Edexcel GCSE Design and Technology · 1DT0
Specification 7.4.2 · Paper 1
Revise: Reinforcement and Stiffening TechniquesA tie bar carries tension: it resists being pulled longer. In a pitched-roof structure, the roof load can tend to push the supporting walls apart. A horizontal tie across the structure at the level where the roof meets the walls helps prevent this spreading.