Valheim Base Defense Guide: Moats, Walls, and Raid Survival

Every boss kill in Valheim unlocks a raid event that will eventually visit your base — “the forest is moving” after Eikthyr, the swamp’s stench after The Elder, and worse after that. Base defense is how you absorb those visits without losing your storage.

How do raids work?

Killing a boss arms a raid event, and the event spawns a wave targeting your position. Each boss unlocks its biome’s raid — the events guide has the full trigger table. Raids announce themselves with a message and a timer, spawn in waves at a distance, and walk to your base. The wave composition tracks your boss progress — killing a boss swaps the raid table to the next tier (Bonemass retires the draugr raids and arms the blob-and-ooze ones), and the Deep North’s Jotun invasions are a category of their own.

What’s the first defense to build?

A moat or a raised earth wall — terrain is the best wall. Dig a trench with the hoe (or pile an earth wall) around your base and ground raid waves can’t cross it; they bottleneck at the single opening you leave, which is where you stack spikes and stake walls. Trolls and blobs laugh at timber walls; they can’t dig.

How do you harden the base itself?

Layer it: outer moat, inner walls, spawn suppression. Workbench radius (and the building guide coverage) suppresses enemy spawns inside it — dense crafting stations act as a soft no-spawn field. Portals stay indoors or behind walls; a raid that breaks your escape route is a wipe. For the bigger threats — Charred sieges, Gjall flyovers, the Jotun invasions — the fight isn’t winnable with walls alone; plan a kill zone at the moat’s mouth and a fallback inside the keep.

Which raids need special answers?

Flying raids and sieges. Wolves and drakes ignore moats — you want roofed-over interior space and indoor portals for those. Fuling and Charred waves can crack walls, so double-layer the outer ring. And anything from the Ashlands up expects you to actually fight, not just hide — the armor tier list and weapon tier list cover the gear.

What do you do while a raid is active?

Fight it on your terms — there’s no skipping them. Raids run on a hidden event timer that rolls while you’re in your base area, and logging out just makes them wait for you; they’re also one of the game’s better materials grinds. Know your biome tier’s threat table, keep the moat dug, and the raid becomes a delivery service rather than a disaster.