Designing gardens in the private sector is a demanding business, involving many different disciplines, yet with one fundamental foundation requirement of due diligence and assiduity at all stages. Many factors become conflated during the design process, and may easily be overlooked.
This article is meant to be read in conjunction with The Site Survey and Logistics Template to be found elsewhere in The Landscape Library, which includes a number of site factors that need to be identified and addressed when conducting a site survey when designing a garden.
This checklist is for use when compiling information for use in the design brief, outside of a logistical, practical schedule of facts. So many elements that require recognition by the designer are not particularly relevant to the actual design, but may heavily influence the style and extent of a project proposal.
To ensure that as many of these factors are included as possible within a design brief, the example of a garden undergoing a designers microscope, a Fantasy Garden will be imagined as follows;
The imaginary site is within a Gated Community, at St George’s Hill, Weybridge, with an existing garden 30m wide x 50m deep, with a cross-fall from left to right, and from top to bottom, with the lowest area being at the far end of the site. The house is c 1920, one of the original buildings constructed when the majority of the area was covered in trees and woodland.
The soil is light and sandy, with a propensity to have clay pockets, with a possible spring crossing the land. The owners have only recently moved in, and want a completely new garden.
St George’s Hill is famed for its large number of multi-million-pound houses, secluded and sheltered within tall hedges and trees, large walls and electronic gates. Private security guards control and patrol the whole estate, restricting access during normal working hours, and no weekend working or contractor visitors at weekends. Vehicles are restricted according to weight and height, the whole site being covered and subject to multiple covenants.
CHECKLIST – ensure all relevant answers are confirmed in writing by the customer.
- Is the building and garden subject to any planning restrictions, beyond those related to St George’s Hill Estate? (The whole site is subject to blanket Tree Preservation Orders) Have you identified the Local Authority details and relevant contacts including Planning Office?
- Name and address of the customer.
- Name and address of the owner (if different, as it may belong to a company or Trust) who may hold a lien over the property)
- Are there any existing site plans or site surveys especially boundaries, levels and falls. If so, are they current or aged? (If there are no such site surveys, the customer should provide or pay for these to be carried out before you commence work, even at the concept stage) These will include any known utilities/water/waste/gas/electricity etc.
- Has a Hydrological Survey been conducted using LIDAR or similar, showing the likely ground water movement across the site? (If no such survey exists, the customer to provide and pay for these before moving beyond concept stage)
- Are there any covenants or restrictions on the actual site relating to colours or type of materials that are permitted or not permitted. (These may include style of brick, colour of mortar, barring of metal or timber gates, height restrictions and a host of other factors that must be drawn to your attention before concept stage)
- Have any trial holes been dug to establish water tables or water retention ability of the soil? (Although the site at St George’s Hill is sandy, there are many pockets of clay which can cause problems with settlement/shifting sand) Have the results been monitored and recorded including weather conditions for a week before the trial?
- Note any soft spots discovered during your survey, especially in lawns and beds, as these may be underground springs or damaged/incomplete land-drains. These will be relevant if planning to cover them with hard landscaping features or foundations.
- Has a tree survey and condition report been commissioned? If so, what were the results and recommendations?
- Make a note of all existing plants that are thriving – not just surviving – as a guide to any planting proposals.
- Conduct or arrange for an Historic Google Earth survey of the property, going back at least fifteen years, and note any alterations in the site, especially with regard to hard landscaping, additions such as a tennis court or swimming pool, etc. Note too, the leaf cover provided by any trees, including along the boundary/overhanging.
- Note all soak-aways, including locations in regard to downpipes on the building/s. These will have been designed to cope with rainwater and surface water at the time of construction, and may not cope with additional volume.
- Consider very carefully, the likely water courses under or over the site. Any existing retaining walls should have drainage installed, with obvious outfalls. Note existing areas of hard surfacing, including patios and driveways/car parks in respect of likely water run-off volumes.
- Contours, spot heights and contours will be crucial in designing any large areas of paving (permeable or otherwise) plus new retaining walls which may impede the progress of ground water. Ensure that a bespoke drainage system, including French drains, surface drains including gullies and swales, perforated pipes, and solid pipes as required are designed to keep water moving unimpeded across the site.
- As all areas of paving must have falls of either 1:60 (porcelain) or 1:70 (natural stone) ensuring your spot heights recognise these essential differences of level when planning at any stage.
- When designing your setting out site plan, ensure all PROPOSED FINISHED levels are accurate, allowing to the aforementioned cross falls to become the starting point for the next level. This advice is especially important when designing steps and flights of stairs, as any miscalculation can affect the risers and depth of the steps. Try and work with dimensions to suit the chosen products to reduce cutting.
- Check that all beds that are designed internally within a paved area have effective drainage under the paving to prevent ponding and flooding within the beds. These pipes should be connected as part of the overall drainage system and catered for by soak-aways or natural off-site falls.
- Ensure that a Products Library is established on site, somewhere they will remain unsullied for the duration of the works. These may include paving, walling, bricks etc, top soil samples, mulch, painted wood colours – anything you propose to include in the project. These should be shown to the customer both wet and dry to ensure they have approved each one, and signed with indelible pen confirming their acceptance.
- Before finalising the Master Plan, check that all fundamental issues, including all primarily drainage, are linked in a logical manner. Any alterations or additions may be made at any stage only if your underground works complexes are integral and capable of dealing with extra capacity.
- When working on sandy or clay soils, ensure that adequate and carefully placed expansion joints are included in the design to prevent ground movement that may occur in large expanses of paving, or between vertical hard surfaces e.g. walls etc.
- DON’T FORGET TO ENSURE THAT YOUR AGREEMENT HAS BEEN SIGNED BY BOTH PARTIES. AN UNSIGNED CONTRACT IS WORTH NOTHING!
Don’t forget to read this article in conjunction with the Site Survey and Logistics Template, as they both compliment each other, one looking at the site in general, with the Designer’s Check List covering the various phases and fundamental elements of the actual design process.