DIY Crawl Space Cleaning Guide

Guide updated for 2024.

Things to Consider Before Cleaning Your Crawl Space

Mold in crawl spaces is very common, especially in wet areas like Indiana. It can often be corrected with a little patience and hard work. Of course, you could hire a professional mold company to do it, but there are reasons for wanting to do it yourself.

The Cost of Crawl Space Mold Remediation

The primary reason for wanting to clean up crawl space mold yourself is cost. This type of work can be very expensive, and if you’re the DIY type, you don’t want to part with your hard earned coin. We understand. We’re DIYers too, which is why we got into such a dirty business. It is likely that you can save some money doing the job yourself, but we will discuss some things besides cost that you may want to consider before getting into the nitty gritty.

Your Buyer May Want the Assurances of a Professional

One of the most common times to discover crawl space mold is in the middle of a real estate transaction. If you are selling your home, you may be required to disclose the presence, or history, of a mold issue (check with your real estate agent or lawyer about laws in your area). Disclosure of a mold issue can trigger panic in a potential buyer, and they may not be convinced that your DIY efforts are sufficient to correct the problem. The deal could fall through, and you could have issues finding another buyer.

Crawl Space Cleanup Is a Long, Dirty Job

Most do-it-yourselfers don’t mind getting a little dirty. However; over the years we have encountered many people who get started on their crawl space cleanup without realizing just how dirty, difficult, and time consuming it is to actually correct a crawl space mold problem. You should think long and hard about the commitments in your life, and how you want to spend your nights and weekends, before you take on a project like this. Of course, it may not be an issue if you have a couple of small spots in a localized area of your crawl space, but the project seems to grow exponentially if mold is spread throughout the space.

Consider Your Health

Severe Allergies or Sensitive Skin

If you experience severe allergies or sensitive skin, it isn’t wise to spend a lot of time in a crawl space. Even with the proper equipment, you could come into contact with mold, bacteria, cleaning chemicals, and all manners of dirt and grime.

Respiratory Issues

It may not be possible for you to work in your crawl space if you have respiratory issues. Even aside from the direct exposure to mold, dirt, bacteria, insulation particles, etc. that may be in the space, it might not be possible for you to spend prolonged periods wearing a respirator.

Claustrophobia

If you have an inability to be in small spaces for an extended period of time, you should avoid going into your crawl space. It is a dark, enclosed space that can strike fear into many. In fact, we have hired more than one employee that didn’t know they had claustrophobia until they put on a face mask and tried to work in a small space. We recommend putting on a respirator and closing yourself in a small closet to test yourself before crawling into your crawl space to work.

Other Health Concerns

You may have bad knees, a fear of spiders, or any number of other health issues to consider. Please pay attention to your health and perform an honest assessment of your abilities.

Think About Hiring a Professional

Given the reasons above, and others, we implore you to at least consider hiring a mold remediation professional. At Indiana Mold Remediation, we strive to provide you the best value possible; affordable crawl space solutions provided by our mold remediation experts. We guarantee our results, and our reputation and customer reviews speak for themselves. If you are outside of our service area, we know there are other reputable mold remediation companies who could give you an honest assessment and a fair deal. We may be able to refer you to somebody if we know a contractor in your area.

For more information on safety in confined spaces, visit OSHA’s page on the subject.

Remove Insulation and Debris From the Crawl Space

Before you go directly after the mold, remove all unneeded materials and debris from the crawl space. This includes anything that will be in the way or needs to be removed anyway like insulation, old plastic sheeting, wood, old pipes, trash, and any other debris left in the crawl space. Heavier items, such as old cast iron drain pipes,  that cannot be removed should be moved out of the working areas as much as possible. Some bricks, stones or blocks can be left in the space for later use to weigh down plastic sheeting or other ground cover.

