| Goodwill and Other Intangible Assets Goodwill The following are the changes in the carrying value of goodwill: | | | | | | | | | | | | | | | | | | | | | | | | | (Millions of US dollars) | Europe | | Siding & Trim | | Deck, Rail & Accessories | | Total | Balance - March 31, 2024 | $ | 192.6 | | | $ | — | | | $ | — | | | $ | 192.6 | | | Foreign exchange impact | 1.1 | | | — | | | — | | | 1.1 | | Balance - March 31, 2025 | $ | 193.7 | | | $ | — | | | $ | — | | | $ | 193.7 | | | Foreign exchange impact | 11.3 | | | — | | | — | | | 11.3 | | | Acquisition of The AZEK Company | — | | | 1,141.2 | | | 3,434.2 | | | 4,575.4 | | Balance - March 31, 2026 | $ | 205.0 | | | $ | 1,141.2 | | | $ | 3,434.2 | | | $ | 4,780.4 | | |
Intangible Assets The following are the net carrying amount of indefinite lived intangible assets other than goodwill: | | | | | | | | | | | | | | March 31 | | (Millions of US dollars) | 2026 | | 2025 | | Trade names | $ | 118.2 | | | $ | 111.6 | | | Other | 7.4 | | | 7.4 | | | Total | $ | 125.6 | | | $ | 119.0 | |
The following are the net carrying amount of amortizable intangible assets: | | | | | | | | | | | | | | | | | | | | | | | March 31, 2026 | | (Millions of US dollars) | Lives in Years | Gross Carrying Amount | | Accumulated Amortization | | Net Carrying
Amount | | Customer Relationships | 2 to 18 | $ | 2,880.3 | | | $ | (165.8) | | | $ | 2,714.5 | | | Trade Names | 5 to 15 | $ | 330.0 | | | $ | (19.6) | | | $ | 310.4 | | | Technology | 10 | $ | 210.0 | | | $ | (20.4) | | | $ | 189.6 | | | Total | | $ | 3,420.3 | | | $ | (205.8) | | | $ | 3,214.5 | |
| | | | | | | | | | | | | | | | | | | | | | | March 31, 2025 | | (Millions of US dollars) | Lives in Years | Gross Carrying Amount | | Accumulated Amortization | | Net Carrying
Amount | | Customer Relationships | 2 to 13 | $ | 47.5 | | | $ | (20.9) | | | $ | 26.6 | | | Total | | $ | 47.5 | | | $ | (20.9) | | | $ | 26.6 | |
The amortization of intangible assets was $183.6 million, $4.4 million and $4.3 million for the fiscal years ended March 31, 2026, 2025 and 2024, respectively. As of March 31, 2026, the remaining weighted average amortization period for acquired intangible assets was 16.7 years. At March 31, 2026, the estimated future amortization of intangible assets is as follows: | | | | | | Years ended March 31 (Millions of US dollars): | | Fiscal 2027 | $ | 315.4 | | Fiscal 2028 | 332.2 | | Fiscal 2029 | 345.5 | | Fiscal 2030 | 332.5 | | Fiscal 2031 | 295.2 | | | Thereafter | 1,593.7 | | | Total | $ | 3,214.5 | |
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