WO2002002889A2

WO2002002889A2 - Vegetated roofing system

Info

Publication number: WO2002002889A2
Application number: PCT/US2001/041254
Authority: WO
Inventors: Brian Lambert; John White
Original assignee: The Garland Company
Priority date: 2000-07-03
Filing date: 2001-07-03
Publication date: 2002-01-10
Also published as: WO2002002889A3; AU2002216766A1

Abstract

A roof system for a building having a roof deck comprises, upwardly from the roof deck, a base membrane affixed to the roof deck; at least one moisture control layer; a vegetation support layer; and a vegetative mass layer comprising a plurality of plants with a root portion and a body portion, such that the root portion affixes the plant to the vegetation support layer and the body portion extends upwardly from a top surface of the vegetation support layer. In many aspects of the invention, the base membrane is a modified bitumen membrane, reinforced with a fiber material. The base membrane and the moisture control layers may be impregnated with a root growth inhibitor. In many aspects of the invention, the plants will have the following characteristics: perennial, low-growing (in the range of 1 to 12 inches) evergreens that tolerate full sun, heat, periods of drought and periods of heavy rain. The plants should require little maintenance, including pruning, fertilizing and pest control, to minimize necessary foot traffic. The plants may be flowering or the foliage may provide color.

Description

VEGETATED ROOFING SYSTEM The present invention relates to a roofing system for a structure in which vegetation is incorporated therein.

Background of the Art The urban environment is unnatural and not generally hospitable to vegetation. A major component of this extensive amount of area comprising roof surfaces, which contribute to modified ecology and change the microclimate. The roofs provide large surfaces for receiving rain water and sunlight. Over the course of a year, temperatures on an urban roof surface can vary by as much as 170 F, from about -20 F to about 150 F. These temperature extremes impose a demand on the building interior heat and cooling systems. Most rain water falling upon a conventional roof surface, once a small amount of evaporation is accounted for, must be handled in storm sewage systems. The loss of wildlife habitat and native flora amounting to the footprint of a building causes a corresponding loss of the ability to remove carbon dioxide and to add oxygen, as well as a loss of some of the natural capacity to remove atmospheric pollutants. City landscapes have effectively become "heat islands" in many locales, due to the reflective properties of acres of black pavement and roofing surfaces.

Beyond the direct physical effects are the psychological effects on persons exposed only to these barren expanses of unvegetated space. The primary advances in "green roof systems have come from Europe. Generally speaking, a "green roof or "ecoroof is a veneer of living vegetation installed on a roof deck of a structure. These systems differ from the very old concept of sod roofs, known in the prairies of the Western United States in the late 19^th century, since there is a clear and distinct roof membrane between the vegetation-supporting layer and the roof deck. The advantages of the green roof are obvious. The green roof may replace lost natural vegetation, restore ecological balance and add visual beauty. It can reduce the annual thermal variation by up to 30 F, eliminate up to 30% of the storm water runoff as well as slow the rate of runoff. It can add oxygen and remove carbon dioxide and other pollutants. The emissivity of the roof surface is effectively reduced and energy is absorbed by the photosynthetic process occurring on the roof. The vegetation and its support layer provide an insulative layer to the roof deck.

A primary objection to widespread use of the green roof concept has been a failure of the roofing industry to provide a suitable substrate for effectively supporting the vegetative mass of the system. This unmet need has been met by the green roof of the present invention.

Summary of the Invention This advantage, and others, of the present invention are provided by a roof system for a building having a roof deck, comprising a base membrane, at least one moisture control layer, a vegetation support layer, and a vegetative mass layer comprising a plurality of plants with a root portion and a body portion, such that the root portion affixes the plant to the vegetation support layer and the body portion extends upwardly from a top surface of the vegetation support layer, wherein the at least one moisture control layer is affixed atop the base membrane and the vegetation support layer is affixed atop the at least one moisture control layer.

Brief Description of the Drawings The present invention will be best understood when reference is made to the accompanying drawings where identical parts are identified with identical reference numerals and wherein:

FIGURE 1 shows a perspective view of a portion of a roof system of the present invention.

