Surface Sampling

Surface sampling helps to definitively determine if what you suspect might be mold on a surface is in fact microbial growth and it can measure how far along the growth is. There are a variety of ways to perform a surface sampling including swab, tape, carpet, and wall. When taking surface samplings for mold testing, you will want to take unique samples for each room, mold color, and mold surface that appears to be affected.

Swab Sampling


In a swab sampling, a moistened swab is contained in a tube, then removed and wiped across a one inch square area on a surface to garner a sample. You should see visible particles on the swab and then reinsert it into the tube. Different swab manufacturers may have different directions for their particular devices so be sure to read the instructions closely.

A swab test can immediately identify if a fungus is present and what type of fungus it is. This is a good test to utilize when mold is visible or if other signs of mold are present. It is a popular form of mold testing because it is cheap, quick,and can tell you every kind of mold that is present in the sample, even if the spores have not yet become airborne.

Tape Sampling


The tape method is the most common kind of surface sampling when testing for mold because you can take many samples quickly. Be sure to clearly label all of your tape samples since you will likely have many. This will also help you better organize your lab results.

To take a tape sample, you simply remove the slider as well as the protective liner (make sure the sticky side does not touch anything besides the surface sample area as this will contaminate results), put the sticky side down on the surface and press down gently to make sure it gets full contact, lift the slide and return it to its protective case. Then mail your samples to a laboratory and await your results.

Carpet Sampling


Taking a sample of a carpet involves the use of an air pump (set at 15 liters per minute), rotameter, carpet cartridge, and tubing. These tools are used to vacuum a small area of the carpet. Mold spores can remain deep inside of a carpet over a long period of time even after cleanings and vacuums, so they can provide insight into the history of the mold growth in that room. Refrain from deep cleaning the carpet before taking a sample as you want as much evidence as possible for your test. Choose a four inch by four inch area that gets little foot traffic, but not zero foot traffic like under the couch.

Insert the cartridge as deep as you can into the carpet and take your sample until you see particles collect on the cartridge filter. Do not exceed ten minutes of sampling time. If dirt appears on the filter, then throw this sample out and start again.

Wall Sampling


Sometimes a water damaged wall can be a small sign of what is hiding behind it. Therefore, mold testing may need to be performed in the cavity behind the wall. In order to do this, a small hole must be drilled into the wall (with written permission from the property owner beforehand). After the dust has settled from the drilling, insert the collection tube into the hole and turn on the air pump for about two minutes with a flow rate of 15 liters per minute.

Sometimes there are holes next to light switches and outlets where you can insert a collection tube to perform the wall sampling, which would allow you to avoid drilling into the wall altogether.

Proper Care of Testing Devices

It is important to clean all testing devices before and after use. If there is debris of any kind caught in the devices, it could drastically alter the results. After esting for mold, it is particularly important to thoroughly clean the instruments as there may be some mold spores remaining and improper cleaning may spread those spores to new areas.

Sampling devices and one-time-use tools should be stored in a cool, dry place. If slides, swabs, cassettes, or tapes are over a year old, then you should not use them and restock with fresh ones.

Mold Test Kit

Purchasing a mold test kit is not recommended. They are extremely unreliable and could be a scam. The use of an EPA approved laboratory to check the status of mold spores from any kind of sampling is the most reliable and legitimate route for mold testing.