For some people, a house with a rooftop garden can be a place to relax, be creative, enhance the aesthetics of the house, and reduce the heat of the sun. Especially if it is located in the midst of limited urban space. On the other hand, one of the concerns and problems with rooftop gardens is the filtration system, water drainage, and waterproofing to prevent seepage into the roof of the house. These issues can be addressed using several geosynthetic materials, such as Sika for waterproofing, drainage cells for drainage, and non-woven geotextile for filtration. For those of you looking to create a minimalist rooftop garden at home, the following article provides detailed practical tips on how to build a rooftop garden with minimal costs using Sika, drainage cells, and non-woven geotextile.
Plant Media Layer on the Rooftop of a House
A rooftop garden consists of several layers. There are at least 5 layers arranged in order from the bottom (base) to the top layer.
1. Waterproofing layer with roof structure (using Sika layer).
2. Drainage cell (drains water to the drainage channel).
3. Filtration or screening layer, preventing soil from entering the lower layer (using non-woven geotextile).
4. Planting medium.
Waterproofing Layer Using Sika
Sika is the bottom layer. Its advantage is that it is liquid-like and can penetrate the pores of the bottom layer of the rooftop, making it effective for long-term waterproofing. Its role as a waterproofing layer allows it to be used as a base and prevent water from seeping into the interior of the roof. Sika is more expensive compared to other types like no-drop waterproofing. No-drop has a rubber-like texture, and if exposed to continuous sunlight, it can cause tears. However, using no-drop waterproofing is less efficient, requiring frequent inspections and reapplication. The layers above it also need to be reapplied frequently.
Drainage Layer Using Drainage Cells
Drainage cells function to drain water. Rainwater or excess water from watering can be channeled to the drainage system. This certainly improves the efficiency of the drainage process. Without drainage cells, the rooftop area could potentially accumulate water and become an excessive load on the structure of the house.
Filtration Layer Using Non-Woven Geotextile
Non-woven geotextile functions as a filtration layer, preventing planting media such as soil from scattering and allowing water to seep into the waterproofing layer. Non-woven geotextile has high strength and flexibility, so it is not easily torn and can make the soil layer more stable.
Planting Media Layer
This layer acts as soil for the plants and provides nutrients.
How to Create a Rooftop Garden at Home on a Minimal Budget?
Creating a successful minimalist rooftop garden requires careful planning, from preparation to maintenance. To that end, there are several important things you need to prepare to ensure your rooftop garden is safe and durable, even on a minimal budget.
Preparation Stage
1. Inspecting the Roof Structure
This step ensures that the roof is strong enough to support the weight of plants, soil, pots, and water. In addition to inspection, you can also clean the area of gravel and debris. You can check it yourself or consult with a contractor.
2. Checking the Drainage System
Proper drainage ensures that water on the rooftop can be properly channeled into the drainage system.
3. Planning the Plant Layout
This planning determines where the pots or planting media will be placed, the drainage system, the position of empty spaces or areas that can be accessed, and the positioning of areas exposed to sunlight.
Geosynthetic Material Installation Stage
1. Installing the Sika Layer
Sika serves to retain water from irrigation or rainwater, which is then drained through the drainage system to the outlet to prevent it from seeping into the roof of the house.
2. Installing Drainage Cells
Their role is to drain water from puddles caused by excessive irrigation and rainwater, which can damage plant quality. You can use drainage cells with the following dimensions and specifications:
– Dimensions: 25 cm x 25 cm x 3 cm.
– 1 bundle contains 80 pieces (5 meters).
– Made from polypropylene material.
– Product durability up to 5 years.
3. Installing Non-Woven Geotextile
Water seeping from the growing medium downward will be channeled to the drainage cells without involving the growing medium. This is because non-woven geotextile has high permeability and strength as a filter (screening). You can use non-woven geotextile with sizes and specifications ranging from 150 to 200 GSM. For example, if your rooftop garden requires 150 GSM, a size of 4 x 100 m, with an area of 400 m².
4. Planting Medium Placement
The planting medium serves to enable plants to grow by absorbing nutrients and other essential elements, as well as providing a space for fertilization.
5. Planting Plants According to Needs/Preferences
With the three previous layers in place, you can experiment with any type of plant without worrying about water pooling, water seeping into the interior of the roof, or the absence of a strong filtration system.
Maintenance Stage
The maintenance section is responsible for regularly checking the rooftop garden after the installation process is complete. Checks are carried out at specific intervals, such as once a week, once a month, and so on. You can check several conditions, such as the drainage system, Sika coating, non-textile geomembrane, sun exposure position, soil layer and growing medium, plant growth, fertilization, and removing weeds that grow over time.
Tips and practical ways to create a minimalist rooftop garden with a minimal budget involve several stages, such as preparation, installation of geosynthetic materials, and maintenance.
– The preparation stage includes inspecting the rooftop structure, checking the drainage system, and planning the plant layout.
– The installation of geosynthetic materials includes laying a waterproofing layer, drainage cells for the drainage system, and non-woven geotextile for water filtration, as well as placing the growing medium.
– The final stage involves regular, ongoing maintenance over a specific period of time.
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