http://www.legislation.gov.uk/apni/1964/36/section/39Business Tenancies Act (Northern Ireland) 1964An Act to provide security of tenure for certain tenants occupying premises for business, professional or certain other purposes by enabling them to obtain new tenancies in certain cases or in certain circumstances to obtain compensation; to make provision for the payment of compensation in respect of certain improvements to such premises; and for purposes connected therewith.texttext/xmlenStatute Law Database2013-02-182009-10-01PART IICOMPENSATION FOR IMPROVEMENTS
39Restrictions on right to compensation for improvements.(1)

A tenant shall not be entitled to compensation in respect of an improvement, other than an improvement to which section 38 applies, unless—

(a)

a notice of improvement was duly served in accordance with this Part in relation to that improvement; and

(b)

the tenant by whom such notice was so served became entitled to execute the improvement either under section 35 or by virtue of an improvement order; and

(c)

the improvement was duly executed in accordance (as the case may be) with the notice of improvement or with that improvement order.

(2)

A landlord shall not be entitled under this Part to compensation from his superior landlord in respect of an improvement in relation to which the notice of improvement (or copy thereof) served by the tenant in respect of that improvement was not duly served on the superior landlord in accordance with this Part.

(3)

A tenant shall not be entitled under this Part to compensation in respect of any improvement which the tenant or his predecessors in title were under an obligation to make in pursuance of a contract entered into, whether before or after the commencement of this Act, for valuable consideration, including a building lease.

(4)

No compensation shall be payable under this Part in respect of any improvement which was made in contravention of the provisions of any enactment.