DeHaven Construction Company
"Specializing in Stucco, Stucco Repair, Interior Painting, Exterior Painting, Texture Coating (Texcote™) & Elastomeric Coatings"
WATER SEEPAGE - CAUSES AND CONTROL (cont.)
Moisture Problems: Inspection
The inspection for water seepage into the basement or crawl space should begin during your exterior inspection. As you walk around the house, record on your worksheet the location of those conditions that can cause water to accumulate around the foundation: faulty gutters and downspouts, improper grading, settlement of walkways, and so on. When you go into the basement, and if there are problem conditions on the exterior, the walls and floor opposite those areas should be checked first for signs of water penetration. Water stains and deposits in the corner of a foundation wall can be a result of a faulty downspout. Even if there are no indications of past or current water seepage, the exterior problem conditions should be corrected.
A basement can have a water seepage problem and be dry when you look at it. Many clients have told me that there were no seepage problems in the basement. After all, they looked at the basement during a heavy rain and found it "bone dry." So how could there be a problem? Well, as previously discussed, there are many causes for water seepage, and depending on the cause, a single rain might not result in seepage. For example, if water penetrates into the basement through the floor slab as a result of a seasonally high water table and the basement is 1 or 2 feet below the high level, a heavy rain will not raise the groundwater level sufficiently to cause water to seep through the floor slab. It takes time for rainwater to percolate into the ground and raise the water table.
Water puddles or flooded areas in the basement are obvious signs of a water problem. In most cases, however, you will not see standing water, and you must then make an evaluation whether there is a condition of water intrusion based on other, more subtle signs. Water-seepage signs indicate only that water has seeped into the basement in the past. They do not indicate the frequency of the seepage or its extent. Consequently, if you see indications of water seepage, you should not engage a contractor to waterproof the house immediately upon taking possession. If you do, it could prove quite costly.
First talk with the homeowner about the condition. It is possible that whatever it was that caused the past seepage has already been corrected. If the problem was corrected by installing buried drainpipes or coating the outside surface of the foundation wall, the correction would not be visible. If the homeowner indicates that the problem has been corrected, you should ask to see a copy of the paid bill. Or get the name of the contractor so that you can call to find out exactly what corrective steps were taken. Quite often a contractor provides a guarantee against water seepage. If there is such a guarantee, you should find out whether it is transferable.
The possibility exists that, even though there are signs of water seepage, the actual seepage might occur very infrequently - such as only after an excessively heavy rain as might occur every few years. In this case, depending on the extent of the seepage and the projected usage of the basement, costly waterproofing measures might not be justified. The best approach when considering the correction of water seepage is to correct immediately any obvious problem conditions such as faulty gutters and downspouts, improper grading, cracks through which water is actively leaking, and so on. However, before undertaking any major water-seepage control measures, such as excavating and coating the exterior surface of the foundation wall, inserting perforated drainpipes below the floor slab, or trenching and installing buried drainpipes in the yard, you should live in the house for at least one full year. This will enable you to evaluate the degree and extent of the seepage over a full weather cycle. If it turns out that the year is particularly dry so that there is no seepage, well and god. Wait another year. By not taking a "shotgun" approach and waterproofing everything, as recommended by many contractors, you might be able to resolve the problem at a cost that truly reflects the work needed to stop the seepage.
Moisture Problems: Indications in an unfinished basement
When looking for indications of water seepage, you should check the walls, the floor, the joint between the walls and the floor, and the bases of all the items stored or standing on the floor. Specifically, look for white powdery deposits on masonry foundation walls and floor. The deposits, called efflorescence, are mineral salts in the masonry that dissolve in the water as it passes through the walls or floor. When the water evaporates from the surface of the walls or floor, it deposits these salts. A thick layer of efflorescence is usually an indication of considerable seepage.
