From what I've gleaned from the budget (via Crowe Clark Whitehill) the main measures affecting the property and construction sectors are:

General changes
  • An accelerated cut in the main rate of corporation tax to 24% from 1 April 2012 with further reductions of 1% per year to give a rate of 22% by April 2014.  The Chancellor signalled his longer term aim of a main rate of 20% in line with the basic rate of income tax.
  • Income tax rates and the capital gains tax annual exemption remain frozen for 2012/13 at their current levels.  The tax-free personal allowance rises to £8,105 for 2012/13 and to £9,205 from 2013/14.
  • Top rate income tax reduces to 45% from April 2013
SDLT

  • 15% SDLT rate on residential properties worth more than £2m acquired through certain corporate vehicles
  • There will be a consultation process on an annual charge on existing residential properties worth more than £2m held through certain corporate vehicles, due to come into effect in 2013
  • There will be a consultation process on introducing capital gains tax from 2013 on residential property owned by non UK companies
  • A new 7% SDLT rate on residential properties worth more than £2m
  • Rules to stop abuse of sub sale relief
Planning Reform

  • National Planning Policy Framework coming into force to refocus planning policy to better support growth, favour sustainable development and localise choice on the use of previously developed land.
  • Introduction of measures to deregulate and simplify planning system, reducing information requirements, making change of use easier – for implementation by April 2013
  • Consultation to allow reconsideration of stalled planning applications
Infrastructure

  • Development of national roads strategy
  • Further investment in road and rail infrastructure
Financing

  • Launch of New Buy to make 95% mortgages available for people to buy a new home
  • Reinvigorated Right to Buy for two million tenants in council housing, with a single discount cap of £75,000 and with the proceeds of sale used to finance new builds on a one to one basis
  • Enhancement of plans to deliver over 15,000 new homes by providing support to construction firms in need of development finance
  • Accelerating the release of public sector land to provide capacity to build over 100,000 new homes
  • Taking forward pilots of auctions of public sector land with the aim of having two sites ready for market by the end of 2012
  • Consultation on potential role that a social housing Real Estate Investment Trust could play to support investment in social housing
Other

  • A number of new Enterprise Zones announced with enhanced capital allowance
  

  • New rules will be introduced which could restrict the availability of capital allowances on fixtures
  • Amendments to VAT in respect of approved alterations to listed buildings