How to Plan Around the Construction Labour Shortage

Why is the construction labour shortage affecting Thai SME contractors?

Construction crews in Thailand are harder to staff today than they were five years ago. Skilled tradespeople — electricians, plumbers, waterproofers, and tilers — have fewer people entering the trade than are retiring or leaving the formal sector, and migrant labour, which fills a significant share of site work, is subject to permitting cycles that can leave a job short-handed for weeks at a time. What once felt like a temporary friction has settled into a structural reality: if your project plan still assumes crews of the same size arriving on the days they always did, the Gantt will mislead you from the first week. The labour constraint is now a planning input, not an excuse to explain delays after they happen.

How does a tight labour market change the way you plan on the Gantt?

When labour was plentiful, you could plan tasks at their theoretical pace — four tilers complete a bathroom in two days — and expect the crew to materialise when the predecessor task finished. In a tight market, that assumption breaks regularly. The bathroom is ready but only two tilers are available because the other two are finishing a job that ran long elsewhere. The task that should take two days now takes four, and the next trade waiting on the bathroom loses two days for a reason that never appears on the original plan. Adjusting for this means planning tasks at the realistic crew size you can already confirm, not the theoretical maximum, and building lead time into subcontractor calls so you are not sourcing a specialist the same week you need them.

Build your crew capacity into each task before the project starts

The most effective adjustment is also the simplest: when you set a task duration on the Gantt planning view, base it on the actual crew size you have already confirmed, not the number you hope to have. If you can confirm three carpenters for framing and the original plan assumed five, adjust the duration before the project starts, not after the crew arrives short. For tasks where you do not yet have a confirmed subcontractor, add a procurement task before the work task on the Gantt — a two-to-three-day buffer representing the lead time to source and commit a skilled trade. That procurement gap is a real part of the schedule, and hiding it inside an optimistic task bar is how most labour-driven delays begin.

Which trades face the worst shortages and how do they affect the critical path?

Shortages are sharpest in specialised trades: MEP rough-in, waterproofing, certain floor finishes, and anything requiring certifications. These are also often critical-path tasks — work that must be complete before a long chain of subsequent work can begin. A two-day wait for a certified waterproofer before tiling can push the handover of an entire zone by a week when downstream trades have no flexibility. Identifying which of your Gantt tasks sit on the critical path and which of those depend on hard-to-source trades tells you where the project is most vulnerable. Those are the tasks to schedule earliest, source first, and protect with the most float.

A worked example: Khun Nattapong's six-month house build in Ayutthaya

Khun Nattapong is managing a new-build residential project in Ayutthaya Province — 320 square metres, six months planned, with a fixed handover date tied to a loan drawdown. At the start of month three, his electrical rough-in crew of four shrinks to two because two workers are held over on a neighbouring site. Rather than waiting to report the issue at the end of the week, Nattapong checks on-site progress updates in SiteBoard that afternoon, sees the task percentage has not moved, and calls the subcontractor that evening. They agree to bring the full crew back in three days, and Nattapong immediately resequences plastering on non-affected rooms to start two days early, keeping other trades productive while the electrical work catches up. The net slip is three days rather than the eight that would have compounded if the gap went unreported until the weekly meeting.

How to reduce your dependence on any single subcontractor

Relying on a single subcontractor for every instance of a critical trade is the most common structural risk on an SME site. When their other project runs long, your work pauses. A practical hedge is to develop two relationships in each critical trade — a preferred sub and a backup who knows your standards and has done at least one smaller job with you. This does not mean splitting every package, which raises coordination cost. It means that when your preferred electrical sub is unavailable for the first week of rough-in, you have a number to call that will not result in an entirely unknown team arriving on your site. Building those relationships before a labour crunch hits costs far less than losing a week to sourcing from scratch mid-project.

Where to place float when you know skilled labour will be thin

The instinct is to add buffer at the end of the project. A more targeted approach is to place float at each handoff between a hard-to-source trade and the next dependent task. If the waterproofing subcontractor is due to finish Thursday and you need the tiler to start Monday, you have built in a one-working-day float. In a tight labour market, that one day often absorbs the reality that the waterproofer needed until Friday. Float placed at the handoffs where labour scarcity is most likely to bite protects the work sequence without compressing the total project window. When you set this up in the Gantt planning view, the effect is visible before any crew has arrived: you can see whether your float choices actually protect the critical path.

How do on-site progress updates help you react before a slip becomes a real delay?

A labour shortage does not always announce itself with a phone call. More often you see it as a task percentage that has not moved by end of the afternoon when it should have reached 60 or 70 percent. The on-site progress update habit — where foremen log percentage and a note at the end of each day — surfaces this signal within 24 hours. A task stuck at 40 percent on day two of a three-day window tells you tonight that you need to call, not Friday when the downstream trade arrives to find no handoff ready. In SiteBoard, those daily updates feed directly into the Gantt so the project manager can see plan versus actual without waiting for a site visit to discover the crew shortfall.

Does sharing the Gantt with subcontractors help with labour coordination?

Yes, and it changes their behaviour in a useful way. When a subcontractor can see their tasks on the Gantt planning view — including the predecessor tasks they depend on and the work sequence that follows them — they manage their own mobilisation more carefully. A sub who sees that their start date depends on a slab that is currently at 70 percent complete will call you if the slab slips, rather than arriving on the agreed date to find the predecessor unfinished. Giving each subcontractor a filtered view that shows their window and what comes before it costs you nothing and creates a shared accountability that a phone call alone rarely achieves.

FAQ: Should I start a task before my full crew is confirmed?

As a general rule, no. Starting a task with half a crew and planning to add workers mid-task usually produces rework and wasted setup time rather than a time saving. The exception is when work areas are genuinely independent — for example, two separate rooms or floors where smaller crews can work in parallel without interfering. In that case, starting with a partial crew in one area while the full crew assembles for another is a deliberate sequencing choice. Mark the constraint explicitly on the Gantt so the dependencies are visible and the recovery plan is clear if the second crew does not arrive on schedule.

FAQ: How much extra time should I add when a skilled trade is hard to find?

A practical rule for SME construction in Thailand: treat sourcing as a task in its own right and add one to two days of lead time per specialist subcontractor engagement on the critical path. For trades where you have no prior relationship — or where a specific skill is genuinely scarce in your area — two to three days of float after the predecessor is a safer minimum. These are not padding numbers; they reflect how long a single call to a busy trade actually takes to convert into a confirmed crew on site.

FAQ: How do I explain a labour-driven delay to the project owner?

Call the owner before they see the gap on the progress page — never wait for the milestone to pass. Frame it as a market condition you identified and are responding to, not a planning failure. Bring three things: the specific task that slipped, the confirmed recovery plan with revised dates, and what you are doing differently to protect the remaining schedule. An owner who watches the live owner sharing link in SiteBoard has likely already seen the actual percentage fall behind the plan. Arriving with a cause and a concrete plan is always better received than a defensive explanation offered after the delay has already cost time.