Weight Loading: What to consider before you start building

When you’re planning the construction of a green facade or living wall of any kind, it’s important to know what the weight loading capacity of your building is. Architects and building designers will often estimate the weight loading capacity, however, their figures are not always accurate, unfortunately.

The engineers at Tensile use accurate data to measure this weight loading for our clients, and we find that we often have to correct the load bearings that have been suggested to them.

Some of the most important weight loads to measure include:

Dead Load

This is the final weight of all the immobile components of the green façade.  There are a few different components to consider with the Dead Load and they are:

  • Growing Medium – knowing which plants are going to be used impacts the growing medium considerably. Knowing if you need well drained soil, a container that supports a shallow root system or if pebbles are required can really impact the load measures. The growing medium measure is typically 1-1.2kg per litre when saturated.
  • Water – elements that are factored in here are the weight of the water retained in the system, the watering system itself, different plants retain varying amounts of water so knowing which ones are going to be used is important. Factoring the environment and weather patterns also impacts the water load.
  • Weight of Planters – considerations include the weight of the planter, soil, cabling or mesh, etc.
  • Weight of Plants – knowing the different plant species is critical in this measurement. Including the weight of the plants, soil, plant pots and any water held by the plants (which varies with precipitation). You also need to know the capacity that the plant will grow to so that you can ensure that the measures will support the green facade now and into the future. The typical weight to allow for is 5-8kg/m2 for climbing plants, and up to 26kg/m2 for large climbers.

 

Wind Load

This will vary from site to site depending on the exposure and aspect, and is the amount of force experienced by wind gusts. Typically, a green facade will see 1kpa, however it’s important to keep in mind that a green facade will have up to 80% open areas, even with full plant coverage.

Pre-tension Load

This is the amount of tension that is held in the cables and mesh that supports the green facade, and will vary considerably from site to site. Main support cables generally have 2-3kN of tension, while most wire mesh systems will have a pre-tension load of 20-30kg per lineal metre.

All these figures need to be used as a guide only, and it’s vital that you have your project properly assessed so that your measurements and calculations are accurate.

To learn more about weight loadings and have you project assessed, speak to our team of experts.

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