Built on knowing what stone does when it's cleaned correctly

Diagnosis first. Method second.

Every surface tells you what it needs. You just have to know how to read it.

Robert Burns started Trebor after twenty-five years of watching the same damage appear on the same buildings: black crust that had been pressure-washed rather than steam-cleaned. Soft brick acid-treated by contractors who assumed all brick is the same. Hard cement mortar on Victorian walls that were built to breathe.

None of it was malicious. Most contractors doing stone cleaning work do their best with limited knowledge of historic materials. But the consequences land on the building, and they last longer than the contractor's invoice.

The diagnostic approach we use is simple in principle: look at the building, identify the stone or brick, identify the soiling type, and specify the method that matches both. In practice, it takes years to build the eye for it. We've spent twenty-five of them on London's building stock specifically.

What we believe about restoration

The best restoration work is invisible. Not in the sense that nothing has changed — a clean Portland stone facade is visibly different from a soiled one. Invisible in the sense that the method leaves no trace of itself. No rounded arrises. No etched tooling. No shadows where a nozzle tracked too slowly. The stone looks like stone. The building looks like itself.

This is achievable. It requires the right method, correctly applied, with the patience to work at the pace the material demands. We don't hurry the work. We don't substitute a faster method because the programme is tight. The building is still standing when the scaffolding comes down, and it will be standing long after both of us are gone. That deserves care.