In most cases, we also use PU wood glue to mount our Treehouse Screws.
The basis of our thinking is tree biology and the wound reaction of trees:
- The tree reacts to injuries by storing resins and essential oils. This seals the vessels and prevents the entering of fungal spores and rot. In addition, these deposits are often inedible for insects.
- The damaged vessels can be imagined as long tubes in which water and nutrients are transported. If the pipe is damaged, the hose will leak and no longer function.
- The loss of the broken passages are compensated. Around the injured zone (e.g., bore of the screw) new vessels will form in the following years.
Why does “TheTreehouse.Shop” recommend PU glue for fixing the screws?
- PU glue expands up to three times its volume when hardened
- It fills all gaps
- Like the tree with its resins and oils, the glue enters the damaged vessels and seals them permanently – so fungi and insects cannot enter the wound
- While the tree itself can only store fungus-inhibiting substances in the active wood (the outer 1 – 5 cm of the trunk), the PU glue seals the borehole far into the interior and prevents fungus from spreading from the core to the outside.
- The glue strengthens the wood immediately around it.
- The tree screw sits bomb-proof in the hole – so you can loosen a tight nut later without having to unscrew the screw again.
Why not use natural resins instead of toxic PU glue?
Natural substances could theoretically provide a breeding ground for fungi and insects. In addition, their hardening and volume increase is not as good as with PU glue.