Building

Building runs on real structural physics: pieces need support, wood decays in the rain, and metal cannot pass through portals.

Building in Valheim is not decoration, it is a system with real physics. Pieces have weight and need support, wood rots in the rain unless you roof it, and a fire without a smoke outlet will choke you. Done well, a base earns you the Rested buff, defends against raids, and serves as the hub for your whole logistics network. The one rule that shapes everything else is that you cannot carry metal through portals, which is why bases and boats both matter.

The hammer and structural integrity

You build with the Hammer in build mode, snapping pieces to a grid. Materials come from your inventory and a nearby Workbench within its build radius. The signature system is structural integrity: pieces have weight and need support to stay up. Stone and wood propagate support differently, and an unsupported piece sags, turns red in the support overlay, and collapses. Core Wood and iron beams extend support distance, so they let you reach further before a structure fails. Toggle the support overlay while you build tall and watch the colors. Red means it is about to come down.

Material tiers

Building materials climb in durability and support as you progress through biomes, and each tier needs its own unlock.

Tier	Material	Requirement
1	Wood	Workbench
2	Core Wood	From pines in the Black Forest
3	Stone	Stonecutter, needs Iron
4	Black Marble	Tar from the Plains
5	Grausten	Ashlands stone
5	Mistlands stone	From Mistlands materials

Higher tiers give more durability and more support, which is what lets you build the tall stone keeps that lower tiers cannot hold up.

Weather, decay, and comfort

Wood pieces exposed to rain take damage over time, so anything not protected by a roof slowly decays, while covered pieces do not. Plan your base so every wood piece sits under cover. Fires need a smoke outlet or the smoke builds up and chokes you, so leave a hole or a chimney above every hearth. Comfort is the payoff for furnishing well: furniture, banners, rugs, and a fire raise the Comfort level, which lengthens the Rested buff you want before every boss fight.

Raised earth walls from the Hoe are the cheapest and strongest defense against raids. A moat or a ring of raised ground stops most attackers cold for a fraction of the material cost of stake walls.

Base essentials and portals

A working base needs a bed to set your spawn and skip the night, a fire with a chimney, chests for storage, crafting stations under a roof, a defensive perimeter, and a portal hub. Portals are paired by a shared tag word and give instant travel between them, which is the backbone of your logistics. The catch defines the entire game: you cannot carry ores or metal bars through portals. You sail metal home by boat and portal everything else, so a Longship run to haul ore is a recurring chore no portal can skip. Keep a stocked portal hub at base linked to an outpost in each biome.