Detailed Description of the Invention The roof system 10 of the present invention comprises a base membrane 12, at least one moisture control layer 14, a vegetation support layer 16, and a vegetative mass layer 18. To establish and maintain integrity of the roof system, each layer of the system will be affixed to the layers immediately above and below the layer. FIGURE 1 shows such a roof system 10 in a sectioned perspective view. This view shows the roof deck 20 on which the system 10 is applied, with a layer of insulation 11, which is optional, as described further below. Fig.l also shows the at least one moisture control layer 14 as a drainage and filter layer 14a and a root reinforcement layer 14b. Atop this layer is a vegetation support layer 16 and the vegetative mass layer 18.

The base membrane 12 presents opportunity for numerous variations, although a few properties are critical to the operability. Specifically, the base membrane will be sufficiently thick and of an appropriate composition to prevent root penetration therethrough. The membrane 12 will, in some aspects, be treated with additives to discourage root growth. In other aspects, the membrane will be treated with antioxidant materials, compounds to retard ultraviolet degradation, and the like. In some aspects, the material will be colored to absorb certain frequencies of solar radiation. The base membrane 12 will also be sufficiently thick and of an appropriate composition to act as a barrier to prevent water and water-soluble compounds, such as fertilizers, from contacting the underlying roof deck or substrate 20. Since the membrane 12 will be affixed to the roof deck 20, at least the side of the membrane facing the deck should be amenable to receiving an adhesive, especially an adhesive which is not soluble in water, for adhering the membrane to the deck.

In one aspect of the invention, the base membrane 12 comprises a multi-ply modified bitumen roof system. In such an embodiment, the roof system can comprise alternating layers of asphalt and ply sheet which are adhered to insulation or to the deck of the structure. In many of these applications, hot asphalt will be applied, although in other aspects a cold-applied adhesive will be substituted for the asphalt. Also, torch-applied membranes would also be found to be useful. If the deck is structural concrete, the roof system which makes up the base membrane 12 will generally be adhered directly to the roof deck, which would be primed to receive the membrane, as would be well-known to those of skill in this art. In situations where a structural concrete roof is to be insulated, the direct application of the membrane atop the concrete will require that the insulation be applied atop the membrane, either below the moisture control layer 14 or in a manner such that the insulation is a part of the moisture control layer. In one aspect of the invention where the insulation is to be atop the membrane 12, the insulation will be an extruded polystyrene material which would be impervious to water.

In the case of non-concrete decks, the most common procedure for insulating the roof would involve installation of the insulation atop the deck 20, with the membrane 12 being installed atop the insulation. This method of installation, which will be well-known to those of skill in this art, has the advantage of using the membrane 12 to provide a moisture-impervious layer to protect the insulation.

In one particular aspect of the invention, the base membrane 12 will be a bitumen based product, having a fiber reinforcing layer embedded in the bitumen. Further, the bitumen will be modified by the incorporation of a styrene-butadiene-styrene / styrene- ethylene-butylene-styrene ("SBS/SEBS") polymer. Additionally, some aspects of the invention will involve the incorporation of recycled rubber, especially ground rubber from tires, to replace the traditional fillers used in a bitumen roofing membrane. While the traditional fiber reinforcing layer will comprise glass fibers or rovings, the invention could also include fibers formed from polymers, particularly recycled materials. Incorporation of post-consumer plastics such as used tires, recycled plastics and the like into an already environmentally-benfeicial product adds to the commercial value of the invention.

A final aspect of the base membrane 12, which is highly desirable but not essential to operation of the invention, is the incorporation of a root-growth inhibiting material into the membrane. It is critical to the invention that roots from the vegetative mass layer 18 do not break through the base membrane 12, as this would compromise the water- imperviousness of the membrane, and, consequently, of the structure, thereby defeating the primary purpose of the roof itself.

