The market also saw a step change in speed of sales, with the average time from listing to sale-subject-to-contract at 26 days, down from 49 days in 2019.
Zoopla expected average price growth to settle at four to five per cent by end of the year.
The overall price increase of six per cent was driven in large part by lack of stock, including particularly a dearth of family homes on the market, as a “reassessment of home” owing to the pandemic saw borrowers want more space.
Total stock for sale was 26 per cent lower this year compared to end of July 2020, and levels were expected to remain depressed well into next year. On the demand-side, the picture was one of growth running at 21 per cent this year.
Supply constraints were most evident for houses, and properties priced up to £350,000.
Zoopla ascribed the lack of supply to three factors: sheer level of activity in the first-half, increased demand from first-time buyers (FTBs) and investors, and softening in new-build completions.
Improved mortgage availability for FTBs was a factor in adding to net demand because people in this group do not have properties to sell.
And, demand from BTL investors grew by 21 per cent in the year to end of July, compared to the same period last year.
Price rise variations
Price growth was highest in Wales at 9.4 per cent, Northern Ireland at nine per cent and the North West at 7.9 per cent.
City-wise, seeing strong growth were Liverpool at 9.4 per cent, Manchester with 7.7 per cent and gaining 7.5 per cent, Belfast.
London continued to lag, with a rise of 2.5 per cent, although this was up on 1.9 per cent in March.
Across the UK, houses have tended to see high-single-figure rises, while price growth for flats was generally in the low-single-figure range.
Slow stock rebuild
Zoopla’s analysis of sales this year showed mortgaged home-movers as the largest customer group at 37 per cent, mortgaged FTBs at 30 per cent, cash owners or investors 24 per cent and at nine per cent of the market, buy-to-let mortgagees.
The house price growth figure of six per cent was greatly inflated compared to 2.3 per cent seen in the same seven months last year.
However, price rises had slowed compared to the figure of 6.3 per cent recorded for the six months to June this year.
The average value of a home in the UK is now £234,000.
Gráinne Gilmore, head of research at Zoopla, said: “The lower of supply of homes listed for sale may lead to a natural slowing in buyer interest, albeit from high levels. A return to more normal levels of market activity will result in a slow rebuilding of stock through H1 2022.”