On paper, dobies, chairs, and wheels all serve the same purpose: holding rebar at the correct elevation so concrete cover is maintained. On the jobsite, though, choosing the wrong support can slow placement, damage formwork, or create inspection issues later.

Experienced crews don’t pick supports randomly. They choose based on movement, placement speed, and spec requirements.

When dobies make sense

Dobies are concrete spacers designed to stay put once installed. They’re typically tied in place and don’t move during placement.

Crews tend to use dobies when:

• Stability matters more than speed
• Rebar should not shift once positioned
• Concrete-to-concrete contact is preferred or required
• Working in walls, columns, or architectural concrete

Dobies are simple and predictable. Once they’re set, they don’t roll, flex, or adjust — which is exactly the point.

When chairs are the better option

Chairs are designed to support rebar while placement continues. They allow crews to move, adjust, and tie steel efficiently across slabs and decks.

Chairs are commonly used when:

• Steel needs to be placed quickly over large areas
• Crews are actively walking and working the mat
• Speed and efficiency matter more than rigid positioning

In high-production slab work, chairs help keep things moving without constantly retying or repositioning steel.

Where wheels fit in

Wheels are used when rebar needs to be supported and moved into position, especially against vertical formwork.

They’re often chosen for:

• Walls and vertical elements
• Large cages that are slid into place
• Situations where dragging steel would scrape cover or damage forms

Wheels maintain spacing while allowing controlled movement — something dobies and chairs aren’t designed to do.

The takeaway

There’s no “best” rebar support — only the right one for the job.

• Dobies are about stability
• Chairs are about speed
• Wheels are about controlled movement

Knowing when to use each keeps placement efficient and helps avoid problems once concrete is down.

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