BC Green Roof Victoria BC Consultants and plant plant growers
  • home
  • About us
    • Green Roof Expert
    • Green Roof Qualification
  • Blog
  • Green Roof Nursery
  • Services
    • Our process >
      • Green Roof feasibility study and budgeting
      • Green Roof Specification
      • Green Roof Warranty
      • Green Roof Maintenance guidance
      • Green Roof inspection
    • Green Roof Investor
    • Green Roof Architect
    • Green Roof Installers
    • Green Roof Contractor
  • Green Roof Technology
    • Green roof materials >
      • Green Roof plants
      • Green Roof Material manufacturers
      • Green Roof material and component placment
      • Green Roof root barrier
      • Green Roof drainage
      • Green Roof filter
      • Green Roof growingmedium
      • seeds
      • Green Roof plant plug
      • Green Roof pot plant
      • Green Roof modules
    • Green roof history
    • Extensive green roof
    • Semi extensive green roof
    • Sloped green roof
    • Intensive green roof
    • Roofs you can drive on
  • Resources
    • Green roof FAQ
    • Green roof case study
  • Light weight Green Roof

Water reservoirs and water logged conditions

4/18/2019

 
Picture
Picture
Why are some plants barely surviving while others thrive?
Plants need water to survive, but did you also know that they need air to surround their roots?
​

Plants like humans respirate (take in and expel air). Plants do this through their leaves, as well as through their root system, absorbing oxygen needed to break down glucose, creating energy for the plant to develop.

This process of converting glucose releases some Carbon Dioxide (CO²) which is also expelled through the leaves and roots.

When a plant stands with its roots in water, and has no adjusted root system like aquatic plants, the required oxygen/air commonly available in the soil is displaced (blocked) by water, resulting in the plant not being able to breath/respirate (aerobic respiration).

Due to the lack of oxygen, the plant respirates anaerobically, producing alcohol, that eventually kills the plants root (root rot).
Picture
Picture
Picture
Industry has played into the concept of plants needing water. Some install irrigation lines, some incorporate water retention fleece or water absorbing mineral wool or water retaining cups.

FLL Guidelines are widely accepted as the leading authority for the planning, execution and upkeep of Green Roofs.

It could be argued that FLL Guidelines would not apply, yet from the other hand, what the standard describes has some food for thought.

Here in coastal BC, we face prolonged periods of rain of up to 6 months (fall and winter) and not all options for watering are equal. In some instance, plants are standing in a water-logged medium, drowning rather than thriving.
Picture
Picture
Plants don't want to grow into some water retention materials as you can see on the pictures above from roofs that are several years old. The vegetation is just laying on top of the medium not developing a healthy root system into the medium that can support diversity. Because of this growth is stagnating and could cause plants to die.

As per FLL:

Picture
Consult us to talk about watering options.
Contact us

Thermal stress, waterproofing failure and Green Roofs

4/18/2019

 
Picture
​As many know, next to environmental benefits Green roofs also extend the life of the roof's waterproofing.

#1 Cause of failure of waterproofing is due to thermal shock (expansion and contraction) of materials, influenced by the environment (heating and cooling of the materials).

A Green Roof (plants with growing medium underneath) shield the waterproofing form the sun, eliminating peak temperature fluctuations.

What is almost always overseen is that at the location of details, such as roof penetrations (upright waterproofing),
where there is no growing medium and plants and at the location of vegetation free zones (gravel ballast) this protective aspect is almost non-existing. The roof effectively becomes a standard roof that has a life expectancy of roughly 20/25 years. The waterproofing underneath a Green Roof could last upwards of 60 years because it is protected.

​Putting this in context: A lot is invested in Green Roofs for its protective/insulating function, yet this investment could fail, at the details.


Picture
Heat penetration through roof build
The image above with our infra-red camera shows the heat that penetrates through a roof seen from the bottom where the blue color indicates where it is shielded from the sun, the color green where there is gravel ballast and the color red where there is exposed 2-ply waterproofing.
Picture
On the left you see a top view of a 2-ply waterproofing and how the migration of heat concentrates around a roof drain.

