Interior Surface Preparation Standard Before Any Coating

Purpose

Guarantee that every interior surface handed to coating is clean, dull, sound, dry and dust-free, so adhesion failure is designed out of the job rather than found by the customer four months later. Three failures this prevents: paint sheeting off a semi-gloss hall nobody deglossed, roller stipple full of sanding dust that shows only in raking light, and a kitchen wall where cooking film lets a fingernail lift the topcoat in a strip. Each is a full re-prep on the shop's time, and each is invisible the day the crew leaves.

Scope

Interior walls, ceilings, doors, trim and previously coated masonry in residential plus small retail, office and restaurant spaces worked room by room. It covers cleaning, deglossing, dust removal, spot priming and the release gate.

It does not cover repair beyond a fastener hole or a hairline (drywall repair standard), joint sealant renewal (caulking standard), the instrument work behind a moisture or adhesion decision (moisture and adhesion testing standard), containment on an RRP-regulated pre-1978 job (RRP containment standard), exterior wash (exterior wash and prep day standard), or cabinet refinishing, a different degrease and sanding schedule.

Roles and responsibilities

Procedure

1. Determine the lead status before any abrasion, scraping or sanding. Establish the construction year from the tax record or permit history and write it in the job record. Acceptance: a stated year, and on a pre-1978 dwelling or child-occupied facility one of a documented negative test, a certified-renovator work plan, or a presume-lead decision. What wrong looks like: a tech already sanding while the lead asks when the house was built. Stop rule: a pre-1978 dwelling or child-occupied facility where the work will disturb more than 6 sq ft of interior painted surface, 20 sq ft exterior, or any window replacement, is a regulated renovation under 40 CFR 745 Subpart E, so with no test and no plan it stops here for a certified renovator and that rule's containment under the RRP containment standard, before an abrasive touches paint. Below that area, or in a pre-1978 office or retail space outside the rule's target-housing and child-occupied-facility scope, prep continues; on a dwelling the Renovate Right pamphlet still goes to the owner. Hazard: dry sanding lead-bearing paint puts lead into the tech's breathing zone and into the carpet of a home with children, and no glove or eye protection addresses an inhalation route.

2. Survey the room with the customer present and photograph every defect you are not fixing. Walk each wall with a work light held near-parallel, tape-marking every hole, crack, stain, gloss band, water mark and soft spot. Acceptance: a photo set covering all four walls and the ceiling, plus a written list of items excluded from the price. What wrong looks like: a crack in the photos and not in the list, which becomes a warranty argument. Stop rule: any soft, spongy or stained area of unknown origin goes to the moisture testing standard first, because a wet substrate fails however well it was cleaned. Hazard: none beyond ordinary ladder use; the work light sits on a stable surface, never in a free hand on a ladder.

3. Wash every surface carrying a film, and treat kitchens, baths and smoking rooms as filmed by default. Use a cleaner rated by its own label for the soil present, applied and rinsed as the label directs, working bottom to top so runs do not streak dry wall below. Acceptance: a clean white cotton rag wiped over one square foot comes away with no visible yellow, brown or greasy transfer. What wrong looks like: amber on the rag above a range. Stop rule: repeat the wash on any panel that fails, and if it fails twice, stop and price a degreasing pass as a change order rather than coating over it. Hazard: label directions are legally binding, so mix and ventilate to the label; alkaline cleaners burn skin and eyes, so chemical-resistant gloves and sealed eye protection go on before the bucket opens, and splash in an eye means flush 15 minutes and get medical attention.

4. Degloss every surface above flat sheen, and every surface whose coating you cannot identify. Sand at 180 to 220 grit on walls and trim, full panels rather than spot patches, with a dust-collecting sander wherever the room is occupied. Acceptance: held at a low angle to a work light the surface returns a uniform dull, with no specular highlights in corners, behind door hardware or under a raised panel's top rail. What wrong looks like: a hall that reads dull straight on and shows a mirror strip when you crouch and sight along it. Stop rule: any panel with shiny islands is re-sanded before dust removal, not after the primer. Hazard: sanding joint compound and old coatings releases respirable dust and a nuisance dust mask is not a control; respiratory protection here means a fitted respirator under a written program per 29 CFR 1910.134, and where the mineral content is unknown the room is isolated rather than left open to the house.

5. Fill fastener holes and hairlines flush, and hand anything larger to the repair standard. Press filler in with a stiff blade, leave it slightly proud, sand flush at 220 grit at the label's recoat time. Acceptance: the flat of a 6 in knife laid across the repair rocks nowhere and shows no light gap, and the edge feathers with no ridge a bare fingertip can find. What wrong looks like: a shrunk dimple in a filled nail hole, which the topcoat telegraphs. Stop rule: a second shrink on the same hole means it is deeper than it looked and goes to the drywall standard. Hazard: overhead sanding drops grit straight into the eyes, so sealed goggles rather than safety glasses for ceiling and door-head work, and grit in an eye gets flushed and looked at, not rubbed.

