On the Green Roof Professional (GRP) Accreditation Training discussion board…

Student 1: With the GRP exam coming up quickly, I’m wondering what you can tell us about what to expect in the exam. Is the Week 10 exercise an example of what the exam is like? (Is there a background scenario that goes with the exercise?) Can you give any advice on preparing for the exam?

Patrick Carey: Hi, Student 1!

person_medium_Patrick_Carey_headshot_144pxThe questions are multiple choice, and there are over 90, I believe. One way I tell student to prepare is to think of the 90 questions as divided into 4 categories, with sub-sections.

The first category is benefits explained. What is the benefit and how does the green roof produce it? Think about general components and optional components of green roof assemblies, design considerations to allow for a particular set of design constraints or to focus on a particular set of benefits or performance goals, assembly component and assembly selection for any of the three types of green roofs for both loose laid and modular systems.

The second category is installation and administration. What are the recommended ways to minimize confusion and conflict? Consider organization of construction documents (specifications and drawings), organizing the chain of liability, organizing the bidding, trade coordination, and trades execution, and managing owner expectations. In other words, think about how to be clear and coordinated. Drill “best practices” and the sequence of construction (CPM methodology).

The third category is waterproofing. Consider roof assembly types, edge detailing, detailing at points of transition, membranes, (what they are made of, how are they applied, what are the advantages/disadvantages regarding EFVM and root protection and slope) and what tools are used. Go through an imagined installation sequence for each type of membrane. Think about leak protection and leak prevention, maintenance requirements for field membrane, flashing, and counter flashing, gravitational erosion strategies for steep slopes, membrane protection during construction and chain of membrane custody.

The fourth category is “The living stuff”… Divide this into botany, horticulture, and soil science.
Botany (plants themselves): Know your major plant cell components and their functions, basic plant parts and their functions (leaf, stem, root), internal plant processes like transpiration, respiration, c3, c4, CAM plant processes. Know the plant life cycles and growth patterns – e.g. how is grass different from a succulent? How is an annual different from a perennial? Describe the stages of growth in different kinds of plants—be specific.

Horticulture (the use of plants): Given a performance goal for a roof, what plants should you pick and how? Know the zones for different kinds of plants, soil depths for different kinds of plants in general, wind erosion constraints, planting methods, coverage expectations (how fast you can get a roof fully covered with vegetation), irrigation- installation, testing, maintenance (and designing a maintenance plan), andgrhc_cmyk_300dpi_baja2 general design.

Soil science: Know the components of growth media and their function, standards for evaluating growth media, ASTM tests for components (ASTM E 2396-2400), structure, chemistry and biology of different soil mixes. Also consider the mixing and installation of growth media, amendment of media to alter different characteristics, cation exchange capacity, media weights in dry and saturated states, wilting point and saturation, conductivity and transmissivity of soil. Also know the relationship between the media and inert green roof components.

Remember, this is off the top of my head. If you figure you have 90 questions, divide them by 4 and you have a very rough distribution of study time. 22.5 questions on each category. Further, you can divide your 22.5 on plants and soil into about 7 each on botany, horticulture, and soil science. For Waterproofing you can divide 11 into membrane ID and composition and 11 on installation and details. For the first category 11 on benefits and 11 on variety of assemblies. For the second category 11 on stuff that occurs before installation begins and 11 on what happens during and after installation.


Jordan Richie: 


The GRP exam is 100 questions, multiple choice. Candidates have two hours to complete it.


The domains tested on the exam are: Pre-Design, Design, Contract Management, Quality Assurance Support and Maintenance. The domains are not weighted equally (i.e. some domains contain more questions than others.) You can expect the questions to be more challenging than those that are included in the weekly quizzes for this course. Hope this info helps!


Continue learning with HeatSpring and Green Roofs for Healthy Cities and expert instructors Steven PeckPatrick Carey, and William Foley.

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