Scheduling Multiple Trades Without Conflict on Site

Why does trade sequencing cause more delays than almost anything else on a Thai build?

Walk onto a typical Thai residential build in week six and you might find the electrician pulling cable through a wall the plasterer is scheduled to close tomorrow, while the plumber is waiting for the structural team to finish cutting the slab penetrations. Nobody is idle because they are lazy; they are idle because the work has a natural order that the schedule never captured. Multi-trade conflicts — a crew that cannot start because the preceding trade has not finished, or finished work that must be torn out and redone — are responsible for a large share of the delays Thai SME contractors experience on site. The root cause is almost never a shortage of labour. It is a schedule that treated each trade as an independent task rather than a linked sequence that must run in the right order.

What is the correct trade sequence for a typical Thai house build?

The standard order on a Thai residential build runs roughly as follows: structural work first, then MEP rough-in — plumbing pipes and conduit before walls close — then wall and ceiling closure, then plastering, then electrical second-fix and plumbing second-fix, then tiling and floor finishes, then painting, then final sanitary-ware and fittings. The exact sequence shifts with the project type — a shophouse fit-out or an office renovation runs differently from a new-build villa — but the underlying principle holds: no trade should be closing a surface before every trade that needs to penetrate that surface has finished inside it. Violating this order creates rework. Rework is always more expensive than a one-day buffer.

How do task dependencies in the Gantt planning view prevent crew conflicts?

The Gantt planning view in SiteBoard lets you link tasks as dependencies so that the start of one task is locked to the completion of another. When you mark MEP conduit rough-in as a predecessor to wall closure, the Gantt shows wall closure starting only after the conduit task is complete. If the electrician runs two days late, the wall closure task shifts automatically and the impact is visible on screen immediately — not discovered on the day the plasterer crew turns up expecting a wall to board. Building dependencies into the plan at the start of the project means the schedule does the sequencing work for you, without relying on memory or a weekly phone call to track which trade must finish before the next can start.

A worked example: a six-unit townhouse in Rayong

Consider Khun Wanchai, running a six-unit townhouse build in Rayong with a 4.8-million-baht contract. He separated electrical rough-in, plumbing rough-in, and wall closure into distinct tasks in SiteBoard, setting plumbing rough-in to finish before electrical and electrical before wall closure. In week nine, the plumber fell three days behind on Unit 2 because a coupling delivery was delayed. The dependency chain showed the impact immediately: electrical on Unit 2 could not start, and wall closure on Unit 2 shifted three days. Wanchai called the electrician before they mobilised and redirected them to Units 1 and 3 instead, keeping two active work fronts running. Without the Gantt dependency, the problem would have surfaced on the day the plaster crew arrived on site — too late to redirect anyone.

Should you organise the Gantt by trade or by room?

Organise by trade, not by room or by floor. The plumber gets all plumbing rough-in tasks linked in sequence; the electrician gets all electrical rough-in tasks in the same way; plastering runs as its own dependent chain that cannot start until both rough-in chains are complete. This structure gives each subcontractor a clear picture of what is theirs, when it starts, and what must finish before they can begin. Share the owner sharing link with your senior subcontractors — not only with the owner — so they can check their own task status from their phones. A plumber who can see on their mobile that concrete penetrations are still in progress will not mobilise a full crew to site expecting to start work on a task that is blocked.

How much buffer time should you leave between trades, and when can you remove it?

A common mistake is scheduling electrical second-fix to start the morning after plastering finishes, with no margin. In practice, plaster needs drying time and a coat of primer before sockets and switches can go in cleanly. On a Thai house build, two to three days between plaster completion and electrical second-fix is a realistic minimum; tiling trades typically need one to two days after slab preparation before they can start. At handover, allow one week between painting completion and the final fit-off so the paint is cured before the client walk-through. Reduce the buffer only when you have run the same sequence enough times to know the real drying duration for that climate and material. A zero-day buffer means any single-day slip cascades into the next trade immediately.

How do on-site progress updates tell you a trade is running behind before it is too late?

Every update a subcontractor logs through the on-site progress updates feature in SiteBoard shows the percentage complete for that task in real time. If electrical rough-in is at 40 percent on the day it should be at 80, the gap tells you immediately that the wall closure behind it needs to shift before the plasterer books the next site day. You do not need to call the electrician to learn this; the progress figure makes it visible as soon as the update lands. Attaching a photo of the current state of the rough-in creates a dated visual record of where each trade stands on any given day — useful for planning, and equally useful if a subcontractor later disputes what the agreed scope covered or when a particular stage was actually completed.

FAQ: What should you do when one trade finishes late and blocks the next crew?

Update the delayed task in SiteBoard to its new completion date, and the Gantt shifts all dependent tasks automatically. Contact the blocked trade before they travel to site and agree a revised start date. If the delay is long enough to affect the overall programme, check whether the blocked crew can be redirected to another zone or another project temporarily — two days lost on Unit 2 do not have to idle a team that can move to Units 4 and 5. Document the cause of the original delay in a task note at the time it happens. If the delay came from a late material delivery or a design change, that note becomes your record for any programme extension conversation with the owner, or for a variation claim against the subcontractor who caused the hold.

FAQ: Should the subcontractor log their own progress, or should the foreman do it?

Either works, but consistency matters more than who does it. The best approach is for the site lead of each trade to log a progress update against their own tasks at the end of each working day using the on-site progress updates feature from their phone. Your project foreman confirms and flags anything that looks inconsistent. This gives real-time visibility without adding to your own workload, and it puts the subcontractor on record for their own progress — which matters if there is later a dispute about how far along a phase was when a problem occurred. If a subcontractor is not willing to log their own updates, assign one foreman to log on their behalf at the end of each day, even if it is only a percentage and a single-line note on what was done.

FAQ: Can two trades work in the same building at the same time?

Yes — with zone separation. If the Gantt is structured by unit or by floor, the plumber can be finishing rough-in on the ground floor at the same time the electrician is doing second-fix on the first floor, as long as the dependency logic within each zone is correct. Zone-splitting is one of the most effective ways to recover a delayed programme: keep the sequence within each zone intact but stagger the zones so one is always a phase ahead of the next. Set up each zone as a separate task group in SiteBoard so the overlaps are deliberate and visible in the plan, not accidental. When two trades genuinely share the same physical space on the same day, expect productivity to fall by roughly 20 to 30 percent — factor that into your task duration, or make a deliberate trade-off between pace and output quality.