Mace and Sir Robert McAlpine picked up a large commercial project each last week as a major report suggested that now was the right time for developers to build.
Mace is understood to have beaten Bovis Lend Lease, Skanska and Sir Robert McAlpine to the deal to build London Bridge Place - also known as the Gem or the Baby Shard - which is thought to be worth about £200 million.
The 17-storey, 55,700 sq m office block is next to the 310 m Shard of Glass, which Mace is currently building on a £426m fixed-price contract.
But Sir Robert McAlpine is thought to have beaten Mace to the £130m Milton Court tower job for Heron Properties.
The project is to build a 36-storey, 284-apartment mixed-use tower, known officially as The Heron, on Silk Street adjacent to the Barbican Centre in the City of London.
The ground floors of The Heron will also be the new home of the Guildhall School of Music & Drama, featuring a 608-seat concert hall, a 227-seat drama theatre and a 126-seat studio theatre.
Brookfield and Galliford Try had been eliminated at an earlier stage, leaving Mace and McAlpine to go head-to-head for the contract.
The pair have been locking horns on a number of big London jobs recently.
In February, Mace won the £120m Park House contract from Land Securities, while McAlpine took the developer’s £100m Selborne House project.
Mace chief executive Stephen Pycroft last year told Construction News that he wanted the firm, which began life as a construction management company in 1990, to be “recognised as the leading high-profile tall buildings construction firm in Europe”.
He said the firm had the capacity to take on two more major contracts alongside the Shard.
It has since won Park House and the Baby Shard, but it is understood that it could still look for another big deal.
Sir Robert McAlpine, one of the UK’s oldest construction firms, is best known for its retail and arena construction.
It is currently working on the Olympic Stadium for London 2012, having built Arsenal’s Emirates ground and the O2 arena in London.
The latest London Crane Survey from consultancy Drivers Jonas Deloitte concluded that now was the right time to start commercial new-builds, with the development pipeline heading towards its lowest level ever and rising rents making profit margins more appealing.
The report was positive news for the London market this week, with less positive signs coming from the Investment Property Databank, which suggested rents in the UK more broadly are still in decline.
The survey showed there were 33 office schemes under construction across central London, compared to 49 just six months ago and 106 in 2008.
Only 530,000 sq m of office space is currently under construction and just 92,000 sq m will be delivered in 2011 - which would be the lowest annual delivery since the survey began in the early 1980s.
Six office developments started on site over the past six months, all of them located in the West End.
But there have been no new starts in the City, Southwark, Midtown or Canary Wharf.