Check the condition of the mortar joints and see if they need to be repointed. Mortar joints refers to the concrete mix that's used between the stones, bricks or concrete blocks. The purpose of mortar is to hold the construction materials in place and tie the different parts together for support. "Repointing" refers to the patching of any decayed areas of the mortar joints. This is a required maintenance item that needs to be done periodically.
You also want to make sure you view all visible foundation areas from the outside of the house as well. Do this during the exterior part of the inspection. On the exterior you'll be looking for the same problem conditions as those of the interior. Most of the time you'll be very limited in what you can see because the soil will cover the vast majority of the exterior foundation areas. Just do the best you can with what's visible. Often you'll find a thin concrete coating over the stone, brick and concrete block foundation walls on the exterior and sometimes even on the interior walls as well. Check to see if there are any areas of this exterior concrete coating or any settlement cracks that need to be patched to prevent water entry.
Make sure you closely view all accessible areas of the foundation, especially if the house is located on a steep hill. See if there are any areas of the foundation that have been altered from the time of the original construction of the house. If you notice any alterations, then recommend that the client check with town hall to make sure all valid permits and approvals have been obtained for the work performed. The last thing you need is to have someone buy a house and find out that the do-it-yourself work done to the original foundation doesn't pass the local codes and is unsafe.
Check the main girder beams, all support posts, the floor joists, and the sub flooring where visible and accessible. I'll describe these items and how to inspect them. The main girder of a house is the large beam that spans the entire width of the house. This is the beam that supports the interior portions of the house and it rests on the top of the foundation walls at the far ends. The main girder in newer construction will usually be made of a built‑up center beam. This is usually two to three wood boards that are approximately 2 inches wide and 12 inches high that rest directly against each other. They're commonly called 2 by 12's in the construction trade. The reason for this installation is that several boards placed next to each other with a Flitch Plate have more strength than one large, solid beam. Built-up girders should have a Flitch Plate between each of the 2 by 12 boards. A Flitch Plate is a 1/4 inch or 3/8 inch steel plate that's added for additional support.
In older houses you'll find one large, solid wood beam. Many of these solid beams will have cracks in them. The cracks are due to settlement and from the wood drying out and expanding and contracting from the weather and temperature changes over the years. Probe all wood girders for rot or wood destroying insect damage. There shouldn't be any areas cut out from the main girder beam since this is the main support for the interior sections of the house. Check for any sagging sections of the main girder that will indicate unusual foundation settlement and sloping floors in the rooms above. Sometimes you'll find a main girder beam or another support beam, resting on a wood board that sits at the top of a concrete or metal support post. This is not an acceptable installation because the wood board will rot over time leaving an open area between the girder and the top of the support post. If you see this condition, recommend repairs be made by a licensed contractor.
Sometimes in some newer construction you'll find a steel "I " beam as the main girder of the house. This is superior construction because the steel "I" beams have tremendous structural support. Check any steel beams for rust that will require painting or repairs.
The support posts of a house are the posts that are found underneath the main girder about six feet apart. These posts support the main girder in the middle sections of the house while the ends of the main girder are supported by the foundation walls. The support posts in newer construction will usually be made up of steel columns about four inches in diameter that are filled with concrete. This is superior construction because the steel posts filled with concrete provide a lot of structural support. Check all steel posts for rust that will require painting or repairs.
In older houses you may find one large, solid wood post that's about four inches by four inches in diameter. You'll even find old tree trunks in very old houses. Many of these solid beams will have cracks in them due to settlement. Cracks are also caused by the wood drying out and expanding and contracting due to the weather and temperature changes over the years. Probe all wood posts for rot or wood destroying insect damage.
There shouldn't be any areas cut out from the support posts. Check for any leaning or bowed sections of the support posts that will indicate the need for replacement. In older houses you often find support posts that have been installed due to sloping floors. The support posts are used to prevent the floors from sagging further. Sloping floors occur over time when the spans between the foundation beams are too wide. Building permits must be obtained for these changes to the original foundation. If the homeowner wants to relevel the uneven floors, this is a big expense. The house will have to be jacked up very slowly and more supports will be inserted. Only an experienced contractor should use house jacks. If you raise the house too quickly, cracks will be created in the walls and floors of the rooms.
Sometimes a house will have to be jacked up to replace the sill plate due to rot or wood destroying insect damage. The sill plate is the wood board at the top of the foundation wall. This is the board where the wooden wall studs are attached to. Replacing a sill plate is an expensive job that only an experienced contractor should do. Homeowners should not try to repair foundation problems themselves.
The floor joists are the wood boards that span the underside of the floors in the house. These are the boards that hold up the floors. The floor joists will run perpendicular to the main girder beam. The floor joists are approximately two inches wide and eight inches to twelve inches high. They rest about 16 inches apart from the center of one beam to the center of the next beam. This type of spacing is commonly referred to as "16 inches on center" in the construction trade. Sixteen inches on center is the typical spacing found in newer construction for all floor joists, ceiling joists, wall studs, and roof rafter beams. Sometimes for additional support, you'll find the beams to be 12 inches on center instead of 16 inches on center. Older houses will have beams that are 24 inches on center which is not as sturdy as 16 inches on center construction.
The floor joists should have diagonal bracing installed. These are small wood boards or metal straps placed diagonally in between each of the floor joists. Their purpose is to "tie" the floor joists together so they don't twist when the wood dries. Diagonal bracing also helps to spread the load exerted on the floor joists from the area above. This way when someone walks on the floor in the room above the weight will be spread across several floor joists, instead of just one at a time.
Probe some wood floor joists for rot or wood destroying insect damage. You don't have to probe every floor joist you see. Just spot check them and probe all areas that appear to have water stains or other potential problems. Often you'll find damage from rot due to water leaks over the years in a bathroom or kitchen above. Check for any sagging sections of the floor joists that will suggest unusual settlement and sloping floors in the rooms above.
Very often you'll find floor joists that have been cut to accommodate the installation of some heating, plumbing or electrical lines. If the cut areas are in the center of the beam and are less than 1/4 inch of the height of the beam, then they generally aren't a structural problem. For example, if a 2 x 8 inch joist has a 2 inch hole in its center, it can still be as strong as it was without the hole. However, if a 2 x 8 inch joist is notched at the top or bottom to a depth of 2 inches, then its strength will be reduced to that of a 2 x 6 inch joist. The reason for this is that when weight is being placed on top of the floor joist, the top of the beam is in a state of compression and the bottom of the beam is in a state of tension. As a result, there's no stress in the middle of the beam because that's where the compression transfers to tension. It's similar to the eye in the middle of a tornado. The two forces on each side equalize one another in the middle section. However, if there are large holes in the center, top or bottom of the beam, then they must be resupported. Probe these areas and tell the client that additional support posts should be installed to prevent any problems with these cut boards.
The sub flooring is the plywood or paneled wood boards which are located on top of the floor joists. The purpose of sub flooring is to support the finished flooring above, such as hardwood, tiles or carpeting, that rests on top of the sub flooring. Probe some wood sub flooring for rot or wood destroying insect damage. Here again you'll often find damage from rot due to water leaks over the years in a bathroom or kitchen above.