A tree trunk can be used wonderfully for various construction projects, for example to support the canopy of a garden house or a covered terrace. Such a trunk is also ideal for building a small, rustic pavilion in the middle of the garden and for climbing plants over the supporting trunks. In order for the trunks to stand securely and last a long time, you must anchor them firmly in the ground. One way to do this is to embed it in concrete.
The tree trunks should be treated before they are cast in concrete
Impregnate wood before inserting
When implementing the project, however, note that tree trunks buried in the ground or concreted in can rot quickly. In order to stop the rotting process and prolong the durability of the wood, you should impregnate it before locking it. This can be done by repeatedly painting over with a wood preservative paint or, this method is more effective, first soaking the entire trunk in wood preservative until the wood has finished with it and then coating it with tar (e.g. bitumen). In addition, you should only concrete well-dried hardwood such as oak, as soft wood rots within a very short time despite all efforts - this applies above all to woods such as birch or spruce.
Concreting the tree trunk: This is how it's done
You can then start concreting. The best way to do this is as follows:
- Avoid pouring concrete in sandy or muddy soil.
- This one isn't tight enough.
- Determine the position of the required holes.
- Dig a rectangular hole.
- This should be three times the size of the tree trunk.
- At depth, this rule applies: a third of the trunk disappears into the ground.
- Dig the hole another third (i.e. one sixth of the length of the log) deeper.
- Fill this bottom third with drainage material: pebbles and gravel.
- Tamp down the drainage layer firmly.
- Now hold the tree trunk in the middle of the hole.
- You may need several people to do this.
- Fill in the freshly mixed cement.
- The top surface should not be completely straight, but sloped outwards.
- This allows rainwater to drain off better.
- Tamp the cement firmly and smooth it out.
Cast in concrete on a sunny and dry day, because then the concrete dries faster and better.
tips
Instead of cementing the tree trunk into the ground, you can also anchor it over the foundation. It comes into less contact with moisture and lasts longer.