Why did my concrete slab sink?

It’s important to address sunken concrete.

The mud-jacking process.

When it is determined that the best solution for an uneven concrete slab is mud-jacking, the process that follows can be fairly simple. First, small holes are drilled into the uneven concrete. Slurry is pumped through these small holes. Slurry may be composed of various materials, such as sand, cement, soil, limestone, bentonite clay, water,  or expanding polymers.

The composition of the slurry mixture used is based on the type of application as well as the mud-jacker’s preference. The slurry fills any gaps and forces the concrete to rise back into place. Once the uneven concrete slab is made even, the small drilled holes are sealed with cement, leaving the only visible evidence of the repair. Over the next 24 hours, the slurry solidifies and stabilizes the subsoil, making future sinking of your uneven pavement unlikely.

While mud-jacking uneven pavement is not a complicated procedure, it should be performed only by a trained professional, as amateur workmanship can cause even more extensive damage. Prior to a mud-jacking procedure, drain pipes, sewers, and utilities must be located and avoided. The area around your uneven pavement must also  be evaluated as to whether it can survive the mud-jacking process.

Some advantages of mudjacking over re-pouring cement include:

• Efficiency. Mud-jacking requires less equipment and fewer workers.
  Adjacent plants and landscaping are disturbed less, as are neighbors, tenants, and passersby by from the loud noise, dust, and cumbersome equipment.
• Price. Mud-jacking a slab or uneven pavement can cost roughly half as much as concrete slab replacement because there is little need for new cement or the removal of old concrete. The overall cost is based on the area of uneven concrete that must be lifted, which may be as little as $5 per foot. For example, a 5×4-foot job, it can cost just $60 (the mudjacker may charge more if the area is in a hard-to-reach location).
• Speed. Mud-jacking uneven pavement typically takes a few hours, where certain concrete pours may take days for removal of old uneven pavement, surface leveling, pouring new cement, and waiting for it to set.
• Environmentally friendly. Mud-jacking uneven pavement makes use of perfectly good concrete, which would otherwise be sent to a landfill.

There are some limitations to mud-jacking uneven concrete.

Mud-jacking may be an ineffective waste of resources in the following situations:

• The concrete surface is spalling or otherwise damaged. The mud-jacking process might further damage the surface of the uneven pavement, which will still be defective even after it’s raised back into place.
• The concrete has risen, caused by expansive soil. The only solution for uneven pavement where the pavement is pushing upwards is to re-pour the cement.
• The cause of the settling and uneven pavement is not addressed. If the soil has settled due to some external factor, the problem must be fixed or the soil will sink again in the future. For instance, a gutter downspout that drains onto a concrete edge must be corrected in order to avoid the need for future repair.
• The underlying soil is swampy.
• There is a sinkhole beneath the concrete.

 

Bob Beisbier, owner of BK Home Inspection, is a Certified Master Home Inspector who has been providing professional and thorough home inspections in southeast Wisconsin for over 12 years. Bob is Infrared certified, DILHR Certified, and provides Home Energy Tune-ups, Environmental Data Reports, Pre-sale Home Inspections and Pre-offer Home Inspections.

No, it’s not spooky spirits in your home!

Particulates tend to stick to the surfaces of materials with which they come into contact, and there are two reasons for this.

The first is those particles are sticky! Particulates from cooking are a good example of this process.

When you fry something (say, breaded squirrel in a lemon and dill butter sauce), you can see tiny droplets of grease buildup on the stove around the frying pan. Grease droplets smaller than those that land on your stove can become airborne. Stove hoods with fans and filters are installed in kitchens so that airborne grease like this won’t accumulate on the wall above the stove.

In homes with stove fans or vents that aren’t being used or aren’t working (or in homes where the occupants cook six squirrels at a time), the ability of the range hood to remove tiny airborne grease droplets from the air overwhelms the system, and those sticky grease droplets can escape from the cooking area and move through the home carried by air currents.

