No general rule in the Ontario Building Code or CSA A23.1 requires epoxy-coated rebar on its own. It becomes required when the project specification or the engineer calls for it, which happens mainly where chlorides from de-icing salt or seawater will reach the concrete: parking structures, ramps, some bridge and highway work, and marine structures. Even in those places, epoxy is now one option among several, and Ontario's highway work has largely moved to stainless steel and GFRP for the most severe exposures.
What epoxy-coated rebar is
Epoxy-coated rebar is ordinary carbon-steel reinforcing bar with a fusion-bonded epoxy coating applied in a coating plant. The bar is cleaned, heated, and coated with epoxy powder that melts and cures into a continuous film. The coating isolates the steel from chlorides and moisture that would otherwise cause it to corrode.
Two ASTM specifications cover the product, and the difference matters for ordering:
| Standard | What it covers | Typical colour |
|---|---|---|
| ASTM A775/A775M | Bars coated straight, then cut and bent after coating | Usually green |
| ASTM A934/A934M | Bars bent to shape first, then coated ("prefabricated") | Usually purple or grey |
| ASTM D3963/D3963M | Fabrication and job site handling of epoxy-coated bars | Not applicable |
The underlying bar on Canadian jobs is still CSA G30.18 steel, usually Grade 400W. The coating thickness is set by the ASTM specifications, in the range of a few hundred micrometres, with larger bars allowed a thicker film.
When it is actually required
Requirements for epoxy-coated bar come from the job, not from a single code clause. These are the places it shows up:
Project specifications. CSA A23.1 treats coated and other special reinforcement (epoxy-coated, galvanized, stainless) as something used only when it is specified or approved by the owner. If the drawings or specification call for it, it is required on that job. If they do not, substituting it is a change the engineer has to approve, because it changes the design (more on that below).
Chloride exposure classes. CSA A23.1 exposure classes C-XL and C-1 apply to reinforced concrete exposed to chlorides, such as parking decks and ramps and bridge decks. Those classes drive higher concrete quality and 60 mm of cover, as covered in our concrete cover guide. The engineer may add a corrosion-resistant bar on top of that, but the exposure class alone does not mandate epoxy.
Parking structures. CSA S413, "Parking structures", sets durability requirements for the design and construction of parking garages, and the Ontario Building Code requires storage garages to be designed to its performance requirements. Early editions of S413 relied heavily on waterproofing membranes with epoxy-coated bar. Later editions moved to a menu of protection systems, combining cover, concrete quality, membranes, corrosion inhibitors and protected reinforcement. So a parking garage may or may not use epoxy, depending on the protection strategy the designer chose.
Ontario highway and bridge work. The Ministry of Transportation started using corrosion-resistant reinforcement in bridge decks in the late 1970s, with epoxy coating as the first step. MTO later concluded that epoxy-coated bar would not deliver the long service life it wanted in most highway environments. In the early 2000s it began specifying stainless steel in severe exposure areas, and in 2005 it started specifying GFRP. MTO's current material specification for steel reinforcement (OPSS 1440) covers uncoated and stainless bars, not epoxy-coated bars, and the City of Toronto's older road specifications excluded epoxy-coated bar unless specifically called for. If you are bidding municipal or provincial infrastructure, the contract documents tell you exactly which reinforcement types are acceptable.
How epoxy coating changes the design
Swapping plain bar for epoxy-coated bar is not a like-for-like change. The coating reduces bond between the bar and the concrete, and CSA A23.3 accounts for that:
- Longer development and lap lengths. The coating factor (k2) is 1.5 for epoxy-coated bars with clear cover less than 3 bar diameters or clear spacing less than 6 bar diameters, and 1.2 for other epoxy-coated bars. Laps can be up to 50% longer than for uncoated bar. Our lap splice chart shows the uncoated baseline.
- Cover is not reduced. The coating does not let you cut back cover. The exposure class still sets it.
- More steel on the bar list. Longer laps and hooks mean more weight, and coated bar is ordered and fabricated as its own item.
This is why the engineer of record needs to sign off on any switch, in either direction.
Handling and placing on site
Epoxy coating only works if it arrives intact. Most performance problems trace back to damage during shipping, handling and placing. Good practice from ASTM D3963 and industry guidance:
- Lift properly. Use nylon or padded slings and a spreader bar. Never drag bundles or use bare chains.
- Store off the ground on timber cribbing. For long outdoor storage, cover the bundles with an opaque material, because sunlight degrades the coating over time.
- Use compatible accessories. Bar supports should be coated or non-conductive (plastic or epoxy-coated chairs), and tie wire should be coated too.
- Cut with shears or a saw, never a torch, then patch every cut end and every damaged spot with the two-part epoxy repair material the coating specification calls for.
- Avoid field bending. Bending coated bar on site risks cracking the film. Get bends done in the shop where the process is controlled.
- Inspect before the pour. The ASTM specifications set limits on how much damaged and repaired coating a bar can have. Damaged bar beyond those limits gets rejected.
Alternatives to epoxy-coated rebar
Where corrosion protection is needed, engineers have other options, each with its own standard:
| Option | Standard | Where it fits |
|---|---|---|
| Stainless steel bar | ASTM A955/A955M | Severe chloride exposure, long design life; used by MTO in bridge decks |
| Galvanized bar | ASTM A767/A767M | Moderate exposure, architectural and precast work |
| Low-carbon chromium steel | ASTM A1035/A1035M | High-strength, corrosion-resistant bar |
| GFRP bar | CSA S807 | Bridge decks, parking, marine and anywhere a non-corroding, non-conductive bar helps |
| Plain bar with better concrete and more cover | CSA A23.1 | Many buildings; often combined with membranes or sealers |
GFRP (glass fibre reinforced polymer) bar does not rust at all, which is why MTO now uses it in bridge decks. It behaves very differently from steel, though. Our GFRP vs steel rebar comparison covers the trade-offs, and our guide to fiberglass rebar and CSA S807 and S806 explains how it is specified.
Deciding what your job needs
A practical way to sort it out:
- Check the drawings and specification. If they name a reinforcement type, that is what the job needs.
- Check the exposure class. C-1 or C-XL on the drawings is a sign the designer considered corrosion. Ask what protection strategy they chose.
- Check the owner's requirements. Municipal, MTO and parking garage owners often have their own rules on acceptable reinforcement.
- Get any substitution approved in writing, including the effect on lap lengths and bar quantities.
We supply straight and fabricated steel rebar and GFRP bar, cut, bent and tagged to your bar list. We don't supply epoxy-coated, galvanized or stainless bar; if your designer allows GFRP instead, we can price it for your job. Send us your drawings, or see our rebar products.
Frequently asked questions
Does the building code require epoxy-coated rebar?
No general Canadian or Ontario code rule requires epoxy-coated rebar on its own. It is used when the project specification or engineer calls for it, usually as one of several ways to protect steel from chlorides in parking structures, bridges and similar exposures.
What is the ASTM standard for epoxy-coated rebar?
ASTM A775/A775M covers bars coated straight and bent afterwards, and ASTM A934/A934M covers bars that are bent first and then coated. ASTM D3963/D3963M covers fabrication and job site handling.
What is epoxy-coated rebar used for?
It is used to slow corrosion where chlorides from de-icing salt or seawater can reach the steel, such as parking decks, ramps, bridge elements and marine work. The coating acts as a barrier between the steel and the chlorides.
Can you cut or bend epoxy-coated rebar on site?
It can be cut with shears or a saw, never a torch, and every cut end and damaged spot must be patched with an approved epoxy repair material. Field bending is best avoided because it can crack the coating.
