Concrete cover — the distance between the reinforcement and the concrete surface — is one of the most critical factors in structural durability. Insufficient cover leads to premature corrosion of reinforcement, which is the leading cause of concrete structure failure. Rebar spacers ensure that the designed cover is maintained during concreting.
Plast Commerce manufactures PVC linear and point spacers in all standard sizes. Our spacers are used on construction sites across Bulgaria for residential, commercial and infrastructure projects. This guide covers everything from size selection to installation techniques.
Types of PVC Rebar Spacers
Linear Spacers
Continuous PVC strips that support reinforcement over their full length. Provide consistent concrete cover across the entire element. Most economical for slabs, walls and other flat elements.
Point Spacers (Omega/Chair)
Individual supports placed at discrete points under the reinforcement mesh. Also called 'chairs' or 'Omega spacers'. Provide strong point support for heavy reinforcement.
Concrete Cover Requirements (Eurocode 2)
The required concrete cover depends on the exposure class of the structural element. Here is a simplified guide per EN 1992-1-1:
| Exposure Class | Min. Cover | Spacer Size | Application |
|---|---|---|---|
| XC1 (dry interior) | 15–20 mm | Linear 15–20 mm | Interior walls, ceilings |
| XC2 (wet, rarely dry) | 25–30 mm | Linear 25–30 mm | Foundations, basements |
| XC3/XC4 (cyclic wet/dry) | 30–40 mm | Linear 30–40 mm | External walls, balconies |
| XD/XS (de-icing/marine) | 40–50 mm | Linear 40–50 mm or Point 40–50 mm | Bridges, marine structures, car parks |
Advantages of PVC Over Other Spacer Types
No thermal bridging
PVC is a thermal insulator, unlike metal spacers which create cold bridges through the concrete cover.
No corrosion risk
PVC spacers cannot corrode or create rust stains on the concrete surface, unlike metal wire chairs.
Consistent cover
Factory-made to precise dimensions, ensuring the specified concrete cover is achieved consistently across the element.
Chemical resistance
PVC is unaffected by the alkaline environment of concrete, ensuring long-term stability of the spacer.
Lightweight and easy
PVC spacers snap onto reinforcement bars quickly. No tying wire needed in most cases.
Cost effective
Lower material cost than metal chairs, faster installation, and no risk of surface defects requiring repair.
Installation Tips
Place linear spacers perpendicular to the reinforcement bars for maximum stability
Space linear spacers at 500–800 mm centres (closer for heavier reinforcement)
Ensure spacers sit flat on the formwork surface — uneven placement compromises cover
For vertical elements (walls, columns), use snap-on spacers that clip securely to the bars
Check cover with a cover meter after concreting, especially for exposed concrete elements
Store spacers away from direct sunlight before use (prolonged UV exposure can make PVC brittle)