Floors, walls, ceilings, doors: food-grade materials and finishes

AgrifoodV · Published 29 October 2026

Building finishes are often the first item cut when the budget is tight, because they do not directly make product. Yet cracked floors, peeling walls and ceilings dripping with condensate are the first things a buyer’s audit team sees, and fixing them means stopping production. Article 7 divided the layout into dirty, intermediate and clean zones; Article 8 answers the next question: which materials each zone must be finished with to hold that boundary over 20 years of operation.

The law says “what”, not “with what”

EU Regulation (EC) 852/2004, Annex II, Chapter II, point 1, sets requirements for food processing rooms surface by surface. Floors and walls must be maintained in a sound condition, easy to clean and, where necessary, to disinfect, which means impervious, non-absorbent, washable and non-toxic materials; walls must be smooth up to a height appropriate for the operations; floors must allow adequate surface drainage. Ceilings and overhead fixtures must be built to prevent the accumulation of dirt, reduce condensation and mould, and avoid shedding particles. Windows must not collect dirt; windows that open to the outside must, where necessary, have insect screens that can be removed for cleaning, and where open windows would cause contamination they must stay closed and fixed during production. Doors must be smooth, non-absorbent and easy to clean.

In the United States, Section 117.20(b)(4) of Title 21 of the Code of Federal Regulations (21 CFR) requires floors, walls and ceilings to be built so that they can be adequately cleaned, kept clean and kept in good repair, and so that drip or condensate from fixtures, ducts and pipes does not contaminate food, food-contact surfaces or packaging. Paragraph (b)(5) requires light bulbs, fixtures, skylights and any other glass suspended over exposed food to be shatter-resistant, or otherwise protected in case of glass breakage.

K.P. Sutton, author of the chapter “Construction: Techniques and Finishes” in the Handbook of Food Factory Design (2013), notes that these regulations are very general and do not explain how to achieve the standard; he also warns that floor failures often cause lengthy production disruptions, so the floor specification should not be reduced for budget reasons.

Floors: the concrete slab first, the coating second

However good a floor looks, it will fail if the concrete slab beneath it is not stable. According to Volume 4 – Food Industry (draft 2026), section 7.7.2, and Sutton (2013), the ground-floor slab in production areas should carry at least 10 kN/m², be at least 150 mm thick, use concrete of at least grade C30 reinforced with steel mesh or steel fibre, and sit on a polyethylene damp-proof membrane of about 0.3 mm. Expansion joints should be no more than 30 m apart and contraction joints no more than 10 m. In wet areas the finished floor falls to channels or gullies within a range of 1:40–1:80; Volume 4 (section 7.7.9.4) takes 1:60 as the standard and notes that falls steeper than 1:40 cause slips and trouble for wheeled vehicles. With resin floors, the falls must be formed in the base concrete.

The finish is chosen by zone and by what soils the floor. The table below combines the guidance in Volume 4 (Table 7.7.4) and Sutton (Table 13.2):

Sources: Volume 4, section 7.7.6.8 (Tables 7.7.4, 7.7.5); Sutton (2013), section 13.6, Table 13.2, pp. 338–342.

Four details are often overlooked, and all of them are in the books. First, temperature: according to Sutton, epoxy systems deform above 60 °C and polyurethane above 110 °C; areas with hot spills or hot washing must allow for this. Second, taint: free phenols in resin react with chlorine-based detergents to form chlorophenols, detectable as a taint at parts-per-billion levels; Sutton advises asking every supplier for proof of taint testing. Third, acids and sugars both attack cement mortar; fruit juice is both sour and sweet, so cement joints are a weak point. Fourth, skirtings: Volume 4 (section 7.7.6.4) and Sutton require coved skirtings with a minimum radius of 50 mm, or 45° splayed skirtings at least 150 mm high at upstands and machine plinths, so that no 90° dead corners remain.

Slip resistance is also a design requirement. Volume 4, section 7.7.6.5, sets surface roughness by the contaminant on the floor: Rz of at least 20 µm for floors wet with water, milk or cleaning solutions; at least 45 µm for vegetable oil; at least 70 µm for animal fat. Channels and gullies are stainless steel, gullies at least 250 mm with a trap and a removable basket; clay drainage is not used in processing areas (Volume 4, section 7.7.9.2 and Table 7.7.7).

