Installation mechanics: what actually holds it up
An installation is a structure with flowers attached. The flowers are the part everybody looks at and almost never the part that fails.
The Florist Heaven desk / Chapter 4 of 4
The frame carries the load, not the flowers
Every piece of an installation has to have an answer to one question: what is holding this up, and what is that attached to. Foliage and flowers are cargo. They add weight, they add wind area, and they contribute nothing to strength.
Weight is also not static. Hydrated mechanics are much heavier than dry ones, and a piece that was manageable on the bench can be a different object once it is soaked and loaded. Estimating the finished weight before you build is a good habit for exactly this reason.
Anything installed above where people stand or sit is a safety question first and a design question second. Venue rules, rigging points, and load limits are the venue's to specify, and where a piece needs rigging it needs somebody qualified to rig it. This site does not publish load figures, because a wrong one would be dangerous and we have no authority to state one.
Attachment: what holds and what slips
Most failures are attachment failures rather than material failures. The tie was fine, the surface it was tied to was smooth and painted, and the whole assembly migrated a few inches at a time over four hours.
- Know the surface: painted metal, varnished timber, and cold stone all behave differently from the rough wood people practise on.
- Prefer attachments that capture the frame rather than relying on friction against it.
- Assume everything will be touched: by guests, by photographers moving it slightly for a shot, and by staff moving furniture underneath it.
- Build in redundancy on anything you cannot see the back of once it is up.
- Consider what the venue will accept: adhesives, fixings into surfaces, and anything that leaves a mark are frequently not permitted.
Water, and installations that do not have any
A large proportion of installation work is designed dry, which means the flowers in it are out of water from the moment they go in until strike. That places a hard limit on what can go into the piece, how early it can be built, and how it behaves in heat.
Which material tolerates that and which collapses within the hour is a conditioning and physiology question rather than a mechanics one, and it is the single most useful thing to know before designing a dry piece for an outdoor afternoon.
What conditioning is doing for the stem, sourced to extension horticulture publications.
Read the conditioning chapterOutdoors changes the problem
Wind is the factor most often underestimated, because a floral installation is a sail. A structure that is entirely stable empty can be unstable once it is covered, and the load is dynamic rather than steady. Heat and direct sun act on the flowers on a much shorter clock than indoors, and ground conditions decide whether anything can be staked at all.
The practical consequence is that an outdoor install needs a decision made in advance about what happens if conditions are bad on the day, and who makes that call. Settling that at the proposal stage is much easier than settling it in a field.
Coming down without damage
Everything that goes up comes down, usually late, usually tired, and usually faster than it went up. Installations that were built to be dismantled come down cleanly; installations that were built only to go up come down in pieces, over the venue's floor.
Photograph what you attached to before you attach to it. It is a two minute habit that settles an argument about a mark on a surface that may well have been there first.