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Leasehold Law

Service Charge 18-Month Rule UK — Section 20B LTA 1985 and Irrecoverable Costs

Section 20B Landlord and Tenant Act 1985 imposes an 18-month time limit on the recovery of service charge costs in residential long leases. Where a cost is incurred more than 18 months before it is demanded from the tenant, the cost is irrecoverable — unless the landlord served a protective notice within 18 months of incurring the cost informing each tenant that the cost had been incurred and would be included in a future service charge demand. When the 18-month clock starts: when the cost is 'incurred' — generally when a valid invoice is raised by the contractor (when the liability crystallises), not when the invoice is paid. Staged invoicing: each invoice in a major works project creates a separate 18-month clock; landlords must track each invoice date. The protective notice: must be in writing; must inform the tenant that costs have been incurred; must state they will be included in a future service charge demand; no prescribed form; no precise amount required; must refer to costs already incurred (not future anticipated costs); must be served on each qualifying tenant individually; proof of service essential. Common traps: delayed certified accounts (Year 1 costs demanded in Year 3 are irrecoverable); managing agent changes (incoming agent may not know historic cost dates); long projects (early costs exceed 18 months before final account issued). First-tier Tribunal: no discretion to waive the 18-month limit; costs outside the limit are irrecoverable as a matter of statute. s.20C LTA 1985: a successful s.20B challenge may support a s.20C order preventing the landlord recovering Tribunal legal costs as a service charge. Scotland: s.20B LTA 1985 does not apply; Tenements (Scotland) Act 2004 and Deed of Conditions govern.

9 min readUpdated 7 June 2026Last reviewed: 17 May 2026service-charge-18-month-rulesection-20b-lta-1985irrecoverable-service-chargeprotective-notice-service-charge

Section 20B — The 18-Month Rule and the Protective Notice

s.20B LTA 1985: a service charge is not payable unless the tenant is notified of the costs within 18 months of their being incurred. If the costs will not be demanded within 18 months, the landlord must serve a protective notice on each qualifying tenant within 18 months, stating that costs have been incurred and will be included in a future service charge demand. When costs are 'incurred': generally when the liability arises — when a valid invoice is raised by the contractor (not when paid). For staged major works projects, each invoice creates a separate 18-month clock. Protective notice requirements: in writing; must inform the tenant that costs have been incurred; must state they will be included in a future demand; no prescribed form; no precise amount required; must refer to costs already incurred (not anticipated future costs); must be served on each qualifying tenant individually with proof of service. Best practice: diary the 18-month notice deadline for every major cost item; issue protective notices for any cost not demanded within 12 months of incurrence (6-month buffer before the statutory deadline). No FTT discretion: the First-tier Tribunal has no power to waive the 18-month limit; breach = cost irrecoverable as a matter of statute regardless of reasonableness.

Common Traps and Interaction with s.20C

Most common 18-month rule traps: (i) delayed certified accounts — costs incurred in Year 1 but accounts not certified and demanded until Year 3; by then, many costs are irrecoverable; (ii) managing agent changes — incoming agent unaware of historic invoice dates and 18-month exposure; (iii) long major works projects — early-phase costs (surveys, scaffolding, groundworks) more than 18 months old before the project is complete and the final account issued; serve protective notices in tranches throughout the project; (iv) retrospective recovery — historic service charge costs cannot be recovered on a flat sale or lease renewal if more than 18 months have elapsed. s.20C LTA 1985 interaction: a tenant who successfully challenges under s.20B can apply for a s.20C order preventing the landlord from recovering its Tribunal legal costs as a service charge — a double penalty for the landlord. Defence options: prove the cost was demanded within 18 months (obtain original contractor invoices and date records); prove a protective notice was served in time (proof of service); argue the liability crystallised later than the invoice date (e.g. settled or adjudicated dispute). Scotland: s.20B LTA 1985 does not apply; service charges governed by Tenements (Scotland) Act 2004 and the relevant Deed of Conditions.

Frequently asked questions

What is the 18-month service charge rule?+

Section 20B LTA 1985 provides that a service charge is irrecoverable unless the tenant is notified of the costs within 18 months of them being incurred — or a protective notice is served within 18 months informing each tenant that costs have been incurred and will be included in a future demand. There is no Tribunal discretion to waive the limit.

When is a service charge cost incurred for the 18-month rule?+

A cost is incurred when the liability arises — generally when a valid invoice is raised by the contractor. For staged major works projects, each invoice creates a separate 18-month clock from the date of that invoice, not from the date the overall project started or the final account was issued.

What must a section 20B protective notice contain?+

The notice must be in writing, inform the tenant that costs have been incurred, and state they will be included in a future service charge demand. No prescribed form and no precise amount is required. It must refer to costs already incurred, not future anticipated costs, and must be served on each qualifying tenant individually.

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