Reviewed by Thermorite UK technical review
About 2 min read 308 words
Last reviewed 25 September 2026. This guide provides general information; a survey remains specific to the individual property.
Section 01
Not knowing is a valid reason to ask
Many homeowners do not have paperwork for earlier cavity work, especially after a purchase, an extension or a change in property ownership. You do not need to make a claim about the cavity before requesting a survey.
Start with what you do know: the rooms or walls that concern you, any signs of earlier work and the property postcode. That is enough to begin an eligibility review.
Section 02
Accessible inspection can provide a focused view
Where access is suitable, a small camera can help show whether material is visible at selected points and how it appears there. Thermorite can explain what is visible in ordinary language.
A focused view cannot show every part of every wall. It is one part of a property-specific discussion, not a reason to assume that all cavities have the same condition.
Section 03
The next step remains open until the property is understood
The accessible findings may lead to a conversation about leaving the cavity alone, considering a localised issue, discussing extraction or reviewing suitability at a later stage. No option is assumed simply because the earlier history is unknown.
Use the survey form’s unknown-wall option to explain that you do not have a clear history. Thermorite reviews the request and confirms any appropriate next step directly.
Built fabric
A wall can look simple from the outside and still need careful context.
Construction, past work, access and visible conditions all matter when discussing what may be relevant.
Start with a free survey
Keep exploring
Related guides
Continue with a closely related homeowner guide, or take the next practical step when you are ready.
What can a cavity survey show?
Learn what an accessible view may help clarify and what it cannot establish.
Read the guide
When to ask about existing insulation
See why uncertainty is a sensible reason to start a property conversation.
Read the guide
Start with an unknown cavity
Use the survey request to explain that you do not have a clear history for the walls.
Start hereUseful answers
Questions about this guide
The answers stay property-specific and explain where an inspection has limits.
Free cavity surveys within 80 miles of Spalding
Concerned about existing insulation? Start with a free cavity survey.
Tell Thermorite what you are noticing and share the property postcode. The team will review the details, confirm eligibility and contact you about a visit.