(Sharecast News) - Self storage company Big Yellow Group said first half pre-tax profits fell 22% due to a lower revaluation gain in the period.Profit before tax was came in at £61.4m from £78.7m in 2017. Earnings per share were 38.8p compared with 50p.Adjusted pre-tax profit rose 9% to £33.3m as revenues rose 7% to £62.2m. Like-for-like occupancy rose 3.4 percentage points to 84.9%.The interim dividend was lifted 9% to 16.7p a share.Big Yellow said it now had a pipeline of 11 development sites, including the proposed increases in capacity of its Battersea and Wapping stores, with a cost to complete of around £100m in addition to the £23m of capital expenditure spent in the first half.These new stores were expected to add approximately 680,000 sq ft of storage space to the company's portfolio, an increase of 15%.Looking forward, chief executive Nicholas Vetch said it was "self-evident that the current political and economic outlook is more uncertain than usual"."We remain focused on strengthening our market leading brand and operating platform; filling stores and then driving rental growth at higher occupancy levels; and developing new high quality stores, while maintaining a conservative capital structure.""We believe this strategy positions the group to provide a good degree of protection against adversity, and at the same time flexibility to invest in our business and exploit growth opportunities when they come along."