When a building "settles".

[HSpencer]

Who knows what exactly happens when a building settles?
I have heard it has something to do with the water table in the ground. I have also heard it has to do with inadequate depth of the footings, whereby the freeze line goes below the footings.
I live in the southwest, where it has been colder than usual. I have noticed some hairline cracks around doors and cabinets in the back of the house. Also noticed a little rising in my driveway to the garage. I am not sure of the code on our footings, but I am thinking 24 to 36 inches.
It has also been very dry here this last few months.
Any engineers out there who can shed light on this?

 

[rodnok1]

Ground swelling and shrinkage will cause most cracks. Probably have one area with slightly different soil or has remained wetter. My in laws put a drainage system in crawl space with clay soil, one are dropped a good half inch causing door problems. Frost heaving is a whole different critter. Footings at different depths will heave less or more. I've seen people plop a deck outside a door and raise 2 inches and jamb the doors because it wasn't deep enough,

 

[Gary S]

Around here, building settling occurs in a few years after a new build when the dirt work wasn't done correctly. If a building is put on undisturbed ground, you don't have settling. If the base of the building (slab or footings) is set on ground that has been disturbed and backfilled, you can expect problems later. It seems that no amount of compacting will ever make it right if the base where you put the footings is dug and put back.
In my cold country, we have a frost line that can go to 6 feet on cold winters when there is no snow cover. Buildings that are put on undisturbed ground, (including surface floating slabs) will have no settling problems. Buildings put on disturbed ground will have problems no matter how deep you go.
There seems to be a "thought" that the frostline dictates how deep your footings need to be. I don't believe that. I believe that the depth of disturbed ground dictates how deep you need to go.
Type of soil makes a lot of difference. If you live on mud soil, expect problems. If you live on sand, you are solid.

 

[NUTTSGT]

While some may not agree with me, I think the drying of your lumber will cause some issues, maybe minor though.

 

[Kevin54]

While some may not agree with me, I think the drying of your lumber will cause some issues, maybe minor though.

It will cause issues. Just like now, we are getting a lot of rain. They are building a house across the road, have it framed and OSB on the outer walls. So all of the OSB and 2x's are thoroughly soaked. Once the roof is on they will start inside and more than likely have it drywalled before everything completely dries out. There is a lot of moisture in a new house.

 

[Blown71X]

Around here, building settling occurs in a few years after a new build when the dirt work wasn't done correctly. If a building is put on undisturbed ground, you don't have settling. If the base of the building (slab or footings) is set on ground that has been disturbed and backfilled, you can expect problems later. It seems that no amount of compacting will ever make it right if the base where you put the footings is dug and put back.

I definately agree with this, I have been fighting this very thing for the last several years.
When my slab was poured, it was done in halves, 6 months apart due to weather (Winter) and access reasons, The back half is almost entirely on fill, the front is not.
About 4 years after it was finished the rear section started to settle, quite a bit (over 1 inch) I have base moulding around my walls so it is very easy to detect.
It has been mudjacked once and held for a couple of years, but is starting to move again, and in the process has cracked in the areas where the mud jacking holes were drilled.

Now the interesting part, We had an extremely dry summer last year, Midway thru is when I really noticed it....My first thought was...well I can`t say it here, foul language was involved....Just for curiousity I scribed a line on the wall behind my toolbox just to watch it.
At that point is was 1/2 inch down and went another 1/4 before it stopped, fast foward to wet fall and now it has risen almost a full 1/2 inch so moisture has a definate effect...I`m not talking parts..this is the whole section.
I have several theorys about why but at this point it is moot, it gripes me to no end and in reality to fix it right, it is most likely going to have to be torn out and redone...At this point that is just not an option so I`ll just have to live with it.

Rick

 

[little d]

HS, you have gotten some pretty good answers to your question; ground prep, soil type, footer depth-size, dimensional lumber "breathing", as my Dad called it, all contribute to "settling". Generally speaking, if everything was done right, this summer everything should tighten back up.
My house was built in 1873, every summer it "shifts" and every winter it all tightens back up. If you are having trouble with sticking doors/drawers, ect..., my suggestion is to plane them in the winter to where they fit tight but not drag and you should be good to go through out the year.

