There are no clear sources how megalithic passage graves were covered. A hill completely covering the tomb, earth or stone covering up until the capstones letting them peak out or no hill at all. The outer boundary speaks for at least some kind of covering, as do some archaeological finds of megalithic structures with hill covers still visible.
While there are no sources of a hill covering the Düwelsteene, it is likely, that the tomb was covered, similarly to the Große Sloopsteene and the megalithic tomb of Rheine, which was found still covered by a hill. With these comparisons in mind the reconstruction of the Düwelsteene was modelled with a hill covering the tomb. While in the first reconstruction the hill covered the complete megalithic tomb, in the newer reconstrcutions of the Düwelsteene the hill reaches up until the capstones, which are still visible above the hill. This was based on finds from Northern Germany, were megalithic tombs were found well preserved sunken in a bog. These tombs showed a hill made from smaller stones up to the capstones. Having the capstones peak out from the hill would make these tombs stand out in the landscape, showing the importance of these monuments. But in the end reconstructions like these are just interpretations of how the past could have looked like.
With the decision of adding a hill, the steepness and the dimensions of the hill had to be defined. In the idealised plan of the Düwelsteene from 1932 there are stones drawn, that could indicate the outer ring of megaliths. When modelling this boundary, it became apparent, that the radius these drawn stones displayed, was almost a circle and too far away from the long sides of the megalithic tomb. Most of the compared megalithic structures had at most two pairs of yokes creating the entrance of the tomb. With the radius of the outer boundary, that the drawn plan showed, the entrance to the Düwelsteene would have been exceedingly long. Most of the megalithic structures of the West Group in the Funnel Beaker culture had an oval boundary, that was somewhat flat on the longer parts of the tomb structure. The reconstruction model of the hill was reduced, to resemble the compared megalithic tombs.
The hill of the reconstructed model was built with the angle of repose for sand in mind. The soil composition of the area, where the Düwelsteene are found is considerably sandy, so the angle of repose for the hill was defined as 30° degrees. With these definitions a hill was modelled on top of the megalithic tomb, with the outer megaliths and gusset masonry enacting as the border of the hill.