The at least one moisture control layer 14 is necessary to relieve hydrostatic pressure due to rain and irrigation water which percolates through the vegetation support layer. In some aspects of the invention, the moisture control layer may also assist in maintaining a minimum level of moisture in the roof system while allowing runoff of excess water to gutters and the like. In some aspects of the invention, the at least one moisture control layer 14 will provide flow conduits for such runoff, shown in Fig. 1 as 14a. In other aspects, the at least one moisture control layer will be able to allow introduction of irrigation water to the roof system. One layer of the at least one moisture control layers 14 may be a filter membrane 14b, which, if used, will be typically at the upper portion of the moisture control layers, that is, adjacent to the vegetation support layer. The filter membrane layer 14b is used to prevent fine particulates arising from the vegetative mass layer and the vegetation support layer from passing into the moisture control layer, where they could clog or block proper runoff. One example of a filter membrane layer 14b would be a spunbonded polyester fabric.

As noted above, the moisture control layer 14 will, in some aspects of the invention, provide an insulative aspect to the roof. The open structure conducive to drainage of water is also conducive to providing a stagnant layer for air, effecting insulation. Because the moisture control layer 14 is relied upon to relieve hydrostatic pressure on the base membrane 12 from water runoff, maintaining the open structure thereof is an important feature. For this reason, incorporation of root growth inhibitors into the moisture control layer 14 is more important than in the base membrane, since root intrusion into the moisture control layer could clog the drainage. Further, the membrane, through its impervious nature, already possesses root inhibition capacity which the open structure of the moisture control layer inherently lacks. Root inhibition compounds are known in the art and compatible with being incorporated into the materials preferred for use with the moisture control layer 14. h the anticipated aspects of the invention, the moisture control layer 14 will constitute, along with the base membrane 12, a relatively permanent feature of the roof system 10. The materials used in the moisture control layer 14 are compatible with being permanently adhered or affixed to the base membrane 12, and this would be the object in many aspects of the invention. However, removably affixed moisture control layers 14 would also be considered a part of the present invention roof system 10.

The vegetation support layer 16 is intended to provide and maintain a root base and growth medium for the vegetative mass layer 18 which is above, and indeed in, the vegetation support layer. By providing a stable matrix, the support layer 16 fixes the vegetative mass layer 18. The material for the support layer can vary widely, and the exact selection thereof will be dictated by a variety of factors, including geographical location, climate zones, microclimate variations, live load weight bearing requirements, and the type of vegetation. The vegetation support layer 16 should be dimensionally stable over time so that it does not shrink or expand excessively and should provide a firm underlayment to tolerate the necessary foot traffic, unless a grid of footpaths is separately provided.

Materials included in the support layer 16 include at least the following: cedar flakes, coir, cork, expanded clay granules, expanded polystyrene, fir bark, perlite, pumice, rockwool fiber, scoria, sphagnum peat, zeolite and ZEOPRO.

In an embodiment of the roof system 10 where seeds would be directly applied to the support layer 16 to germinate into the vegetative mass layer 18, an appropriate support layer would comprise expanded clay granules, coir or peat, perlite and zeolite. In one embodiment, the four components would be present in equal amounts by weight. In another embodiment, the coir or peat component would be in the range of about 45 to about 50% of the mixture, with either the perlite or expanded clay components slightly increased beyond 25% by weight and the other components corresponding decreased. This support layer 16 would be in the range of about 3 to about 3.5 inches thick and have a density in the range of 40 to 45 pounds per cubic foot, but would impose a maximum weight of not more than 11 pounds per square foot.

In an embodiment of the roof system 10 where the combined support layer 16 and vegetative mass layer 18 would be provided in a carpet-like form, an appropriate support layer would comprise expanded clay granules, coir or peat, perlite and zeolite. In such a system, the coir or peat components would generally dominate, being present in the range of from about 35 to about 40% by weight, with the other components being present in at least about 5% by weight, but not exceeding about 30% by weight. This support layer 16 would be in the range of about 2.75 to about 3.4 inches thick and have a density in the range of 35 to 44 pounds per cubic foot, but would impose a maximum weight of not more than 10 pounds per square foot.

