However, the supplier of ventilation products said there will be a “small number” of job cuts as part of a cost-saving programme.
Trading outside the UK, which accounts for half of group revenues, reached 91% of prior year levels in May.
UK activity remains subdued but was down 58% in May, from a 70% plunge in April.
Cash in the bank increased to £49mln from £41mln in the two months to May 31, while there are £120mln available in a revolving credit facility.
Shares rose 7% to 177.5p on Friday morning.