Before you buy a home, you should hire a professional inspector to conduct a thorough analysis of the true state of the house, beyond what meets the eye.
But taking a step back for a minute, you can narrow down the field of houses you're considering by developing a more educated eye. You'll want to learn how to distinguish between a major structural issue and a minor cosmetic matter. You'll want to make a list of required and desired changes. Keep that list top of mind when evaluating the asking price of the home and what you're prepared to offer.
House Styles: Learn about the most common house styles so that you can properly read the real estate listings. You might want to watch my video tours of historic homes in Cambridge or An Architectural Tour of Harvard Square as a fun first step.
“Intake Session”: Pretend you're a doctor conducting a first physical exam of a patient. Find out as much about the patient's (house's) history as you can, such as how long the current owners have lived there, what changes they've made, what condition the house's exterior is in, why they are selling the house.
Roof of the House: Pay particular attention here. Problems with the roof will be expensive to address. Don't climb up on a ladder to investigate, but ask questions. Find out when the roof was put on the house and what materials were used. Find out if the roof has leaked in the past and if so, how and when it was repaired. Look at the pitch of the roof. Know that a flat roof, or even one with a gentle pitch, can be difficult to waterproof. Find out if the roof has been re-covered with two additional layers of shingles on top of the original layer. This might be a local building code violation and can cause structural issues. If you see water stains on the walls and ceilings, chances are there is a leaky roof. This will mean financial and structural problems down the road. However, don't be fooled by the absence of water stains as they may have been hidden by a new paint job. Test the ventilation by placing a thermometer in the attic on a warm and relatively wind-free day. If the temperature is 10 or 15 degrees more than what it is outside, you'll know that there isn't adequate air flow. This causes problems in summer and winter and can compromise the effectiveness of your house's insulation.
Gutters: Determine how well they have been maintained. Neglected gutters become clogged and then rotted, and can lead to a wet basement when backed up water spills out. Look for splits or missing portions of the gutter. This may indicate an ice dam problem, a serious matter that causes ruined ceilings, walls, and floors. Note deteriorated gutters or sealant around chimneys and other elements that project through the roof as these can also contribute to a leaky roof.
Foundation: Find out which material has been used. Wood is problematic as it's porous and water can get in. Even pressure-treated lumber which contains water-repellant chemicals lasts just 30-40 years and isn't meant to eliminate the need for a stone or concrete foundation. Concrete-block was common in the first half of the Century. This is weaker than today's reinforced concrete foundation and also more susceptible to water. Reinforced concrete is strong and stable. Another common material choice used in older homes is fieldstone, sometimes called “rubblestone.” These irregularly-shaped rocks are joined with mortar. They don't age well, tend to leak, and can't be waterproofed.
Tip: Wet basements are common. There are many products on the market to address this, many of which are meant to be applied to the inside of the problem wall. This is not the recommended course of action. Don't fight water; instead attempt to divert it or install a sump pump to pump it back out in the direction from whence it came. But, remember, if a storm floods your basement, it may simultaneously knock out your power supply, and then your electric pump will be of no use. Best to fix the basic problem and divert the water away from the foundation.
Cracks: Not all cracks in the foundation are causes for worry. Vertical and diagonal cracks are generally harmless, a natural result of settling and the shrinkage of concrete. If these cracks are not more than a quarter of an inch wide, you can probably leave worry at the door. If you spot bigger cracks, however, especially in a house that's less than 10 years old, you should bring these to the attention of a professional home inspector. It is the horizontal cracks that can be of greater concern as they can indicate negative grading or poor drainage. The worst-case scenario, while rare, involves horizontal cracks in the basement wall which can necessitate rebuilding the foundation. Needless to say, you'd rather not have to do that.
Slabs: Under the floor of the house, slab foundations (pads of concrete) are poured on top of the ground. Slabs make sense if you don't have to worry about winter frost or a place to put the heater. But here are some of the negatives: they can crack, they can be cold and hard underfoot in spite of carpeting or tile, they're not well insulated, and they can make plumbing additions complicated. Plus, if you have a termite problem, you'll be hard pressed to combat it.
Crawl Spaces: This refers to a way of building on a concrete foundation. For a proper crawl space, the walls extend below the local frost line and stick out at least eight inches above the ground line's highest point. Whether the crawl space is below the frame of the house or supporting the house's deck, be sure to look at the footings. These are solid concrete pads that hold the weight of the foundation wall (the wall of concrete supporting the house's wooden frame). By understanding where they are compared to interior walls, you can understand the structure of the house.
The Soundness of the Structure: OK, let's have some fun here. Can you draw a straight line? First, stand outside the house, at each corner, and look down the sight line to see if it's straight. If it's an older house and you don't see deformation of the structure, that's good. Here's an entertaining test you can do to judge how much wood a house has in it. Stand in the middle of the room and jump up and down. If the floor moves a lot, there's a good chance that a wall is missing underneath or the joists are not large enough. Whether or not you have an engineering degree, you can conduct a test to see if the windows and doors close properly or if they are “out of square.” Back to the straight lines-if the ridge of the roof is not perfectly straight, have a professional home inspector find out why. This is the most obvious symptom of a weak house structure.
Now this might surprise you, but if you're considering a house with structural weaknesses, don't write it off so fast. Not only can it be corrected, it doesn't have to be expensive. One word of warning: pay attention to the sills (the wooden members attached directly to the foundation walls upon which the rest of the building sits), especially if the house was built before the mid-70's when pressure-treated lumber came into more general use and helped keep sills dry. You don't want to hear the very long list of things that can go wrong when your house's sills are rotted. I'll share with you just a few: Sagging floors, windows that won't open or close in a smooth way, porches that have slipped away from horizontal. While carpenters can handle these problems, fixing them is akin to major surgery. And like any good doctor, they have to diagnose the cause of the problem too to make sure it won't happen again.
The Remodeled House: It's wise to take it slowly before you irrevocably alter an old house, whether you're changing original materials or the spaces themselves. Not only do you want to do your homework about the style of the house and what changes were made when, what's worth preserving versus what could stand some innovation, you also want to think about the ways in which people today - yourself included -- live in their spaces and therefore what their needs are in a home. That is, before you tear down interior walls and make one giant space, you might want to think about the cost of heating such a space or about the demand for individual rooms that fulfill different purposes. Beware of prior renovations where corners were cut or poor workmanship was in play. If you have the heart and soul of a remodeler, I'd suggest waiting for an original.