In an embodiment of the roof system 10 where the combined support layer 16 and vegetative mass layer 18 would be provided in a mat substrate, an appropriate support layer would comprise expanded clay granules, coir or peat, perlite and zeolite. In such a system, the coir or peat components would again generally dominate, being present in this case in the range of from about 30to about 50% by weight. However, in this case, the perlite component may be omitted in some circumstances, and will usually not exceed 20 % by weight, the zeolite will be in the about 20 to about 40% by weight range, and the clay will be present in the about 10 to about 30% by weight range. This support layer 16 would be in the range of about 1.25 to about 2.5 inches thick and have a density in the range of 40 to 52 pounds per cubic foot, but would impose a maximum weight of not more than 8.5 pounds per square foot. In a yet further embodiment of the roof system 10 in which the vegetative mass layer

18 is transplanted into the support layer 16 in the form of plugs or small plants, an appropriate support layer would comprise expanded clay granules, coir or peat, perlite and zeolite, h such a system, no component would always dominate, and, in fact, each of the four components would be present in this range of about 10 to about 40%) by weight, with the preferred ranges being at least 16% by weight for each component, with no component exceeding 35% by weight. This support layer 16 would be in the range of about 3.25 to about 3.75 inches thick and have a density in the range of about 35 to about 40 pounds per cubic foot, but would impose a maximum weight of not more than 11 pounds per square foot. The vegetation selected to provide the vegetative mass layer 18 will have several general characteristics, but will be selected for a particular application. The general characteristics will be: perennial, low-growing (in the range of 1 to 12 inches) evergreens that tolerate full sun, heat, periods of drought and periods of heavy rain. They should require little maintenance, including pruning, fertilizing and pest control, to minimize necessary foot traffic. The plants may be flowering or the foliage may provide color.

A large number of specific plants provide these characteristics, but a partial list of acceptable plants includes the following: Acanea caesiiglauca, Acanea microphylla, Acanea novae-zealandiae "Blue Haze", Achillea tomento "Compinkie" or "Snow Cap", Alyssum montanum "Mountain Gold", Anacyclus depressus, Antennaria dioica "Rubra", Antennaria "McClintock", Antennaria hybrids, Anthemis carpatica, Arabis ferdinandi- coburgi, Arabis scopoliani, Arabis blephar "Red Sun", Arabis x. sturii, Arenaria montana, Arenaria pupurascens, Armeria maritima "Pink Lusitania", Artemesia frigida, Atriplex semibaccata "Corte", Aubrieta "Bengal", Aubrieta "Grandiflora", Baccharis pilularis, Bellis perennis "Pomponette" (biennial), Bolax glebana "Nana", Carex species (retroflexa), Campanula cochlearifolia "Bavaria", Campanula carpatica "Clips", Campanula poscharskyana, Campanula portenschlagiana, Cerastium alpinum lanatum, Cerastium arvense, Cerastium tomentosa var. columnae, Chamaemelum nobile "Treneague", Chrysanthemum hosmariense, Chysogonum virginianum "V. Pierre", Ceonothus prostratus, Cliptocarpus vitalis, Coreopsis auriculata "Nana", Coreopsis lanceolata "Goldfink",

