Drainage installation in Toowoomba, day by day: what actually happens in your yard.

Nobody enjoys having a machine in the back yard. The part that makes it tolerable is knowing what happens next, so this page is the same walk through we give at the free measure, written down: how long each stage really takes, what stalls it, what you have to do, and what the yard looks like when we drive away.

Tick this off the weekend before.

Everything on this list saves crew time, and crew time is money at roughly $95 to $130 an hour. Your ticks are saved in this browser, so you can come back to it, and the print button gives you a clean copy to stick on the fridge.

What actually stalls a Toowoomba drainage job.

Six things cause almost every delay we see, and four of them can be dealt with before the crew arrives.

1. Rock. On the Range side, around Middle Ridge and Rangeville, basalt sits close to the surface, and a trench that was a two hour job becomes a full day with a rock breaker. Add roughly $60 to $140 per metre where it happens. It is the one delay nobody can predict precisely from the surface.
2. Underground services in the wrong place. Plans show where a service was meant to go. Potholing shows where it is. A water main sitting 300mm off its plotted line means the trench moves, and that is an hour, not a day, provided it is found by hand rather than by bucket.
3. Council inspection scheduling. Where an inspection is required the trench stays open until it happens, and bookings usually need 2 to 5 business days. This gets planned at quote stage, not on the morning.
4. Rain. Covered in its own section below, because in black soil it is the big one.
5. Scope changes on the day. Adding a run, moving a pit or changing the outlet after materials are cut costs half a day and a variation. If you are unsure about anything, raise it at the measure.
6. Access surprises. A gate 100mm narrower than it looked, a pergola post in the way, or a garden bed the machine cannot cross. All of it is solvable, and all of it is faster to solve the week before.

Noise, dust, smell, pets and working from home.

A tracked excavator is loud, and the volume peaks during trenching. Expect roughly half a day to a day and a half of that, concentrated rather than spread out. A concrete saw only appears where a driveway or path crossing is involved, and it runs for 20 to 60 minutes, not all day. Queensland limits audible building work to 6:30am to 6:30pm Monday to Saturday, with none on Sundays or public holidays, and we work 7am to 5pm inside that.

Dust is a genuine issue in a dry Toowoomba spring. Black soil is fine and it travels, so shut the windows on the work side, bring the washing in, and cover an outdoor setting you care about. In wet weather the opposite problem applies and the crew works off boards to keep the mud contained. Smell is only a factor if a sanitary drain has to be opened, which is a separate job to stormwater, and it is managed with plugs and short exposure. Stormwater trenches do not smell.

Pets are the thing we worry about most. An open trench and a gate that keeps being opened is a bad combination for a dog, so plan for dogs to be inside, boarded or with a neighbour on trenching day. Children need a clear rule that the trench is out of bounds, including in the evening after the crew has gone. Any trench deeper than about 1.5 metres has to be benched, battered or shored under Queensland work health and safety rules, and anything left open overnight gets covered or fenced. If you work from home, the practical advice is to schedule calls for the afternoon of trenching day and treat the morning as a write off for anything requiring quiet.

What a clean site looks like at the end, and where the waste goes.

At handover the yard should look like this. Trench line backfilled flush or a few millimetres proud, because it will settle. Turf back down and watered, or fresh turf laid with the joints butted. Topsoil, not black subsoil, as the top layer under the turf. Paths, driveway and kerb swept and hosed. Pit lids sitting flush and level with the surrounding surface, not proud enough to catch a mower. No aggregate, offcuts, solvent tins or geotextile scraps left anywhere, including in the trench. Silt controls removed from the outlet. And the excavator tracks brushed off the concrete rather than left to set.

The spoil goes to a licensed facility as clean fill unless you have asked for it to stay. A 40 metre trench at 300mm by 500mm produces about 7 to 8 cubic metres of loose material, which is one to two tandem tipper loads, and cartage plus tip fees run roughly $250 to $600. Excess aggregate goes back on the truck. Pipe offcuts and packaging leave with the crew rather than being buried in the trench, which sounds obvious and is one of the more common things we find when we open up somebody else’s work. Nothing gets burned, which matters on the Downs in fire season. If you are weighing up doing some of the prep yourself, the DIY comparison is honest about which parts are worth taking on, and the ag drains page shows what the finished subsoil work should look like.

Before you pay the balance, ask for three things: the photographs of the open trench showing bedding and geotextile, the flow test video or camera footage where it is part of the scope, and the compliance certificate if the job needed one. Those three items are what a warranty claim, an insurance claim or a buyer's solicitor will eventually want, and they are far easier to get on the day than a year later. The warranty page sets out exactly what to keep and for how long.