DIY Home Inspection [Checklist for Small Problems]
A homeowner can catch most expensive problems early by doing a simple visual inspection twice a year: measure and photograph foundation cracks to track change, check caulk and grout for gaps that let water behind tile, look for staining under sinks and around windows, test GFCI outlets, and inspect roof flashing and gutters from the ground. Magnification helps where the first signs are hairline cracks, pinholes, or early mold.
A house tells you about its problems early, but quietly. A crack that widens a fraction of a millimeter, a gap in the caulk line, a faint brown ring on the ceiling. Noticed early, most of these are small repairs. Here is a practical routine for finding them yourself.
How often, and what to bring
Twice a year is a reasonable rhythm, spring and fall. Bring a flashlight, a tape measure or ruler, a notepad or your phone for notes, and something to magnify with. A phone covers the last three: in LoupeLens you can zoom, use the flashlight, and take a photo with one tap, which gives you a dated record of each spot you check.
The record matters more than the magnification. Much of home inspection is about change over time, and a photo of a crack beside a ruler is what lets you say, with confidence, that it has or has not moved since last time.
Foundation and basement
Nearly all concrete foundations develop cracks as they cure and as the ground settles. Most are harmless. The job is to sort them.
- Vertical or slightly diagonal hairline cracks with edges that line up are typical shrinkage cracks. Note them, photograph them, and check again next time.
- Cracks wider than a few millimeters, or that are wider at one end suggest ongoing movement. Mark the ends with a pencil and date so you can see if they extend.
- Horizontal cracks in a basement wall, or stair-step cracks following mortar joints in block, can indicate pressure from outside. These are the ones to have a professional look at.
- Displacement, where one side of the crack is proud of the other, is also a reason to call someone.
At 5x with the flashlight at a low angle you can see whether a crack is a clean line or has crumbling edges, whether there is white powdery efflorescence (a sign water is moving through the concrete), and whether the crack goes through paint or just through a surface coating. Photograph every crack with a ruler in frame.
Bathrooms and kitchens
Water is the enemy of houses, and most of it gets in through failed joints rather than dramatic leaks.
Caulk and grout
Run a finger along the caulk where the tub meets the tile and where the countertop meets the backsplash. Look for cracks, pulling away from one surface, or dark staining that means mold behind it. Missing grout, even a short section, lets shower water behind the tile and into the wall. Both are cheap to fix and expensive to ignore.
Early mold shows as tiny dark specks in the caulk before it becomes an obvious stain. At 5x to 8x you can tell specks from shadows and decide whether to clean or re-caulk.
Under sinks
Empty the cabinet and look at the supply lines, the shutoff valves, and the drain trap. A slow drip leaves a white mineral crust or a green tint on brass, and the cabinet floor shows a stain or swelling. Check the compression nuts on the supply lines for a crust of dried minerals, which at a few times magnification is unmistakable.
Appliance hoses
Washing machine and dishwasher hoses should be free of bulges, kinks, and cracks at the fittings. Rubber hoses are generally considered due for replacement every few years; braided stainless is more durable.
Windows and doors
Look at the exterior sealant around each window and door frame for gaps and shrinkage. Inside, check the bottom corners of the window frame and the sill for staining or soft, swollen material. Double-pane windows that have fogged between the panes have a failed seal; the glass unit needs replacing, not the whole window.
On the weatherstripping, look for compressed, torn, or missing sections. A flashlight held on the other side of a closed door at night will show you where light, and therefore air, gets through.
Electrical
- Press the test button on every GFCI outlet (kitchens, bathrooms, garage, outdoors). It should click and cut power; press reset to restore. If it does not trip, replace it.
- Look at outlet and switch covers for discoloration or warmth, both signs of a loose connection behind the plate.
- Check the date printed on the back of each smoke alarm. Most manufacturers and fire safety bodies advise replacing the whole unit at 10 years. The date is small, gray on white, and easier to read at 3x.
- Open the panel door and read the breaker labels. If they are faded or missing, relabel them now, while everything works.
Attic and roof
From the ground, with binoculars or the phone zoomed to 10x or more, scan the roof for lifted or missing shingles, cracked rubber boots around vent pipes, and flashing that has pulled away from a chimney. Look in the gutters for a heavy deposit of shingle granules, which signals the roofing is wearing out.
In the attic, go up on a bright day with the lights off first. Points of daylight mean holes. Then with a light, look for dark water staining on the underside of the sheathing, especially around penetrations, and for compressed or damp insulation. Check that bathroom fans vent outside and not into the attic.
Exterior walls and grading
Walk the perimeter. Soil should slope away from the house. Look for gaps where siding meets trim, peeling paint that exposes bare wood, and small round holes that might indicate wood-boring insects. On brick, check the weep holes near the bottom of the wall are open and the mortar is not crumbling.
Small exit holes, sawdust-like frass, and mud tubes along the foundation are all worth a close look at 5x to 10x, and worth a photo to show a pest professional if you find them.
A simple inspection log
| Area | Check | Record |
|---|---|---|
| Foundation | Crack width, direction, displacement | Photo with ruler, pencil marks at ends |
| Bath and kitchen | Caulk, grout, under-sink drips | Photo of any staining |
| Windows | Exterior sealant, sill staining, fogging | List of units needing work |
| Electrical | GFCI test, alarm dates, panel labels | Replacement dates |
| Roof and attic | Shingles, flashing, staining, daylight | Zoomed photos from the ground |
| Exterior | Grading, siding gaps, insect signs | Photo of any holes or tubes |
Keep the photos together in one album so that next time you can compare like with like. Because captures from LoupeLens land in their own album in Photos, this sorting happens on its own. Over a few years, that album becomes the most useful document you own about the house.
Related reading: phone magnification for home inspectors and reading labels on fuses, cables, and appliances.
Frequently asked questions
Which foundation cracks are serious?
Horizontal cracks, stair-step cracks in block walls, cracks with one side displaced relative to the other, and any crack that is visibly widening over time deserve a professional assessment. Thin vertical or diagonal hairlines with aligned edges are usually shrinkage cracks and simply need monitoring.
How often should I inspect my home myself?
Twice a year is a good baseline, typically spring and fall. Add a quick check after major storms and whenever you notice a new stain, smell, or sound. Photographing the same spots each time makes changes obvious.
How do I know if a smoke alarm needs replacing?
Look for the manufacture date printed on the back or side of the unit. Most manufacturers and fire safety organizations recommend replacing the whole alarm 10 years after that date, regardless of whether it still beeps when tested.
What does white powder on a basement wall mean?
That is usually efflorescence, mineral salts left behind when water moves through concrete or masonry and evaporates. It is not harmful itself, but it tells you moisture is getting through, so look for the source outside: grading, downspouts, or a crack.