It’s always interesting and at the same time important, to understand the opinion of the different type of figures who work in the world of timber buildings. For this reason in the last few years we proposed some surveys which always gave us satisfying results, and suggested us some food for thought. The last one we made was about multi-storey buildings.
In the following analysis we wanted to share with you the most significant data about the surveys we made.
More than 220 people filled in our poll about timber tall building. The queries we made were about the advantages and the limits of timber buildings, trying to offer some food for thought to the interviewees.
The survey it’s been divided in two parts depending from the geographical provenience of the interviewees: Italy and the rest of the world. This allowed us to compare the opinions of Italian designers with the rest of the world, revealing in certain cases some significant differences. In total, 87 Italians and 133 people from 33 different nations of 5 continents answered the survey.
Most of the interviewees were designer and Carpentery/CLT producers, but we also had answers from other kind of professional figures as researchers, producers, students, journalists and consultants.
It’s interesting to note that a considerable part (25%) of people who filled the survey has never designed a timber building. More than 23% of the non-Italian interviewees has designed/built a 6 or more storeys timber building.
For what concerns the limits which have slowed down the spread of tall timber buildings, at the first place we find the lack of knowledge of designers and builders.
It’s also interesting to underline how fire issues are considered more limiting by non-Italians interviewees.
Diagrams from left to right: – Static, – Codes, – Fire, – Production technologies, – Cost, – Lack of knowledge of designers and builders.
For what concern the benefits attributed to the use of timber in tall timber buildings, we can tell that off-site prefabrication, reduction of time and the possibility to avoid the use of water and build with dry materials are universally considered as the main advantages. The weight reduction on the R.C. foundation is also perceived as a considerable benefit.
What about the carbon footprint? On one hand the 58% of non-Italians interviewees thinks that it’s a real advantage and indicated it as the most important, on the other hand only the 29% of Italians considers it as a considerable benefit, assigning it the maximum importance.
Diagrams from left to right: – Energetic efficiency, – Reduction of time on the building site, – Dry building system, – Off-site prefabrication (instead of on-site), – Carbon footprint (CO2 timber storage), – Vehicular traffic reduction (camion), – Modularity, – Lightweight structural mesh (about 30% less than a traditional building).
Durability and acoustic are recognized as the most important limits of building structures.
Diagrams from left to right: – Durability, – Slab vibrations, – Building vibrations, – Acoustic, – Visible beams on the ceiling intrados.
More than 2/3 of Italians and almost the 3/4 of non-Italians interviewees consider that the actual knowledge and technologies are sufficient to develop tall timber buildings.
Almost everyone who’s been interviewed thinks that hybrid structures are the key to overcome the height limits of timber buildings.
Speaking about the dimensions of the structural grid, almost everyone agree that the commercial buildings need the widest one.
Diagrams from left to right: – Residential, – Office, – School, – Hotel, – Commercial (Shops), – Campus.
There are some relevant differences between non-Italian and Italian interviewees about the possibility to have a façade independent from the structural frame. The 74.3% of non-Italian people who filled the survey thinks that is an advantage while just the 47.1% of Italians has the same opinion.
Generally, the possibility to have visible timber structural elements it’s not considered as a primary requirement. In fact, only the 29.4% of non-Italian interviewees answered yes. In Italy that is definitely considered as non-relevant (86.2% answered no)
Talking about fire resistance and fire reaction, the first one is considered as the most important issue by more than 2/3 of the interviewees.
The main purpose of this query was to provide food for thought about this peculiar aspect of the timber building design. Too often fire reaction is considered as secondary compared to resistance. It should not be forgotten thatwood is a material with class of reaction D-s2, d0, corresponding to the combustible and potentially inflammable materials.