Closed cell foam sheets can be useful in campervan and vehicle-conversion projects where a lightweight polyethylene sheet, low water uptake and firm protective layer are needed. They should not be treated as a complete certified van-insulation system without checking thermal, fire and installation requirements for the whole build.
Quick answer
AFP30 and AFP45 are rigid cross-linked polyethylene foam sheets. They can be considered for lining, spacers, protective pads and suitable insulation-related uses, but All Foam does not publish an R-value or acoustic reduction figure for these grades. Do not copy performance numbers from another supplier's closed-cell foam, because a different formulation can have different thermal and fire properties.
Why closed cell foam is popular in van conversions
Van walls, floors and doors expose materials to vibration, moisture and tight spaces. Competitor van-insulation systems often use closed-cell foam because the cell structure limits water uptake and the material can be fitted in relatively thin layers.
That does not mean every closed-cell sheet is interchangeable.
All Foam's AFP30 and AFP45 are cross-linked polyethylene grades supplied as unbacked sheets. They are different from adhesive-backed specialist automotive liners sold by dedicated van-insulation suppliers.
What AFP30 and AFP45 actually are
AFP30 has a nominal density of 30 kg/m³. All Foam describes it as waterproof and non-absorbent. It is the lighter general-purpose grade and is available in black or white.
AFP45 has a nominal density of 45 kg/m³ and greater load-bearing support. Its water absorption is specified at no more than 1% by volume. It is supplied in black.
Both grades are available online in 3mm to 100mm thicknesses and are supplied unbacked.
Neither grade is offered by All Foam as fire retardant.
These verified properties are a better basis for selection than a generic claim that one material is "best van insulation".
Where sheet foam can be useful
Closed-cell PE sheet can be considered for:
- protective lining behind panels
- firm spacers and anti-rattle pads
- areas where low water uptake is useful
- local thermal breaks where the project's thermal design supports it
- floor or furniture interfaces where a stable sheet is needed
- fabricated pads around service openings or fittings
The suitability of each use depends on temperature, fixing method, clearances and the surrounding materials.
Thermal performance needs actual data
A frequent mistake in campervan content is to quote an R-value from one supplier and apply it to another closed-cell foam.
Thermal conductivity depends on the exact material. All Foam's current AFP30 and AFP45 web specification does not publish an R-value for use as building or vehicle insulation.
If your conversion needs a calculated thermal performance, use a product with the required verified thermal data or obtain the relevant technical information before specifying the sheet as an insulation layer.
Do not estimate a U-value from thickness alone without the material's tested conductivity.
Fire performance matters in vehicles
Closed cell describes cell structure, not fire rating.
All Foam's AFP30 and AFP45 are not offered as fire-retardant grades. If your campervan build, conversion standard, insurer or vehicle use requires a particular fire classification, do not assume these products meet it.
Use a material with the required evidence for that application.
Our fire-retardant foam guide explains why generic words such as flame resistant or fire retardant should not be substituted for a named test requirement.
Moisture resistance is useful but does not eliminate condensation
Low water uptake can be helpful in a vehicle, but condensation is a whole-vehicle issue.
Warm moist air can still reach cold metal through gaps, fixings and unsealed edges. Water can also enter through leaks or door drainage paths.
Do not block factory drain holes or ventilation routes with foam. Treat corrosion before covering metal and follow the vehicle conversion design for vapour control and ventilation.
Closed-cell sheet may form one moisture-resistant layer, but it cannot correct a leaking seal or poorly ventilated interior.
AFP30 or AFP45 for a campervan?
AFP30 is the lighter 30 kg/m³ grade and is a sensible starting point where the sheet mainly needs to line, separate or provide lightweight protection.
AFP45 is denser and more load-bearing. It can make sense where the foam must carry more local pressure or remain more rigid under a panel or fitting.
The denser grade is not automatically better insulation. Choose it because the mechanical job needs the extra rigidity, not because the density number is larger.
Read AFP30 vs AFP45 for the broader comparison.
Thickness should follow the available space and job
A 3mm sheet can act as a separator or thin pad but has very little depth for thermal resistance or compression. A much thicker sheet occupies more of the cavity and can interfere with trim panels, wiring or furniture fixings.
Measure the finished cavity after allowing for cables, clips and panel ribs. Avoid compressing thick foam into a space where it prevents the trim from fitting correctly.
Where a thermal target exists, thickness should be calculated from verified material data rather than chosen by appearance.
Fixing unbacked polyethylene foam
The current AFP30 and AFP45 sheets are supplied without self-adhesive backing.
Depending on the location, the foam may be mechanically retained, close-fitted or bonded with a separately selected compatible system. Polyethylene can be difficult to bond with general-purpose adhesives, so check adhesive compatibility with both the foam and vehicle substrate.
The fixing method also needs to tolerate the vehicle's temperature range and vibration.
Test any adhesive on an offcut before committing to a large area.
Protect wiring, drains and service access
Do not permanently cover components that require inspection or maintenance.
Keep wiring looms accessible where the conversion design requires it. Avoid compressing cables behind rigid panels. Do not cover drain holes inside doors or areas designed to shed water.
Around heaters, exhausts, chargers, batteries or high-temperature components, follow the equipment manufacturer's clearance and material requirements. Do not assume ordinary polyethylene sheet is suitable simply because it fits the space.
Acoustic expectations should be realistic
A closed-cell foam sheet can reduce rattles or decouple hard surfaces in some installations, but All Foam does not publish a tested sound-reduction figure for AFP30 or AFP45.
Road-noise control often uses several different materials for panel damping, decoupling and barrier mass. A lightweight PE sheet cannot be described as complete soundproofing.
Use the sheet where its verified mechanical properties suit the job rather than promising a decibel reduction that has not been tested.
A practical campervan checklist
- Identify the exact area: floor, wall, door, furniture or trim interface.
- Check whether thermal data is required for the conversion design.
- Confirm any fire-performance requirement before buying.
- Measure the available cavity depth and service clearances.
- Keep drainage and ventilation routes open.
- Choose AFP45 only where greater load-bearing rigidity is useful.
- Select a fixing method compatible with polyethylene and the substrate.
- Test a small area before a full installation.
- Keep high-temperature and safety-critical components within their manufacturer's specified clearances.
Related closed cell guides
The closed cell foam for boats guide covers similar moisture-related considerations in marine projects. For general PE foam uses, see clever uses for closed cell foam sheets.
Final answer
Closed cell polyethylene foam can be useful in a campervan, but the product must be selected from verified properties rather than from broad van-insulation marketing. AFP30 and AFP45 offer low-water-uptake, rigid PE sheet options, but All Foam does not publish van-specific R-values, acoustic ratings or a fire-retardant classification for them. Use them for suitable lining, protective and insulation-related roles only where the complete conversion specification supports the material.