 

[e-tek]

HS, you have gotten some pretty good answers to your question; ground prep, soil type, footer depth-size, dimensional lumber "breathing", as my Dad called it, all contribute to "settling". Generally speaking, if everything was done right, this summer everything should tighten back up.
My house was built in 1873, every summer it "shifts" and every winter it all tightens back up. If you are having trouble with sticking doors/drawers, ect..., my suggestion is to plane them in the winter to where they fit tight but not drag and you should be good to go through out the year.

That works as far as sticking goes - but you get some "nice" uneven gaps around your doors at some points in the year!

 

[Frank The Plumber]

Everything under any circumstance will settle, we are temporary, our stuff is temporary. Just a matter of buying time to keep it standing in our life times. The cheapening of our society is not allowing us to do this. If you want a problem free structure you have to spend on the part you can't see. Low bid construction defeats all of this.

 

[IDASHO]

If a building is put on undisturbed ground, you don't have settling.

ALL buildings settle. It is built on DIRT afterall.

The only variable is to what degree it settles. And this is based more upon the soil composition than building quality/methods.

 

[cowboyjosh]

Im a builder and even my house has seasonal issues.

I have a driveway pad the heaves up a few centimeters every winter and settles back down in the summer right where the garage floor meets the driveway. My walnut hardwood floors are a good humidistat, because when its bone dry outside, even with the humidifier on inside, the floors pop, creak, and make all sorts of noise; when its humid out like it is today (76%) the floors are more or less quiet.

If your not seeing any cracks that you can stick the edge of a nickel into, your probably alright. Just keep an eye on things. You might mark the cracks and periodically check to see if they have widened.

I agree with "Frank the Plumbers" comments 100%, but even when we spend oodles of money on the structure and things we can't see, buildings are only as good as the dirt they sit on. In Colorado we have BIG PROBLEMS with EXPANSIVE SOILS which will cause a house to heave, and in some cases literally cracking in half.

I almost would like to start a new discussion titled "things wrong with your house that aren't really wrong, but still irritate you".

 

[cowboyjosh]

Oh, I forgot to mention. A buddy of mine who's a structural engineer for a large insurance company sent me some pictures of some houses in Ohio which range in age from brand new to 40 years that have had foundation failures after the wet winter they have experienced. He has looked at houses where the poured basement walls of some houses are literally collapsing in. In another case, a basement wall is kicking out from the footer and so is the exterior wall of the house. I guess it shows that even if a house is stable for decades, it can still experience structural failure.

 

[rsanter]

if you dig too close to the footings/foundation and then do not fill it in fairly soon and do not compact the fill....that can cause some problems

animals/rodents burrowing under your footings/foundation can cause a problem

if the soil was not properly compacted before construction...that can cause a problem

building on an area where it transitions from hardpack or rock to an area that is softer or has been disturbed...can cause a problem

yes, the shrinking or swelling of the lumber in the structure can cause a slight problem for a while

a new house as the structure settles in can cause some cracks and shifts but that should only be for the first few years

a foundation that cracks....yep that can do it

earthquake......yes

bob

 

[Frank The Plumber]

Stop by a construction site in the early stages. I get to see all the cost cutting BS that takes place. Everyone gets all excited about the foundation walls. Well the footings are the key and first element that makes a quality home. I have not seen a footer with rebar in 20 years, I have not seen a one foot thick footer, the footer is in almost every case supposed to be double the width of the foundation, does not happen, supposed to have a foundation key, nope. Supposed to be installed upon undisturbed only 95% compacted earth, nope. Supposed to be backfilled and compacted to 95%, nope. Sure you might say "that's not code" OK, but that still is the minimum formula for the correct construction of a home. You end up with a mess because of about $400 worth of time cutting or cost cutting measures. Does it go into your pocket, nope, but it sure can come out. Too many people buying homes because the floors are pretty or the granite color is nice, walk around the development and take a look at the meat and potatoes, stop looking at the garnishes. Specify your footing integrity, personally inspect it. Inform yourselves.

 

[HSpencer]

Many thanks to all responders. Plenty of good information. I don't have a big problem really. My house is well built and close to 35 years old with no problems except these recent hairline cracks between the cabinets and walls, and a very minor opening of miter joints around the door trim. My house is built on undisturbed clay soil. The footings good, and no cracks in the blocks. The joists and sills are still really good, solid and the colorings are not too dark in the wood, as if they had been wet or molded. I really think the cracks mentioned were a result of a slightly changing water table in the soil. As one poster said, I believe they will tighten back up in the summer. Thanks to everyone!!!!!

