Garden design - survey and safety

1. Introduction to Garden
Planning and Design
Week 2 – Surveying and plan
drawing; Designing for safety

2. Learning objectives
 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
obtained from survey (homework).
 State four safety issues that can be
addressed through design

3. 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)

4. Surveying techniques
 Single point surveying –small areas with defined
boundaries. Triangulation 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.

5. 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. A4 paper will be too small, A3 is
better, anything larger may need a board.
 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

6. 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.
 Join the dots!

7. 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.

8. 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.

9. 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.

10. 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.

11. 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.

12. Learning outcomes
 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
from survey (homework).
 State four safety issues that can be
addressed through design