Top 5 Home DIY Mistakes and How to Avoid Them

A building permit is a document of permission issued by your local building department. There are different rules depending on where you live, but the rule of thumb is if you are altering part of the structure of your house, you need a permit to do so. When in doubt, ask your local building authority. If you don't have a permit and you're found out, they can shut your project down in mid-hammer. Some cities are more lenient than others, but in some places, the housing authority drives around looking for houses with active projects and no posted permit.

The purpose of a permit is to make sure everything is being done correctly and safely. It may be a pain to do so, but you need to apply for a permit if you're diving into a major DIY project. What's required to obtain a permit also varies, but you'll probably need to provide your plans, a detailed work outline and approval by an architect or engineer. The building department will review the materials and then decide whether or not your plan meets local codes. If you pass, you get a permit, pay a fee based on the size of your project and get to work. If you don't, it's back to the drawing board, and you can resubmit.

One thing you can count on above everything else in the world of DIY is that a project will almost always cost more than you thought it would. Doing a detailed budget for your project is important so you can have a good idea of what you can afford. But it's tough for even experienced DIY-ers to get a really accurate estimate. Any project can throw you a curveball and you can always expect the unexpected. Especially in older homes that have been tinkered with over the years, you never can tell what a previous homeowner decided to do. Tools break and need to be replaced. You spot a small leak replacing your sink and that leads to a larger plumbing issue. You measure incorrectly and need to buy more materials. All of these issues will lead to budget overruns.

Here's an example of how a budget can get out of control: You decide to paint your dining room. You buy paint, trays, rollers and a drop cloth and think the spending is over. After discovering wallpaper underneath the paint, you decide to remove it. This leads you to the store to buy stripping tools and materials. Removing it is tough, and you mangle your walls. The only choice now is to tear the existing drywall down and replace it. Tearing down the drywall, you damage your hardwood floor, and it needs some minor repairs. You finally finish the demolition, hang new drywall, paint and fix the floor.

What started out as a $100 job has now swelled to at least five times that amount. Some budgets grow so much that you need to put the project on hold. You can avoid this by getting as detailed as possible when budgeting and adding a cushion for unexpected costs.

Besides added costs, another thing you can count on if you're tackling a job yourself is that it will almost always take longer than you think it will. Most people engaging in a home renovation aren't able to do so full-time. They have jobs and become DIY weekend warriors, or they take "staycations" and attempt to get a project completed in a week or two. Professional contractors tend to take longer, so it's highly unlikely that a DIY-er will finish sooner than expected or even on time. In fact, in the DIY world, "on time" becomes a sliding scale.

This can be a problem because if the project isn't finished in the time you've carved out for it, life can get in the way and you can end up with a half-finished bathroom for days, weeks or even months. If you're dealing with plumbing or electrical issues, you could end up without running water or power in your house for a period of time as well. Avoid short-changing yourself on time by having realistic renovation goals. If you're not sure how long a task should take, ask someone who knows or do some surfing on DIY message boards on the Internet. A knowledgeable employee at your local hardware store can also give you an idea of how much time you'll need. And finally, get a friend to help you and then help him or her in return. Working with a partner will always speed things up.

Tackling a job best suited for a professional, a.k.a. biting off more than you can chew, is a sure-fire way to spend more money and take more time than you can afford. An inexperienced or even a seasoned DIY-er can turn a small problem into a big one in a hurry by not knowing exactly what he or she is doing. If you get surprised with an issue you don't fully understand in the middle of a job, your instinct may be to press on and try to figure it out. You should deny this instinct. When you're met with a surprise, like a simple light switch installation that turns up a bird's nest of old wiring, stop and call a professional if you have any doubt about what you're doing.

You can get away with learning a few things on the fly here and there by researching your problem on DIY Web sites, but most times, you'll end up costing yourself, doing damage to your home or even putting yourself in danger. The best way to assess your skill level is to be honest about your know-how. Only you know what your capabilities are, and there's no hard and fast rule for what constitutes a DIY job. But here's an idea of what may be best left to the pros:

It's expensive enough to have to sink so much money into materials when renovating, which is why many home renovators skimp on tools and end up trying to bore into a brick wall with a 12-volt drill. In this case, the job requires an electric hammer drill and using anything else can be fruitless and even dangerous. There are many kinds of hammers, and using a claw hammer when you need a rubber mallet could damage the spanking new drywall job you just finished. Using a cheap post-hole digger instead of a power auger when you're digging holes for fence posts will take you longer and in some cases may not even be possible. You get frustrated halfway through the digging process, cut it short and end up with an unstable fence. These are just a few scenarios that can arise from working without the proper tools.

If you've bought a house you plan on renovating yourself, you'll need a basic set of power tools and well-stocked toolbox at the very least. A rechargeable cordless power drill is a must-have. When it comes to saws, most of your tasks can be handled with the trio of a circular saw, a chop saw and a reciprocating saw. The reciprocating saw is great for demolition, the chop saw gives you perfect angles for wood trim and the circular saw makes most of your longer cuts. Get a good level, measuring tape and some safety equipment as well -- goggles, gloves, respirator and a hard hat. If you're doing a job that requires a tool you probably won't need again, go to your local home improvement store, where you can rent every kind of tool for every kind of job by the hour, day, week or month.