ᐅ Green Roofs on Flat Roofs – What Are the Advantages and Disadvantages?

Hello,

Since our plot allows almost all roof types, we are considering a green flat roof because we really like the modern look and the greenery is said to offer numerous benefits, for example in terms of insulation and thermal lag. Unfortunately, I haven’t found much about the disadvantages. My wife’s biggest concern is that pests and birds might settle up there, causing ongoing problems such as bird droppings on the terrace and/or insects, spiders, and wasps inside the house. What experiences have you had with your green roof?

We built with a flat roof; the only reason we decided against green roofing was the additional cost. It would have been 55€/m² (about $59/ft²) net. With approximately 90m² (970ft²), that quickly adds up to nearly €6,000 (€7,000 with tax), which I would hardly benefit from.
However, we had no concerns regarding pests or anything like that. Why would there be any? How would they get through the waterproofing?

The structural design of the FD must be adjusted to accommodate the increased weight.
The slope needs to be raised from at least 2% to at least 4% – which requires a different elevation elsewhere in order to achieve this.

We had the 9 x 6 m (30 x 20 ft) garage greened and are now waiting for it to sprout again in spring.

matte1987 schrieb:

We didn’t have any concerns about pests or anything like that. Why would we? How would they even get through the waterproofing?

Along the exterior wall by the window?

How do you find the heat protection in summer? Brick or timber frame wall? Concrete ceiling?

I somehow worry that the flat roof will heat up quickly without greenery?

Driveshaft84 schrieb:
Along the house wall towards the window?

How do you find the heat protection in summer? Brick or timber frame wall? Concrete ceiling?

If that’s the case, you probably shouldn’t have grass or similar around the house either, since insects could come from there and reach the house wall along to the windows...

Regarding heat protection, I can’t say much yet, as we only moved in December.
The construction is solid, with brick walls and reinforced concrete ceilings and roof.
Last year, during construction, it was always comfortably cool inside...

Your plot is located in a natural setting, and your wife may not necessarily embrace insects, small bugs, dirt, and tiny creatures, but she should expect to have daily contact with them. This applies regardless of which type of roof you choose. Just a friendly piece of advice. Otherwise, I cannot provide an answer to your question.