Where are the places to look to find structural cracks in a house?
Monday, October 22, 2018
It may seem silly that it requires training to look for cracks in a house. A crack, especially one big enough to indicate structural problems, should jump out at you without any special education. But it doesn’t usually work that way.
We regularly meet homebuyers at the beginning of an inspection that tell us their number one concern is that the house might have structural problems. Then they say that, after looking at the whole place pretty carefully, they didn’t see anything—but just wanted us to take a second look to be sure. Then we find signs of problems that were in plain sight, but can be easily overlooked if you don’t know how and where to look. So this blog is our beginner’s course “Crack Spotting 101— How to find cracks in the walls and floors of a home.”
There are three areas to examine: 1) the site, 2) exterior of the house, and 3) the interior. And they should be looked at in that sequence. Each one informs you about what to look for at the next step. Many of the clues you will be looking for are not where you will find the cracks; but, when all are put together, they lead you to where to search more closely for the tell-tale signs of structural problems.
- Look at slope of the site - Study the way the ground level changes around the house. Ideally, the builder constructed a raised soil pad and the ground slopes away gradually from the walls on all sides. But, if it doesn’t and the the home is on a sloping site, any structural problems are likely to be found at the lowest and highest levels of the ground around the exterior walls. See our blog post How much is the ground required to slope away from a house? for the current code requirements for site drainage
- See how the roof drains - It’s important to get the water coming off the roof to move away from the house, preferably with a gutter system and rainwater leaders that extend out a few feet. They may not be necessary for a particular homesite, but look for evidence of poor drainage at the soil surface around the house, such as a shallow river-like washout like the one shown below, or a depression in the ground with bits of debris in it that indicates ponding water during a heavy rain. Drainage problems are most likely at L-shaped inside corners.
- Note any trees close to the house - Trees absorb a tremendous amount of water from the ground in the area under the drip line of the canopy. This can cause the soil to subside under the foundation where a tree is close to the house. Conversely, some tree species have aggressive, large roots near the surface that can lift a foundation. If you see evidence of a recently removed tree near the home, that can conversely cause the ground to rise as the soil moisture level rises.
Look at adjacent houses - If the home is in a development, look at the homes surrounding it. They will often have similar problems, which may be more advanced or already repaired. See our blog post Do similar problems occur in houses in the same neighborhood? for more on this.
- Look up at the roof - for any sunken spots in the roof surface or sag at the ridge line. A sunken spot often means a long-term roof leak and the location should be noted for investigation in the attic and ceiling below it later. The sag at the ridge can be caused by an undersize or deteriorated roof structure, and may cause the walls to spread outward below the dip.
- Sight down the walls from the corners - with your head against the wall. Look for any bowed out, concave, bulging, or wavy areas. Horizontal cracks are likely where you see them.
- Look closely - Hairline cracks are easily overlooked unless you study the wall surface carefully. You probably immediately notice the long horizontal crack in the photo below, but what about the web of cracks at the bottom of the photo?
- Check around the edge of windows and doors - for cracks between the window or door frames and surrounding walls. Also, diagonal cracks coming out from corners.
- Find any recent repairs - like areas of stucco with a texture that doesn’t quite match what surrounds it or that are thicker or lumpy, replacement siding, filled-in cracks. Do the repairs look new or older? Any repairs that have opened up again, or one side has shifted forward, like in the photo below, indicates a problem that is getting progressively worse.
- Look behind anything leaning against or hanging on the wall - to determine if it is innocent storage or a cover-up.
- Sight up the line of the connection of the walls of any any addition to the home - looking for any separation. Chimneys in an exterior wall of a home also can pull away from the main structure over time.
- Check the corresponding inside area where you noted any structural distress or potential problems outside - The location of a structural problem will often show itself on both sides of a wall.
- Look at the line where the walls meet the ceiling - for horizontal cracks and a sagging ceiling.
- Examine the corners where exterior and interior walls meet - especially near the ceiling.
- Look for diagonal cracks emanating from the corners of windows, doors and cased openings - which may coincide with cracks already found on the exterior at same corners. Cracked panes of window glass can also be a sign of a stressed window frame.
- Check the operation of doors and windows - looking for any that are binding or not openable, or doors that have trimmed to fit an out-of-square jamb. Sometimes doors are simply removed when the opening distorts badly, so note any missing doors.
- Look inside any built-in cabinets at the back wall - a place where cracks are often missed.
- Feel the floor under your feet for any slope - as your walk around the rooms. Most people are actually very sensitive to an out-of-level floor if they are tuned-in to looking for it. A marble or steel ball can be helpful to find sloping floors, which are an indication of structural problem below—usually a fractured concrete slab or failing piers.
- Scan the baseboards - for any gap between the bottom of the baseboard and the floor, another indication of movement in the floor or wall. In the photo below, the floor slab has dropped at the corner of the home and the gap between the parquet flooring and shoe mould has been caulked-in.
We hope these tips help you when searching for signs of structural problems in a home. If your concern is about a specific crack pattern, visit our blog posts What causes stair-step cracks in a block or brick wall? or What causes a horizontal crack in a block or brick wall? or How can I tell if a diagonal crack in drywall at the corner of a window or door indicates a structural problem? or What is concrete spalling?
Also, if you are worried about the possibility of sinkhole activity on your property, find out more at these blog posts:
- What are the warning signs of a sinkhole?
- What causes sinkholes?
- How can homebuyers protect themselves against buying a house over a sinkhole?
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To learn more strategies for getting the best possible home inspection, here’s a few of our other blog posts:
To read about issues related to homes of particular type or one built in a specific decade, visit one of these blog posts:
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