Walls and ceilings: panels, plinths and the service void

According to Sutton and Volume 4 (section 7.7.5), production walls must be smooth, durable and easy to clean, without ledges, gaps or sills; vertical corners are rounded, and external corners carry stainless or galvanised steel angles against impact. Wall tiles, once the most common hygienic wall finish, are no longer recommended because they break easily and have many joints. Volume 4 adds a comparison useful to investors: polypropylene sheet is the cheapest of the common cladding materials and resists impact and chemicals well, but has high thermal expansion and poor resistance to surface spread of flame, so it is used only where fire performance is not decisive and must be approved by the fire authority.

Insulated sandwich panels are now used in most production areas. Sutton records that many total-loss factory fires have been blamed on expanded polystyrene cores, which create a huge “fire load” that is almost impossible to extinguish safely once alight. Alternative cores include polyurethane, phenolic foam, mineral wool and polyisocyanurate (PIR); according to Sutton, the last two carry negligible fire risk. Panels have poor impact resistance, so they are mounted on concrete plinths integral with the floor; Volume 4 (section 7.7.5.5) and Sutton both recommend this plinth method because it limits water penetrating the base of the wall. Wash areas, mixing areas and places with high temperatures and regular abrasion should use stainless steel facings; for normal use, polyester-powder-coated steel is sufficient.

For ceilings, the books prefer walk-on suspended panel ceilings: a flat, flush, self-finished underside, with a service void above where maintenance staff can repair pipes and cables without entering the production floor. Sutton recommends that the ceiling carry 0.25 kN/m² and sit at least 2 m below the lowest roof member; Volume 4 (section 7.7.3.1) recommends about 2.5 m. All penetrations through the ceiling must be sealed; the void must not store process equipment and must be included in the cleaning and pest-inspection schedule. Light fittings must be sealed, with glass protected by polycarbonate so that fragments cannot fall into product, in line with 21 CFR 117.20(b)(5).

Doors, windows and access to the clean zone

Doors are where the zoning boundary from Article 7 is most easily breached. The books set out these requirements (Sutton, sections 13.10–13.11; Volume 4, sections 7.7.10–7.7.12):

• Access to processing areas: double doors and an air lock with an insect-trapping device, and hand-wash basins operated by knee, elbow or sensor; doors are self-closing.
• External doors: steel, power-operated, sealed including the gap underneath so that birds and rodents cannot enter; surface-water grids at entrances; main doors large enough to move major equipment in and out; canopies over loading docks.
• Internal doors: no timber or glass facings; polycarbonate vision panels on corridor doors; sliding doors without floor channel tracks, which collect water and debris.
• Windows: avoided in processing areas; where used, fixed, glazed with polycarbonate rather than ordinary glass, with sills sloping 45° inside so nothing can be placed on them and 60° outside so birds cannot perch. Ventilation is provided by the air-handling system, not by opening windows.

Timber must not be used for door leaves or frames in production areas unless it is fully encased in steel or plastic. In AgrifoodV’s assessment, this list should be copied directly into the construction tender documents, because small details such as door tracks, window sills and manhole covers are exactly what contractors tend to swap for cheaper options when they are not specified.

Vietnamese conditions: soft ground, high water table, acidic fruit juice

Volume 4, section 7.7.6.6, warns that the ground in many industrial zones in the Mekong Delta, Ho Chi Minh City and Hai Phong consists of soft clay, mud and fill with low bearing capacity. Without proper treatment, the floor settles unevenly, the slab cracks, the resin coating tears and stainless steel channels break. The book gives a specific build-up:

• Foundation: the slab rests on piles driven to firm strata; concrete is never poured directly on fill that has not been preloaded and compacted.
• Sub-base: 100–150 mm of crushed stone compacted to K98, a level blinding concrete, then a 0.3 mm polyethylene membrane lapped at least 150 mm with taped joints to block moisture rising from the water table.
• Slab: C30 concrete at least 150 mm thick, with steel fibre or two layers of steel mesh.
• Testing before coating: substrate strength of at least 25 N/mm², substrate relative humidity no more than 75%, pull-off adhesion of at least 0.75 N/mm² (section 7.7.2.4).

