1 · Continuous-flow mixing rig

Trailer-mounted unit that meters the three components in real time, mixes under low shear, and feeds the injection lance. The rig is what makes the foam consistent across a whole property — manual mixing on site can't hit the density specification. Power from a generator or a domestic 16A supply.

2 · Borescope camera

Slim 9 mm endoscope with built-in light. Used twice on every job — pre-fill to assess cavity condition, and post-fill to verify coverage at random sample points. Images go into the homeowner pack and the ECO4 grant evidence file.

3 · 22 mm SDS percussion drill

Cordless SDS hammer drill with a 22 mm masonry bit. Cuts cleanly through brick or block without spalling the face. Dust extraction shroud captures debris so the kerb stays clean — important on terraced streets and conservation areas.

4 · Injection lance and nozzles

Low-pressure injection lance with replaceable nozzles sized to the cavity width. The nozzle inserts to the back of the cavity and is withdrawn as the foam fills — a single drill hole covers roughly 0.5 m² of wall at standard 600 mm spacing.

5 · Removal vacuum (when needed)

Industrial cavity vacuum with extension wands. Removes existing EPS beads, mineral wool, or failed urea-formaldehyde foam before Cavipor goes in. Approximately 60% of grant retrofits we survey have failed or partial existing fill that needs clearing first.

6 · Mortar plug kit

Pre-mixed mortar in three standard tones — buff lime, grey sand-cement, and red-buff for stock-brick areas. Custom mixes for listed and conservation work. Plugs are tooled flush with surrounding pointing and weather in over the following weeks.

Mineral binder · primary component

A calcium-mineral binder system based on hydraulic and pozzolanic chemistry. Sets through a hydration reaction (not curing or off-gassing). Provides the alkaline matrix that holds the aggregate and resists mould growth, microbial activity, and rodent attack. Around 60% of dry mass.

Fine mineral aggregate

Sub-millimetre mineral filler that controls density and thermal conductivity. Voids around the aggregate trap still air — the actual insulator. The aggregate grading is what hits λ 0.035 W/mK at 30 g/l: lower than EPS beads, lower than blown wool, comparable to phenolic foam without the fire or off-gassing concerns.

Water-based foaming agent

The third component generates the foam structure during injection, then dissipates as the binder sets. Once the install is complete, the foaming agent is no longer present in the cavity — what remains is the mineral matrix and trapped air. Zero residual VOC. No off-gassing during occupation.

Vapour-open · μ ≈ 3

Cavipor lets the wall breathe. Water vapour passes through the foam at roughly the same rate as a lime mortar. This matters in older brick stock where moisture must be able to escape outward — a vapour-tight cavity fill in a 1930s solid-brick-outer cavity wall traps damp and risks interstitial condensation. Cavipor avoids that failure mode.

Hydrophobic mineral matrix

The set foam is vapour-open but liquid-water-resistant. Driving rain that penetrates the outer leaf runs down the inner face of the brick (as it would in any cavity) and exits at the cavity tray, rather than being absorbed by the fill. This is the opposite behaviour to old urea-formaldehyde foams that wicked moisture across the cavity.

A2-s1,d0 fire class

Non-combustible (A2), with the lowest smoke production class (s1) and zero flaming droplet rating (d0). Post-Grenfell, A2 is the threshold that allows external wall systems on buildings over 11 m without the EWS1 process. For cavity walls specifically, A2 means the cavity isn't a fire pathway between flats or floors.

25 year manufacturer guarantee

BASF Cavipor is guaranteed for 25 years from the date of certified install. The guarantee covers material performance — thermal conductivity, fire class, structural integrity of the fill. The installer (CleverBloom) is the registered system applicator on the certificate.

No annual service required

There is no moving part, no electrical component, no filter, and no consumable. The mineral matrix is set and stable. The only ongoing maintenance is the standard external-pointing inspection that any masonry wall needs — typically every 20–30 years for re-pointing in exposed areas.

Vapour-open behaviour confirmed

Post-install, the wall should behave the same way a properly empty cavity behaves — vapour passes outward, driving rain runs down the inner face of the outer leaf and exits at the cavity tray. We recommend a thermal-imaging spot-check 6–12 months after install on any property with internal damp history, included in our service plan.

Reversible · vacuum removal

Cavipor is one of very few cavity fills that can be reversed. Industrial vacuum extraction recovers ~95% of the mineral matrix. The remaining residue disposes with builders' rubble — no hazardous waste designation, no special-waste fee. This matters for properties that may be demolished, deeply renovated, or returned to an empty cavity for structural repair.

External pointing survey

Cavipor only performs if the outer leaf is weather-tight. Cracked pointing, failed render, or a defective DPC will undermine the fill's thermal performance and risk damp regardless of what's in the cavity. CleverBloom includes a free pointing condition report with every Cavipor install and quotes remedial work where needed.

MVHR companion (post-retrofit air)

A filled cavity tightens the building envelope. In houses with no extract ventilation, this can shift the moisture balance toward winter condensation on cold internal surfaces. We recommend a baseline MVHR conversation as part of any cavity-fill scope — decentralised iV-Compact or PRANA units cover most retrofit cases.