Danny Lipford » Attics and Basements

How to Solve Moisture Problems Under Your Home

Danny Lipford — Tue, 03 Nov 2009 15:11:23 +0000

We live in an older home that is raised a couple of feet off the ground with a crawlspace under it. In the past few years, the hardwood flooring in several rooms has started to warp and cup. What could be the problem? -Mary

Hi Mary,

It sounds like you may have excessive moisture and humidity in the crawlspace under your home. Here’s what you can do to correct it:

Make sure the ground around your foundation slopes away from the house (1/2″ per foot or more).
Divert rainwater run-off from the roof away from the foundation by installing gutters and extending the downspouts so water is diverted beyond the planting beds and out into the yard.
Check your air conditioner unit to be sure the AC drain pipe isn’t clogged and extend it if needed to direct condensation water away from the foundation of your home.
Inspect the crawlspace under your home. While the soil may be moist, it shouldn’t be saturated or have standing water.
Look for any plumbing leaks as well as excessive dampness, mold, and mildew.
If mold or mildew are present on the joists or bottom of the subfloor, treat under the house with a product such as Concrobium Mold Control (available at The Home Depot along with a fogger to rent).
Clean out any debris and stored items under your house, and fill in any holes or depressions.
Cover the entire crawlspace with thick, black plastic sheeting (6 mil or higher). Overlap the seams by a foot or more and run the plastic up the sides of the foundation.
For extreme moisture problems, consider taping the seams in the plastic together, block the outside vents, and install a dehumidifier in the crawlspace to remove excess moisture from the air.
Good luck with your project,

Related posts:

Faced Insulation Problem in Attic Solved

Danny Lipford — Mon, 19 Oct 2009 17:59:39 +0000

I recently added an additional layer of faced fiberglass insulation to my attic. Since then I noted you stipulated unfaced insulation for the attic if you already have a layer of insulation. What should I do? -Rod

Hi Rod,

As you’ve discovered, since you already had insulation in your attic, the layer of new insulation you added should have been unfaced to prevent moisture from becoming trapped between the layers. The good news is that the solution to your problem isn’t that difficult.

Simply peel the facing paper off the top layer of insulation. Though you might loose a little of the insulation that sticks to the paper, with most brands of insulation, the facing will peel off easily. While you will have spent a little more in both time and materials on the project than if you’d used unfaced insulation to begin with, the results will be about the same.

Good luck with your project,

How to Rid Your Home of Mold and Mildew

Danny Lipford — Mon, 05 Oct 2009 20:49:03 +0000

Our house has a musty smell, and we recently found mold growing inside some of the closets and cabinets. How can we get rid of it? -Joseph

Hi Joseph,

Since mold and mildew require warm, moist conditions to grow, start by eliminating any unwanted sources of water, such as leaks in the roof, dripping pipes, or gaps around tubs or showers. Check to be sure your outside walls are weather tight and that rain isn’t coming in around windows and doors. Finally, correct any moisture problems under your home in the basement or crawlspace.

Humidity levels indoors over 60% can promote mold growth, so monitor the relative humidity in your home with a humidity gauge (hygrometer). If the humidity is high, lower it by running the air conditioner or installing a dehumidifier. Also, consider improving air circulation in your home by using bathroom and kitchen vent fans, as well as paddle or portable fans.

To remove small amounts of mold and mildew, scrub the surface with water and detergent then dry it thoroughly. For more serious cases, use a product specifically made to kill mold. While diluted bleach can kill mold on nonporous surfaces, it’s largely ineffective on porous materials, including wood, and will damage fabrics.

Good luck with your project,

Further Information

How to Prevent and Remove Mold (article)
Eliminating Mold in Your Home (video)
How to Reduce Mold and Moisture Under Your Home (video)

How to Finish a Basement in Your Home

Danny Lipford — Mon, 28 Sep 2009 16:34:56 +0000

I’m planning on finishing our basement myself at little at a time. How should I go about it? -Tony

Hi Tony,

When finishing a basement, you should tackle the job in this order:

Check your local building codes for requirements such as ceiling height, stair proportions, and the location and size of egress windows and doors.
Make sure the envelope around your basement is waterproof, and correct any moisture or humidity problems that may exist.
Test the basement for the presence of radon gas, and take steps to lower it if needed.
Draw a detailed plan for the space.
Frame up any interior walls.
Rough in the wiring, plumbing, and ductwork.
Hang and finish the drywall on ceiling and walls.
Install interior door units.
Install trim molding.
Paint walls and trim.
Install any built-in cabinets.
Finish up plumbing and wiring.
Install flooring.

Good luck with your project,

How to Properly Install an Attic Gable Vent Fan

Danny Lipford — Thu, 03 Sep 2009 14:42:06 +0000

I would like to install an attic vent fan in the gable vent of my house, but to install it on the side away from the prevailing wind will be extremely difficult. Could it be installed instead in the gable vent on the windward side to draw air into the attic?
-Jeff

Hi Jeff,

If your attic uses soffit vents at the bottom and gable vents at the top for ventilation, having a gable vent fan drawing air into the attic would not be the best solution, since it would tend to create positive pressure in the attic which could reverse the natural air flow that occurs when heat rises up through the soffit vents and out through the gable vents.

