Property owners adding a conservatory or roof light in the hope of improving their home have been told house values are set to increase over the next five years.
According to the National Housing Federation (NHF), the next two years are set to bring "substantial falls", before a number of rises see values reach a level that is a fifth higher than the current average house price.
In a map of the next 60 months, the organisation believes 2009 will finish with values down 12.2 per cent, before next year brings a 4.6 per cent drop.
However, things will then begin to pick up, with 2011 bringing growth of 1.1 per cent.
The Olympic year of 2012 should see values boosted by 7.5 per cent, the body believes, while the following 12 months will see a rise of 8.4 per cent.
According to the NHF, properties will increase in value by 6.8 per cent – representing a total of 20 per cent gain on current values.
It will mean the average cost of an English home will be £227,800 – £38,000 higher than the £189,800 projected for the end of this year.
Around 1,200 independent non-profit housing associations around the country are currently represented by the NHF.