Standard Rebar Lengths in Canada: How Long Is a Bar?

In Canada, a standard length of rebar from the mill is 12 m (about 39 ft) for 10M bar and 18 m (about 59 ft) for 15M and larger. Those are the stock lengths fabricators cut from; the bars that arrive on your site are cut to whatever your bar list calls for, up to that length. Anything longer than 18 m needs a special arrangement, and in practice long runs are almost always spliced instead.

Standard mill lengths for Canadian rebar

The Reinforcing Steel Institute of Canada (RSIC) Manual of Standard Practice lists the standard mill lengths for carbon-steel bar:

Weights use the CSA G30.18 nominal mass per metre. Our rebar weight chart gives the weight of bars at other lengths.

So when someone asks how long "15M rebar" is, the answer is 18 m from the mill. The M in 15M is the bar size, not a length; our rebar size chart explains the naming.

Not all bar starts as a straight length: some rebar is also rolled in coils. For the person ordering, it makes no difference, because you order by bar list, not by the form the steel arrived in.

Stainless steel and FRP bar are different. The RSIC manual notes that standard lengths for stainless and fibre-reinforced polymer (GFRP) bar depend on the mill. If your job uses either, ask about available lengths before the bar list is finalised. Our guide to buying GFRP rebar covers this for fiberglass bar.

Stock lengths vs cut lengths

Most contractors never handle a full mill-length bar. A fabricator takes the stock lengths and cuts each bar to the length on the bar list, bends it if needed, then tags and bundles it by mark. That is what "cut and bend" means.

A few practical points about cut lengths:

• Lengths are given to the nearest 20 mm. RSIC standard practice rounds bar lengths to the nearest 20 mm because of practical fabricating considerations. Where an exact length is critical, the drawings or bar list should say so next to that item.
• Bent bars are cut to their developed length. An L-bar or a stirrup is cut to the full length of steel needed, including hooks and bends, before it is bent. Our post on rebar bending charts shows how bend dimensions add up.
• Offcuts are part of the job. Cutting short bars from 12 m or 18 m stock leaves offcuts. Good detailing and cutting plans reduce waste, which is one reason bars cut from a proper bar list tend to work out better than buying full lengths and cutting on site.

If you are buying straight bar to cut yourself, think about how your lengths divide into the stock length. A run of 4.5 m pieces fits four to an 18 m bar with no waste; 5 m pieces leave a 3 m offcut from every bar.

What length you get at a store or yard

Home centres and building supply yards sell rebar in short pre-cut pieces that are easy to carry and fit in a pickup. The lengths vary by store. Check the label for the size, length and grade, and make sure it matches what your drawings call for, in metric bar sizes. A US #4 bar, for example, is not the same as a 10M or a 15M; see our post on Canadian vs US rebar sizes.

Short retail bars suit small jobs: a few pins, a small pad, a repair. For footings, walls and slabs, the number of laps you need with short bars adds up quickly, and each lap is extra steel and extra tying. Our post on where to buy rebar in Ontario compares stores, yards and fabricators.

Maximum rebar length: can you get bars longer than 18 m?

Bars longer than 18 m are possible only by special arrangement with the fabricator. The RSIC manual points out that supply, transportation (both length and width) and handling limitations often make it more practical to use lap splices, welded splices or mechanical couplers instead.

The limits are practical:

• Supply. Mills roll to standard lengths. Anything longer is a special order, if it is available at all.
• Trucking. Long loads need longer trailers and can run into the length limits and permits that apply on Ontario roads. Our post on steel beam lengths and delivery limits covers how length affects delivery in Ontario.
• Site handling. An 18 m bar is already awkward to unload, carry and place. Smaller bars sag and whip, larger ones are heavy, and every metre of extra length makes that worse.

Bent bars have their own limits. A bent shape has to fit on a truck in three dimensions, so large hooked or cranked bars are constrained by shipping width and height as well as length. Bars bent to a large radius are often shipped straight and bent into place in the field. RSIC publishes guidance on the practical sizes of radius-bent bars that can be shipped; your fabricator will flag any shape that cannot travel.

When the run is longer than a bar

Walls, footings and slabs are often much longer than 18 m, so bars have to be joined. There are three ways to do it:

1. Lap splices. Two bars overlap by a set length and the concrete transfers the force from one to the other. This is the default for most work. The length depends on bar size, concrete strength, bar position and coating. Our lap splice length chart gives values for metric bars.
2. Mechanical couplers. A threaded or swaged sleeve joins two bars end to end. Couplers save steel and reduce congestion, which matters with large bars. See rebar couplers vs lap splices.
3. Welded splices. Possible with weldable bar under the right procedures, but less common. Our post on weldable rebar in Canada explains when it is used.

Where splices go is a design decision. The engineer may restrict laps to certain zones or require staggering, and the detailer lays out bar lengths so splices land where they are allowed. That is one more reason long reinforcement should come from a detailed bar list rather than a "buy full lengths and lap them wherever" approach.

Planning bar lengths on your job

A few habits that save time and steel:

• Give your detailer the real dimensions. Bar lengths come from the drawings. If dimensions change on site, tell the fabricator before bars are cut.
• Think about placing, not just supply. A bar that is technically available at 18 m may be impossible to place in a tight trench or between existing walls. Shorter bars with laps can be easier to install.
• Account for laps in your quantities. Every splice adds a lap length of steel. On long footings and slabs, laps are a real part of the tonnage.
• Keep bar marks with the bundles. Cut bars of similar lengths look alike on site. The tags tie each bundle back to the placing drawing.

Getting bars cut to length

Standard lengths matter mostly to the fabricator. What matters to you is getting every bar at the right length, bent to the right shape and tagged so your crew can place it without measuring and cutting on site.

Send us your drawings for a free take-off and quote. We detail, cut and bend 10M to 55M bar to your bar list and deliver across the GTA and Ontario; ask us about the lengths and delivery that suit your site. See our rebar products for straight bar, fabricated dowels and stirrups, and GFRP.