Why a termite diagnosis is essential before insulating a roof frame
Termites: understanding the risks for the structure and site safety
Termites don't just "nibble" wood. They can weaken a roof frame from the inside, with no visible sign, until there's a risk of failure. Before starting a job, a diagnosis lets you know what you're dealing with, and avoids a bad surprise when walking on, drilling into, or loading the structure.
Insulation and roof frame: how the works can hide or worsen an infestation
Loft insulation, especially box-in or blown-in insulation, can hide the galleries and make future checks harder. It can also complicate a curative treatment if the infestation is discovered afterwards. Spotting it upfront avoids "closing the light" on the problem.
Responsibilities: what you need to secure before starting the works
Check whether the home is in a zone declared at risk, and have the diagnosis carried out by a qualified professional. If an attack is confirmed, plan the treatment before the insulation, then trace the actions (report, quote, photos) for your client and your insurer. It's your safety net.
When to do the termite diagnosis: the right moments on an insulation job
Before the technical visit: spotting the signs and triggering the diagnosis
Even before measuring your surfaces, keep an eye out. Timber that sounds hollow, small mud tubes, fine sawdust, discarded wings near the windows and doors. If the home is in a termite-risk zone or if you have a doubt, trigger a proper diagnosis with a certified operator. You save time, and you avoid hiding a problem under the insulation.
Before signing the quote: building the diagnosis into your works process
The right moment is also before locking in the quote. Plan a dedicated line and a clear timeframe for the diagnosis, especially if you're working on ground floors, joists or the roof frame. This secures your choice of insulation and cladding, and limits surprises. The goal: a job with no stoppages along the way.
Just before installing the insulation: confirming there's no active attack
A final check right before closing up the surfaces. Once the timber is visible, check there's no active attack or persistent damp. If treatment or replacement is needed, do it before installation, then record the decision (photos, report). You start with lasting insulation, not a cover-up.
How a termite diagnosis focused on the roof frame proceeds
Priority areas to check: loft, joists, purlins, truss feet and bearings
The diagnosis starts with a survey of the accessible timber areas. In the loft, the operator follows the load-bearing pieces. They check the joists and purlins, then the truss feet and their bearings on the masonry. They look for simple signs. Timber that sounds hollow, galleries, earthy traces, deformations. Areas near air inlets and timber-to-wall contact points remain the most exposed.
Inspection methods: visual inspection, probing, moisture and points of attention
The base is a methodical visual inspection, with a torch. Then comes light probing with an awl or screwdriver to detect weakened timber, without unnecessary dismantling. A moisture check helps spot conditions favourable to attacks. Points of attention: secure access, insulation hiding the timber, old repairs, and areas that can't be seen, to be noted in the report.
Documents to obtain: the diagnosis report and evidence useful for the job file
Ask for the dated and signed diagnosis report. It states the areas visited, the signs observed, the parts not inspected and the access limits. For your job file, also keep the photos, the survey plan, invoices for any previous treatments and, if needed, the treatment company's certificate. This informs the decision: repair, treat, or reinforce the roof frame.
What to do if the diagnosis reveals termites in the roof frame
Immediate measures: securing the site, limiting access and protecting the building
After a positive diagnosis, your priority is securing the site. Avoid walking on or storing loads near the infested timber. Isolate the area to limit contamination and keep clear markers for the company that will intervene.
- Close off loft access and mark out the passage.
- Remove sources of damp: leak, condensation, blocked ventilation.
Treatment and repair: possible options before insulation (curative treatment, replacement, drying)
Before insulating, the roof frame needs to become sound again. A professional carries out a suitable curative treatment, often by injection and spraying. If a piece is too weakened, replacement or reinforcement is safer. In parallel, drying addresses the cause.
- Biocide treatment with traceability and safety instructions.
- Targeted replacement of degraded load-bearing elements.
- Drying, fixing water entry points, improving ventilation.
Planning: coordinating treatment, drying and resuming the insulation works
Don't start the insulation until the check has been done. Otherwise, you risk sealing in the infestation and damaging the performance. Keep a simple, shared order of works.
- Treatment, then a follow-up visit and report.
- Drying the timber and checking the moisture level.
- Resuming the insulation, without drilling into treated areas without approval.
Key points to build into your quotes and organisation in 2026
Clauses to plan for: start conditions, exclusions and additional works
Plan a start date clause subject to site access, suitable weather and validation of the initial diagnosis. Add clear exclusions, for example degraded substrates, unmapped networks, presence of asbestos. Also specify how additional works are handled, with an amendment, unit prices and timeframes, to keep a clear framework if opening up the surfaces reveals surprises.
Coordination with other diagnoses: damp, timber condition, loft ventilation
Before insulating, align with the other checks. A damp diagnosis, a timber condition check and a ventilation review avoid wet insulation and a condensing loft. Plan who does what and when. Readings, recommendations, and a costed option if a ventilation improvement becomes necessary.
Traceability: photos, reports and follow-up to avoid disputes after insulation
Build a simple photo file. Before, during, after. Especially on the specific points, the continuity of the insulation, the hatches and duct passages. Add a dated report, the product data sheets, and the evidence the funding scheme requires. You gain peace of mind if a client disputes something afterwards.
