the system

MEDITERRANEAN GREEN ROOF

The green roof system

The Mediterranean green roof: a new frontier

A new mindsetWithin Harpo, the Mediterranean green roof division team has the objectives of spreading a culture of bringing city dwellers closer to nature, by raising awareness of issues such as the protection of biodiversity, lowering temperatures, reducing CO2 and other pollutants, protecting the permeability of surfaces, reducing energy requirements and improving liveability of the urban environment for both the public as a whole and the individual, by spreading sustainable building techniques, such as green roofs.

Continental weather and climate conditions have encouraged the spread of green roofs in Central European countries, with systems which, in our climates, are often difficult to apply.After several years of experience in Italy, we have become aware that, in the Mediterranean climate, the approach to green roofs must be different, due to both the different weather conditions and the different benefits that can be obtained.Here, in fact, green roofs can play an important role in thermal insulation in the summer, less relevant in the north. The more violent rains necessitate increased absorbency of the surfaces. In addition to this, the specific aesthetic culture of the Mediterranean must also be considered.Through the experience gained so far and the results obtained through research carried out at Italian research institutes, Harpo is now able to offer technologies and systems designed to better reflect our climate, while continuing to invest in the development of new, increasingly advanced systems.

Systems for the Mediterranean climate have to offer high performance in terms of passive cooling in the summer and high water availability and at the same time reduce maintenance costs and water requirements in relation to typical Mediterranean plants.

General features

• Light: low weight• Versatile: extremely low thickness of the

system• Low maintenance• Long service life• Low water needs due to superior performance

by the Harpo substrate in storing large amounts of water available for plants

• High capacity to retain fertilisers• High draining capacity• Reduced runoff • Excellent passive cooling system for summer• Use of recycled raw materials • Complete accessories• Complies with UNI 11235

“instructions for the design, execution, monitoring and maintenance of green roofs”

◆› Energy saving◆› Low water needs◆› Summer cooling◆› High usability

TerraMediterranea Substrate

MediFilter MF 1 Filter sheet

MediPro MPWater retention felt

HarpoPlan ZD UVAnti-root

waterproofing

MediDrain MDDrainage, storage and

ventilation element

mediterranean green roof

system

Styl

e H

ouse

/Sca

rpa

Types

ExtensiveSedum Perennials Composite Aromatic

InexpensiveLightweight 120 to 200 kg/m2

Low thickness: 11-18 cm Reduced maintenance Only emergency watering Can only be used with paths

Purpose and benefitsEnvironmental compensation Passive summer coolingReduced runoffIncreased life of waterproofingImproved efficiency of crystalline silicon photovoltaic panels

IntensiveLightweightGarden Carriageable

Total usabilityHigh aesthetic valueCarriageable solutions also availableWeight from 225 kg/m2

Thickness > 20 cmMedium to high maintenanceWater needs to be assessed on the basis of vegetation

Purpose and benefitsIncrease in property value Creating accessible areasHigh impact image Passive summer cooling Reduced runoffIncreased life of waterproofing

MAINTENANCE

LowAverage

High

EXTENSIVEINTENSIVE LIGHTINTENSIVE

AccessoriesWide range of Harpo accessories

Thermally insulated control wells

Drainage channels

Waterproofing protection profiles

Draining / gravel guard / containment profiles

Anchors for safe maintenance

TerraMediterranea Substrate

A

I

B

L

F

G

H

CE D

I

I

A C E

D

B

A

C

C

This is the layer from which the plants derive nourishment and is the cornerstone of the system.The TerraMediterranea substrate is produced by Harpo specifically for green roofs.It is mainly mineral-based material (volcanic lapillus, pumice). The organic matter is reduced to the minimum necessary, as it would mean a decrease in thickness over time, a structural change of the substrate and make it easy to be attacked by weeds.It is a material with high technical performance. A few of its features are listed below: • reduced weight at maximum water saturation• high permeability over time• high air content• cation exchange capacity• physical structure and chemical stability• long-term texture stability• high water retention and water availability• high capacity to absorb and keep nutrients

Working design: technical office support

➊ Continuous drainage• Sizing of the drainage

capacity• Checking available drains

➋ Specific technical details in the vicinity of the main nodes

➌ Protection from the roots and waterproofing

➍ Pitched roofs

22

4

31

1

11

Technical performance of the system: research and development

Research site with testing tanks at the agricultural school in San Michele all’Adige.

Research site with testing tanks at the Forest Ranger Natural Learning Centre in Basovizza, Trieste.

SolutionAdsorption

ExchangeRoot absorption

Granules of K+

fertiliser

Soil solution

TerraMediterranea Substrate

H+ Root

H+

H+

H+

H+

K+

K+ K+

K+

K+

K+

K+K+

High cation exchange capacity (CEC) to reduce the quantity and frequency of fertilisation.

I

Summer thermal performance of the Mediterranean green roof systemH

Rain rate

Example of a runoff curve

Runoff

Runoff coefficient testG

Permanent wilting point

Field capacityVolumetric water content (%)

Water potential (MPa)

Volume of water available for soil volume

Water savingF

Water runoff Temperature trend in August

Hydraulic stability over time (back filter)L

Water flow

TerraMediterranea Substrate

Filter formation

Arch of coarse particles

MediFilter MF 1

MediDrain MD

SAND

SUBSTRATECLAY

Tem

pera

ture

Time

Sheath Sedum Weeds Ground cover shrubs

Prec

ipita

tion/

Run

off (

mm

)

Precipitation Runoff

Time (min)

head officevia torino, 3434123 trieste italy

Harpo spatel. +39 040 3186611 info@harpogroup.itharpogroup.it

factoryvia caduti sul lavoro, 7z.i. noghere 34015 muggiatrieste italy