If you're selling a home with an older conservatory, expect the buyer's surveyor to ask detailed questions about its planning history. With conveyancing activity picking up in the spring 2026 market, this scrutiny is becoming more prevalent. This isn't a new phenomenon - it's standard due diligence during conveyancing (the legal process of transferring property ownership). The financial and legal implications can catch sellers off guard, particularly when the conservatory predates your ownership or lacked proper documentation at the time of construction.

The Planning Permission Problem

Conservatories built in England and Wales before current planning rules or without proper permissions trigger buyer concern because of potential future enforcement action and resale complications. Rules differ in Scotland and Northern Ireland - check with your local planning authority. The buyer's lender will require clarity before releasing mortgage funds. This scrutiny forces sellers to either produce historical documentation, obtain retrospective planning permission (often impractical for decades-old structures), or consider indemnity insurance - which comes with a cost.

The number that matters: indemnity insurance premiums typically range from several hundred to several thousand pounds depending on the property value, the indemnity insurer's assessment of enforcement risk, and your location. A property worth £500,000 with an unregistered conservatory might face a premium of £800 to £2,000 (as a rough industry guide), though this varies substantially by underwriter and local authority enforcement history. This cost can shift who pays it - seller or buyer - and becomes a negotiation point that delays completion.

Building regulations (the technical standards structures must meet for safety and energy efficiency) compound the problem. Even if planning permission was granted, a 20-year-old conservatory may lack building regulations certification. Buyers' solicitors flag this because it affects the property's legal status and future saleability. Obtaining retrospective certification is rarely possible; indemnity insurance becomes the only practical route.

What This Means For Your Sale

The financial impact depends on whether the buyer's lender will accept indemnity insurance at all. Some high-street lenders refuse to lend on uninsured planning breaches. Buy-to-let lenders are typically stricter than residential lenders. This can shrink your buyer pool and create a deadlock: the buyer can't get a mortgage without insurance, but they won't commit to the property until the insurance solution is agreed and priced.

Timing matters. A surveyor's report flagging the issue early gives you weeks to obtain quotes and negotiate terms. Finding out at completion stage - when your buyer's conveyancer finally raises it - risks the deal collapsing or forcing hasty, expensive decisions.

The rate is: indemnity insurance premiums typically increase with property value and decrease with elapsed time since construction. A conservatory built in 2005 (20 years ago) presents lower enforcement risk than one built in 2015, so insurers charge less. Location also shifts the needle - areas with active local authority enforcement see higher premiums than those with lighter-touch approaches.

Protecting Yourself

You may wish to consider raising this with your solicitor before listing. Obtaining indemnity insurance quotes upfront if you suspect a planning gap demonstrates good faith to buyers and removes a major sale obstacle. The alternative - hoping the issue doesn't surface - typically costs more in negotiation leverage or deal collapse.

You may wish to consider documenting what you know: when the conservatory was built, by whom, whether any planning applications were made (check your local authority's records online), and whether any subsequent works required sign-off. Even gaps in documentation are valuable information because they help insurers assess risk accurately.

You may wish to speak to your solicitor about disclosure requirements. Actively hiding a known planning breach exposes you to misrepresentation claims after completion. Transparency, paired with insurance, is the legally and financially sound route.