What can we help you with?
Technical flooring, delivered directly
- ESD flooring, urethane cement, terrazzo, and polished concrete
- In-house W-2 installation crews and experienced field leadership
- National service coverage with project-specific staffing plans
- Testing, documentation, and defined project closeout
- Dedicated support for corporate procurement and multi-site contracting
Phone: +1 (844) 687-1961
Joint Preparation & Depth
At Craftsman Concrete Floors, joint preparation is part of selecting and installing the right filler. We coordinate cleaning, filling depth, and backing with the joint type and the selected material rather than applying one detail to every opening in the floor.
The joint walls need to provide a suitable bonding surface, and the installed filler needs the depth and support required by its system. Preparation is part of our polished concrete repair and joint-filling process.
Prepare the joint for the selected filler
Confirm the joint type and selected filler first: a saw-cut contraction joint and a formed construction joint can require different preparation details, and the material should be intended for joint filling. Cleaning then targets the joint walls where the filler bonds, following the instructions for the selected material rather than only removing loose debris.
Identify the joint and the filling system
A saw-cut contraction joint and a formed construction joint can require different preparation details. Confirm the joint type and selected filler before establishing the cleaning depth, filling depth, or backing arrangement.
Also confirm that the material is intended for joint filling. Our joint filler versus crack repair guide explains why a rigid repair product is not automatically suitable.
Clean the joint walls, not just the loose debris
Removing loose material from the opening does not necessarily prepare the surfaces where the filler must bond.
For example, Metzger/McGuire’s Spal-Pro RS 88 instructions require removal of:
- Saw laitance.
- Dirt and debris.
- Coatings and sealers.
- Frost and visible moisture.
The manufacturer warns that incomplete removal compromises adhesion. Simply raking debris out of the joint is not an acceptable cleaning method for that product.
Its preferred methods include a dustless concrete saw with a suitable diamond blade or sandblasting. When using a saw, the instructions call for a blade slightly wider than the joint or cleaning both joint walls.
We coordinate preparation with the selected material’s instructions and the project’s silica exposure controls.
Establish the required preparation and filling depth
Craftsman frequently uses Metzger/McGuire MM-80 epoxy joint filler. The table below summarizes preparation and filling depths from the manufacturer’s May 2004 guide specification for interior contraction and construction joints exposed to material-handling vehicle wheels.
| Joint condition | Guide-specification requirement |
|---|---|
| Saw-cut joints | Clean to the full original saw-cut depth before installing filler. |
| Saw-cut joints deeper than 2 inches | Prepare and fill to a minimum depth of 2 inches. |
| Formed construction joints that are not saw-cut | Clean to a minimum depth of 2 inches. |
These are MM-80-specific reference details. Other products and joint conditions can require different depths or backing arrangements. For installation, we confirm the current manufacturer instructions and project requirements.
Confirm backing and the polishing sequence
Backer rod is not automatically appropriate beneath semirigid floor-joint filler, so we confirm the required fill depth and whether backing is permitted before placing the filler. Joint preparation and filling also need to fit the planned grinding and polishing work, and filler readiness for shaving is a separate check.
Confirm whether backing is permitted
Backer rod is not automatically appropriate beneath semirigid floor-joint filler.
Metzger/McGuire prohibits compressible backer rod with Spal-Pro RS 88 in standard saw-cut contraction and control joints. That prohibition applies to the stated product and joint types; it is not a blanket rule for every joint.
We confirm the required fill depth and whether backing is permitted before placing the material.
Coordinate preparation with the polishing sequence
Joint preparation and filling need to fit the planned grinding and polishing work. The filler’s readiness for shaving or further processing is a separate check from whether the joint has been properly prepared.
Our joint-filler shaving and repair-grinding guide covers those processing milestones.
Project Gallery
Frequently Asked Questions
Not necessarily. The joint walls also need to meet the selected filler’s bonding requirements. Spal-Pro RS 88, for example, requires removal of saw laitance, dirt, debris, coatings, sealers, frost, and visible moisture; simply raking out debris is not sufficient.
The required depth depends on the joint type, selected filler, and project requirements. Craftsman frequently uses MM-80, whose May 2004 guide specification includes a 2-inch minimum preparation and filling depth for saw cuts deeper than 2 inches. That reference should not be applied automatically to another product or joint condition; installation follows the current manufacturer instructions and project requirements.
Only where the selected system’s detail permits it. Spal-Pro RS 88 prohibits compressible backer rod in standard saw-cut contraction and control joints. Other joint conditions must be evaluated under their applicable instructions.
We identify the joint type and selected filler, then coordinate cleaning, filling depth, backing, and placement with that system’s requirements and the polishing sequence.
Polished Concrete Knowledge Center
Resource links
Performance & Safety
Design & Aesthetics
Installation Guidance
Economics & Sustainability
Maintenance & Aftercare
Comparative & Decision-Making
Blog
Craftsman Publishes 2026–2027 ESD Flooring Technical Guide
ESD Epoxy Flooring Case Study: 34,000 SF Dallas, TX
