Should I worry about warped, sagging floors in old houses?

Question

A lot of the houses I am looking at in Atlanta, mostly due to their age, have warped or sagging floors. I find it really off-putting, but the more houses we look at, the more common it appears to be. Obviously, if the floors are soft, I would be concerned, but we walked a property today and the original floors were sagging either side of the central column of the floor, but were solid. The joists looked good in the crawl space. I'm wondering if this is just a fact of life, particularly with the older houses, here in the south east. Should I see this as a deal breaker? Or should I just suck it up and call it 'character' like everyone else seems to do?

Many thanks, in advance!!

Richard F. · Answer

Tilting, sagging, and soft floors describe three very different symptoms, with multiple potential causes. The actual type of construction also is an important factor.

For any type of wood construction, a floor can be soft between the supporting floor joists if the subfloor has deteriorated due to water intrusion or wood destroying pests. Normally this softness will be between the joists, which generally are on 16" or 24" centers. If a larger area is notably soft, without rigid areas over the joists, it is likely the joists are unsupported due to deterioration at one or both ends, or the joist has previously been cut somewhere mid-span, often to run piping or ducting...improperly.

Tilting, sagging, or humps are generally due to the sill plates deteriorating and collapsing at perimeter footings, or to one or more individual supporting central posts or their footings deteriorating and collapsing. Sometimes, DIY owners or cheap contractors remove supporting posts unknowingly.

Of course, foundations may be reinforced concrete, or CMU Blocks on concrete footings; or bricks, posts, or timbers with no, or minimal footings, directly on dirt. The foundations themselves can also collapse due to lack of lateral support, severe water intrusion, wood destroying pests, or settling due to improper construction methods.

These types of damage may, or may not, be visible for inspection. For this reason, you really need to pay attention when visually inspecting the interior and exterior of a property prior to committing to a purchase, looking for any telltale signs. Repair costs will vary dramatically, depending on the extent and type of repair needed and cannot be accurately estimated until fully uncovered and visible. Whether the areas are readily accessible, or if interior walls, floors, or ceilings need to be partially removed for access is a critical cost factor to consider. You also need to be pretty familiar with how the structure actually is constructed to fully appreciate the potential complexity.

Concrete slabs can crack severely for a few reasons, creating an offset that causes a hazard. They can also (as can wooden subfloors) be leveled to some extent using a liquid leveling compound for the installation of floorcoverings such as tile, LVP and other options. If there is a structural failure, this should be addressed first to prevent any further collapse of the structural framing, that will then damage new floor and wall coverings.

Stephen Quesinberry · Answer

You’re not wrong to pause on it. This does come up with older homes in the Southeast, especially crawl-space construction.

In many cases, some amount of sagging or uneven floors is simply a function of age, original construction standards, and long-term settlement, not necessarily a structural failure. If the floors are solid underfoot, the joists look sound, and there’s no active moisture or rot in the crawl space, it’s often something that’s been that way for decades.

That said, I wouldn’t automatically call it “character” either. The key is understanding why it’s happening and whether it’s static or progressive. A few things I’d think through:

• Has it clearly stabilized over time, or are there signs of ongoing movement?
• Is it isolated to one area or consistent throughout the house?
• Any history of moisture or prior repairs in the crawl space?

Has it clearly stabilized over time, or are there signs of ongoing movement?

Is it isolated to one area or consistent throughout the house?

Any history of moisture or prior repairs in the crawl space?

From an investment standpoint, it’s also worth thinking about tenant and future buyer perception. Minor unevenness is common and usually acceptable, but noticeable slopes can impact marketability and resale, even if structurally sound.

If there’s uncertainty, but you like everything else, getting a structural engineer to give a quick opinion is usually money well spent.

Understand it, price it appropriately, and decide if it fits your risk tolerance and exit plan.

Allan Smith · Answer

Ah, Sloped Floors! Well as houses get older they have this more and more. At this point, about every house built in 1920 in this country now has sloped floors.

Your job is to evaluate if you need to do anything about it.

1. First, confirm structural integrity. A little sloping in a 1950s house is probably just going to have to stay. But warped floors in a 1998 house means something is wrong (at that age, it's likely under-engineered framing). Sloping in a 1970s house probably means an issue with water drainage outside, which will also need framing repair if it's been going a while.

2. Next, you look at your exit strategy and what is required. Rent it for 5 years then tear down and build? Who gives a rip about sloping. Fixing up to sell to a premium audience? Probably gotta make it dang close to level to sell. Fixing up to sell at a price below median for the area? A little slope is probably okay, just make sure to address any structural concerns or weaknesses.

This is more my opinion, but how much slope matters a lot too of course. I have a 1920s house that I rent STR and it's a rollercoaster everywhere. I have to shim furniture so people don't watch TV with their head tilted haha. It's bad enough to affect day to day living so yes this affects value to all end users.

But in your typical 12' room, say a 1/2" slope would not be noticeable to most people. A 1" drop would be noticeable to you and many occupants, and starts to need some attention unless it's an old, working class neighborhood.

Brian Greenway · Answer

Copy that! Thank you @James Mc Ree.

James Mc Ree · Answer

It can't be a safety concern. You don't want folks tripping. This is one of those things that gives an older home character. It's normal, within reason.

The floor sags when the underlying joists sag. Compare the joist heights and you can probably see the root cause of your sagging. Joists can be jacked up and sistered to address some joist sagging. Keep in mind this can create new problems as your house has settled into its current shape.

Brian Greenway · Answer

Thanks @Ken M. that's the thing, this particular property is not in need of a major rehab at this point and someone has recently finished the hardwood flooring that sits on top of said warped floors. The beauty of this property is that I can live with/fix (economically) any of the other imperfections. I was just curious how many people out there 'live with' warped floors. My main concern is would this affect my 'EXIT' from the property, should I chose to do so at a later date.

The thicker carpet is a good idea, but this would be the communal area for a co-living space. So, carpet not ideal.

Should I worry about warped, sagging floors in old houses?

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