The technical side of green renovation: pitched roofs

Around the world, architects know where to find us to create green buildings and, fortunately, we are joining in earlier and earlier in the design process. Why is this important? Because a green roof or living wall cannot always simply be added to a building. There are a few things that can be taken into account. The earlier in the design phase this is done, the easier the construction or installation of the greenery will be later in the project.

We give the floor to Max de Vos. Max is responsible for Research & Development within Sempergreen and is one of the specialists when it comes to the technical side of things. As there is a lot to tell about the technical side of green renovation, we will devote several articles to this subject. In this article, Max explains more about renovating sloping roofs.

Green roof solution for each type of roof

When the idea arises to renovate a pitched roof with greenery, the first question that arises is: what kind of roof structure are we dealing with? The majority of cases involve a roof construction with a vapour-permeable roof membrane. Sempergreen offers vapour-permeable green roof solutions for this type of roof; after all, this roof needs to breathe. 

”Vapour-permeable roof membrane? Then also choose a vapour-permeable green roof solution!“

Fortunately, at Sempergreen we have suitable solutions for various roof structures. You can find them on our website.

In the renovation and preservation of houses in Bergen op Zoom (the Netherlands), the vapour-permeable pitched green roof system was applied. Read more about this project here. 

Powerful story

Question two that is of great importance for the realisation of a renovation with green roof is, of course, what the load-bearing capacity of the roof is. Our vapour-permeable green roof systems range in weight from 51 - 86 kg/m2. Other green roof systems for pitched roofs vary in weight between 100 - 135 kg/m2. 

Maintenance

Pitched roofs are in general highly visible from street level. And with a green roof, this naturally is a treat. It is therefore important not only for the building owner, but also for passers-by that the beautiful green roof stays beautiful. We therefore recommend taking extra care of the green roof four times a year by removing blown-in weeds, (re)nourishing the vegetation and checking the rainwater drains. We provide maintenance instructions and are always ready to answer your questions. Of course, proper fall protection is a must here, for the safety of employees. 

Plants require water

Just like in the garden, plants on a sloping roof need water. The plants are often in full sun and can therefore use an extra sip. For sloping green roofs, we recommend having an irrigation system installed from the start. This requires a convenient water supply and a power outlet, depending on the green roof system chosen. It is important to consider this early on in the project. Our specialists can connect early in the project to explain all details. Feel free to contact them if you have any questions.

“The earlier in the process we connect, the easier the final realisation will be”

Yellow and green combined

And if you are going to renovate sustainably, why not immediately install several sustainable solutions on one roof? The pitched green roof system can accommodate solar panels so that the building's users not only enjoy the greenery but can also convert the power of the sun into usable energy for the building. Naturally, a different roof load per square metre applies to the installation of solar panels. In this case too, our specialists are happy to advise you. To find out more about this beautiful, sustainable combination, click here for an inspiring article about Solar Green Roofs.  

Next time, we will dive deeper into the technical side of green renovation with green solutions on flat roofs. For example, did you know that the height of the parapets is incredibly important when realising a green roof, especially when it comes to the increasingly common Retention Roof (or blue-green roof)? You'll find out all about it soon, so keep an eye on our website!