If a new roof tile keeps breaking, inspect its support before placing another. If the wood stays in place but looks rotten after rain, check durability and weather cover separately. This is the accepted pre-1.0 diagnosis; it does not establish current-build support values. If part of the room has already fallen, start with the partial-collapse recovery sequence to preserve your footing, working bench and spawn before rebuilding.
With the Hammer equipped, aim at a building piece and read its support color. Blue is the strongest end of the display; colors toward red mean less remaining support for that material. Ground, trees and boulders provide full support, while well-supported stronger materials can also give ordinary Wood its full support. The color describes support, not hit points or weather condition.
A new piece extending from weak support can break once the support calculation settles. Each piece depends on its material and connections to supported neighbors. The game does not divide a beam’s capacity among everything attached to it: adding furniture or another roof tile does not use up a shared weight budget. Improve the actual support connection instead of emptying chests to lighten the floor.
Wait after adding or removing a support and inspect again before extending. Freshly placed pieces can look stronger while support values are still settling. Add a shorter, more vertical connection to a grounded post when the roof remains weak; a temporary color improvement is not proof the new bay will hold.
Hammer repair restores durability but does not improve an inadequate support path. Rain can make exposed wood look damaged, but weather wear and a collapsed roof are different problems. Cover the wood and repair its durability after the support is sound.
Hammer3 Wood + 2 StoneInventory
Mechanics sources: Valheim Wiki: BuildingValheim Wiki: Wood structuresValheim Wiki: WeatherValheim Wiki: Building stability