An alternative to dehumidifier?

Q.    We live in a house that is essentially built into the side of a hill and as a by-product of this our basement always requires dehumidification. At a recent street fair I was exposed to a product called Humidex. The product seems to work like a large exhaust fan sucking the cold moist air that is at the bottom of the basement floor to the outside via a vent.

I wonder if you have any experience with this product or if you can offer us some ideas on how to make our basement more usable without the expense of a dehumidifier. The Humidex product boasts many claims which I could not substantiate with any Internet search.

A.    Neither could I substantiate their claim through their website. Nowhere did I find how the make-up air comes from.

A typical dehumidifier, still best for drying the air in a basement

Humidex claims that while the unit exhaust the “dirty, polluted” air from the basement, this dirty air is replaced with clean air. How? Sucking a lot of air from the basement floor to the outside will require that the negative pressure created be equalized. That means that the make-up air will either come from outdoors or get down to the basement through the basement or upstairs windows in warm weather when they are open. That make-up air from outside will be warm and moist, and will be brought into a basement that is kept cooler because it is underground, which compounds the problem. It could lead to condensation on the floor and on the lower parts of the walls.

Since it is not clear whether the unit has an intake as well as an exhaust, I called them and asked the question. The answer is what I suspected: the make up air comes from upstairs through grilles installed in the floor. They claim that the system works very well, that they have sold many units over 26 years with a money-back guaranty.

But of much greater concern is that, if the Humidex does not provide make-up air through the unit, as an air-to-air heat exchanger does, and if the house is reasonably tight and the windows are closed (like in the winter time), the make-up air is very likely to come as a back-draft through chimneys, including the heating appliances – a serious safety problem during the heating season since it will pull into the house the combustion gases that contain carbon monoxide!

Asked that question, the sales person answered that there are enough leaks in a house to provide the make-up air. Knowing that air, like water, moves through the easiest paths, their answer does not satisfy me because the closest source of make-up air is likely to be from the furnace or boiler located in the basement as well. The sales person insists that this is not the case.

At this point, it is up to each prospective purchaser to decide whether or not to buy. I would not for myself.

Waterproofing of basement attracts centipedes

Q.  I live in central New Jersey and had a water problem in my basement. I had a waterproofing company install the type of system where they jackhammer out the concrete along the walls, pierce the foundation block to let the water out, create a pitched trench, use blue stone as a base, and perforated pipe on top of that to catch the water, add a plastic sheet on the wall which goes into the trench and fill the trench with concrete.


The pitched trench leads to a sump pump in the corner and the water is pumped to the outside. The system works fine and we have not had any water problems since. However, we do have something else, which I am not so sure is worth the trade-off of the water.

Since the system was put in, we see centipedes in the basement and some of them make their way to my first-floor kitchen and occasionally to my second floor. These centipedes are extremely unnerving to me. They are about 2 inches, sometimes 3 inches in length, with a thick body, lots of legs and move quite rapidly.

I feel very certain that they are coming from the area of the sump pump, which has a cover, or perhaps up the wall of the trench behind the hard plastic piece. We have pets, so I am hesitant about using an exterminator, although I’m not sure even that will help.

Please let me know your suggestions. These creatures have made living in my home much more unpleasant than the water in the basement.

A.  Centipedes are fond of damp areas. It follows that when the plastic was applied to the walls, it created a damp environment between the plastic and the foundation. I have always questioned the use of lining foundation walls with plastic sheets for that very reason. It is fine to dig a trench in the concrete along the walls and install a drain leading to a sump pump, but why bother with the plastic?

Although I always warn against waterproofing block walls, it is OK if there is a way for the blocks to drain, as they would with the system you had installed. Waterproofing the block walls would not have created the damp environment the plastic lining provides.

To control the centipedes, you have the choice of using residual sprays better applied by a pest management professional who will know where it will be most effective, or drying the basement by removing the plastic, something you may be reluctant to do, understandably, considering what you paid for it. Keep in mind that the best control for many predator insects is the removal of their food supply found in damp environments.