Cotoneaster dammeri, Cotula reptans, Cotula squalida, Delosperma cooperi, Delosperma nubigeum, Dianthus deltoides cvs., Dianthus gratianopolitanus mix, Dianthus laciniata, Dianthus simulans (Gracilus), Dianthus myrtinervius, Ephedra distachya, monoserma, regeliana, Erigeron compositus, Erigeron glaucus, Erigeron trifidus, Eriogonum umbellatum, Fragaria vesca cvs., Genista pilosa "Vancouver Gold", Genista sagittalis, Gazania linearis "Colorado Gold", Gazania ringens, Globularia cordifolia, Helianthemum nummularium "Wisely Pk.", Herniaria glabra, Iberis sempervirens "Snowflake" "Little Gem", Juniperus horizontalis "Blue cvs.", Lavendula dwarf hybrids, Liriope spicata dwarf cvs., Lithodora diffusa "Grace Ward", Loiseleuria procumbens, Marrubium rotundifolia (horehound), Menta requienii "Corsican", Muhelenbeckia axillaris (nana), Myoporum parvifolium "Burgundy carpet", Ophiopogen japonicus, Origanum vulgare, Orbexilum simplex, Orostachys iwarenge, Oxytropis lambertii, Persicaria affinis "Dimity", Petrorhagia saxifraga (T. saxifraga), Phyla alba (Lippia alba), Phyla nodiflora (incisa, canescens, repens), Potentilla aurea, Potentilla fragiformis, Potentilla nepalensis, Potentilla verna nana, Raoulia australis, Rosularia chrysantha, Rubus calycinoides "Emerald Carpet", Ruschia hamata, Ruschia pulvaris, Santolina incana "Nana", Saponaria ocymoides, Scutellaria alpina "Arcoblanco", Sedum acre "Gold Moss", Sedum album cvs., Murale, sedum kamtschaticum ellacom (selsk), Sedum sexangulare, Sedum spathulifolium, Sedum spurium, cultivars, Sedum mixture, Stachys bysantia "Silver Carpet", Tanacetum argenteum, Tanacetum densum ssp. amanti, Tecrium chameadrys "Prostratus", Thymus "Berthram Anderson", Thymus "Doone Valley", Thymus microphylla, Thymus praecox, Thymus pseudolanuginosis, Thymus pulegiodes, Thymus serpyllum "Minus", Thymus serpillum, Verbena canadensis "Coral", dwarf cvs., Verbena tenuisecta, Veronica allioni, Veronica "Giles Van Hess", Veronica incana, Veronica filifolia, Veronica oltensis, Veronica pectinata "Blue Reflect.", Veronica prostrata "Heavenly Blue", Veronica repens, Veronica rupestris, and Viola cornuta cultivars.

As generally described, the present invention is applicable to substantially horizontal roof surfaces, that is, roof surfaces in which any slope present in the roof is there for drainage purpose and amounts to a few degrees or so of variation from the horizontal. When the present invention is to be used in association with a pitched or otherwise sloped roof , it may be necessary to provide additional features as a part of the base membrane 12 to confine the vegetation support layer 16 and the vegetative mass layer 18. Typically, these elements would be confined into discrete cells, using an upstanding tendon system, such as a polymeric tendon system marketed by Presto Products Company of Appleton, WI, under the trademark GEOWEB. While such a polymeric tendon system is typically used in association with holding vegetative growth on earthen slopes, attaching the same sort of tendon system to the base membrane 12 of the present invention will achieve the same purpose. The polymeric tendon systems will usually be provided with holes in the tendons to allow free passage of material, such as water, fertilizer and the like, but also including pieces of support layer 16 and roots of the vegetative mass layer 18 from one cell to the adjoining cells, further embedding the vegetative mass into the cells.

As has been described in describing the various vegetation support layers 16, the vegetative mass layer 18 may be applied to the roof system 10 in a variety of manners. For example, in some cases the vegetative mass layer will be grown from seeds directly placed on the support layer 16. In other cases, a pre-grown carpet including the support layer and the vegetative mass layer will be applied directly atop the at least one moisture control layer 14 h yet other cases, a pre-grown mat including the support layer and the vegetative mass layer will be applied directly atop the at least one moisture control layer 14. In yet further cases, the vegetative mass layer 18 will be generated through the transplantation of plugs or small plants directly into an already-installed support layer 16.

Fertilization and irrigation techniques for enhancing the viability of the vegetative mass layer 18 are well known from the hydroponics industry and, as such, will be generally applicable to this application. While the best mode of practicing the present invention has been disclosed and described, the present invention is not limited to the foregoing specification, but is instead determined by the accompanying claims.

