Taxed Both Ways: What the New Canada US Tariffs Mean for Roofing Bids

If you buy or sell roofing material across the Canada US border, there are two dates that matter right now. One has already passed. The other is next week.

On August 22, a 50 percent additional US duty took effect on a long list of Canadian goods, and that list reaches further into a roof assembly than most people expected. On September 8, Canada's counter tariffs take effect on roughly 27.6 billion dollars of US imports, at 15, 25 and 50 percent.

Material crossing that border is now taxed in both directions, and the rules are not the ones the industry got used to over the last few years.

What Actually Took Effect on August 22

The US action came through three presidential proclamations signed on July 20 under Section 338 of the Tariff Act of 1930. That statute lets the President impose duties to offset another country's discrimination against US commerce, capped at 50 percent and requiring 30 days of notice. Trade counsel have described this as the first time the provision has been used to impose tariffs.

The duties were originally set for August 19. A proclamation issued on August 18 pushed them back three days, and they took effect at 12:01 a.m. Eastern on August 22, 2026.

If you saw the earlier date in trade coverage, that is why. The tariffs are live now.

The covered goods sit under new tariff headings 9903.03.12, 9903.03.13 and 9903.03.14, and US note 51 lists 554 subheadings in total. The proclamations are titled around alcoholic beverages, dairy and motor vehicles, which is exactly why so many importers have been caught out. Two of the three lists have almost nothing to do with the sector named at the top of them. Cement, plywood, furniture, textiles and a range of building products are all in there.

Screen by code, not by category. Sector intuition will mislead you here.

The Part That Is Catching People Out

For the last several rounds of tariff action, a USMCA claim was the escape hatch. If your goods qualified under the agreement, they came in free of the additional duty.

That is not how this one works.

US note 51 states explicitly that products eligible for special tariff treatment under general note 3(c)(i) remain subject to the additional ad valorem rate. In plain terms, qualifying under USMCA does not exempt a covered product. This is a deliberate reversal of the pattern set by earlier actions, and it is the single most important thing for anyone who has been relying on origin paperwork to keep landed cost down.

The duty also stacks. It applies on top of ordinary customs duties and on top of existing Section 232 measures, unless a specific exclusion applies. On the more useful side, the additional duties are generally eligible for drawback, so if you are importing material that later gets exported, that is worth a conversation with your broker.

Which Roofing Products Are on the List

Trade press reporting on the original proclamation identified the following categories as covered:

• Portland cement, excluding white cement
• Roof coatings and primers
• Flashing and seam tapes
• Membrane and underlayment materials
• Reinforcement fabrics
• Paper faced gypsum cover boards
• Selected plastic sheets, nonwoven materials and wood panels

Asphalt shingles and conventional asphalt roll roofing were not covered.

That last line is the one worth sitting with. The shingle is exempt and the underlayment under it may not be. The deck, the underlayment, the tape and the cover board on a single assembly can each carry a different duty depending on which direction they crossed and which eight digit code they were classified under.

Treat that list as a starting point rather than gospel. The proclamation lists and US note 51 govern, not a summary, and classification is done at the eight digit level. Confirm each specific product with your supplier or your customs broker before you price anything off it.

What Happens on September 8

Canada published its counter tariff list on August 25, effective 12:01 a.m. on September 8, 2026. Rates run at 15, 25 and 50 percent, set to match the corresponding US rate on the same goods, and cover about 27.6 billion dollars of US imports.

The building relevant categories include:

• Flat rolled steel and semi finished steel products at 50 percent
• Plywood and laminated veneer lumber at 50 percent
• Paper faced plasterboard at 50 percent
• Sawn softwood lumber, including pine, fir and spruce, at 25 percent

Two mechanics are worth knowing on the Canadian side.

First, the counter tariffs apply to goods originating in the United States as determined under the CUSMA marking regulations. US origin goods that do not meet those requirements can end up exposed to both the Most Favoured Nation rate and the countermeasure duty. Non qualifying paperwork is worse here, not better.

Second, goods already in transit on the effective date are exempt, provided you can document the shipment. If you have material on the water or on a truck right now, keep that paperwork.

Existing remission orders are expected to extend to the new measures. Where relief is available, request remission at the time of entry rather than paying and filing for a refund afterward. Refund claims can take several months to come back.

What to Do This Week

Five things, in order of how much they will save you.

1. Get HTS codes on every open bid. Not product names, not spec sheet descriptions. Customs acts on the eight digit code, and two products that look identical on a submittal can land in different places. Ask your supplier in writing.
2. Model the landed cost at 50 percent. Do not wait to be surprised by an invoice. Run the number on the products you actually buy in volume and find out which jobs are already underwater.
3. Check how long your quotes stay open. A 30 day material quote written in early August can turn into a losing job in September without anybody doing anything wrong. Tighten quote validity windows now.
4. Fix your bid documents. This is where the money is. Construction attorney Trent Cotney's advice on the original action was to be proactive, watch your contracts, and make sure you are addressing it on bid docs. A materials escalation clause and a tariff contingency written before the award is worth more than any argument you will make after it.
5. Talk to a customs broker, not just your supplier. Suppliers know their products. Brokers know note 51 and the drawback rules, and the difference between those two kinds of knowledge is currently worth 50 percent of your material cost.

The Wider Point

Roofing has spent two years being told that tariffs are a headline problem. They are not. They are a bid document problem, and they are now a classification problem, which is a much less comfortable thing to be exposed to because the answer sits in a code you have probably never looked at.

The contractors who come out of this fine will not be the ones who guessed the policy direction right. They will be the ones whose quotes had an end date on them and whose contracts had a clause.

ArcticAnchor manufactures snow retention systems for standing seam, exposed fastener and tile roofs. This article is general industry information and not legal, customs or tax advice. Confirm classification and duty exposure for your own products with a licensed customs broker or trade counsel.

Sources

• Department of Finance Canada: List of products from the United States subject to counter-tariffs effective September 8, 2026 (August 25, 2026)
• Troutman Pepper Locke: Three-Day Suspension of Section 338 Additional Duties on Canadian Imports (August 21, 2026)
• Aprio: Section 338 Canada Tariffs: Product Coverage and Key Considerations (August 25, 2026)
• Gateway Lines: Canada Section 338 Tariff: What the 554 Codes Actually Cover (August 25, 2026)
• GHY International: Canada to Impose New Counter-Tariffs on U.S. Goods Effective September 8, 2026 (August 27, 2026)
• Roofing Contractor: Trump Tariffs Reach Some Canadian Roofing Materials (July 24, 2026)