What is heavy wooden structure

Post anchors - installation and types

Post anchors are also called post bases or column bases, but not every post anchor is the same. Today we show all types of post anchors, what they are used for and of course how you can use them to fasten posts. There is a special and suitable post anchor for pretty much every project. If you have any questions, just leave a comment.

Why do I need post anchors?

If you want to fix wooden posts vertically in or on the ground, then it is a good idea to use a post anchor. It gives the construction the necessary support so that wooden structures can withstand heavy loads, such as wind. They can be used in all conceivable constructions, be it if you want to build a pergola or if you want to build the carport yourself, then you also need post anchors.

Another reason to install post anchors is to protect the wooden post from moisture from the ground. If you place the wood directly in or on the ground, it absorbs moisture and the wood begins to swell, mold or rot. No wood preservative would protect here in the long term. This would create the risk of collapse. Even if it didn't come to the worst, the wooden structure wouldn't last as long as it would with an anchor.

On the sketch you can see the application of some types of post bases.

Post anchor types

Now let's look at the different types.

Pick-up of the post

First, we distinguished the way in which the post is attached to the anchor. One way of connecting is to grip the post. Here the post is placed in a mold, with the other fastening one literally spears the post or slits it and pushes the anchor into it. The last variant is a plate on which the post is screwed. This principle is rarely used outdoors because the connection is not very stable. Problems can arise here, especially in stronger winds.

Admission options are:

  • comprehensive from the outside
  • drilled and impaled
  • slotted
  • screwed

The most stable constructions are realized with extensive connections. Then come the drilled assemblies.

Visible connection

The most common types are the shape U and the shape H. This is due to the fact that this type of assembly is very easy to implement.


U-post bases and H-post bases have the advantage that they are very cheap, enable a very stable connection and they can be installed extremely quickly. The connection to the post is also no problem at all with the right screws. The application is also suitable for extremely heavy posts. There is also a half-liner in Form-L. Here the fixation is only visible on one side. Post screws can also be used for light and smaller posts.


The disadvantage of these post anchors is that the attachment is visible. This fixation is often not desired, especially with noble buildings.

Overview of visible and invisible post anchors

Here we can see an overview of the different types of post anchors:


V shape post anchor

U shape post anchor

H shape post anchor

L shape post anchor

P shape post anchor

I shape post anchor

P shape post anchor

T shape post anchor

Invisible attachment

Type I, for example, is used for the invisible connection of post and post anchor. The post is drilled centrally from below and then the point comes directly into the post. If the tip has a thread, it is screwed in, otherwise it is glued. This means that a maximum of a few centimeters below the post are visible. Form P can also be used. This has a metric thread. Another type is the slotted assembly as in the form T. Here, the wooden post must be slit with the help of a circular saw and then for cleaning with a chisel, after which it can be inserted into the carrier. Dowels are best suited for fastening.


The advantage is the invisible possibility to fix a beam.


Invisible post anchors are not as stable as the visible ones. Problems can arise with wind suction loads in particular. Even very heavy beams are not suitable for assembly. In addition, it requires much more experience to produce a fixation and the workload is greater. This assembly is not particularly suitable for beginners.

tip: The thicker you choose the post, the less the anchor is visible.

Attachment to the ground

There are also differences when it comes to fastening to the floor. There are the following options:

  • set in concrete
  • dowel
  • screw

With a post anchor set in concrete, there is a further step, namely digging a hole and creating a foundation. The anchor is set in this concrete foundation before the concrete hardens. The other versions work with dowels and screws.

Flexibility through adjustability

Some post anchors can be adjusted laterally and in height. This can be very useful if the beam size does not match the construction or if measurement errors need to be corrected. So you can still change the position, especially through height adjustability. There is also a solution for uneven floors. Here you can fall back on height-adjustable post shoes.