The most significant piece is the lattice now found located on the western façade, over the portico. Its contour repeats the model of the southerly portico of Valdediós, rectangular finishing off in a semicircle. The decorative idea consists in a vertical vegetation stem from which parallel branches curved over themselves and with abundant volutes sprout on both sides. The stalks are interrupted by heart shaped broadenings, with a chiselled heart inside, both on the vertical trunk and the branches.
This temple, located on the left-hand side bank of the estuary of Villaviciosa, almost entirely preserves the nave of a pre-Romanesque building, identified and documented in the archaeological work carried out in years 2002 to 2004.
The archaeological excavations have made it possible to prove the nave of the present temple, from the foundations to the cornice, belongs to the first boost for construction of the building and was altered in the 12th century with the inlay of the southerly door and the arch of triumph for access to the new sanctuary. This is looked after stonework masonry with limestone slabs, with powerful sandstone ashlar in the corners. Therefore, it is certain the three windows of the southerly façade and that of the northerly façade are in place, together with the two cornice modillions located on the NW and SW corners of the nave.
As that of Valdediós, this design is the copy of a paleo-Islamic prototype of Andalusian origin, interpreted freely and with lack of understanding by an Asturian sculptor.
The building had three small two-light windows on each side wall of the nave. It still has the three of the Southern façade and one on the Northern façade. They all reproduce the same type: a monolithic lintel resting over jambs of a piece, configured by inbuilt small columns, with flat and gorgerin truncated pyramid-shaped capital. The direct model of these pieces is also found in the small windows of the Northern and Southern façades of San Salvador de Valdediós.
Finally, a powerful single-roll modillion still remains in the North-western corner of the Western façade, in opposition to the fragment of its counterpart in the opposite corner of the same façade, identified in the same way in this last restoration. It belongs to the most common type of Asturian architecture.