Wi-Fi Through Concrete Floors, Explained
Wi-Fi flies through drywall but dies in concrete, and the steel rebar inside makes it worse. Multi-floor homes need a per-floor plan — one router cannot serve three concrete slabs no matter its price.
TL;DR / Quick Fix
Quick fix: give each concrete-separated floor its own signal source — a mesh node or access point wired back to the router. Place the main router centrally on the middle floor, and test each floor separately instead of expecting one router to punch through slabs.
Follow these steps
- Accept what concrete does. Concrete absorbs Wi-Fi and the rebar inside reflects it. Expecting one router to cover floors above and below concrete is planning to fail.
- Put the router on the middle floor. If you must use one router, center it vertically as well as horizontally. The middle floor gets the best compromise while you plan per-floor coverage.
- Add a node or access point per floor. Each concrete-separated floor needs its own source. A mesh node or access point on each floor, wired back where possible, beats any single-router heroics.
- Wire the backhaul if you can. An ethernet cable between floors gives each node a perfect feed. Even one wired link to the worst floor transforms the whole system.
- Test floor by floor. Walk each floor with a speed test after changes. Concrete homes have sharp boundaries, so verify each slab separately instead of averaging the house.
- Consider powerline as a backhaul where cable is impossible. If you cannot run ethernet between floors, powerline as a backhaul can carry the node feed through the wiring. Test it, since old wiring can limit this trick.
What NOT to do
- Do not buy a more powerful single router for concrete floors. Power does not punch through rebar-filled slabs, so the money buys disappointment.
- Do not stack all nodes on one floor. Nodes clustered together leave the far floor dark, so spread them vertically through the house.
- Do not expect 5 GHz to reach through concrete. Use 2.4 GHz for inter-floor links where possible, since it penetrates better, and keep 5 GHz for same-room speed.
- Do not skip testing the stairs. Stairwells often leak signal between floors, and knowing where it leaks tells you the cheapest node spots.
Frequently asked questions
Why is Wi-Fi fine upstairs but dead downstairs?
The concrete slab between floors blocks the signal, and the rebar inside scatters what gets through.
Can any router beat concrete?
No. Physics wins, so the answer is more signal sources — one per floor — not one stronger router.
Is 2.4 GHz or 5 GHz better through floors?
2.4 GHz penetrates better. Use it for reaching across floors and save 5 GHz for speed within a room.