All fiberglass insulation should be removed from the space. This in and of itself can be a very large job, but is needed to do a sufficient job of cleaning. Over time, fiberglass insulation becomes soiled with mouse droppings and other contaminants, as well as mold spores that have accumulated between the fibers over time. You can drag the insulation out, as is, for disposal or bag it first. If you bag the insulation first, keep in mind the size of the hole the bag will need to fit through to get out. A typical, fully insulated crawl space could require 50-100 contractor size trash bags to empty the space of insulation. If your crawl space access is on the interior of your home, you will need to protect surfaces with plastic sheeting. Take plastic bags out through a near window if the entry door is far away.

Also remove any paper left on the floor joists from the insulation. This may require a fair amount of work if the installers used a lot of staples. Very small amounts of paper under staples are unlikely to cause any major issues and can be left in place.

For these reasons, we don’t recommend that you insulate crawl spaces with fiberglass insulation between floor joists. Insulation can hold moisture at the wood surface, right where you don’t want it.

Foam insulation, either rigid foam board or spray-on foam, can generally be left in place assuming there hasn’t been an adhesive failure. These types of insulation can be cleaned if needed on the surface and rarely support mold growth any deeper than the surface.

Clean the Floor Joists and Decking

Doing the actual cleaning is just going to take a lot of elbow grease and the right cleaner. Finding the right cleaner can take a little trial and error, and may depend upon your comfort level with different chemicals.

Start With Soap and Water

Starting with the safest and gentlest cleaner, create a solution of dish soap and water and put it in a spray bottle. Spray the solution on the moldy surface, and gently scrub it with a soft bristle brush. If the mold on the surface appears to go away with no underlying staining, you are in luck! You should be able to clean the entire space with soap, general cleaners like Simple Green, Dawn dish soap, or other general purpose surface cleaner. In these cases we recommend the use of percarbonate solutions like Oxiclean. The carbonate residue left behind can help prevent mold in the future and some stain removal and brightening of the wood will occur while cleaning.

The percarbonate solution we recommend is one cup of OxiClean (or equivalent brand) with one gallon of hot water. Some minor staining that may remain when you are completed can be bleached out later, so don’t worry if there are a few small areas that don’t appear to come completely clean.

A Stronger Cleaner

If there is still a significant amount of staining (like dark black spots) after the soap and water test, you’ll have to use a stronger cleaning solution. Many stronger chemicals for mold removal involve some amount of bleach. Some use peroxide, but we haven’t found a peroxide solution that is as effective as chlorine bleach based products to remove staining on wood.

While bleach is effective, it does come with added dangers, such as irritation to eyes, skin, and the respiratory system. Ideally, you would always start with a soap and water or percarbonate solution and only use a bleach based cleaning product or mixture on small areas afterward to clean up remaining stains. After cleaning, you can apply a solution of 1 cup of sodium carbonate to 1 gallon of hot water, or 1 cup of bleach to 1 gallon of hot water, to help prevent mold from coming back.

Finishing Touches

Once the cleaning is completed and you are happy with the overall cleanliness of the space, there are a few more things to consider.

Preventative Treatments

Treating the wood with a preventative could help you avoid this issue in the future. It isn’t a substitute for fixing the water issues, but it is an additional layer of protection. A mixture of sodium carbonate (washing soda), sodium bicarbonate (baking soda) and a little soap can be effective and inexpensive. Borate salts like boric acid, borax or Tim-Bor (sodium octaborate tetrahydrate) are also possible choices. Contact Indiana Mold Remediation to discuss available preventative measures.

Vapor Barrier or Encapsulation

A plastic vapor barrier is required by code in most areas of the country, and will likely be required if you are preparing the home for resale. An encapsulation system can go even further to protect your crawl space from the dangers of water and mold.

Drainage Systems

If your crawl space retains standing water after it rains, you need to repair your drainage system or install a new one. Most drainage is a matter of trenching and routing incoming water to a sump pit. This is also something you can do, but it is beyond the scope of this guide to discuss it.

Ventilation

Active ventilation helps to exchange air in the space and prevent moisture build up. Closing all crawlspace vents and actively drawing air from the crawlspace and sending it outside can create a negative pressure that helps draw conditioned air from the home into the crawlspace. This is a way to condition the space and prevent the build up of moisture in the crawl space air. There are reasons you may not want to do this, so if you are in doubt we recommend you contact us, or your local professional, for advice.