Moisture Problems: Walls
Look for efflorescence, peeling and flaking paint, and scaling sections (surface deterioration) on the foundation wall. Any one of these items can indicate some degree of seepage. Porous walls, such as those made of cinder blocks, may have damp spots. Masonry block walls are constructed with interior voids. When the hydrostatic pressure on the exterior portion of the wall is high, the voids often fill with water. As a result, the wall might be quite wet to the touch. (CAUTION: This might also be caused by condensation.) Vulnerable areas for seepage are cracks and the joints around pipes passing through the wall, such as the inlet water pipe and the drainpipe leading to the sewer. Look closely at these areas for water streak stains and efflorescence.
A poured concrete foundation wall is supposed to be more watertight than a concrete-block wall. This, however, assumes that the poured concrete wall is properly constructed. Quite often, it isn't. If the entire wall is not constructed with a single pouring, the joints between the sections constructed with each pour are vulnerable to water leakage. I inspected a new house just after construction was completed. The inspection was performed during a heavy rain, which was opportune, although not planned. While inspecting the basement, I found water leaking out of the joint at the seam between the individually poured sections of the foundation wall. The builder's mason apparently had not properly prepared the joint for a new pour, and consequently a cold joint with a poor bond was formed.
Look for seepage in a poured concrete wall around the tie-rod holes - holes in the concrete wall around the small diameter metal rods that are used to hold tie the forms together when the wall is being poured. More often than not, these holes have been patched over. Also, these tie rods can corrode away over a period of time and when below grade are vulnerable areas for water intrusion. Sometimes you see efflorescence and water streaks just under the hole or patched sections. Occasionally I find these holes plugged with corks. This is not considered a permanent patch, and if seepage should develop, they should be plugged with hydraulic cement.
Moisture Problems: Floors and floor joints
A vulnerable space for water seepage is the joint between the foundation wall and the floor. Look closely at this joint as you walk around the entire basement. Water stains and efflorescence are an indication of seepage. You might find silt deposits at the joint. This is also an indication of some degree of seepage. The fine silt is in suspension in the water as the water seeps in from the exterior. When the water evaporates, the silt is deposited. If you find evidence of water seepage through the joint between the floor slab and the foundation wall, you should record it on your worksheet for later correction. The joint should be sealed with either hot tar or a hydraulic cement.
Cracks tend to develop in the floor slab near the base of metal columns. Look for these cracks and any other cracks in the floor slab. Specifically, look for water stains, efflorescence, and slit deposits. Cracks in basement floors are a common phenomenon and can be due to shrinkage of the concrete. Usually they are of no concern other than the fact that water can seep through them. Therefore, they should be sealed. However, if the cracks are extremely wide or show evidence of heaving, they are of concern and should be checked further. In all probability, a cracked and heaved floor slab is the result of water pressure being exerted on the underside of the slab by a high water table.
Some homes have a clean out and trap for the house waste line located in a pit below the basement floor slab. The bottom of the pit should be dry. If it is wet, it is an indication of a high groundwater level or a crack in the drain line. Occasionally, I find that the top of the clean out is open. It should normally be plugged. Some homeowners remove the plug so that the open clean out can function as a drain if the basement becomes flooded. This is definitely not the way to eliminate the water in a flooded basement. If the basement periodically floods and there is no drain in the floor, a sump pump can be installed in the lowest section of the floor. The water can then be pumped out of the basement. With the clean out plug removed from the top of the house trap, the possibility exists that if the sewer line becomes overloaded (as is the case in some communities), sewage can back up and flood the basement. I know of several homes where this has happened. It was quite unpleasant.
Some people lose interest in a house when they find a sump pump in the basement. They think that the house has water problems. That is not necessarily so. There might have been periodic problems resulting from a seasonal high water table, but the sump pump might have controlled the water level. Or the pump might have been installed when the house was built in order to prevent a problem. To determine whether there are still problems, you must look beyond the sump pump. Look for signs of water seepage.
