Introduction to GardenPlanning and DesignWeek 2 – Designing for safety andsustainability; surveying and plandrawing
Learning objectives State four safety and sustainability issues that can be addressed through design. Describe how to carry out basic linear surveying techniques, including the use of tapes, offsets and triangulation Describe the methods used for recording surveying data. Produce a simple scale plan using data supplied.
Planning for safety Safety considerations are an integral part of garden planning. Common hazards are: slipping and tripping; drowning (children); skin irritation and poisoning; falls; electrocution. These are all related to particular garden features – such as slippery paving or steep steps without handrails. Planning can minimise such hazards.
Hard landscaping Paving can become slippery if algae grows on it – if there is no ‘fall’ to allow water to run off the surface or it is in shade. Planning decisions - rough or textured surfaces where the paving is in shade, or using a porous surface such as gravel instead. Uneven surfaces made up of two or more materials can create ‘toe catchers’ which can lead to trips. Planning - avoiding such surfaces, or ensuring that they are level. Steps can be a tripping hazard in the dark or if they are uneven in height or too steep. Planning decisions - making sure that the steps are suitable for the gradient, including handrails or adding lights to the side of the risers.
Water A drowning risk for children. However the reflection, movement and sound added to a design by water can greatly enhance a garden. Planning can minimise the risk and keep the benefits. For example, using a wall fountain or pebble pool, which have concealed water reservoirs, enables water to be used safely in gardens used by small children.
Electricity in the garden Lights, fountain pumps, supplies to the shed and greenhouse all require electrical work in the garden. All work should be done by a qualified electrician. Cables if buried must be armoured and their positions noted. Planning can include using solar powered lights to avoid the need for cables; planning cable runs under lawns to avoid the possibility of them being disturbed by digging etc.
Plant toxicity A common hazard in gardens is injury or poisoning by plants. Planning can minimise this risk by identifying harmful plants and either excluding them or planting them appropriately. For example Euphorbia sp have toxic sap and cause skin irritation. Planting taller varieties of these by a path would not be advisable as they may brush legs in passing.
Sustainability A sustainable garden will stay looking at its best and have minimal negative effects on the wider environment Water is a major consideration – irrigation is time consuming and expensive. Suitable planting is key. Choice of materials – permanent and otherwise – including the use of reclaimed or recycled materials. Soil improvement – composting. Effort – sustainable maintenance; how much time do you have?
Equipment needed for basic surveying ‘Chain’ – a 100ft (30m aprox.) long tape on a reel. A metal tape measure or folding rule Wooden pegs A set square A compass A string line (with as little stretch as possible) A clip board, paper and pen A spirit level (if surveying slopes)
Surveying techniques Single point surveying – for small areas with defined boundaries. Triangulation of points from defined points (such as the corners of a courtyard). Measurements along a base line – used to plot the house outline and features Offset measurements from a base line – used to plot curves and features less than 8m from the base line. Triangulation from two points on a base line – used for fixed points in a larger area (more than 8m from the base line). Always orient the survey to North using the compass – that is, record the deviation from magnetic north of your base lines. Note that plans should be drawn with North at the top.
Drawing to scale This method ensures that the distances on the ground are accurately represented in the correct proportions on the plan. Using a scale and the right size of paper means that the entire site can be seen from above on the plan. A scale ruler makes the conversion easy. A scale of 1:1 is actual size, 1:50 means that each centimetre on the plan is 50cm on the ground etc. The scale chosen should be large enough to show sufficient detail but not so large as make the plan unmanageable. For most gardens 1:100 or 1:50 is appropriate
Drawing the plan Having chosen the scale, plot the building first taking the information from your survey notes. If there is no building then draw on your base line in pencil to scale. Plot the building or base line at the appropriate deviation from North (North is at the top of the page – use a protractor to measure the degrees). Work out from the building. To plot triangulated points use compasses set to first one measured length and make an arc on the paper, then set them to the other length and make an arc. Where the two arcs cross is the point of the feature recorded. To plot offset points use a set square and ruler.
Learning outcomes State four safety and sustainability issues that can be addressed through design. Describe how to carry out basic linear surveying techniques, including the use of tapes, offsets and triangulation Describe the methods used for recording surveying data. Produce a simple scale plan using data supplied.