Claims

CLAIMS What is claimed is:

1. A roof system for a building having a roof deck, comprising: a base membrane affixed to the roof deck; at least one moisture control layer atop the base membrane; a vegetation support layer atop the at least one moisture control layer; and a vegetative mass layer comprising a plurality of plants with a root portion and a body portion, such that the root portion affixes the plant to the vegetation support layer and the body portion extends upwardly from a top surface of the vegetation support layer.

2. The roof system of Claim 1 wherein the base membrane comprises a modified bitumen with at least one layer of having a fiber reinforcement embedded therein.

3. The roof system of Claim 2 wherein the bitumen is modified by a styrene-butadiene- styrene / styrene-ethylene-butylene-styrene polymer

4. The roof system of Claim 1 wherein the vegetation support layer comprises material selected from the group consisting of : cedar flakes, coir, cork, expanded clay granules, expanded polystyrene, fir bark, perlite, pumice, rockwool fiber, scoria, sphagnum peat, and zeolite.

5. The roof system of Claim 4 wherein the vegetation support layer consists essentially of expanded clay granules, in the range of at least about 25 % by weight; coir or peat, in the range of from about 25 % to about 50%> by weight; perlite, in the range of from about 20% to about 30% by weight and zeolite, in the range of from about 20% to about 30% by weight.

6. The roof system of Claim 5 wherein the vegetation support layer has a thickness in the range of about 3 to about 3.5 inches thick and a density in the range of from about 40 to about 45 pounds per cubic foot

7. The roof system of Claim 4 wherein the vegetation support layer consists essentially of expanded clay granules in the range of from about 5 to about 30% by weight; coir or peat, in eth range of from about 35 to about 40% by weight; perlite, in the range of from about 5 to about 30% by weight; and zeolite, in the range of from about 5 to about 30% by weight.

8. The roof system of Claim 7 wherein the vegetation support layer has a thickness in the range of of from about 2.75 to about 3.4 inches thick and a density in the range of about 35 to about 44 pounds per cubic foot.

9. The roof system of Claim 4 wherein the vegetation support layer consists essentially of: expanded clay granules, in eth range of from about 10% to about 30% by weight; coir or peat, in the range of from about 30% to about 50%> by weight; zeolite, in the range of from about about 20 to about 40%> by weight, and perlite, which if present, will not exceed about 20 % by weight

10. The roof system of Claim 9 wherein the vegetation support layer has a thickness in the range of about 1.25 to about 2.5 inches thick and a density in the range of 40 to 52 pounds per cubic foot.

11. The roof system of Claim 4 wherein the vegetation support layer consists essentially of: expanded clay granules, coir or peat, perlite and zeolite, in which each of the components is present in the range of about 10 to about 40%> by weight.

12. The roof system of Claim 11 wherein each of the components is present in the range of from about 16% to about 35%> by weight.

13. The roof system of Claim 11 wherein the vegetation support layer has a thickness in the range of from about 3.25 to about 3.75 inches thick and a density in the range of about 35 to about 40 pounds per cubic foot.

