null
  Loading... Please wait...

Ask Mr. Crawlspace

What do I do with my foundation vents when I close my crawl space?

It is best to leave existing foundation vents in place and seal them with a foam insulation board. The insulation board should be cut to the size of the vent and installed from the interior of your crawl space. Once the insulation board is fitted, the edges should be sealed with a caulking and/or foam adhesive.

Read More »


I am building a new house. Should I arrange to have vent holes put in my foundation?

No, unless they are required by code in your area.  For a closed crawl space in areas that are not required to have vent holes, just have your mason install the foundation without openings. [...]

Read More »


What about the gaps around electrical and plumbing penetrations between my crawl space and living space?

Sealing around electrical and plumbing penetrations prevents air from moving into the wall or living space from the crawl space.Use a caulking or expanding foam that is fire rated for sealing these voids to make sure you meet state and local building code requirements.

Read More »


Should I plug up any holes between the crawl space and the house?

Yes, closing penetrations between the crawl space and living space prevents air contaminants in the crawl space from entering the living space. Use a caulking or expanding foam that is fire rated for sealing these voids to make sure you meet state and local building code requirements.

Read More »


What’s the best way to insulate my crawl space?

Most building codes allow for several options such as insulating the floor joist system or insulating the foundation walls. In my opinion, insulating the walls is more efficient and, in most cases, is less expensive. [...]

Read More »


Do I need to have insulation between the floor joists in my crawl space?

No, not unless it’s required by code. The best method of insulating the crawl space is to use a closed crawl space system with insulation on the inside of the foundation walls. Studies by Advanced Energy have shown savings of up to 18% on new structures using closed crawl spaces and wall insulation. (Be sure to check [...]

Read More »


What if my insulation is stringing down and has mold and mildew on it?

Stringing and falling insulation means the insulation has been wet at one time. Wet insulation offers no insulating values, so remove it and remediate the mold and mildew. Be sure to use insulation on the interior of the exterior foundation walls [...]

Read More »


What if I see mold or mildew on the floor joists in my crawl space?

Mold and mildew can be easily removed with appropriate cleaners. Some cleaners just clean the mold stains off the wood but don’t prevent future growth, so make sure you know which kind is being used. (Always follow product labels and directions.) [...]

Read More »


What should I do about plumbing leaks?

Get a professional plumber to correct any plumbing leaks before an enclosed crawl space is installed. But in addition to fixing leaks, make sure that condensation drains and pressure relief valves are plumbed to the exterior or to an appropriate drain within the crawl space. Your plumber can handle this, too.

Read More »


How do I fix water problems in my crawl space that are coming from the outside?

Correct the problem from the exterior if you can. Often you have to redirect the flow of water by installing gutters, improving grade around the house so the grade slopes away from the house, installing a foundation drainage system or installing an interior drain system. (Always check your state and local building codes and contact your local pest management, [...]

Read More »