How to make concrete and install your mailbox
To install your mailbox in the ground properly it is recommended to install it using a concrete base. If you don't do this your mailbox can start leaning or even tip over in the worst case when there is a lot of wind.
The most easy method is to use premixed concrete:
Buy 2 bags of concrete mix. You can find these bags in pretty much every local DIY store. You only need to add water to the mix. 2 bags of 25 kg are enough to install 1 mailbox securely.
To install your mailbox according to the official post norms in Belgium, the mailbox lid /opening needs to be at a height between 80 cm and 1,3 m above ground level. Measure the distance between the bottom of the support and the lid / opening of the mailbox. Dig a hole that is at least 10cm wider than the support and adjust the height to make sure the mailboxes is installed within the local norms and appears pleasing to the eye on your property. Place the mailbox fixed to its support in the hole and pour the concrete mix into the hole. Make sure the concrete stays at least 5cm below ground level. Install the mailbox perfectly horizontal (in both directions) and vertical using a spirit level. Provide enough support during the drying duration to make sure everything stays level. You can use some wood and clamps to hold everything in place. Let the concrete dry out for at least 3 days. Remove the temporary supports and fill the area above the concrete with soil, gras, tiles, ... to finish things off. Your brand-new mailbox is now ready for use !