# Aluminium foil and foil-faced board

> A continuous metal layer is a near-perfect RF barrier in principle — 40 dB and better — but seams, staples and penetrations mean installed performance is governed entirely by workmanship.

- Canonical URL: https://emfbase.com/shielding/foil
- Collection: Shielding & remediation
- Record id: `shielding:shielding-foil`
- Status: verified
- Last verified: 2026-08-12
- JSON: https://emfbase.com/api/shielding/foil
- Also known as: aluminium foil shielding, foil insulation board

## Key values

- **Form:** foil
- **Targets:** radiofrequency
- **Grounding required:** Yes — ungrounded installation can make things worse
- **Datasheet attenuation:** 30–60 dB — broadband, workmanship dominated [sbm-2024]

## Failure modes

- Unbonded seams behave as slot apertures and can leak more than the surrounding material blocks
- Creates a vapour barrier where none was designed, risking condensation inside the build-up
- Ungrounded foil can increase AC electric field readings in the room

## Related records

- [Carbon or nickel shielding paint](https://emfbase.com/shielding/paint): A conductive coating applied to walls and ceilings, quoted at 30–40 dB in the cellular bands; it must be bonded to a grounded conductive strip to also control low-frequency electric fields.

## Sources

- `sbm-2024` Institut für Baubiologie + Nachhaltigkeit (IBN) (2024). *Building Biology Evaluation Guidelines for Sleeping Areas (SBM-2024)*. https://buildingbiology.com/site/downloads/SBM-2024_EVALUATION_GUIDELINES_EN.pdf — ngo, link checked 2026-08-12

Data licence: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Dataset version 2026.08.1. Retrieved from EMFBase, https://emfbase.com.

This record is reference data, not medical or legal advice. Regulatory limits, scientific guidelines and precautionary values are labelled separately and answer different questions.