Below stairs, properly clean.

Cellars are a distinct cleaning discipline. They're below ground (so moisture migrates through the walls from surrounding soil), they're often unventilated (so airborne spores and dust accumulate), and they're typically used as long-term storage (so clutter builds up over years). Standard cleaning methods that work upstairs — dry dusting, mopping with a wet mop, aerosol sprays — are wrong for cellars. They either spread spores around or trap moisture against surfaces that are already damp.

Our cellar cleaning protocol starts with HEPA-filtered extraction. We use a sealed-vacuum with a 0.3-micron HEPA filter to capture dust, cobwebs, debris and any suspected mould spores without recirculating them into the air. This is critical — cellar dust often contains mould spores, mouse droppings, and historic coal dust, all of which should be captured not aerosolised. Once the loose debris is removed, we assess the surfaces for damp staining, efflorescence (the white mineral salts left by evaporating water), and active mould growth.

We never apply bleach or aggressive biocides to a damp cellar without first addressing the source of moisture — that just kills the visible mould and leaves the substrate primed for re-growth within weeks. Where appropriate, we apply a borax-based or quaternary-ammonium biocidal treatment that kills spores at the substrate, and we'll flag any ongoing damp source (high ground level, failed tanking, broken downpipe) for your attention. Many cellar cleaning jobs end with a recommendation to speak to a damp specialist before re-fitting storage.