Preparing your site: ground, supports and truck access
Contents
In short
- Site preparation comes down to three things: the ground, the supports and truck access.
- Newly filled land can sink, so let it settle or compact it before making supports.
- Before delivery day, check the level of every support and measure its position against the drawing.
- Walk the truck route from the main road to the house position, checking width, bends and power lines.
Start with the ground
Firm-looking soil does not prove it can carry the load. First find out whether the land is original ground or new fill, and how high floods have reached.
- Firm original ground: usually the easiest. Level it and make the supports.
- New fill: many sources suggest leaving it for 6–12 months to settle, or compacting it well first. If you build right away, the supports may sink unevenly.
- Soft or low-lying land: this may need piles. Ask an engineer or a builder who knows the local soil.
- Flood-prone land: ask neighbours how high the water has reached, and raise the floor above that level.
Choosing supports for your site
Ask the seller how many support points the house needs, its total weight, and whether they provide a support layout. This table sums up the common options.
| Support | Suits | Watch out for |
|---|---|---|
| Concrete piers | Firm ground, small houses | Every point must be level |
| Piers with tie beams | Sites at risk of uneven sinking | More time and budget |
| Concrete slab | Firm ground that does not flood | Plan drainage so water does not sit under the house |
| Piles | Soft ground | Should be specified by an engineer |
We do not give footing sizes or depths here because they depend on the weight of the house and the real soil. Do not copy figures from a sample house. For several units or uncertain ground, have an engineer check the design.
Sort out drainage first
Water under the house brings damp and softens the ground. Slope the ground away from the house so water does not collect around the supports. Keep the floor off the soil so air can pass, and leave room to reach the pipes underneath. If the ground under the house is bare soil, talk to your builder about termite protection.
Check level and position
- Set one reference level with a water level or laser, then mark it on every support.
- Check at least twice, because a small error can make doors stick.
- Measure the distances between supports against the drawing, then check that the diagonals match so the house is not twisted.
- Clear concrete crumbs and soil off the supports before the truck arrives.
- Check that the drain and power cable positions match where the house will sit.
Access for the truck and crane
A 3 m wide house on a truck is wider than the truck, and with the truck bed it can stand about 4 m or more. Ask the seller for the vehicle size, then walk the real route.
- Width: the road must be clearly wider than the house, including gates and spots where cars park.
- Bends: long vehicles need room to turn. Look at corners and the entrance to your land.
- Overhead: branches, signs, bridges and power lines.
- Road surface: dirt or gravel tracks may not take the load after rain.
- Crane position: it needs firm, flat ground with room to extend its outriggers fully.
Take special care with power lines. Bangkok's Metropolitan Electricity Authority has warned people to stay at least 3.1 m from 12,000–24,000 V lines. If the crane arm has to work near a line, contact the local electricity authority before installation day.
Checklist before delivery day
- Supports are finished and have cured for the time your builder specified.
- Levels and positions match the seller's drawing.
- The route is clear, and neighbours or the estate office have been told.
- Someone on site can make decisions for the owner.
- Power is available for the crew, and there is a plan if it rains.
- Photos of the site have been sent to the seller in advance.
Frequently asked questions
What if the truck cannot reach the house position?
Ask whether a crane can reach it, or move the position. Some models can be delivered in parts and assembled on site, but agree this before ordering.
Does rain mean postponing installation?
Agree the terms in advance. If heavy rain softens the ground or blocks the truck, the job may move, and the truck may still cost money.
How long should new fill be left?
Many sources suggest 6–12 months, or compacting it instead. A builder who sees the site should make the call.