On a triangular hillside plot at the edge of Santo Tirso in Portugal, Nuno Brandão Costa sinks a single-storey house into the slope — the land continues over the roof, and the house is discovered only as one descends.
The site is a transition area between the town fabric and the valley to the south, its geometry elongated and narrowest at the top. Brandão Costa reads this as a natural constraint: construction is concentrated at the broader, lower end, where the ground allows an L-shaped plan to be laid out on a single floor. Each wing is oriented to maximise solar light and the southern aspect — the bedroom wing and the lounge each turned to face the valley, the whole perimeter organised to let the interior breathe and reach outward.
The move that defines the project is topographic. The slope above the house is freed entirely, its upper elevation unbuilt, continuing across the roof as a continuous garden that bridges the natural ground level without interruption. From outside — from above — the house is nearly invisible. The land reads as whole.
Two elements punctuate the upper elevation and mark the construction beneath. To the north, a volume in silvered glass houses the garage and the entrance hall — a body whose mirrored surface reflects the garden and sky, occupying the plot's geometric centre with quiet precision. To the south, a low, square, white opaque box rests on the angle of the ground-floor façade, forming a covered porch that extends the living space outward. The two volumes are opposed in material and geometry — one transparent and reflective, one opaque and still — each resting on a different part of the garden.
The result is a house that achieves its openness through compression rather than expansion. The generosity of the interior spaces is discovered by going in and going down — what the exterior withholds, the plan delivers. Stone walls and existing pathways from the surrounding plots contribute to the landscape's texture, and the house absorbs these conditions rather than asserting against them.