Water forms on new basement walls

Q.   Our new house has water on some of the basement walls. The builder says it is condensation from humidity. It is on the above ground portion of the concrete basement walls. Is this common with new construction?

A.    Yes, it is. Concrete exudes a lot of water because it requires about twice as much water to pour it in place for it to cure properly.

It takes one to two heating seasons for the excess moisture generated by the entire construction process to dry. In your case, the moisture appears only at the top of the concrete walls because it is colder above grade than it is below.

Laundry-room drain is backing up

Q.  My house is a 50-year-old small ranch with a full basement. It has no sump pump. About a year ago, my basement laundry room drain started to back up. About a gallon of water comes up, but goes back down within five minutes or so. If I am doing a few loads of laundry, the first back-up has a sewer odor.

About seven months ago, I had my plumber come and rod out the drain. He worked for about an hour trying to clear it but was not able to do so. He could only go about 22 feet.

The next day, I had a sewer man come over. He put a camera down my main drain. The pipes looked quite clean except for a few small roots for which he said he had some solution to kill them. He could not get the camera down the laundry room drain as the pipe is too small.

He put a transmitter down the drain pipe as far as he could, then went over the basement with something like a Geiger counter. It made a lot of noise by the foundation of my house so he said this is where the tile is broken from the weight of the house over the years. He said he could enlarge the laundry room pipe so he could put a camera down there to see what the problem is. Then he would have to tear the basement floor up at great expense to repair the drain tile.

I dread this as my basement is full of 50 years of living (my husband built the house). I am planning on having another sewer man give me a second opinion. The recent severe rains we had flooded part of my basement from the window wells. Because of the drain problem, the water did not go down fast enough. Your opinion and suggestion are really needed.

A.  Usually, the main drain from a house to the city sewer or a septic tank is made of cast iron. This does not break easily. Furthermore, a house should not settle if built on solid, undisturbed ground. If the house has settled, you would be able to tell, as cracks would develop in the walls, and windows and doors may be binding, etc.

Since your husband built the house, does he remember what he used for the drain pipe? Does your municipality have a building-inspection department that issued your husband a building permit and checked on the excavation before concrete footings were allowed to be poured? These are insurances that the house was built on solid ground.

You should have a Roto-Rooter or similar drain-clearing firm come and run its auger through the pipes – these specialists can go much farther than the 22 feet your plumber did. They have solved clogging problems where others have failed. Ask them if there is any charge if they do not succeed in clearing your drain.

The window wells may need to be cleaned. Be sure to remove leaves and any other debris that gets in the wells. More clearance may be needed between the soil in the wells and the window sills – a foot or more should be the minimum, and the soil should be covered with several inches of stones, still leaving a 6-inch clear space between the top of the stones and the window sill. The drain pipe may need to be shortened.

You may also have a grading problem, causing water to get in the wells from the sides. Check it out and correct any negative slope around the wells, so surface water runs away from the foundation.

But if rain came in through your window wells because of the failure of the drain in them, consider installing plastic covers over the wells to keep the rain from getting in them.

If it is determined, after all else, that the sewer pipe is broken, see if it can be repaired from outside. Some skilled plumbers and septic contractors have made such repairs by digging a small tunnel under the footing to replace a piece of pipe under a slab if there is a joint not too far back under the slab.

Water from driveway leaks into basement

Q.    I have a cement driveway that is sloping toward the house. I moved the basement steps, used Waterplug, and troweled 2 inches of cement on the block wall. I also put up a cement curb next to the house outside but the basement still leaks. Do I have to tear up part of the driveway and re-taper it?

A.    If it is definitively ascertained that the leakage is taking place at the joint of the driveway and the house foundation, you may be able to have a concrete contractor or a mason apply a vinyl-reinforced cement topping to the existing driveway to reset the slope for a short distance from the house, just enough to keep the water away from the foundation. He or she should know how to clean and prepare the existing concrete driveway for the patch to stick to it.

You can determine yourself if the leakage is occurring at that joint from surface water by running a garden hose on the driveway toward the joint between the driveway and the foundation.

