Design Considerations for Different House Types

One of the nicest things about houses is that they are uniquely designed, and each unique design calls for unique considerations. Design considerations for houses include several factors, but since the final set of design drawings, also known as construction drawings or working drawings, guide the actual construction, these residential construction drawings are critically important. Let’s try and understand exactly what construction drawings are and how they may change according to the different type of houses under construction.

What construction drawings aim to do is provide contractors, fabrication suppliers and even owners an accurate dimensional and graphical representation of the finished structure. The contractor uses these for the actual construction, the suppliers can use these to fabricate, assemble or install components, and the owners can view in detail what their building will look like. These drawings include ‘production information’, specifications and bills of quantities provided by designers to the construction team. Residential construction drawings are part of tender documentation and contract documents. They are legally important and constitute a major part of the agreement between employers and contractors.

What makes construction drawings so crucial is their accuracy and the fact that they are concise and coordinated. Details specified include the materials, standards, techniques, etc. needed to start and maintain construction. Graphic details include component arrangement, detailing, dimensions, layouts and installation methods. All of the details are drawn to scale as part of elevations, plans, sections and detail drawings.

Construction drawings typically contain separate trade drawings, e.g. mechanical, electrical, plumbing and fire. Standard architectural hatchings and symbols enable trade professionals to easily decipher and understand them.

Using Building Information Modelling (BIM) facilitates the development of coordinated 3D models with sufficient information to manufacture, install or construct each element represented in the models, and these models help develop clash-free drawings.

In brief, construction drawings include the following information:

• Foundation Plans – plans that include footing dimensions and locations
• Wall Framing Plans – plans that include lumber sizes - usually 2x4 or 2x6
• Sub-floor Plans – plans that show the arrangement of services
• Roof Plans – plans of the building’s roof, including type, pitch and framing
• Interior Elevations - drawings of interior walls
• Detail Drawings – drawings of built-in shelving, mouldings and columns
• Schedules – lists of the quantities of each element, such as windows and doors
• Structural Layouts
• Electrical and Telecoms Drawings - plans that show where outlets, TV sockets, switches and fixtures are located and where electric lines should run
• Plumbing Schematic Drawings – plans that show piping and plumbing fixtures

An additional type of drawing included in the set of construction drawings for most projects

are reflected ceiling plans. A reflected ceiling plan is a view while looking up at the ceiling, involving the location of light fixtures, ceiling level changes and moulding locations.

Considering the major drawings in detail, we look at exactly what information lies within.

Exterior & Interior Elevations

Exterior elevations are straight scale drawings of exterior sides – front, rear and both sides. Information included are the exterior shapes, floor-to-floor heights, building height, openings, exterior wall doors or windows, the fall of the land, exterior finishes, ridge heights, roof pitches and exterior architectural styling details. Interior elevations include the inside view of each wall, room height, wall openings, finishes, cabinets and wall-mounted elements.

Building & Wall Sections

The view resulting from an imaginary vertical cut or cross section of a house’s interior is known as a section. These include internal finishes, ceiling height, ceiling type (flat or vault) and window and door dimensions.

Exterior & Interior Details

Exterior and interior details consist of elements, materials and information resulting from zooming into specific exterior or interior areas through a horizontal cut, vertical cut or elevation.

Schedules

Information about materials used in a specific area defines a schedule. An example would be a door schedule. This would represent information such as the total number of such doors, different door types, their location and material types on a single drawing. Similarly, there are schedules for windows, room finishes, cabinetry, plumbing fixtures and appliances.

Framing & Utility Plans

Structural drawings that show the floor and roof framing members, the material size and the location of the weight acting on the framing members (or loads) are known as framing plans. Elements of the major trades – mechanical, electrical, plumbing and fire – and the element locations and appliances are part of the utility plans.

Site Plans

A view of the building from the top that includes the construction site, lot boundaries, location of utility services, setback requirements, easements, driveways, walkways and topographical data with the terrain slope make up the site plans.

