading – either by humans or livestock. It is then applied to the wattle and allowed to dry, and often then whitewashed to increase its resistance to rain.
The wattle is made by weaving thin branches (either whole, or more usually split) or slats between upright stakes. The wattle may be made as loose panels, slotted between timber framing to make infill panels, or it may be made in place to form the whole of a wall.
Daub is generally created from a mixture of certain ingredients from three categories: binders, aggregates and reinforcement. Binders hold the mix together and can include clay, lime, chalk dust and limestone dust. Aggregates give the mix its bulk and dimensional stability through materials such as earth, sand, crushed chalk and crushed stone. Reinforcement is provided by straw, hair, hay or other fibrous materials, and helps to hold the mix together as well as to control shrinkage and provide flexibility. The daub may be mixed by hand, or by treading – either by humans or livestock. It is then applied to the wattle and allowed to dry, and often then whitewashed to increase its resistance to rain.
