Design and Development of a Roof Garden
- Design Parameters -
(page 7/10)

Selection of Hardscape Materials
The selection and construction of light standards, walls, fences, wind screens, pergolas, curbs and other structural elements should all be considered in relationship to the structural limitations of the roof and its supports below. The omnipresent factor of weight has a strong effect on which materials are used and their placement in the landscape. Lightweight materials should be used wherever and whenever possible.

Paving
As previously mentioned, the consideration of the paving material’s reflectance should be of primary consideration. Secondly, the type and pattern of paving materials chosen are as important to the viewers from surrounding buildings as they are to the actual user of the space. The color, tone and contrast of these materials can create a strong visual interest. Paving materials should be selected for lightweight qualities and durability. Paving if at all possible should allow for the permeation of water to aid in the drainage and removal of heavy rainfall amounts.

Methods of Anchoring
The structural elements, including lighting fixtures need to be carefully anchored when used on rooftops. Special care and method must be employed to avoid penetrating the waterproofing systems. There are many such methods for anchoring and these will be fully developed and detailed during the project’s design phase.

Furniture
Furniture and site amenities are a critical component in the roof garden’s success. Frequently, adequate and abundant seating is often overlooked and is one of the most important elements in the comfort of the user, as well as, in the actual overall project usage. Furniture should be heavy enough to not require anchorage. Wood furniture or heavy poly-resin furniture is more comfortable to the user than metal or concrete seating.

Pools and Fountains
The use of water and fountains add greatly to the enjoyment and use of roof deck gardens. There are several factors to consider when using water as a design element.

The weight of water in roof top gardens in most reference materials is widely misunderstood. Most, if not all, reference materials assume the weight of water to be greater that that of the plantings. This is in error and for the most part a water feature will weigh less than the planted areas. Therefore, no special provisions to support the weight of the water are required in planning the garden. However, lightweight manufactured cap stone should be used when creating a naturalistic water feature.The finishes weight is the area of concern when designing the feature.

Generally in our climate, a flexible water retaining system is preferred to a rigid system because although drained during the winter season, water will still accumulate in the basin. If a rigid system is used there will be cracking and eventual failure of the system.