Floor Plans

This overhead view shows wall width with scaled parallel lines, room dimensions, doors, windows, built-in elements, such as plumbing fixtures, cabinets, water heaters and furnaces. Floor plans can include data regarding finishes, construction methodology or electrical element symbols.

Completing a set of construction drawings involves regular and constant dialogue between the project’s stakeholders and depend on the type of house being constructed. The considerations vary for different types of houses, such as: single story vs multi story, built on site vs prefab, smart houses vs traditional houses, environment friendly, etc. Types of houses can also be dependent on the number of stories they have. For instance, single-storey houses consist of just one floor, and a multi-storey building features multiple storeys and has vertical circulation, such as ramps, stairs and lifts.

Multi-storey buildings can be classified as:

• Low-rise - buildings of 4 storeys or less
• Mid-rise - buildings of 5 to 10 storeys, with lifts
• High-rise - more than 10 storeys
• Skyscraper: 40 storeys or more
• Super-tall: more than 300 m
• Mega-tall: more than 600 m

 These multi-storey buildings must consider the design of the following features in great detail: 

• Access and circulation
• Fire safety and evacuation
• Structural design
• Ventilation
• External air movement
• Shading, views and right to light
• Construction methods
• Access for maintenance and cleaning

Houses built on site and prefab houses are different in a number of ways and thus must be designed accordingly. Site-built homes are built entirely on the site. They typically use 2 by 4s and 4 by 6s precut wood for framing and trusses and follow all state, local or regional codes at the site’s location. Prefab homes or modular homes are manufactured in sections at a factory, transported to the site and joined by contractors. These homes can be built on non-removable steel chassis.

Modular homes are becoming an increasingly popular choice for several reasons. They are manufactured with sustainable materials and have many features, such as house orientation, good ventilation, insulation and shading, designed during the early stages. Solar power and greywater systems can be easily incorporated into modular homes during design, resulting in less time and money being spent on the actual construction.

Modular houses can be created using recyclable materials and do not typically use timber, making them environmentally friendly. Also, modular houses can use ‘green’ lighting and HVAC options. These homes can be designed for further future expansion, helping to relocate them, if required.

For all its advantages, design considerations for modular homes must take into account certain restrictions imposed by the location of its site and the incompatibility of luxury buildings. Some zones specify that only brick houses can be constructed there, mainly in housing estates, though it is possible to build a modular home with a brick façade. Some sites are not easy to access, making it difficult to transport modular houses to the site. The materials and style that are compatible with modular houses may not depict luxurious design.

Besides prefabricated homes, trends indicate an upward trajectory in the use of smart buildings. A building that employs automation to remotely/automatically control heating, ventilation, air conditioning, lighting, security and other systems can be considered a smart building.

These buildings use sensors, actuators and microchips to collate and manage data for the functions and services of a house. Intelligent and adaptable software is installed to link the core systems of lighting, power meters, water meters, pumps, heating, fire alarms and chiller plants with sensors and control systems. Smart houses are fully integrated and can have automated/sensor-driven elevators, access systems and shading.

Energy use can be minimised by utilising chilled water systems to continuously monitor HVAC set points, heat loads and demands. Smart systems connected to weather stations can use information on heat, humidity, wind, rain and cold for optimum and energy-efficient HVAC usage. Occupants of a smart home enjoy a higher quality of life with smart lighting, thermal comfort, improved air quality, security and sanitation, with lower costs and leaving a smaller carbon footprint than those living in a traditional home.

An important part of residential construction drawings is ensuring conformity to codes and standards of specific areas. In general, there are few restrictions on site-built houses other than minimum sizes and restricted covenants. Developments are increasingly allowing modular houses and smart homes.

To conclude, accurate and precise drawings for building design can be created by experienced and technically qualified professionals, which helps to ensure that any kind of house type can be developed with adequate design consideration. With the ease of outsourcing procedures, high-quality building and planning drawings are affordable and technically near-flawless.