Pre-tax profits were pounds 1.9m in the six months to 30 April, down from pounds 2.4m in the first half last year. Turnover was almost unchanged at pounds 40.5m.
Margins came under pressure at GSL, the intruder alarms subsidiary, which has opened several new branches and brought in a new marketing director. More effort will be put into sales and marketing, and GSL's distribution systems are being reviewed by consultants.
The CCTV business had added extra staff and more products during the first half as it tried to address a bigger market than the narrow audience for high-priced equipment. Overheads had therefore increased, and while operating margins matched industry levels, the business had suffered from adverse currency movements.
Gardiner is the biggest independent security equipment distributor in France, and Richard Clemons, chairman, said demand was starting to recover after the recession.
The company, which said the extra spending on recruitment and infrastructure was unlikely to show benefits in the second half, raised the interim dividend from 0.23p to 0.25p. Mr Clemons said last year's dividend had been three times covered by earnings, and Gardiner would move slowly towards the industry average of two times cover.
The results matched City expectations, and the shares closed 1 2 p higher at 221 2 p.