For fruit plants, Volume 4 (section 7.7.6.9) selects heavy-duty polyurethane or vitrified ceramic tiles with epoxy grout, because the citric and malic acids in fruit juice corrode concrete. Section 7.7.6.7 recommends 316 stainless steel channels where salt or hot clean-in-place (CIP) chemicals are present, and 304 for dry areas and neutral effluent. The comparison in Table 7.7.5 shows the trade-off: polyurethane is seamless and handles thermal shock and impact better; tiles take very high point loads but are brittle when heavy objects fall, and their joints wear over time.

On fire safety, cladding materials and panels must be checked for fire hazard against QCVN 06:2022/BXD (with Amendment 1:2023, consolidated by the Ministry of Construction on 28 September 2026 in consolidated text No. 92), and the design must pass fire safety appraisal (Volume 4, sections 7.7.5.4 and 7.7.13.1). In AgrifoodV’s assessment, on delta ground the slab foundation and damp-proof membrane must be decided together with the coating; however expensive the coating, it will fail when the ground settles. The air inside the plant, where ceiling condensation begins, will be covered in Article 11 on ventilation, air conditioning and positive pressure.

What companies should do

AgrifoodV recommends:

• Prepare a room-by-room finishes schedule (floor, skirting, wall, ceiling, door, drainage) tied to the zoning drawing from Article 7, and include it in the construction tender documents.
• For new buildings on soft ground, require a geotechnical survey and slab foundation design before choosing the coating; for existing buildings, test substrate strength, moisture and adhesion before signing the flooring contract.
• Require the flooring contractor to lay a trial area and submit resin taint test results; specify thickness, roughness and temperature range for each area.
• Specify mineral wool or PIR-core panels with fire test certification, and do not accept substitution with cheaper cores during construction.

AgrifoodV supports companies in defining the design brief, reviewing finishes schedules and guiding the design of processing plants.

References

1. Sutton, K.P. “Construction: Techniques and Finishes”, chapter 13 in Baker, C.G.J. (ed.), Handbook of Food Factory Design. Springer Science+Business Media New York, 2013, pp. 325–353 (sections 13.2 ground slab and falls; 13.5.14–13.5.15 panels and plinths, p. 337; 13.6 floors, Table 13.2, resin temperature limits and taint, pp. 337–342; 13.7 ceilings, pp. 342–343; 13.8 lighting; 13.10–13.11 doors and windows, pp. 347–349). DOI: 10.1007/978-1-4614-7450-0_13.
2. Tập 4 – Công nghiệp thực phẩm [Volume 4 – Food Industry], in the series Ứng dụng khoa học và công nghệ thực phẩm trong phát triển kinh tế [Applying food science and technology in economic development] (draft 2026), sections 7.7.2 (concrete slab, testing existing floors), 7.7.3.1 (suspended ceilings), 7.7.5 (walls, partitions, panels, plinths), 7.7.6.4–7.7.6.9 (skirtings, slip-resistance roughness, floors on soft ground in Vietnam, 304/316 stainless steel, floor finishes, floors for fruit plants), 7.7.9 (drainage), 7.7.10–7.7.12 (doors, windows, hand washing), 7.7.13.1 (fire safety).
3. Regulation (EC) No 852/2004 of the European Parliament and of the Council of 29 April 2004 on the hygiene of foodstuffs, Annex II, Chapter II, point 1(a)–(e); consolidated version of 24 March 2021. eur-lex.europa.eu.
4. 21 CFR 117.20 “Plant and grounds”, paragraphs (b)(4)–(5), Part 117 Subpart B (Current Good Manufacturing Practice), Electronic Code of Federal Regulations, consulted on 29 October 2026. ecfr.gov.
5. QCVN 06:2022/BXD National Technical Regulation on Fire Safety of Buildings and Constructions (issued with Circular 06/2022/TT-BXD) and Amendment 1:2023 (Circular 09/2023/TT-BXD), consolidated text No. 92 of the Ministry of Construction dated 28 September 2026.

Article by AgrifoodV, compiled and interpreted from the sources above (accessed 29 October 2026). This content is not a substitute for design advice or legal advice for any specific project. Cover image: Anna Shvets / Pexels.

© 2026 AgrifoodV. Nội dung được phép trích dẫn khi ghi rõ nguồn và đặt liên kết tới bài gốc; không sao chép toàn văn. Xem Điều khoản sử dụng nội dung.