ᐅ Pad footings directly behind unreinforced L-shaped retaining walls

Hello and thank you in advance for your help.

We have leveled our plot by adding fill to have everything on the same level. To support the slope formed along parts of the property boundary, unreinforced L-shaped retaining wall blocks were used. Mostly, blocks 80cm (31.5 inches) and 60cm (23.6 inches) high were installed.

Now, a fence is to be placed along the boundary. This fence will be mounted on individual footing foundations rather than attached to the L-blocks (since they are unreinforced).

In this context, it is often mentioned that foundations must be founded below the frost line to prevent frost damage. However, the L-blocks already have a frost-protected footing. If I dig a hole above a 60cm (23.6 inches) high L-block down to its base and build my footing foundation there, would that be considered frost-protected? Or are there smarter ways to set the fence foundations in this situation?

I would appreciate any feedback 🙂

Tweener schrieb:

Or are there smarter ways to install the fence here?

A simple double-wire mesh fence? You would install it like this: Drill a 30cm (12 inches) hole into the ground with an earth auger, pour in some concrete mix, add water, and then set the post in. That’s how the fence installers do it around here.

nordanney schrieb:

Simple double-wire mesh fence? You would install it like this: drill a 30cm (12 inch) hole into the ground using an earth auger, pour in concrete mix, add water, and then set the post. That’s how the fence installers do it here.

Thanks for the quick reply.
Exactly, a simple double-wire mesh fence in sections with privacy panels. Is 30cm (12 inches) really enough? That definitely wouldn’t be below the frost line.

Privacy screen panels act like sails, meaning they are subject to wind loads, so the posts need to be longer and embedded deeper (50cm (20 inches)).

And what about the topic of frost-protected foundations? That hasn’t been mentioned so far 😀
How does it work with fill soil behind L-shaped retaining walls?
If the fence foundation basically rests on the footing of the L-shaped wall, can I prevent frost heave this way?

We did the same with our carport. On the side facing the neighbor, we logically could only dig the foundation holes down to the base of the (reinforced) L-shaped concrete block (~60cm (24 inches)). Then we poured concrete, set the H-anchor, and built the carport. And where would frost heave come from? There is concrete beneath the fence post as well, in the form of the L-shaped concrete block's base. Below that is the frost-protected foundation / gravel layer of the L-block. So, I don’t see any issue. Our carport is still standing fine!