You don't have to be an expert to detect problems in your home's foundation, but detecting problems is only half the battle. The other half – and the most difficult one – is to repair these problems before it's too late. The earlier you discover problems, the more likely it is that you'll be able to repair them without spending too much money.Over time, natural settling, erosion and other factors can undermine your home's foundation. Often, though, signs of such problems are easy to detect. Following are five common indicators of foundation weakness, and how to address them:1. Narrow cracksCracks less than a quarter-inch wide usually are no cause for alarm, and you can easily repair them. These repairs are made even easier if the crack just happens to be located where the concrete naturally tends to crack from shrinking as it cures. If water is seeping through the area, you can protect your home by applying a high-quality, paintable silicone caulk or epoxy putty to seal the space.2. Poor drainageThe soil around your home should slope gently away from exterior walls. But on older properties, the soil settles over time, which can cause groundwater to seep toward your home and your foundation. If your basement walls seem damp, ensure you have adequate grading, and that all water drains away from your home. Changing the grade around your home may be enough to prevent further damage.3. Wide cracksCracks exceeding a quarter-inch may indicate serious foundational problems. Unfortunately, these issues can't simply be solved by installing caulk or epoxy putty alone. In addition to filling these cracks, you should contact a foundation repair expert to evaluate the damage to your foundation.4. Severe cracks and buckled wallsPerimeter walls, ceilings and other structural components that have bowed, tipped, buckled or developed severe cracks will need substantial reinforcement to keep them from deteriorating. And that type of damage could also create safety hazards in your home. Repairs will require wood or steel braces, wall anchors, and/or carbon-fiber mesh. These repairs can technically be completed on your own; however, if bowing has exceeded three inches, you'll need to have a professional excavate and rebuild all or part of the foundation.5. Ill-fitting doors and windowsBecause doors and walls are installed after cutting an opening in the wall, these areas are the weakest and most vulnerable parts of the home. Because of this vulnerability, your home's doors and windows will typically be the first to show signs of settlement. Small gaps in the frame may be repaired with caulk or epoxy putty, while larger gaps indicate the need for foundational repairs. In some instances, it might make sense to purchase new windows and doors for a more proper fit. However, this will only temporarily solve the foundational problem that caused the poor fit in the first place.Foundational problems can grow to become serious issues, so addressing problems early is highly recommended for avoiding the dangerous consequences of neglect. You can perform simple repairs yourself, but make sure to get an expert opinion if you see signs of major foundation problems.