14. The roof system of Claim 1 wherein the plurality of plants in the vegetative mass layer comprise plants selected from the group consisting of Acanea caesiiglauca, Acanea microphylla, Acanea novae-zealandiae "Blue Haze", Achillea tomento "Compinkie" or "Snow Cap", Alyssum montanum "Mountain Gold", Anacyclus depressus, Antennaria dioica "Rubra", Antennaria "McClintock", Antennaria hybrids, Anthemis carpatica, Arabis ferdinandi-coburgi, Arabis scopoliani, Arabis blephar "Red Sun", Arabis x. sturii, Arenaria montana, Arenaria pupurascens, Armeria maritima "Pink Lusitania", Artemesia frigida, Atriplex semibaccata "Corte", Aubrieta "Bengal", Aubrieta "Grandiflora", Baccharis pilularis, Bellis perennis "Pomponette" (biennial), Bolax glebana "Nana", Carex species (retroflexa), Campanula cochlearifolia "Bavaria", Campanula carpatica "Clips", Campanula poscharskyana, Campanula portenschlagiana, Cerastium alpinum lanatum, Cerastium arvense, Cerastium tomentosa var. columnae, Chamaemelum nobile "Treneague", Chrysanthemum hosmariense, Chysogonum virginianum "V. Pierre", Ceonothus prostratus, Chptocarpus vitalis, Coreopsis auriculata "Nana", Coreopsis lanceolata "Goldfink", Cotoneaster dammeri, Cotula reptans, Cotula squalida, Delosperma cooperi, Delosperma nubigeum, Dianthus deltoides cvs., Dianthus gratianopolitanus mix, Dianthus laciniata, Dianthus simulans (Gracilus), Dianthus myrtinervius, Ephedra distachya, monoserma, regeliana, Erigeron compositus, Erigeron glaucus, Erigeron trifidus, Eriogonum umbellatum, Fragaria vesca cvs., Genista pilosa "Vancouver Gold", Genista sagittalis, Gazania linearis "Colorado Gold", Gazania ringens, Globularia cordifolia, Helianthemum nummularium "Wisely Pk.", Herniaria glabra, Iberis sempervirens "Snowflake" "Little Gem", Juniperus horizontalis "Blue cvs.", Lavendula dwarf hybrids, Liriope spicata dwarf cvs., Lithodora diffusa "Grace Ward", Loiseleuria procumbens, Marrubium rotundifolia (horehound), Menta requienii "Corsican", Muhelenbeckia axillaris (nana), Myoporum parvifolium "Burgundy carpet", Ophiopogen japonicus, Origanum vulgare, Orbexilum simplex, Orostachys iwarenge, Oxytropis lambertii, Persicaria affims "Dimity", Petrorhagia saxifraga (T. saxifraga), Phyla alba (Lippia alba), Phyla nodiflora (incisa, canescens, repens), Potentilla aurea, Potentilla fragiformis, Potentilla nepalensis, Potentilla verna nana, Raoulia australis, Rosularia chrysantha, Rubus calycinoides "Emerald Carpet", Ruschia hamata, Ruschia pulvaris, Santolina incana "Nana", Saponaria ocymoides, Scutellaria alpina "Arcoblanco", Sedum acre "Gold Moss", Sedum album cvs., Murale, sedum kamtschaticum ellacom (selsk), Sedum sexangulare, Sedum spathulifolium, Sedum spurium, cultivars, Sedum mixture, Stachys bysantia "Silver Carpet", Tanacetum argenteum, Tanacetum densum ssp. amanti, Tecrium chameadrys "Prostratus", Thymus "Berthram Anderson", Thymus "Doone Valley", Thymus microphylla, Thymus praecox, Thymus pseudolanuginosis, Thymus pulegiodes, Thymus serpyllum "Minus", Thymus serpillum, Verbena canadensis "Coral", dwarf cvs., Verbena tenuisecta, Veronica allioni, Veronica "Giles Van Hess", Veronica incana, Veronica filifolia, Veronica oltensis, Veronica pectinata "Blue Reflect.", Veronica prostrata "Heavenly Blue", Veronica repens, Veronica rupestris, and Viola cornuta cultivars.

