Here are boutique hotels and small eco-resorts in Sri Lanka known for using natural, local or low‑impact materials in their buildings and design. I’ve listed each with a short note on the materials or building approach and a source you can check.

• The Mudhouse (Anamaduwa / northwest Sri Lanka) — Cluster of uniquely crafted huts built using traditional wattle‑and‑daub, thatch, timber and other locally sourced natural materials; minimal mains electricity in guest areas, strong “back‑to‑nature” focus. (srilankatailormade.com)

• Jetwing Vil Uyana (Sigiriya) — Boutique eco‑hotel built around reconstructed wetlands and paddy‑dwelling style villas; designed as a low‑impact development using vernacular forms and landscaping that integrates natural materials and habitats. (en.wikipedia.org)

• Diyabubula — Small artist‑designed jungle hideaway near Dambulla with villas and water‑garden landscaping integrated into the site; architecture and finishes emphasize natural elements and hand‑crafted details. (en.wikipedia.org)

• Moksha (Kitulgala) — Contemporary boutique project by architect Amila Ruwan Liyanapathirana that uses locally sourced brick, reclaimed timber and other natural materials to create permeable façades and a nature‑integrated experience. (designboom.com)

• Wild Coast Tented Lodge (Yala coast / close to Yala National Park) — Luxury tented boutique property whose tent pavilions, bamboo cladding and open‑air pavilions are designed to sit lightly on the landscape using natural materials (canvas, bamboo, timber). Good for wildlife + low‑profile beachfront architecture. (vanityfair.com)

• The Kandy House (Kandy) — Heritage manor converted into a boutique guesthouse; restored with traditional materials and craftsmanship (timber, local stone and period details) that preserve the building’s historical fabric. (thetimes.co.uk)

• Fort Bazaar (Galle Fort) — Boutique hotel inside a restored merchant’s house in the UNESCO Galle Fort; restoration retains original masonry, timber and courtyard features — an example of adaptive reuse of historic natural materials. (thetimes.co.uk)

• Haritha Villas (Hikkaduwa area) — Small villa collection / boutique property that highlights locally sourced and recycled materials in construction with a strong garden/yoga pavilion focus. (en.wikipedia.org)

Notes and quick tips

• Many of these properties emphasize sustainability and low impact but vary in luxury level (from rustic eco‑huts to high‑end tented lodges). Check room types and amenities if you need AC, private bathrooms, or full electricity. (experiencetravelgroup.com)
• For authentic “natural materials” experiences, The Mudhouse and Moksha focus most explicitly on using traditional/locally sourced building methods; Jetwing Vil Uyana is notable for integrating buildings into an engineered wetland/ecosystem. (srilankatailormade.com)

If you’d like, I can:

• Narrow this to a specific region (e.g., south coast, Cultural Triangle, Kandy),
• Check current rates and availability for any of these properties (I’ll look up live booking info), or
• Send direct links and contact details for up to 5 of them.