By BUILDER Magazine Staff. The NAHB opposes the Canadian lumber tariff because it boosts home prices. Each dollar increase in the price of 1,000 board feet of lumber adds about $20 to the price of an average new home. For smaller, less expensive homes built for low- and moderate-income families, lumber represents an even larger share of the construction. Even a small price increase knocks thousands of potential first-time home buyers out of the market.