How to remove lichen and/or mold from plastic siding

A question - were there elevated spore levels in the rest of the house? It sounds like you disturbed something removing the old drywall. If that's the case you might be OK.

You need to identify the source. Once you've done that you can usually deal with the problem yourself.

The hard part is going to be identifying the source. Mould is usually caused by condensation on the walls, which in turn is caused by poor ventilation and insulation. So there's warm, damp air in the room which when it comes in contact with the cold wall forms condensation.

If there was no visible mould before removing the drywall, then you should be all right - but I'm not an expert so please don't quote me on that.

When you replace the drywall make sure you install adequate insulation and ventilation in the room and then perhaps test again for spores before decorating. If the levels are still high then you'll need to do more investigation.

This is a problem best suited to the professionals, but if you must do it yourself the number one priority is the safety of you and those around you. This can be a very hazardous task, if you do not take every precaution to contain and remove the spores properly.

The first thing you'll have to think about is containment, you don't want to spread the mold spores while you clean the area. You'll want to seal off the area (under negative pressure) with plastic sheeting, making sure all seams are properly sealed.

Once the area is sealed off, you'll need the appropriate clothing.

• Respirator
• Tyvek suit (or other clothing that covers your whole body).
• Rubber gloves.
• Goggles.

Now it's time to start cleaning. Before you begin make sure the infected area is damp, this will minimize the chances the spores will become airborne. You'll start by scrubbing the affected area with a Borax-water mix (1cup Borax/1 gallon water) using a scrub brush, to remove as much of the mold as possible. Wipe up any excess mess with rags, and dispose of them in a thick plastic bag (Contractor bag). Rinse the area with a small amount of the Borax solution, then let it dry completely. Once dry you'll want to pour a small amount of disinfectant (Isopropyl Alcohol), and allow that to dry as well.

Now that the mold has been removed, you can paint the affected area with Kilz if you like. The most important step at this point is to address the moisture problem in the area, or it's likely the infestation will return. You'll want to do what you can to make sure there is no standing water in the area, and that any moisture drains away and dries quickly.