6. Spot-prime every stain, every bare substrate and every repair before the field coat. Match the primer to what is bleeding: a shellac or solvent-borne blocker for tannin, water, smoke and marker; a bonding primer for hard, slick or chalky surfaces; a drywall sealer for new board and skim. Acceptance: at the primer's own label dry time the stain is not visible through the film under a work light at a low angle. What wrong looks like: a water ring returning as a faint tea-colored halo an hour after priming. Stop rule: one more coat of the same blocker; if it bleeds a third time the source is still active and the job stops for a moisture trace rather than a third coat. Hazard: shellac and solvent-borne primer vapor is flammable and heavier than air, so pilot lights, the range and the water heater in that zone go off before the can opens, extraction sits at the low point of the room, and the respirator program above applies. If a pilot cannot be shut off, the product changes to a waterborne blocker rather than the step proceeding.

7. Remove dust from the whole room, not just the sanded panel. Vacuum ceiling, walls, trim, sills, casing tops and floor with a HEPA-filtered vacuum, then wipe walls and trim with a barely damp microfiber, changing cloths each room. Acceptance: a fresh dark microfiber drawn across one square foot of wall and one foot of casing top comes away with no visible gray transfer. What wrong looks like: a clean wall under a casing top that snows onto the wet cut line an hour later. Stop rule: any surface failing the cloth check is vacuumed and wiped again before coating, never carried on a plan to wipe as we go. Hazard: casing tops are reached from a ladder, so it foots on the floor covering rather than a drop that can slide, and nobody stands above the second step from the top.

8. Run the release gate: raking light, cloth, and an adhesion result where the coating is unknown or glossy. Walk each surface again with the light near-parallel and repeat the cloth check. Where the substrate carries an unknown or high-sheen coating, inspection alone does not release it: the adhesion test and its failure-plane read belong to the moisture and adhesion testing standard, which returns a classification. Acceptance: uniform dull, no cloth transfer, and a classification at or above that standard's 4B gate. What wrong looks like: lattice squares lifting in sheets, which is a bond failure in the existing system, not in your prep. Stop rule: below the gate, prep stops and the surface goes to the strip-versus-bond-coat decision with the customer, in writing, before a topcoat is warranted. Hazard: none added here; the knife cut, and its status as a regulated disturbance on a pre-1978 surface, belong to that standard.

9. Release the room in writing or red-tag it. Enter the release line with the room name, date, the tech who prepped, the tech who inspected, and every declined item. Acceptance: no room is released by the same person who prepped it. What wrong looks like: a room coated on a verbal "it's good" with nothing in the record. Stop rule: a room that cannot be released stays red-tagged with tape across the door and takes no coating, whatever the schedule says. Hazard: none, a desk decision, named because paperwork is where an SOP quietly loses its teeth.

The record this produces

Per room: construction year and lead determination; the condition photo set; the excluded-items list with customer initials; wash rag-check result; degloss inspection result; primer product and coat count on each stain; dust cloth-check result; tape classification where run; the release line with two names and a date. It files against the room, not the job, so a callback on the guest bath pulls up the guest bath.

One run of this procedure, filled in

A 1996 four-bedroom, four rooms in scope: kitchen, hall, two bedrooms. Step 1: county record says 1996, so RRP does not reach the job and no test is required. Step 2: 11 fastener holes across the four rooms, one hairline over the hall door head, and a 6 in water ring on the kitchen ceiling. The ring routed to the moisture standard, which read 9 percent on a pin meter against a 12 percent gate, so prep continued.

Step 3 rag check, four panels: hall and both bedrooms clean, the kitchen wall above the range came away amber. Re-washed to the label, second rag check still amber. Two failures on one panel fired the stop rule: prep there halted, a degreasing pass went out as a change order, the customer approved, and the panel took a third wash with a degreaser rated on its own label for cooking film. Third rag check clean.

Step 4: hall and trim were semi-gloss, sanded at 180 grit; the raking-light pass found shiny islands under both door top rails, re-sanded before dust removal. Bedrooms were flat and took a 220 grit scuff. Step 5: 11 holes filled, one re-filled after a shrink dimple; the knife rocked nowhere on the second pass. Step 6: the ceiling ring took one coat of solvent-borne blocker with the range and water heater shut off, and did not reappear at the label dry time. Step 7: cloth transfer clean in all four rooms at the first check. Step 8: hall trim carried an unknown enamel, so the adhesion call went to the moisture and adhesion testing standard, which returned 4B and cleared the gate. Step 9: prep tech and lead are two different names on all four rooms, dated. Two gate failures, at steps 3 and 4, both caught inside the procedure rather than under a topcoat.

References

• 29 CFR 1910.134, OSHA respiratory protection: medical evaluation, fit testing and a written program before any respirator is worn.
• 40 CFR 745 Subpart E, the EPA Renovation, Repair and Painting rule, for the pre-1978 gate at step 1.
• Cleaner and coating labels and technical data sheets, the binding authority on mix ratio, ventilation, dry time and recoat window.
• See related: the drywall repair and texture match standard, the caulking and sealant renewal standard, the moisture and adhesion testing standard.