Can you insulate during construction, before the roof or plaster is on?

Yes, and the timing is one of the few things in building you actually want to get right early. Walls are the big one: while the frame is up and the wall cavities are still open, before the plasterboard goes on, we can wet-spray cellulose straight into the open cavity so it fills it completely around the studs, noggins, pipes and wiring. There's no drilling and no patching afterwards, which is why it's the cleanest way there is to insulate a wall. Ceilings are different: there you want the roof on and dried in first, then the ceiling pumped once the sparky's run his wiring and the downlights are sorted. The trick is just coordinating the order with your builder so the walls get sprayed at the open-frame stage and the ceiling gets pumped after the roof's on. Get us in early and we'll tell you exactly when to slot each part in.

At the open-frame stage, frame up, roof on so the timber stays dry, electrical and plumbing roughed in, but before the plasterboard is fixed. That's the window. Once those wall cavities are open we wet-spray cellulose straight in so it bonds in place and fills the cavity completely around every stud, noggin, pipe and wire, with no gaps. Because we do it before the plaster, there's no drilling holes in finished walls and no patch-and-paint repair afterwards; the cost and mess of that is exactly what you avoid by getting the timing right. The catch is it's a narrow window in the build program, so the move is to talk to us early and have your builder leave us a slot between the rough-in and the plasterer. Miss it and the walls have to be done as a retrofit later, which means drilling.

After both. You want the roof on and watertight first so the ceiling cavity stays dry. Most insulation performs poorly and has a shorter service life if it gets wet, which the Australian Government's yourhome guide spells out. Then you want the electrician to finish: cabling run, downlights and exhaust fans fitted, so we know exactly where the hot fittings are and can keep the proper clearance around them when we pump. Insulation packed against a hot downlight is a genuine fire risk, so that order matters. Once the roof's on and the wiring's done, a new ceiling is an easy pump. It's open and clear, no old batts to work around, and we lay the cellulose as one seamless blanket across the whole ceiling.

Get us in for a look early, before the plasterer's booked, and we'll map it to your build program. For the walls, your builder leaves us a slot after the electrical and plumbing rough-in but before the plasterboard goes up; that's when we wet-spray. For the ceiling, we come back after the roof's on and the sparky's finished. If you're owner-building or renovating and the walls are already open, that's the moment to call: don't let the plasterer close them up first, because once they're lined the only way in is drilling from inside. We're happy to talk straight to your builder about the sequence; we've slotted into plenty of builds and it's a simple bit of planning that saves you the drilling and patching down the track.