Hello everyone,
Our local development plan requires a green roof if building with a flat roof. Since we are building with a flat roof, it seems we have no choice but to install a green roof.
The specifications from the prefab home manufacturer state the following: an increase in roof load of 1.8 kN/m² (37.5 psf) for the green roof. The green roof is to be installed by the client. [Provider] will construct the flat roof system with a rainproof rubber membrane, which is not root-resistant. Further in the text, it states that the roof structure is designed for a standard snow load of 0.85 kN/m² (17.8 psf).
Can I therefore correctly assume that the roof's load-bearing capacity is 2.65 kN/m² (55.3 psf)? Which corresponds roughly to 265 kg (584 lbs).
How should I properly install the green roof? According to the house seller, it was roughly explained that you only need to put some soil and seeds on it, and the rest happens on its own. The cost for the green roof was also mentioned as “around 1,000 euros.” Apparently, this statement isn’t entirely accurate, as I have found various contradictory information online.
Additionally, I have received a quote where an excavation contractor offers to deliver, spread, and level lava rock for the flat roof with a thickness of 10 cm (4 inches) – without green roofing. Doesn’t there need to be an additional protective layer on the roof beforehand? Or is the rubber membrane from the home manufacturer sufficient?
What other costs should I expect?
Our local development plan requires a green roof if building with a flat roof. Since we are building with a flat roof, it seems we have no choice but to install a green roof.
The specifications from the prefab home manufacturer state the following: an increase in roof load of 1.8 kN/m² (37.5 psf) for the green roof. The green roof is to be installed by the client. [Provider] will construct the flat roof system with a rainproof rubber membrane, which is not root-resistant. Further in the text, it states that the roof structure is designed for a standard snow load of 0.85 kN/m² (17.8 psf).
Can I therefore correctly assume that the roof's load-bearing capacity is 2.65 kN/m² (55.3 psf)? Which corresponds roughly to 265 kg (584 lbs).
How should I properly install the green roof? According to the house seller, it was roughly explained that you only need to put some soil and seeds on it, and the rest happens on its own. The cost for the green roof was also mentioned as “around 1,000 euros.” Apparently, this statement isn’t entirely accurate, as I have found various contradictory information online.
Additionally, I have received a quote where an excavation contractor offers to deliver, spread, and level lava rock for the flat roof with a thickness of 10 cm (4 inches) – without green roofing. Doesn’t there need to be an additional protective layer on the roof beforehand? Or is the rubber membrane from the home manufacturer sufficient?
What other costs should I expect?
We are currently in the process of greening the flat roof of our extension. This is entirely voluntary and not required by any building permit or planning permission. After observing how a company handled the green roofing on our prefabricated garages, I feel confident to tackle the next roof myself. Our local roofer is lending me his material hoist, and I have ordered everything else online. Just try searching for "DIY green roof" in one of the major search engines. You will find several suppliers.
Regarding the structural considerations, the weight of the green roof must be taken into account. My system weighs about 40 kg/m² (8.2 lb/ft²). In addition, you need to consider water retention capacity and any potential snow load.
Regarding the structural considerations, the weight of the green roof must be taken into account. My system weighs about 40 kg/m² (8.2 lb/ft²). In addition, you need to consider water retention capacity and any potential snow load.
MarkoW. schrieb:
May I ask how much you are paying for this? (per sqm)Of course, we are at around 50 euros per square meter (approximately $54 per sqm), all included — root protection membrane, drainage mats, substrate, and greenery (pre-grown sedum mats with at least 90% coverage), as well as delivery to the site.AxelH. schrieb:
Of course, we are looking at around 50 euros, all inclusive – root barrier membrane, drainage mats, substrate, and vegetation (pre-grown sedum mats with at least 90% coverage) – plus free delivery. Thanks, so we’re actually far from the promised 1000 euros 🙂 I would definitely try that myself, but getting up to the roof might be tricky (unless you can arrange a roofer’s hoist through connections).
Did you happen to order the "Comfort" package? Then I ended up at the same shop 😉
MarkoW. schrieb:
unless you can get a roofer’s lift through connectionsWell, the roofer lives in our town. I stopped by, asked politely, and it was sorted out right away.MarkoW. schrieb:
Did you happen to order the "Comfort" package? Then I ended up at the same shop 😉Yes, directly in the neighboring country in Haarle.Similar topics