Archive for the ‘basement’ category

Should I Install Sub-Floor Panels When Finishing a Basement?

March 25th, 2010

We are installing a rec-room in our basement. Some of the books I have read recommend installing sub-floor panels over the concrete floor in order to provide extra warmth and help prevent moisture. Is it worth the extra expense? If so, is there a brand you would recommend?


ComfortBase from HomosoteWhen installing carpet or floor covering on a concrete basement floor, always try to add some type of insulation. The concrete slab is in contact with the damp soil. This will make the floor covering cool and subject to condensation, resulting in a musty, mildew smell. A little insulation will make a huge difference.

I suggest ComfortBase from Homosote. It is a 1/2-inch-thick resilient fiber-board that cushions hard concrete and provides a thermal break. The single-ply concrete flooring system is perfect for finishing basements or improving concrete slab floors, while also increasing the floor surface temperature. ComfortBase is easy to apply over concrete floors with adhesive, or floating the panels on the surface.

You can only build a rec-room if the basement is totally dry. It’s a great product but a little hard to find at times. Many home improvement folks don’t know about the it, so you can educate them.

Foundation Cracks

March 10th, 2010

We have a 1100-square-foot 1950’s ranch. The interior basement walls look good, but we have several hairline cracks visible on the one-foot exterior block that we can see. Is urethane caulking a good idea? Thanks!!


If the cracks are vertical and next to an outside corner, it could indicate some wall movement. When a block wall moves inward, a crack often appears near the corner in the vertical mortar joint. You can check the walls for movement with a plumb bob or a long level. The walls should be within 1/2 inch of plumb when compared to the corners.

Minor cracks on the outside of the block wall could be filled with a urethane or polyurethane caulk but this is not a structural repair – just cosmetic. If you are considering selling your home soon, caulk may not be a good idea because it raises the question of what the caulk is hiding.

Check for movement and other cracks inside. If you do have cracks or movement over 1/2 inch, consider a review by an independent basement consultant.

Sump Pump

March 9th, 2010

How long should a sump pump last? Mine runs quite frequently, and is about 13 years old. I have a backup, but I think I should replace the main pump before it breaks down. The crock is 24 inches across and about 5 feet deep. I can’t get any info off the pump to see what brand it is. I would like to replace it with the same one or a better one. Any hints on a good pump and where to get one?


A typical sump pump is designed to operate for 100,000 cycles. The other wear issue is corrosion and the age of electrical parts. At 13 years, I would be looking for a replacement. Jim Murray makes a great line of pumps with high quality construction, and they’re in the Milwaukee area. You will find Jim Murray brand pedestal and submersible pumps at many local outlets.

How long should your pump last? If it runs every 30 minutes, it will operate twice per hour or 48 times per day. In a year, it will operate for 17,520 cycles. So running every 30 minutes, it should last about 5.8 years. Do you think yours is on borrowed time?

Basement Finishing: Insulation and Obstacles

March 4th, 2010

I have a 1920s house with a dry, block basement. I’m thinking of insulating and finishing it, but hesitant about the ceiling. I have a high-efficiency furnace, but the old-style heat runs with foil-faced cardboard between the joists, serving as cold air returns. This area has a lot of other electrical and plumbing obstacles in the way.

I have found fire-rated faced batt insulation. Would it be legal to insulate my basement ceiling with it? Alternately, I’m thinking of just insulating with R-11 Kraft faced, and covering it with straight-edge ceiling tile (2″ x 4″) fastened directly to the joists.


When finishing a basement there is little reason to insulate the ceiling, except to deaden sound transmission through the floor. The upper and lower level will be about the same temperature, so insulation is not needed between the floors.

You should however insulate outside walls. Pay particular attention to the area above the foundation wall to the floor framing. This is an area with a lot of potential for air leaks because of all the framing joints. The best insulation and sealing would be spray-foam from the top of the basement wall, over the sill plate, on the band joist, and to the subfloor. Check with your local code officials for their requirements.

I am not aware of any fire-resistant rated fiberglass. You can’t use a paper or Kraft faced fiberglass because the paper is flammable. Don’t insulate between the floors; it is a waste of materials and time.

Moisture Problems Inside the Home

January 20th, 2010

We have a rental house with home humidity above 60%. The dehumidifier in the basement frosts up. Renters tell me that their clothes smell musty from the dampness, and the windows have condensation. The north side of the house is cold. The house was built around 1957. We want to correct the problem, but don’t know what to do. We have had several furnace contractors give us recommendations such as tiling the exterior of the foundation and grading away from the house. What is the best solution?


You are describing all the problems with excessive moisture in a home during cold weather. You can find a complete analysis along with steps for solving your problem on the Free PDF Articles page. Here’s a link to the article:

Fogged Up? Clearing the Air About Window Condensation Problems.

You need to look for the sources of the problem – a damp basement, plumbing leak, clothes dryer, back-drafting gas appliance, plants, cooking, a humidifier, etc. Eliminating the source should solve the problem.

You should also consider ventilation. Bath and kitchen fans tend to remove excessive spot moisture. People are also a big source of indoor moisture (people, pets, plants).

Insulating a Poured Wall Basement

January 13th, 2010


We are in the process of finishing off our poured wall basement. It will be 2×4 construction and is about 80% below grade. I plan to use R-13 unfaced fiberglass insulation. Is this the best choice to insulate and prevent moisture/mold issues?  My thought was that it will allow the walls to breath. Our home is about 6 years old.



When finishing a basement, you should check with the local building inspection department to understand what they require. In the state of WI, no vapor barrier is to be used when finishing a basement. This confirms your idea – if water ever enters the wall, it can evaporate to the heated space.

The best option is to set the studs an inch or so away from the wall, complete the wiring, then have a contractor spray foam insulation from the floor slab up to the sub-floor of the first floor. This seals any air gaps while providing excellent insulation and water resistance.


Efflorescence (Salt Stains)

January 12th, 2010


I have a client who has what appears to be white crystals appearing on his concrete basement floor. It has been wet in the past, so I am wondering if something is crystallizing after evaporation of the moisture in the basement floor. Do you have any idea what the material might be and how to get rid of it?



The tan and white deposits are called efflorescence. They are from salts and lime in the concrete. Whenever water moves through concrete, mortar or block, the salts move with the water. The water evaporates and leaves behind the efflorescence deposits.

You can remove the efflorescence with a mild acid. You need to remove the deposits for any type of coating to stick. I suggest using UGL Brand ETCH. It’s a powder that you mix with water. ETCH is available at most hardware stores. You can also remove most of the surface deposits with a wire brush – but you must treat with an acid for real cleaning.