Harmony Timber Solutions - Timber Engineering Experts. Part of the Wyckham Blackwell Group of Companies we are one of the UK’s largest independent timber engineering companies and are a leading manufacturer for off-site construction and engineered Timber Frame Kits, Timber Frame, Roof Trusses & Open Metal Web Joists. We supply timber Roof Trusses for any project, including extensions, new builds, residential developments, and commercial projects. The timber roof trusses are individually designed components made from strength graded timber joined together with steel nail plates and use 40% less timber than traditional cut and pitched roofs. Combining the lightness of timber with the strength of steel webs, our Posi Joist floor designs give the most versatile open web system available to the modern building designer.