Companies such as Wolseley, CRH and Hanson have significant proportions of their overall businesses in the US. Most of the concern centres on the US housing market, which is starting to weaken after the terror attacks on 11 September.
Analysts expect that US public spending on roads will help offset the housing downturn, but also point out that margins in the housing sector are better than in roadbuilding.
Peel Hunt analyst Stephen Rawlinson said: "A lot depends on what happens the US, because they all have heavy exposure there. The US housing situation is the only dark cloud around for these companies. Volumes will be maintained but margins will be lower."
The predictions come as Building publishes a list of the top 25 UK building materials companies (see below). It shows the top three, Wolseley, CRH and RMC, pulling away from the pack, each with a turnover exceeding £5bn.
Teather & Greenwood analyst David Taylor said the consolidation sweeping the sector was likely to continue as large European companies such as Lafarge and St Gobain moved into the UK. This year, Lafarge has already snapped up Blue Circle, and Anglo American has bought Tarmac.
Taylor said: "There is a gradual process of consolidation, just like the housebuilding sector."
The table shows that the top 10 has remained relatively unchanged in 2000-01 compared with 1999-2000. Turnover increased for every company except two, and six firms' staff numbers fell.
