I can't agree enough with Greebo's statement that you should be present for the inspection. Even if you don't know why the inspector is doing everything he's doing, you can see that he's being as thorough as possible without causing damage to the house. Remember, Mike Holmes is called in when the homeowner discovers there's a problem, and so he has the homeowner's blessing to cut holes, pull up floorboards, and get to the root of the problem. Inspectors aren't allowed to cause damage to walls, floors etc; they can SOMETIMES remove screwed-in fixtures (because replacing said fixture is trivial and makes no additional holes).
However, Holmes will also show viewers what, if anything, the inspector should have caught but didn't. Basically, if it's visible, obviously wrong (or indicating deeper issues), and the inspector didn't make note of it, Holmes will call the guy out for it. There have also been times when Holmes has actually defended the inspector because he either did note an issue that the homeowners thought was minor, or because he couldn't have known there was a problem because it was so well-hidden by the previous homeowner.
Anyway, there are plenty of things an inspector should do that don't cause damage to the home. They are centered in five main aspects of the home: foundation, structure, plumbing, electrical, and HVAC. The following are some basic tests that any inspector worth his salt will tell you about.
- For slabs or basements: Are there any obvious large cracks in worrisome areas? Are there any running cracks in tile floors, or obvious change of grade angle in other types of flooring?
- For below-grade foundations (basements/crawl spaces); are there signs of bowing or excessive settling of the foundation?
- For pier & beam: Is there any obvious sign of deterioration of the piers or joists?
- Is the earth eroding or pulling away from any foundation members, for any reason?
- Is water collecting against the side of the house or underneath it, due to improper drainage?
- Is water leeching through the slab or basement walls/floor?
- Is the roof sound? Any signs of wear, damage or old age that indicate repair or replacement?
- Is the "skin" of the house weathertight? Are there any cracks, breaks or gaps in brick or mortar?
- Are the gutters appropriately designed, installed and maintained to ensure water is collected and directed away from the house?
- Any creaking, flexible or unstable floors, indicating joists are loosening?
- Tap tile floors with your hand or a hard heel. If you get a hollow sound, the tile is not properly adhered to the substrate; a lot of those will necessitate pulling up and relaying the floor.
- Any obvious bowing or "waving" of walls or ceilings indicating improper construction?
- Is there a stud every 16" (your average inspector may not check every wall, or even any wall, but a simple radar stud finder can be used on a few walls in the original house and any additions to it)?
- For floors not directly on the slab: Is there a joist every 12", cross-braced every four feet? You may not always be able to tell, but in houses with basements you can at least check some of the first floor)
- Any signs of lead paint? (unless there is loose or flaking paint, the inspector may not be able to test for lead without the homeowner's approval, and so it may cost extra)
- Any signs of asbestos? (Asbestos was very common in home building materials; various types of home insulation, roofing shingles, flooring tile, even popcorn ceilings in houses older than about 1980 can contain asbestos; it's fine AS LONG AS it is left alone, but virtually any inspector will strongly recommend it be removed)
- Do all lights work? Do all switches do something obvious?
- Do all outlets work?
- Are there any overloaded circuits (panel switches controlling too many lights/outlets)? Rule of thumb; Other than major appliances (HVAC, washer, dryer, dishwasher/disposer, and hot water heater should all have their own panel switch), count outlets or light bulbs controlled by a single switch, and if you count more than 12 that circuit has too much on it.
- Are all outlets properly grounded? Believe it or not there are plenty of houses with two-prong outlets all over, and that was perfectly legal when the house was built. However, you have to know this up front; you can't plug in most high-amperage devices, including many vacuum cleaners, without a three-prong properly-grounded outlet, and it will cost a lot of money to have the house re-wired.
- Is there any knob & tube electrical wiring? K&T was also legal at one point, and it is grandfathered, but if you're looking to renovate in the future you will need to know it's there and budget for an upgrade to Romex wire. K&T is also rarely grounded. Opening up a switch box, or taking a good look at the panel, will tell you this.
- If GFCI is present on circuits, do they work? What outlets are protected (if GFCI is there at all, you want it in all "wet areas" including the kitchen, bathrooms, exterior outlets and basements)?
- If GFCI is NOT present, would it have been required in a house this age (built or last renovated 1996 or later)?
- If AFCI is present, it is present in all bedroom branch circuits? Does it work (there are arc fault testers, but generally that feature is not part of the average outlet tester)?
- If AFCI is NOT present, would it have been required in a house this age (I believe 2006 and later)?
- In a house older than about 30 years, are there any obvious signs of lead pipes, especially on supply lines? (Lead is bad no matter where it is)
- In a house older than 50 years or so, any obvious signs of clay drain pipe? (Clay isn't toxic and generally it's fine to have, but it's VERY old material and may be a harbinger of various plumbing problems like cracks or collapse)
- In a house between 10-20 years old, any obvious signs of PVC (white plastic) supply lines? (PVC leaches Bisphenol-A, or BPA, into your water, which can affect young children. It's acceptable if not ideal for drains, but it should not be used for water supply lines, especially hot water)
- Smell all the sink and tub drains, and the dishwasher. Any smell of sewer gas or general decomposition? In a house that's been vacant for months, a little of this is normal; the traps have gone dry. Run some water down the drains, then repeat the check at the end of the inspection. In a house still being lived in or recently vacated, foul-smelling drains indicates missing or improper P-traps on one or more drains, or improper slope of pipes causing wastes to back up in the pipes.
- Run water through all faucets down all drains. Check that the sink doesn't back up from a slow drain (improper venting or improper angle of drain pipe; water being forced uphill). Fill each sink to the overflow drain (if present) and ensure the overflow drain drains properly.
- Any obvious signs of water damage around any of the water faucets or drains? A leak or burst pipe may not be immediately obvious except in certain circumstances, but if that leak has caused water damage, the damage will be visible when the water isn't.
- If there is a sprinkler system in the yard, does each zone work? Are there any broken or stuck heads?
- With the A/C on (if you can; don't turn on the A/C if the outside temp is below 60 degrees or you risk freezing the evaporator coil), check the temperature of the air coming out of all vents. It should be 20 to 30 degrees colder from each vent than the OUTSIDE ambient air temperature.
- With the heat on, check the temperature of the air coming out of the vents. It should be 20 to 30 degrees warmer than the current INSIDE ambient air temperature.
- With just the fan on, or the system operating normally for the season, check the airflow through all vents. Measure the air speed with a simple wind gauge; that figure, plus the size of the vent, can be used to calculate CFM of the system. Compare that to the blower's CFM rating, and if it's not within about 10%, there's a leak or blockage wasting capacity.
- Check the vents themselves with a mirror; look for dust accumulation. A duct cleaning isn't terribly expensive but you may want the seller to cover a complete checkup and maintenance if the overall airflow is low.
- Check the filter; if it is highly caked with dust, you may consider redoing the airflow tests with the filter removed, to ensure that the blower itself is moving enough air when unimpeded.