ᐅ Gravel or crushed stone between wood substructure – allow water to drain?

Hello Forum!

I’ve been reading along here for a while and have already gotten some great ideas thanks to you! Now I want to become more active and ask my first question:

Would you recommend the following:

We have a wooden deck in the garden made of timber planks with a 1 cm (0.4 inch) gap between each plank, as is common. It’s well installed and everything fits perfectly. Recently, we have repeatedly had wasps in our garden trying to build nests (in the playhouse, on the roof beam, now in the birdhouse). Each time, we noticed early enough. Now the thought occurred to me (and internet research confirms this has happened to others) that the wasps might try to build a nest under the wooden deck. There is enough space and access. So I am considering removing the timber planks and filling up to the top edge of the planks with gravel or crushed stone (no sand) to prevent wasps from nesting there. The only downside I can think of is that during heavy rain, water might not drain as well (no drainage).

Would you recommend this, or does anyone here have experience with something similar?

Many thanks for your answers!

grubenbuddler ;-)

I wouldn’t recommend that. The purpose of the substructure is to keep the beams from sitting in water. If you fill up to the top with gravel, ventilation from below is missing, and the beams will rot quite quickly. You can also use strong chemicals against wasps. You can spray those diagonally under the beams as well.

Wastl schrieb:
I wouldn’t recommend that. The purpose of the substructure is to keep the beams out of contact with water. If you fill up to the top with gravel, the ventilation from below is missing and the beams will rot quite quickly.
Can you also use chemicals against wasps? You can spray them diagonally under the beams as well, right?

Thank you very much. That’s a good point!

Do others here in the forum agree, or are there supporters of this approach?

Thanks for your answers!

P.S.: As for the chemicals, especially spraying them diagonally from above through the narrow gaps—I’d rather avoid that.