A second reason that airborne particles are attracted to a surface is that all airborne particles and surfaces carry an electrical charge. In the world of electrical charges, opposites attract. A negatively charged airborne particle will be attracted to a positively charged surface. So, if they come close enough to each other, the negatively-charged particle will land on and stick to the positively-charged surface (just like male and female squirrels).

The act of a particle being attracted to a surface, making contact with it, and then sticking to it, is called plating out.

In most homes, we don’t notice this discoloration because most homes are designed with air flow adequate to prevent it. However, there are design issues as well as human behavior that can cause plating out anyway.

Any home in which air currents carry particulates that come close to a surface may suffer ghosting. It’s most commonly visible on carpets and walls, but may appear anywhere. Bear in mind that since the particulates are airborne, it’s the movement of air that brings them into close contact with home surfaces. Air currents are key.

Doors that have inadequate clearance from a newly installed carpet are one source. If a new pad and carpet are installed over a tile or hardwood floor, the clearance beneath the door will be reduced. Each time the door is opened or closed, air will be forced against the carpet and particulates will plate out on the carpet. Over time, the carpet under the door swing will become discolored.

Another very common example is above baseboard heating units. As the heat source within the baseboard housing heats the air, it draws in cool, particulate-laden air from the layer of cool air just above the floor. As the air is heated, it rises from the housing, and particulates flow against and plate out on the wall just above the baseboard heater housing.

Any place in the home that draws air through a small space or which pushes room air against a surface may create ghosting.

Bob Beisbier, owner of BK Home Inspection, is a Certified Master Home Inspector who has been providing professional and thorough home inspections in southeast Wisconsin for over 12 years. Bob is Infrared certified, DILHR Certified, and provides Home Energy Tune-ups, Environmental Data Reports, Pre-sale Home Inspections and Pre-offer Home Inspections.

If a basement is unfinished, does it still need foundation insulation?

Yes, unless the floor above is insulated. Even if used only for storage and heating and cooling equipment, the basement is thermally connected to the rest of the house.

Is floor insulation above a basement or a crawlspace an alternative to foundation insulation?

Yes, but keep in mind that pipes, ducts and HVAC equipment located in the basement would also need to be insulated to protect pipes from freezing. Sometimes these can be grouped in a small area with insulated walls while the floor above the rest of the basement is insulated.

Does placing insulation on the exterior improve energy performance?

If the basement incorporates passive solar design with a significant amount of south-facing windows, exterior insulation will be beneficial, provided the walls are exposed to solar gain. In a typical basement however, the energy savings are negligible.

Should the interior of foundation walls have vapor barriers?

If interior insulation is used, yes. The concrete must be allowed to dry, but moist basement air typical of Midwest summers should not be allowed to reach the cool wall where it can condense. Batt insulation specifically designed for the interior of foundation walls has a perforated poly facing that prevents air from circulating through the batt, but allows water vapor from the wall to escape.

Will foundation insulation increase the risk of termite entry?

Foundation insulation does not increase the risk of termine entry. If termites are present in the soil and wood is used in the building, the risk of infestation exists. Exterior insulation may reduce the probability of early discovery, and inhibit treatment when discovered.

It is a good idea for the purposes of foundation inspection for termites to allow an open band or a small area where foundation insulation is omitted?

In some southern states with a high incidence of termite infestation, including Florida, North and South Carolina, Georgia, Alabama, Mississippi, Louisiana, eastern Texas, southern and central California, Georgia, Tennessee, and Hawaii, rigid foam insulation is not allowed to come in contact with the soil. In other areas, a 6-inch gap between the top of the foundation insulation and any wood framing member is required to permit visual inspection for termites. An InterNACHI inspector can be hired to perform required pest inspections.

Will exterior foundation insulation materials be chemically attacked by damp-proofing?

In can happen. Always follow the insulation manufacturer’s instructions for damp-proofing.

What about waterproofing a foundation?

Codes often require waterproofing instead of damp-proofing if the wall is adjacent to habitable space. Manufacturers of some foam products offer specific recommendations for waterproofing their foam systems.

How long will exterior foundation insulation last?

Properly installed foundation insulation should last as long as insulation installed anywhere else in the building.

