Everything.

If you are a builder, there is no sane way to bid on contracts with such hugely variable COGS.

And how the HELL do you even attempt to fix the US housing supply if you are tariffing Canadian lumber? You can't.

- US imports 20% of its lumber from Canada vs. 70% local lumber.

- Raw lumber costs are about 1% of the price of a house in California.

- Lumber prices were much much higher during the pandemic and are actually not that high right now: https://tradingeconomics.com/commodity/lumber (it's at 9 months low and cheaper than in 2018).

Guess this is what happens when you elect a group that prioritizes enriching themselves over ensuring you don't starve in the street like a filthy animal.

Likewise, how do you attempt to fix US manufacturing if you are tariffing Canadian aluminum?

As for the housing... stop using lumber maybe? Us Europeans build houses out of bricks and mortar or outright concrete.

Lumber framing only makes sense if you want something dirt cheap (and yet, US matchsticks and cardboard houses go for millions of dollars?!) or something that needs to be earthquake resilient and affordable.