15. A roof system for a building having a roof deck, comprising: a base membrane affixed to the roof deck, said base membrane comprising a modified bitumen with at least one layer of having a fiber reinforcement embedded therein; at least one moisture control layer atop the base membrane; a vegetation support layer atop the at least one moisture control layer, said vegetation support layer comprising material selected from the group consisting of : cedar flakes, coir, cork, expanded clay granules, expanded polystyrene, fir bark, perlite, pumice, rockwool fiber, scoria, sphagnum peat, and zeolite; and a vegetative mass layer comprising a plurality of plants with a root portion and a body portion, such that the root portion affixes the plant to the vegetation support layer and the body portion extends upwardly from a top surface of the vegetation support layer, the plurality of plants comprising plants selected from the group consisting of Acanea caesiiglauca, Acanea microphylla, Acanea novae-zealandiae "Blue Haze", Achillea tomento "Compinkie" or "Snow Cap", Alyssum montanum "Mountain Gold", Anacyclus depressus, Antennaria dioica "Rubra", Antennaria "McClintock", Antennaria hybrids, Anthemis carpatica, Arabis ferdinandi-coburgi, Arabis scopoliani, Arabis blephar "Red Sun", Arabis x. sturii, Arenaria montana, Arenaria pupurascens, Armeria maritima "Pink Lusitania", Artemesia frigida, Atriplex semibaccata "Corte", Aubrieta "Bengal", Aubrieta "Grandiflora", Baccharis pilularis, Bellis perennis "Pomponette" (biennial), Bolax glebana "Nana", Carex species (retroflexa), Campanula cochlearifolia "Bavaria", Campanula carpatica "Clips", Campanula poscharskyana, Campanula portenschlagiana, Cerastium alpinum lanatum, Cerastium arvense, Cerastium tomentosa var. columnae, Chamaemelum nobile "Treneague", Chrysanthemum hosmariense, Chysogonum virginianum "V. Pierre", Ceonothus prostratus, Cliptocarpus vitalis, Coreopsis auriculata "Nana", Coreopsis lanceolata "Goldfink", Cotoneaster dammeri, Cotula reptans, Cotula squalida, Delosperma cooperi, Delosperma nubigeum, Dianthus deltoides cvs., Dianthus gratianopolitanus mix, Dianthus laciniata, Dianthus simulans (Gracilus), Dianthus myrtinervius, Ephedra distachya, monoserma, regeliana, Erigeron compositus, Erigeron glaucus, Erigeron trifidus, Eriogonum umbellatum, Fragaria vesca cvs., Genista pilosa "Vancouver Gold", Genista sagittalis, Gazania linearis "Colorado Gold", Gazania ringens, Globularia cordifolia, Helianthemum nummularium "Wisely Pk.", Herniaria glabra, Iberis sempervirens "Snowflake" "Little Gem", Juniperus horizontalis "Blue cvs.", Lavendula dwarf hybrids, Liriope spicata dwarf cvs., Lithodora diffusa "Grace Ward", Loiseleuria procumbens, Marrubium rotundifolia (horehound), Menta requienii "Corsican", Muhelenbeckia axillaris (nana), Myoporum parvifolium "Burgundy carpet", Ophiopogen japonicus, Origanum vulgare, Orbexilum simplex, Orostachys iwarenge, Oxytropis lambertii, Persicaria affinis "Dimity", Petrorhagia saxifraga (T. saxifraga), Phyla alba (Lippia alba), Phyla nodiflora (incisa, canescens, repens), Potentilla aurea, Potentilla fragiformis, Potentilla nepalensis, Potentilla verna nana, Raoulia australis, Rosularia chrysantha, Rubus calycinoides "Emerald Carpet", Ruschia hamata, Ruschia pulvaris, Santolina incana "Nana", Saponaria ocymoides, Scutellaria alpina "Arcoblanco", Sedum acre "Gold Moss", Sedum album cvs., Murale, sedum kamtschaticum ellacom (selsk), Sedum sexangulare, Sedum spathulifolium, Sedum spurium, cultivars, Sedum mixture, Stachys bysantia "Silver Carpet", Tanacetum argenteum, Tanacetum densum ssp. amanti, Tecrium chameadrys "Prostratus", Thymus "Berthram Anderson", Thymus "Doone Valley", Thymus microphylla, Thymus praecox, Thymus pseudolanuginosis, Thymus pulegiodes, Thymus serpyllum "Minus", Thymus serpillum, Verbena canadensis "Coral", dwarf cvs., Verbena tenuisecta, Veronica allioni, Veronica "Giles Van Hess", Veronica incana, Veronica filifolia, Veronica oltensis, Veronica pectinata "Blue Reflect.", Veronica prostrata "Heavenly Blue", Veronica repens, Veronica rupestris, and Viola cornuta cultivars.