Within inches a burning hot waterproofing cools down significantly (expansion and contraction).
At time of installation the waterproofing membrane is somewhat malleable due to its plasticizers. The ongoing expansion and contraction of waterproofing and the migration of plasticizers result in the material becoming stiff.
The stiff membrane can no longer move with the motion of expansion and contraction (bridge) and thus cracks. 
Picture
BC Green Roof advanced methodology can form a continuation of the protective property of a Green Roof mitigating the negative aspects of environmental stress.
Picture

March 04th, 2015

3/4/2015

 

Thin / shallow and light Green Roofs; what to expect or how to adjust

BC Green Roof prides itself to be on the forefront of Green Roof technology providing assistance, training and inspections, educating those in the field about the ins and outs of Green Roof technology.

In line with our commitment to strive for better understanding and implementation of Green Roof technology we have dedicated part of our effort to the creation of educational articles, providing inside details how specific aspects work.

Site specific limitations - Thickness of growing media, specifically: Weight -.

In this article, we go in detail into what a light weight Green Roof is, what could be expected in terms of plant diversity and water/air available for green Roof plants.

Over the year we have been asked several times to inspect - disappointing Green Roofs - where, The question could be asked - how come is it disappointing -

Green Roofs should not be disappointing, within reason thy should be what you expected them to be, if not this article sheds light on what influences the outcome (expectations).

Generally speaking expectations should be in line with what is technically possible when considering a projects limitations (weight)

Once you understand what plays a role when considering a thin layer of growing media, and thus decreasing a Green Roof’s weight, expectations could be adjusted, avoiding disappointments –ore- building technical limitations should be addressed, in order to accommodate a green roof system that within reason preforms to expectation.

Expectations should not exceed what technically is hard to achieve !

Read the full article

Go to
Go to

Or download it as PDF

Other informative Green Roof articles:

Filter material in Green Roof construction
Go to

Do green roofs burn ?

Go to

October 07th, 2014

10/7/2014

 

BC Green Roof prides itself to be on the forefront of Green Roof technology providing assistance, training and inspections, educating those in the field about the ins and outs of Green Roof technology.

Green Roof Fire

Do Green Roofs burn?

In January 2014 we performed a series of tests, visualizing the performance and differences of Geo-textiles when used in Green Roof applications (www.bcgreenroof.ca/geotextile-study). After receiving very positive reactions to this educational rapport it was time to respond to another question we often receive:

Picture



BC Green Roof wants to visualize what can be expected after installing a Green Roof in terms of performance compared to several other common roofing materials used in construction.

You may download the full rapport
(click here)

January 12th, 2014

1/12/2014

 

Filter material in Green Roof construction

This article sheds some light on filters / Geo-textiles and visualizes how they work.

BC Green Roof has in depth knowledge and expertise when it comes to the technology behind Green Roofs.

We have received comments from several individuals that they find it hard to find in depth information with regards to the technology behind Green Roofs.

We hear that benefits of Green Roofs are rather easily to find, however, information regarding detailing and the inner workings of Green Roofs is hard to find.

You may contact-us at an time in case you have any questions or have suggestions on specific subjects.

Picture

Above one of the pages out of the study.

You may download the full study raport in PDF

(click here)

November 20th, 2013

11/20/2013

 

BC Green Roof believes that there is room for improvements in the industry, and that others involved should become aware of where improvements could take place.

Also we often received the comment from others involved in the development of Green Roofs, that thy did not realize specific aspects within a build to be a key component, and thy thanked us for bringing this up to them, so they could deal with it up front, avoiding problems in the future.

Whit the above in mind, we have put together a presentation that will guide people threw all aspects involved when considering a Green Roof. We make people familiar with the options in drainage, growing mediums and plant material, as well we point out what to avoid.

Upcoming weeks we will hold educational presentations for members of the architect Institute of BC (AIBC) and from there we might grow this out by involving other parties.

The main goal of our presentation is to question - did you know and to approach it as - lets talk and potentially learn

Victoria BC Green Roof educational presentation to AIBC members

Picture

You may download the evaluation questionnaire attendees filled out, That gave us and should give you some more insight.

(click here) to download the PDF


Below the cover of the presentation's inventation letter

Victoria BC Green Roof on TV

11/20/2013

 

After representatives from Shaw TV Go Island learned of BC Green Roofs Nursery, thy where eager to come over and have a lock at the options people have, when thy are planning a Green roof.

As we are still working hard on getting more varieties of plant material in, as well as getting sample structures up for next spring to flourish, Go Island broth their camera over to capture some of our plant material that had slowly gone in winter mode.

More information about our plant material you can find under nursery , as well, we explain different options in regards to greening a roof under Green Roof Materials.

    Categories

    All

bcgreenroof is a sub activity of passion landscape & construction ltd.
blog
Green Roof nursery
Contact us