Garage to Office – The Do’s and Don’ts
COVID-19 is having a fundamental impact on the necessity and layouts of offices. Most businesses have realised that they can allow their staff to work from home. There is also the overhead costs from an office that will be minimised with home-based offices. In this article, we discuss the conversion of a garage into an office.
This means that many people will be setting up their office spaces at home. This conversion is in most cases not ideal and might result in less than ideal living and working conditions.
Due to the vastness of the topic, there are a few crucial considerations that will not be addressed in this article. Firstly, we will not discuss the Zoning, Town Planning Schemes and By-Laws. Secondly, we will not address the COVID-19 Occupational Health and Safety arrangements, as set out in the COVID-19 Occupational Health and Safety Measures in Workplaces COVID-19 (C19 OHS), 2020. Thirdly, we will not discuss the application to the Local Authority for approval.
We are focusing solely on the implications of converting a double garage (6×6 meters) into a home office from a National Building Regulations and a SANS10400 perspective, by looking into the following aspects:
- Population
- Sanitary
- Ventilation
- Lighting and Power
- Energy Efficiency: Orientation, Fenestration, Thermal Insulation, Permissible air leakage in habitable rooms:
A garage has the sole function of storing automobiles. Thus, the room itself is not defined as a habitable area. A habitable room is a room that involves eating, sleeping, living, or working areas for any person.
Population
Occupancy is the particular use or the type of use to which a building or portion thereof is normally put or intended to be put to use.
Domestic residence (Class of Occupancy: H3) is where the occupancy consists of two or more dwelling units on a single site. A dwelling house (Class of Occupancy: H4) is where the occupancy consists of a dwelling unit on its own site, including a garage and other domestic outbuildings.
By converting a garage into an office, that portion of the domestic residence or dwelling house will be used for offices, changing the Class of Occupancy from H3 or H4 to G1.
According to Table 2 of SANS 10400-A:2010, the allowable design population for G1 is 1 person per 15m2. Based on the above for a double garage of 36m2, you are allowed to have two people in the office space.
Sanitary Allowance
SANS 10400-P:2010 makes allowance for the sanitary fixtures based on the occupation classification. The rule of thumb is to provide at least one toilet pan and one washbasin. If there are no sanitary fixtures nearby to accommodate the office, please keep access to the existing drainage installation as well as natural ventilation in mind if a new toilet pan and washbasin should be installed in the available 36m2.
Ventilation
To comply with SANS 10400-O: 2011 the total area of an openable glazed window in an external wall, shall not be less than 5 percent of the floor area of the room. Thus, for a 36m2 double garage, the requirement is at least a 1,8m2 openable glazed window.
The regulations make provision for habitable areas to be well ventilated, either mechanically or naturally. If the habitable room is to be mechanically ventilated it should have an effective local extraction ventilation system with high-efficiency particulate air HEPA filters, which is regularly cleaned, maintained, and the vents do not feedback in through open windows. The minimum outdoor air requirements for general office areas are 2 Air changes per hour and 7,5 litres per second per person.
Lighting and Power
Depending on occupancy and activity, minimum lighting levels shall be determined with the requirements of SANS 10114-1 and SANS10400-O. For natural lighting, the openings should be situated in an external wall and shall be provided with a zone of space outside it. The area of the openings shall not be less than 10 percent of the floor area. Thus for the 36m2, we require a glazed opening of 3,6m2.
SANS 204:2011 stipulates the maximum energy demand and energy consumption for lighting in the occupancy or building class. For G1 offices or the population of 1 person/15m2, the energy demand is 17W/m2 and the energy consumption is 42,5kWh/m2.
Energy Efficiency
In 2011 SANS 204 the energy efficiency in buildings was published. This standard specifies the design requirements for energy efficiency in buildings and of services in buildings with natural environmental control and artificial ventilation or air conditioning systems. SANS 204 should be read in conjunction with SANS 10400. The following are a few considerations to keep in mind when converting a 36m2 area into a home office:
a) Orientation: Rooms, where people spend most of their hours, should be located north.
b) Fenestration: SANS 10400-XA: 2010 states that a building with up to 15 percent fenestration area to net floor area per storey should comply with the minimum energy performance requirements. If the fenestration exceeds 15 percent area to the net floor area, then it should comply with SANS 204.
c) Thermal Insulation: Attached buildings such as garages shall not compromise the thermal performance of the main building, but it can be exempted if it does not contain habitable spaces:
i) Figure 2 Option A: Thermal performance of the main building is achieved, excluding the walls and floor of the garage.
ii) Figure 2 Option B: The thermal performance of the main building is also achieved, with the garage included in the enclosed perimeter.
iii) If your garage is not included in the thermal performance calculations of the main building, there are a few thermal insulation items that should be incorporated in the internal upgrade of the 36m2:
a) Floor insulation for concrete slab-on-ground.
b) Roof and/or ceiling insulation to comply with minimum required R-values, depending on climatic zones, and must be installed correctly.
Permissible air leakage in habitable rooms: Habitable rooms should be sealed at the following building elements: glazing, roof lights, chimneys, flues, roof lights, skylights, external doors, roofs, walls and floors.
Please contact us if you require assistance in converting any area in your home into an office, contact BOAZ Architects.
You can also call Carina Botha on 082 920 3158 or email her at carina@boaz.co.za
