The average size of landlords’ property portfolios has risen for the second successive quarter, according to latest research by Paragon Mortgages.

The specialist buy-to-let lender’s quarterly Private Rented Sector Trends Survey for Q3 showed the average size of landlords’ rental portfolio was 14.9 properties (13.5 in Q2).

Paragon said there appears to be a rising trend in the average size of portfolio, which has remained fairly consistent throughout 2012 and 2013, with the average size only fluctuating between 12 and 13 properties. When the survey first began in 2002 the average portfolio size was nine properties.

The survey also revealed that 15% of landlords are planning to expand their portfolios in the last quarter of 2014. Of those looking to buy, 63% are planning on purchasing terraced houses, which is an increase on 55% in Q2 and over a fifth (27%) of landlords plan to buy semi-detached properties.

John Heron (pictured), managing director of Paragon Mortgages, said: “With the wider housing market gaining back some momentum, landlords are beginning to be more active in expanding their portfolios. However, our research does indicate that tenant demand is rising, and in order to meet this demand the PRS will need to see an increase in investment from landlords.”