If the house has a sump pump, look down into the pit. If there is water in the pit and you are inspecting it during the dry season (the water table is usually highest during the spring), the sump pump will probably be operating continuously during the spring. Try to check the sump pump operation. However, do not actuate a pump unless there is water in the pit. When you actuate the pump, watch the water level to see if it drops. You might find that the motor that drives the pump is operational but the coupling between the pump and the motor is broken. In this case, it will sound as if the pump is working, but it is not, and the water level will not drop. A sump pump is relatively inexpensive and can be repaired or replaced easily.
Although a sump pump is sometimes located in the low section of the floor (when it is being used to collect surface water), it should not be located where it will present a tripping hazard. The pump can be placed n a corner where it will not take up valuable floor space and can be connected to the low spot in the floor by a drainpipe placed below the floor slab that discharges into the sump pit.
After inspecting the walls and the floor for signs of water seepage, you should check the bases of items stored or standing on the floor for water stains and rust. You might find that the walls and the floor of the basement appear to be freshly painted. If you see this, you should be suspicious because the new layer of paint will cover almost all the signs of a water seepage problem. There are some areas, however, that are often omitted when painting the basement. These should be checked for water stains and rust. Specifically, look at the base of the steps leading to the basement and in particular the back of the bottom step. Also look at the base of columns. Wood columns might have stains or may be rotting, and metal columns might be rusting. The base of the inside portion of a furnace sheet metal casing is often overlooked when painting. Look inside. Is there extensive rust? If there is, it might have been caused by a past flood. However, it could also have been caused by a faulty humidifier, so do not jump to a quick conclusion.
Moisture Problems: Seepage indications in a finished basement.
Usually the finished walls in a basement are a few inches or more away from the foundation walls. Therefore, seepage indications on the foundation wall will not be reflected in the middle and upper portions of the finished wall. Look at the bottom portion of the wall for signs of water intrusion. If the wall is paneled, look for rotted and warped sections and water stains. Sometimes there are grayish mold spots or mold fungi on the walls, a condition caused by excessive dampness. With a plasterboard wall, look for water stains and blackened areas and spots. The latter is mold and mildew. In some cases, the lower portion of the plasterboard wall might have deteriorated.
Next, look at the floor. If the floor is raised above the level of the concrete floor slab, the wood flooring and the wood framing members used to raise the floor are vulnerable to rot in the event of seepage. The wood framing below the floor should be pressure treated but often is not. Try to walk all over the floor, especially around the perimeter. If there are any rotting sections, they will feel soft and spongy beneath your feet. If the floor is covered with resilient tiles, the rotting sections might be visible since the dampness in the wood tends to loosen the tiles.
An area that is particularly vulnerable to water seepage is the portion of the basement that faces a yard where the overall topography is inclined toward the house. Even if the ground adjacent to the house is graded pitching toward the house. The walls and the floor of the vulnerable section should always be checked for signs of seepage. Sometimes this is quite difficult; some homeowners might inadvertently (or intentionally) block the area with furniture. If the area is blocked, ask the homeowner if it is alright to move the furniture.
If the floor slab is covered with resilient tiles and there is a problem with heavy seepage through the floor, it is usually noticeable by looking at the tiles. The joints between the tiles become swollen and filled with a white crusting of mineral deposits (efflorescence). Some tiles become loose, and efflorescence is noted below them. Occasionally the tiles are covered with wall-to-wall carpeting. In this case, the tiles cannot be examined for signs of seepage. However, some checking for seepage can be done. Ask the homeowner for permission to lift the edge of the carpet off the tacking strip along a section of the exterior wall. If there is seepage in the area, the tacks will be rusted and the wood strips water stained or rotted.
If the basement is heated with baseboard convectors mounted on an exterior wall, another place to look for signs of seepage is below the convector. If there is some seepage in that area the joint between the floor slab and the wall), the base of the convector will be rusted.
On occasion a portion of the basement might become flooded as a result of faulty plumbing, an overflowing sink or tub, a malfunctioning water heater, and so on. Flooding from the above is basically a one-time affair and will not cause the type of damage that results from repeated wetting. There will be water stains, but there usually will not be rot, peeling or flaking paint, efflorescence, or heavy rusting.
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