If you are unable to install the fan on the end away from the prevailing wind, consider installing a roof mounted power vent fan near the top of the attic instead.

Good luck with your project,

Further Information

Combining an Attic Vent Fan with a Roof Ridge Vent

Danny Lipford — Tue, 25 Aug 2009 16:31:10 +0000

Our contractor installed a ridge vent on our roof. We were still getting significant heat build up in the attic, so he then installed a solar roof fan that moves 500 CFM (cubic feet per minute). I noticed you said that these two systems should not be combined. Should we remove the solar vent fan? -Ron

Hi Ron,

Attics are vented using the natural circulation that occurs when hot air rises. Vents in the soffit beneath the eaves at the bottom of the attic draw in cool outside air while gable or ridge vents at the peak of the attic allow heated air to exit. In hot climates, a power vent fan is often mounted behind a gable vent or cut into the roof near the peak to assist this process by forcibly expelling additional hot air from the attic.

Combining an attic power vent fan with a ridge vent is usually not recommended because:

It could reverse the natural flow of hot air out the ridge vent.
If air is drawn in through the ridge vent while it’s raining, it might pull rainwater in with it, which could lead to leaking or mold in the attic.

While a power vent fan combined with a ridge vent can work against the natural flow of air through the attic, it will still exhaust more hot air than not having a fan at all, it’s just not the most efficient way to go about it.

Since your solar vent fan only moves 500 CFM (a third to half that of a typical hardwired attic vent fan), it probably won’t move enough air to reverse the action of the ridge vent. Also, since the fan is powered by the sun, it should turn off when the sky is overcast during a storm, which will keep it from drawing rain into the attic.

So, while it’s may not the most efficient way to cool an attic, in your case I would continue using the solar vent fan. You might want to check the attic occasionally when it’s raining to see if there is any water coming in the ridge vent.

Further Information

Fixing Foundation Drainage Problems with a French Drain

Julie Day — Fri, 26 Jun 2009 16:29:57 +0000

Help! We bought a great house, but soon learned that when it rains, the water runs toward the house and foundation, causing flooding. The cost of professional grading is prohibitive, but we aren’t physically able to do a major DIY grading job ourselves. Any ideas? -Brenda

A French drain around the perimeter of your house would be a great, inexpensive way to divert water runoff without having to regrade the entire yard. Think of a French drain as an underground “gutter” system that collects and drains water before it enters your home’s foundation.

Building a French drain involves digging a 12” to 18” deep channel, that slopes downhill to route water toward a chosen exit point away from the house (make sure you know the location of buried utility lines and pipes before digging). You then put corrugated plastic pipe in the channel, and fill the hole to the top with gravel. Water is lazy – it chooses the path of least resistance – so it will fall into your channels and be diverted before it reaches your foundation.

A French drain will require some heavy digging, as well as hauling and shoveling gravel. It also requires careful planning, as the channels must slope properly or water will collect in them without running off. However, once you’ve planned your design, you could enlist the help of friends, family, or even hired laborers to help with the physical work. Alternately, you could hire a licensed landscape contractor to build the French drain for you, and it would likely be much less expensive than regrading the entire yard or building retaining walls.

In addition to the French drain, make sure any rainwater from your roof is directed away from the foundation of your home – you’d be surprised how much water can be eliminate that way. If you have gutters, extend the downspouts away from the foundation or toward the French Drain.

Further Information

Drainage Solutions (Video)
How to Keep Water from Damaging the Foundation of Your Home (Video)
How to Install French Drains for Yard Drainage (About.com)
How to Create a French Drain (Repair-home.com)

How to Keep Water from Damaging the Foundation of Your Home

Danny Lipford — Thu, 11 Jun 2009 15:33:29 +0000

Rainwater that doesn’t drain away from your foundation can cause moisture problems in basements and crawlspaces. To keep this from happening, check to see that the ground slopes away from the foundation of your home at least 6 inches over a distance of 10 feet.

Adding an extension on the bottom of gutter downspouts is another way to direct water away from the foundation. Also, make sure borders on flower beds have openings to allow rainwater to drain away from the house.

How to Install Fiberglass Insulation in Your Attic

Joe Truini — Wed, 10 Jun 2009 16:19:04 +0000

When installing fiberglass insulation in your home, be sure to put the paper or foil vapor barrier facing toward the heated and cooled living area of the home (down in attics, up under floors, in on walls) to prevent condensation from occurring.

If you are applying an additional layer of fiberglass insulation to your attic, use unfaced insulation on top of the existing insulation to keep from trapping moisture between the layers.

How to Reduce Mold and Moisture Under Your Home

Allen Lyle — Tue, 09 Jun 2009 21:17:29 +0000

The crawlspace under your home can be a breeding ground for mold. Taking the following steps can keep it from happening:

Make sure the crawlspace has plenty of ventilation.
Fill in any low spots in the crawlspace with sand.
Cover the ground under the entire crawlspace with a layer of 6 mil or thicker plastic.
Put a layer of sand on top of the plastic to hold the plastic in place and absorb any excess moisture.