If this test does not result in leakage, the water is coming from somewhere else — perhaps from underground — and that is much harder to take care of. In that case, the simplest solution is to let it happen and control it from the basement by installing a fiberglass gutter system that is glued to the concrete floor against the foundation wall. It collects the water and leads it to a sump pump.

Water accumulates in basement entrance

Q.  A basement entrance that is about five feet deep was remodeled a couple of years ago with new walls and stairs. With heavy rainfalls, there is now an accumulation of water at the bottom of the stairs, an area of about 4 by 8 feet.

What to do? Installing a sump pump is not possible as there is no practical means of discharge due to the property location. Would it be feasible and workable to install a drain in the middle of the bottom of this basement entrance way? How would this be done (if you deem it possible) and to what depth would the hole be, and would it filled with stones or what other material?

This was suggested by a handyman but after spending the money to replace the walls and stairs I would like to get an expert opinion to make sure the plan works

A.  My question is to ask why the people who installed the new walls and stairs did not also build a drywell under the bottom pad that I assume to be concrete. That’s simply negligent, and you have a right to have them correct this gross oversight. Enough of the 4-feet by 8-feet concrete should be removed to allow digging a deep drywell.

In my opinion, the entire 4-foot by 8-foot pad should be removed and a hole at least 3-feet deep excavated. I would not fill it with stones as they will reduce the amount of the well’s water capacity. Drywells have a limited life as they fill with soil that gets in them so it is important to make them as big as possible.

The perimeter of the hole should be lined with concrete blocks set on edge so the holes in them are horizontal to let water reach and be absorbed by the soil of the walls. The blocks should be stacked to the level of the bottom of a new pad. The pad needs to be built on a form resting on the blocks and must be reinforced with steel re-rods. A drain should be set in the middle of the pad and the concrete must gently slope from the perimeter to the drain for it to function properly.

Frost causes cracks in foundation

Q.    I have a room in the basement that was built as an addition afterwards by previous owners. Above it is a cement parking area. The area is damp in the summer so I use a dehumidifier. With this long winter in Canada, with thaw and freeze cycles, I have noted cracks in the foundation bricks. Prior it was treated with Zinsser WaterTite Waterproofing Paint.

The ideal situation is to excavate from the outside but it is not my property and the expense is high for a non-used room.


  1. Should I continue to use the Zinsser WaterTite for repair?
  2. Should I look at supporting inside foundation with cement brick foundation on 3 sides?
  3. What do the cracks indicate?

See attached photos [reproduced below]. Any suggestions would be appreciated!




A.    The cracks indicate that frost pressure from outside has pushed the walls in slightly. This may have been caused by extensive water penetration, perhaps from a negative-grade condition outside, which could include the parking area. If the ground and the concrete slope toward the foundation, rain and melting snow in sufficient amounts can saturate the soil, and frost does the rest.

A dehumidifier is fine to use in the summer to lower the relative humidity, which could cause molds to grow.

Painting the inside of hollow block walls with waterproofing coatings is a bad idea. Water can accumulate in the blocks’ cores and cause serious moisture problems in the living areas. I would not recommend using any of these coatings.

The photos you sent do not show that the situation is very serious at this time. But recurring yearly events are likely to aggravate the situation.

The outside grading should be examined carefully, and so should the slope of the parking area. Adding soil to change the slope of the grade is relatively simple, but the concrete area is more involved. Discharge from downspouts should also be checked to make sure that it does not remain close to the foundation.

Since this is not your property, any repairs should be the responsibility of the owners.

Painting over mold stains

Q.    We had a new home built and after we closed, we noticed spotty areas of mold on the ceiling of our unfinished basement. Either the wood used already had the mold on it or it occurred during the construction process when they closed up the basement without adequately drying it out. The builder was pretty responsive and hired a mold remediation company to clean it up. After they completed their process we were left with “mold stains” on the wood. It is a year later and there is not further growth. Should we paint these areas? We do not want any problems selling the house in the future.

A.    The mold developed because of the high level of moisture exuding from the concrete and other components of the building process. You are fortunate in having had a responsible contractor who took care of the problem. You certainly can paint the basement ceiling to make it more attractive. Prime first with a stain blocker like B-I-N.