Can a new antistatic layer be laid in a space where an old antistatic layer has already been laid?
We received an inquiry today from a Czech customer asking if it's possible to lay a new antistatic layer in an area where an old one has already been laid.
Our engineer replied as follows: Yes, but certain conditions must be met. Laying a new antistatic layer in a space with an existing old layer is feasible, but it must be ensured that the old layer will not affect the conductivity, grounding effect, and overall performance of the new layer. The following are detailed precautions and construction requirements:
1. Confirm the condition of the old antistatic layer
Before laying the new layer, the old antistatic layer must be checked for the following problems:
Bubbling, cracking, delamination
Conductivity failure (resistance not meeting standards)
Surface contamination (oil, wax, chemical residue)
Dampness or mold
If the old layer is severely damaged, **it must be removed**, otherwise it will affect the adhesion and conductivity of the new layer.
2. Test if the old antistatic layer still has conductivity.
Use a professional surface resistance tester or grounding tester to check the old layer's:
* Surface resistance
* Volume resistivity
* Grounding resistance
For example, our SL-030B antistatic surface resistance tester.
👉 If the old layer is **completely non-conductive**, it is generally recommended to **remove and redo it**.
👉 If the old layer still has some conductivity, it can be used as a **substrate**.
3. Ensure grounding continuity between the old and new layers.
Most importantly: the new layer must be effectively grounded.
Common methods include:
* Directly connecting the copper foil grounding wire of the new antistatic layer to the existing grounding point.
* Re-arranging the grounding system, but maintaining isolation from the old layer.
* Eliminating the old layer grounding and using only the new layer grounding, but the old layer must be well insulated.
⚠ If there is no good conductive path between the old and new layers, the following problems may occur:
* Static electricity in the new layer cannot be effectively released.
* Localized static electricity accumulation causes potential damage.
* ESD standards are not met (e.g., ANSI/ESD S20.20, IEC 61340).
4. Surface Treatment: Sanding is Required
The surface of the old antistatic layer is usually very smooth. To ensure the new layer adheres firmly, the following is necessary:
👉 Mechanical sanding (using a sander) to increase roughness.
👉 Thoroughly cleaning the surface.
👉 Using adhesive to enhance adhesion if necessary.
Avoid the following:
* Hollow spots
* Dampness
* Delamination
5. Thickness and Height Issues
If antistatic flooring or antistatic rubber mats are laid in multiple layers, the following needs to be considered:
* Door gap height
* Equipment casters, shelf cut-in angle
* Floor flatness
Too thick a gap will affect space utilization.
