Basement and Lower Level
Lower Level photos: P 91-P 102, P 208
Before a house is built, the builder and any engineers and architects will consult books that list the correct size beams and support posts needed. They will also check these books for the correct spacing needed for the beams and support posts. The sizes and spacing are based upon a particular weight factor in the construction of the building. This is why an architect has to sign off on the blueprint plans before obtaining town approvals. Anyone can use these published books but architects and engineers are more experienced at using them.
Some houses are built on a concrete slab and therefore there's no lower level to inspect. In northern climate areas, if a house has a basement or crawl space then the foundation footing must be below the frost line. The footing refers to the base of the foundation walls. The frost line is the depth of the soil where the ground moisture freezes in the winter time. When the water in the soil freezes it expands. If the footings are not installed deeper than the frost line, then the foundation walls can heave and crack when the ground freezes. How deep the frost line is will depend upon how cold it gets in the winter time.
Check the lower level steps and any exterior entrances for the lower level to make sure they're in good condition and safe. All stairs need to have handrails and evenly spaced steps for safety. This will help prevent any tripping hazards. When you're inspecting the basement area move in a clockwise or counter clockwise direction so you make sure you don't miss anything.
Some lower level areas will be finished with rugs on the floors and sheetrock on the walls and ceilings and you can't view behind these finished coverings. Finished lower level areas add more value in price to a home but they make inspections more difficult for home inspectors and appraisers. Some lower level areas will be inaccessible due to personal items of the seller put there for storage. Just tell the client that you don't have X-ray vision and you'll try to evaluate as much as possible. Any inaccessible areas can't be evaluated. So just do the best you can.
Check the construction materials used for the foundation walls. The foundation will be made of poured concrete in newer construction. Concrete block foundation walls are also common to find. Concrete block walls should be filled with concrete at the top section or have a cap plate at the top. This will help prevent termites and radon gas from coming into the house. The termites and radon won't be able to travel through the voids inside the concrete blocks.
Brick construction and stone construction walls are usually found in older houses. Due to the cost of construction today, you probably won't find brick or stone foundation walls in newer houses.
The floor of the lower level should have a concrete covering. The vast majority of the time the floor will be covered with concrete. If there is a dirt floor, you should recommend that a concrete covering be installed. This will help prevent water, termite and radon entry in the house. Covering a dirt floor with concrete can be expensive, so tell the client to obtain an estimate before closing on the house.
I'll give you some background on the definitions of cement, concrete, concrete blocks, cinder blocks and mortar. You probably won't need to know this for most home inspections but it might help you in case a client asks some in‑depth questions.
Cement is in a powder form without sand and water added to it.
Concrete is a ready-mix product that contains cement and sand so all that's needed is to add water to this mix and set it and wait for it to harden.
Concrete blocks are used in newer construction. Concrete blocks have a gray color.
Cinder blocks are found in older houses. They appear more porous and are usually only found on interior walls and not for foundations because they're not as strong as concrete blocks. Cinder blocks can have a blackish color to them because they've aged.
Mortar is used as an adhesive to hold stones, bricks or blocks together. Mortar is made of cement, sand, and lime with water added. The lime is added because it acts as an adhesive. You don't need to add lime to the concrete for walls and floors. The reason for this is, you're not as interested in the adhesive qualities in these areas as you are with the rigidity of walls and floors. Lime gives the cement an adhesive quality, but at the same time it weakens the rigidity. As a result, it's not used in walls and floors.
Check for any large cracks in the walls and floors. Some concrete floors will have a gap about 1/2 inch around the perimeter of the lower level floor. This usually indicates the presence of a floating floor which is used to help prevent water problems in a lower level. The purpose of a floating floor is to drain away any water that enters the house through the foundation walls. The water travels through the opening around the perimeter of the wall and then down underneath the concrete slab where it can drain away.
Poured concrete foundation walls will usually have thin metal bars noticeable in some side sections of the walls. These thin metal rods are called Form Ties and they have no structural impact and are one of a few construction methods available to form concrete walls. The purpose of the form ties is to hold plywood boards in place to mold the concrete while it's poured during the construction of the walls. After the concrete has hardened, the plywood is removed. The metal rods should then be cut and the openings sealed to prevent any water penetration or rusting conditions. Poured concrete walls should also have thick metal reinforcing bars, often called re‑bar in the center sections to add support and hold the concrete together. These bars are embedded in the concrete and may only be visible from the top of the hardened wall. Re-bar is placed inside the wall to resist bending and shear loads induced on the wall and have a structural impact as to the performance of the wall.
Concrete block walls should have a metal zigzag shaped bar between every other course of blocks. This bar is called Dura‑wall which gives strength to the block wall, similar to re-bar.
Sometimes sections of the compacted soil underneath the house will settle a little bit more than other sections. As long as the settlement cracks are less the 1/4 inch wide, then it's a normal condition.
You'll always find some minor settlement cracks in the walls and floors. These minor cracks are caused by the settling of the house and the expansion and contraction of the construction materials. When a house is built, the soil it rests on should be solid ground. The builder can compact the soil for less settlement over time. Sometimes sections of the compacted soil underneath the house will settle a little bit more than other sections. This is called differential settlement. If the foundation footings are undersized, then this too can lead to settlement cracks in the house. As long as the settlement cracks are less than 1/4 inch wide, then it's a normal condition. Just tell the client to have the cracks caulked and sealed to prevent water entry and to monitor these cracks for future movement.
All construction materials will expand and contract with the weather and temperature changes during the year. This can also create these minor cracks you'll find. However, the cracks that you're looking for are long horizontal cracks or cracks over 1/4 inch in width. These cracks are much more serious, and if you find any, tell the client to have a licensed contractor evaluate them and give estimates for any repairs needed. Cracks over 1/4 inch wide indicate excessive differential settlement of the house and aren't normal. You'll find large cracks from time to time, so just remember to be careful and not to rush the inspection where you'll overlook them.
Long horizontal cracks are another indication of potentially serious problems with the foundation. You won't find these cracks so often, but if you do you better recommend that a licensed contractor evaluate the foundation for the client. Long horizontal cracks can indicate that the foundation wall is being pushed inward by the soil. The wall will collapse if this movement continues. One possible cause for this type of crack is during the original construction of the house. After the foundation walls are constructed, the soil is then pushed back up to these sides of the walls by the bulldozers. If the bulldozer exerts too much pressure on the side of the foundation wall it can cause the wall to crack and move inward. Obviously, you can't see any cracks behind finished areas or personal items in the lower level. That's why you have to notify the client of the limits of the inspection due to inaccessible areas.