Split/Choose between wooden substructure - water infiltration?

Hello forum!

I have been reading along on and off for a while now and have already gotten some great suggestions thanks to you! Now I want to be active as well and ask my first question right away:

Would you advise me as follows:

We have a wooden terrace in the garden with wooden planks and about 1 cm gap between each (as usual). It is wonderfully installed, everything fits perfectly. Now, we have repeatedly had wasps in our garden trying to build a nest (in the playhouse, on the roof beam, now in the birdhouse). Each time, we noticed it in time. But now the thought came up (and research on the internet confirms that this has apparently happened to others) that the wasps might try to build a nest under the wooden terrace. There is enough space and access. Now I am considering taking up the wooden planks and filling the area up to the top edge of the wooden planks with gravel or grit (no sand), so that wasps cannot build there anymore. The only downside I can think of: then water may not drain as well during heavy rain (no drainage).

Would you advise me to do this or maybe someone of you has experience with this?

Many thanks for your answers!

The pit digger ;-)

I wouldn't recommend it to you. The purpose of the substructure is that the beams do not lie in the water. If you have gravel all the way to the top, the ventilation from below is missing and they will rot quite quickly. You can also bring out the chemical big guns against wasps? You can also spray them diagonally under the beams?

I wouldn’t advise you to do that. The point of the substructure is that the beams don’t lie in water. If you fill up to the top with gravel, ventilation from below is missing and they will rot quite quickly. You can also bring out the chemical big guns against wasps? You can spray it diagonally under the beams as well?

Thank you very much. A good point!

Do others here in the forum see it the same way or are there also supporters?

Thanks for your answers!

P.S.: With the chemicals, and then also sprayed diagonally from above through the thin gaps: I actually want to avoid that.