IN SHORT
- Porous materials absorb moisture. Non-porous ones don't.
- Organic porous materials, such as plasterboard paper, timber and carpet backing, can feed mould.
- Timber becomes susceptible once its moisture content passes about 16%.
- Visible growth on porous materials is often a removal job, not a cleaning job.
Porous, semi-porous and non-porous
Porous materials are the sponges of your home. They readily take up moisture, and when they're organic (made from things like paper, timber or natural fibres) they can feed mould once they're damp.
- Porous: carpet and underlay, insulation, plasterboard, ceiling tiles, paper and cardboard.
- Semi-porous: unfinished timber, plywood, particleboard and masonry.
- Non-porous: glass, metal, plastic, tiles and other finished surfaces.
Mould can grow on non-porous surfaces too, but because they don't absorb water, the growth tends to stay on the surface and is easier to remove.
How growth gets started
Mould spores are in the air all the time. They stay dormant until moisture becomes available, and once a material stays damp for long enough, growth is very likely.
Timber and other wood-based materials become highly susceptible once their moisture content goes above about 16%. That moisture can come from many places: rising damp in older buildings, leaks, construction defects or condensation that isn't managed.
Why the material matters
Because mould can grow into porous materials rather than just on top of them, the industry standard treats them differently. Where porous materials such as plasterboard or insulation have actual growth (Condition 3), they are generally removed and replaced rather than cleaned. Non-porous surfaces can usually be cleaned.
Whatever the material, the moisture behind it needs attention. If it stays, mould can come back.
WHERE DRYSAFE FITS
Our assessment includes moisture readings, so you can see which materials are holding moisture before any work starts. Mould needs moisture, so we take readings and understand where the moisture could potentially be to help you take the right steps to prevent it from reoccurring.