The things worth knowing before you sign anything

A clearance certificate says that a licensed asbestos assessor has inspected the area after removal and found it fit for reoccupation. The important part is who signs it: an independent licensed asbestos assessor, not the contractor who did the removal. If the same company removes the material and clears its own work, the certificate is worth considerably less than it looks. For friable work, clearance also depends on air monitoring results rather than on inspection alone.

Air monitoring and clearance certificates

Material leaving a site is classified before it moves, and the classification determines which facilities can legally receive it. Clean excavated natural material has the most destinations and the lowest rate. Material that fails its classification has the fewest and the dearest, and the distance to the nearest licensed facility becomes a real part of the price. Mixing contaminated material with clean soil does not reclassify it, it just makes a larger volume of the expensive kind.

Spoil removal and cartage

Water, sewer, gas, electricity and telecommunications all have to be disconnected and confirmed in writing before a structure comes down. Those bookings sit with the authorities, not with the demolition contractor, and they are routinely the longest lead item on the job. They are started the day approval lands rather than the week before demolition. Any contractor willing to start without them is a reason to stop.

Demolition

Bonded material has the fibres held in a cement matrix: fibro sheeting, eaves, roofing, wet area linings. Friable material is loose or broken down enough that the fibres are no longer bound: pipe lagging, loose fill insulation, badly weathered sheeting. Friable work needs a higher licence class, full enclosure, negative pressure, decontamination facilities and air monitoring. The same material can move from one category to the other simply by weathering, which is why condition is assessed before anything is touched.

Friable asbestos removal

Nobody knows how much rock is in a block until the dig opens up. A fixed figure for rock is either padded against the worst case or it is a variation waiting to happen. The honest structure is to price the strip, the access and the cartage from a site visit, and price the rock itself by the cubic metre at a rate agreed before work starts, so the final number follows what was actually excavated. A geotechnical report narrows the range considerably.

Rock excavation

Ask each quote the same six questions. Is asbestos removal inside the price, and is independent clearance inside it too. Do the slab and footings come out. Is the pool included. Who pays if spoil is classified as contaminated. Is the cartage included or charged per load. What is the price if the programme slips because disconnections are late. A cheap number with four exclusions is not a cheap job.

Demolition for homeowners