Should foam insulation above grade be protected?

Foam above grade must be protected from both sun and physical damage. Ultraviolet light degrades and destroys most foams. In addition, damage from lawnmowers, balls, and other incidental contact can degrade the appearance and performance of the foam. Common materials used to protect the foam above grade include two- or three-layer stucco finishes, brush-on elastomeric or cementitious finishes, vertical vinyl siding, cement board, aluminum coil stock, and fiberglass panels.

Will insulating the foundation increase the risk of radon problems?

Radon entry into a home occurs through cracks and other openings below grade. The use of foundation insulation should minimize thermal stresses on the foundation and help minimize cracking, thus reducing radon entry.

Should crawlspaces be ventilated?

The CABO (Council of American Building Officials) One and Two Family Code requires 1 square foot of crawlspace ventilation for each 150 square feet of floor area. Operable vents 1/10th as large can be used if a vapor barrier is installed. Warm, damp summer air can condense on the cool earth, even when covered with a poly vapor diffusion-retarder, increasing the risk of crawlspace moisture problems. Installing a vapor barrier and closing the operable vents is preferred. If local code interpretation requires crawlspace ventilation, insulating the floor and incorporating a vapor barrier is preferred.

Do foam insulation boards installed on the interior require fire protection?

All foams require thermal protection equal to ½-inch of gypsum wall board when installed on the interior of a building, including a crawlspace. The only exception is Celotex Thermax™ polyisocyanurate, which may be installed without a thermal barrier where approved by the local building code official.

Are insulating concrete form (ICF) systems less expensive than an insulated, poured-in-place concrete wall?

ICFs can be competitive, but costs are project-specific. Foam used in these systems should address the same concerns outlined above for foam board.

In summary, taking time to plan the best insulation system for you new home, and taking stock of the insulation currently installed in your home, can lead to energy savings in the long run.

Bob Beisbier, owner of BK Home Inspection, is a Certified Master Home Inspector who has been providing professional and thorough home inspections in southeast Wisconsin for over 12 years. Bob is Infrared certified, DILHR Certified, and provides Home Energy Tune-ups, Environmental Data Reports, Pre-sale Home Inspections and Pre-offer Home Inspections.

What you need to know is that all single family homes with an attached garage, a fireplace, or fuel burning appliances (including a gas forced air furnace) must have carbon monoxide detectors on every level of the home. For new construction the carbon monoxide detectors will need to be hardwired, but for existing homes the carbon monoxide detectors can be battery operated.

One note however, there currently is no fine or penalty for not having carbon monoxide detectors. But if you are selling your home, home inspectors are required to look for carbon monoxide detectors and make note when they absent.

Even if you don’t want to install a carbon monoxide detector until you decide to sell your home, you should install the carbon monoxide detector now for the safety of everyone in the house.

Bob Beisbier, owner of BK Home Inspection, is a Certified Master Home Inspector who has been providing professional and thorough home inspections in southeast Wisconsin for over 12 years. Bob is Infrared certified, DILHR Certified, and provides Home Energy Tune-ups, Environmental Data Reports, Pre-sale Home Inspections and Pre-offer Home Inspections.

Testing for formaldehyde can also result in peace of mind for the customer when the levels turn out to be low. However, it is important to measure formaldehyde in newer homes, particularly if they are 5 years old or newer. With increased focus on energy conservation, newer homes have been built so tightly that they can’t “breathe.” Additionally, some of the newer building materials contain formaldehyde. Therefore, this combination of tightly-closed homes and formaldehyde in the building materials increases the possibility of elevated formaldehyde levels. BK Home Inspections can test that for you.

There is a lot of good information about formaldehyde on the EPA website. Click the following link to learn more: http://www.epa.gov/iaq/formalde.html

Bob Beisbier, owner of BK Home Inspection, is a Certified Master Home Inspector who has been providing professional and thorough home inspections in southeast Wisconsin for over 12 years. Bob is Infrared certified, DILHR Certified, and provides Home Energy Tune-ups, Environmental Data Reports, Pre-sale Home Inspections and Pre-offer Home Inspections.