How to Schedule Painting to Avoid Rework and Delays

Why is painting one of the most disruption-prone trades on a Thai build?

Painting looks simple — a crew, some rollers, a few days of work. But on a typical Thai residential or commercial build, the painting programme sits at the intersection of almost every other finishing trade. The wall must be fully plastered and the plaster must have cured. Electrical conduit and plumbing pipes must already be installed inside the wall before it closes. Gypsum ceiling boards must be fixed before ceiling paint can begin. Tiles and screed must be laid so painters can protect the floor or avoid working next to grout that is still setting. When any of those predecessor trades run late, the painting crew either sits idle or starts on surfaces that are not ready, creating extra coats and sanding that the contractor pays for twice. Thai SME contractors frequently underestimate the painting programme because they treat it as a single task rather than a sequenced set of tasks with real dependencies.

What is the correct painting sequence for a Thai residential or commercial build?

The painting programme on a typical Thai build runs in four distinct phases. Phase one is priming, applied to plaster walls only after the plaster has cured for at least seven days and all first-fix MEP inside those walls is confirmed complete. Applying primer before plaster is fully cured traps moisture and causes blistering within months. Phase two is filling and sanding, addressing plaster cracks and surface blemishes that primer reveals. Phase three is the first topcoat, applied to primed and filled walls only after sanding and dust clearing. Phase four is the most critical sequencing decision: the gap between the first topcoat and the final topcoat must include all second-fix MEP — electrical switch plates, light fixtures, air-conditioning installation, and sanitary ware — plus door hardware and any tiling that abuts the wall. The final topcoat is applied after all trades that touch the wall surface are finished, to cover marks from the follow-on work. Painting everything in one pass, without the two-topcoat gap, means repainting every surface touched after the final coat — which is typically most of them.

How do inter-coat drying times translate to Gantt task durations in SiteBoard?

In SiteBoard's Gantt planning view, each painting phase becomes a separate task with a minimum duration based on the material and site conditions. In Bangkok's humidity, water-based topcoat requires a minimum of twenty-four hours between coats for surface drying and forty-eight hours for full recoat adhesion. Oil-based enamel on doors and skirting requires at least forty-eight hours between coats. Set up the Gantt with five painting task groups per zone: plaster cure, priming, filling and sanding, first topcoat, and final topcoat. Set the final topcoat task's predecessor to the later of the first topcoat completion and the second-fix MEP task completion. This dependency ensures the painting crew does not start the final coat before the electricians and plumbers finish their second-fix work — the single most common cause of paint damage on Thai residential sites.

A real example: a Bangkok shophouse where painting rework cost 42,000 baht and three weeks

A contractor in Ladprao, Bangkok, was finishing a four-storey shophouse renovation on a twelve-week programme. The painting subcontractor completed the first topcoat in week eight on schedule. The electrical second-fix team then ran four days late installing light fittings and switch plates. Rather than wait, the site supervisor allowed painting to continue with the final topcoat in the same week, expecting the electricians to be careful. Within two days, the electricians had scuffed six door frames, left adhesive residue on two feature walls, and cracked the paint surface around three socket boxes. Touch-up painting required cutting in and repainting full wall panels on three floors — not just spot-filling — to match the original finish colour and batch. The re-painting cost came to 42,000 baht in labour and materials, and delayed handover by three weeks because the contractor needed the touch-up dry before final cleaning. Had the Gantt planning view in SiteBoard linked the final topcoat task to the electrical second-fix task with a finish-to-start dependency, the site supervisor would have seen the conflict before work began.

How do you protect fresh paintwork from follow-on trades in SiteBoard?

The best way to protect fresh paint is to remove the need for other trades to work near it. In SiteBoard's Gantt planning view, structure the schedule so the final topcoat is the last task in any given zone before final cleaning and snagging. If this is not possible — for example, in an apartment block where air-conditioning installation overlaps with painting on different floors — set zone-by-zone dependencies so painting and second-fix MEP are always in separate zones at the same time. Add a one-day buffer task between second-fix MEP completion and the final topcoat in each zone to allow the MEP subcontractor to clear tools and debris before the painters move in. Record zone-by-zone status as on-site progress updates in SiteBoard so the painting subcontractor knows which zones are clear before mobilising, and the owner can see on the owner sharing link which floors have received their final coat.

What should you record for painting milestones in SiteBoard?

When tracking the painting programme as on-site progress updates in SiteBoard, record the phase completed, the product applied, and the room or zone covered. For the priming phase, note the brand and thinning ratio, and attach a photo of the primed surface. For the first topcoat, record the colour code and batch number — different production batches of the same colour can look visibly different, which matters if touch-up is needed after handover. For the final topcoat, record the date and attach a photo of the finished surface per zone. These records take under two minutes to create from a mobile phone on site, but create a timestamped, photo-backed record that serves as evidence if the owner disputes the finish quality after handover. A photo of the completed final coat, dated before follow-on trades returned to the zone, shows that the contractor delivered a sound surface.

FAQ: Can painting start before all wet trades are finished?

Priming can begin in a zone as soon as the plaster has cured and all first-fix MEP work inside those walls is confirmed complete, even while wet trades such as tiling are still active in an adjacent zone. What cannot be done is applying topcoat in a zone where screed or tile adhesive is still curing, because dust and vapour from the curing process contaminate the paint surface and cause adhesion failure. The rule is: a zone is ready for topcoat only when all wet materials in that zone have reached their design cure time and the floor surface is clean and stable. Running painting in a zone-by-zone rotation — primering zone A while tiling finishes in zone B, then first topcoat in zone A while zone B begins priming — maximises crew productivity while respecting material physics. Plan this rotation in SiteBoard's Gantt planning view rather than leaving it to on-site judgement.

FAQ: How do you schedule touch-up painting before project handover?

Touch-up painting is best planned as a formal task in SiteBoard's Gantt planning view, not an afterthought the painting crew handles on the last day. Set a touch-up task to begin forty-eight hours after all second-fix trades have finished and furniture or fit-out items are in place, to capture every scuff and mark from the final mobilisation phase. Allow one day per floor as a minimum duration for a standard residential project. Set the touch-up task as a predecessor to both the final cleaning task and the owner walkthrough inspection milestone. If the owner sharing link shows the client that the walkthrough is scheduled before touch-up is complete, they will arrive to see marks on the walls. Sequencing the touch-up before the inspection signals to the owner that the contractor is systematic rather than reactive.

FAQ: What is the minimum number of coats for a quality finish on Thai interior walls?

Thai interior walls on a standard residential project typically receive one coat of primer, one filling pass where needed, one first topcoat, and one final topcoat — four steps in total. Using a quality primer and two coats of a reputable brand such as TOA, Nippon, or Dulux is generally sufficient for a uniform finish on well-prepared plaster. Applying only a single topcoat over primer is a common cost-cutting shortcut that the owner often does not notice at handover but will notice within a year as lap marks and uneven coverage appear. Skipping primer entirely on new plaster is a more serious defect: the plaster absorbs the first coat unevenly, the finish appears patchy, and adhesion to the substrate is weaker than the manufacturer's specification. Building all four phases as separate tasks in SiteBoard's Gantt planning view, rather than a single painting task, makes it visible to the project manager and to the owner on the owner sharing link that every phase was completed in order.