ᐅ Can you pile up material without compacting it?

Those who have been following my house construction thread know that our plot is situated a bit lower than the surroundings.

Our general contractor is now raising the foundation slab by 1.5 meters (5 feet) — but only for the house itself. The 2.80 meters (9 feet) in front, as well as the sides by the parking spaces and the garden, will remain at -1.50 meters (-5 feet).

I have the option to get excavation material Z0, including free delivery, and I’m wondering if it makes sense to start dumping some of it in the front yard during the early phase (construction start October 1) so that at least the path to the house is somewhat passable.

Can I simply fill it in without compacting, or do I need to compact it in layers with a rammer? Eventually, paving will be installed on top, and it will only be used as a parking space.

My personal opinion: First, finish your house and then take care of the outdoor areas. You will still be able to add fill later; it won’t be the last free opportunity to get excavation material for filling from somewhere. Just make sure you don’t unintentionally bring in more than necessary.

The material will be in the way, so first let the shell structure be built, and then backfilling and compaction will have to be done anyway. But as you correctly say, in layers!!

Don’t start too many construction projects at once. You might still need to install rainwater pipes, set up a cistern, etc. You’ll get back what you invest now. Therefore, I agree with Zaba12 to focus on the house first.

In the future, other builders will also be glad if you take on the earth-sheltered house construction and they don’t have to get rid of it.

I could have the “ditch” between the house and the street filled in directly from the road – I wouldn’t do more than that for now. I already have an offer from the general contractor here – he would do that filling at the same time as preparing the base for the foundation if we were to hire him.

But why does zone 0 need compaction? Aren’t the natural settlement and the rain enough?

Z0 refers to the pollutant class, not the grain size.

With a 1.5 m (5 feet) layer without compaction, you will end up with a bumpy surface, and over the years, noticeable settlements and waves of more than 10 cm (4 inches) are likely. This is especially true in heavily trafficked or parked areas, where settlement will occur.

Even for a driveway, the fill height will remain for at least one year after compaction before any surface covering is applied. Settlements can still occur during this time.

For screened soil, compaction losses of 10–15% are to be expected. Compaction is done layer by layer. You need to pay attention to the compaction depth of your compactor. There are walk-behind models that manage only the top 5 cm (2 inches), while others can compact up to 30 cm (12 inches).