That鈥檚 according to the Associated General Contractors of America (AGC), which has analysed new government data.

Prices rose on average 0.4% in March, with metals and lumber the major contributors to that increase, it found. That followed increases of 0.6% in February and 0.8% in January.

鈥淟umber and metals prices shot up in March, while contractors鈥� inboxes are bulging with 鈥楧ear Valued Customer鈥� letters announcing further increases for many products,鈥� said Ken Simonson, the association鈥檚 chief economist. 鈥淩apid-fire changes in tariffs threaten to drive prices higher for many essential construction goods.鈥�

The index for steel mill products jumped by 7.1% in March. Aluminium mill shapes jumped by 5.1% for the month, and the index for lumber and plywood rose 2.7%.

Since the prices used to calculate the indexes were collected on 11 March, US President Donald Trump鈥檚 administration imposed new tariffs of 25% on steel and aluminium imports, 25% on some goods from Mexico and Canada, 145% on imports from China, and 10% on most other countries.

Higher tariffs on many countries were imposed on 9 April but then suspended for 90 days. Additional tariffs on copper and lumber are still under review.

Jeffrey Shoaf, the chief executive officer of the Associated General Contractors of America, 鈥淥ur members are trying to deliver the best value for the public and private sector clients they serve. But it is hard to deliver that best value when you have no idea how much you are going to have to pay for many of the materials required to build projects.鈥