 

[HSpencer]

Another thing that I can't help thinking about is all the flooding that has happened in various parts of the country this last year. It is simply horrific if one's home is flooded. I saw the news on Nashville a while back, and other places. I can't help but thinking how this must totally ruin a house.
It seems like we are living in a whole different weather situation that the past. The destruction of tornadoes, and floods and the snows in the south. As Frank the Plumber said, we are indeed "temporary" on the earth. I get amazed when I look at homes well over a hundred or two hundred years old, still standing, untouched.
Our fathers and grandfathers truly knew how to build!!!! And also Frank talks of the shoddy "thrown up" constructions of the "house boom" of the last several years. I feel fortunate that my non-McMansion home is at least pretty well built and dependable.

 

[nate379]

I know for a fact that footings around here don't go under the frost line. Frost line is 10ft.

I have also heard it has to do with inadequate depth of the footings, whereby the freeze line goes below the footings.

 

[nmanitou]

HSpencer, I have some experience in geotechnical engineering. It doesn't sound like you have serious settling issues. Maybe more wood shrinkage symptoms. Clay soils can be subject to shrink/swell variability and maybe the recent dry spell you mentioned has allowed some shrinkage to occur. It is very difficult to provide good advice because soil conditions are very site dependent as you can imagine.

Clay soils settle more slowly than granular (sandy) soils, but since your house is over 35 years old any settlement due to footing loads would have occurred by now. Some problems can happen due to "differential settlement". That happens when there are different soil conditions and settling properties - One section of footing over sand fill, and another over undisturbed clay soils, for example. This is often noticeable in newer additions to older homes.

Clay soil can be very sensitive to water content, so keeping the soil well drained around the footings is important.

Not sure what else to tell you, but thought it might help you to diagnose if you have a serious issue or just normal building moans and groans.

 

[HSpencer]

@nmanitou

Good advice, thanks. I do believe it is all in the water table as you state.

 

[Motofixxer]

Well if structures aren't built "like they used to be", then that's a good thing in this case I opened a wall up to replace some 80 year old original windows. This is what I found for headers above the windows. All I could think is What were they thinking???

 

[Zeke]

Well if structures aren't built "like they used to be", then that's a good thing in this case I opened a wall up to replace some 80 year old original windows. This is what I found for headers above the windows. All I could think is What were they thinking???

That 4 x 6 is not original.

 

[little d]

^^^^+1, non of that looks like it is 80years old.

 

[tcianci]

Well if structures aren't built "like they used to be", then that's a good thing in this case I opened a wall up to replace some 80 year old original windows. This is what I found for headers above the windows. All I could think is What were they thinking???

What they were thinking is that 80 years from now some one will open up this wall and say WTF! In any event, note that the thing is still standing.

 

[wssix99]

Who knows what exactly happens when a building settles?
I have heard it has something to do with the water table in the ground. I have also heard it has to do with inadequate depth of the footings, whereby the freeze line goes below the footings.
I live in the southwest, where it has been colder than usual. I have noticed some hairline cracks around doors and cabinets in the back of the house. Also noticed a little rising in my driveway to the garage. I am not sure of the code on our footings, but I am thinking 24 to 36 inches.
It has also been very dry here this last few months.
Any engineers out there who can shed light on this?

Can you post pictures?

If the foundations are done properly, a house will not "settle." Lumber will shrink when it dries out and the house will "move" as its loaded with furniture, etc. If properly done, the walls will not crack when this happens. More often than not, drywall is hung improperly (drywall manufacturers actually make directions - which no one ever reads!) and the walls crack as a result of the normal movement of walls.

The driveway is probably a totally different issue. What part of the country do you live in? Is the driveway on top of clay?

 

[ducati]

Against popular assumptions here, a house will settle. Unless you know how to change physics, your home will settle. The only place it won't settle is if you actually build it on solid bedrock. Having properly sized footings will help the structure not settle as much. and at the same rate. I just got done with a building that had footings in some area's that were 24"x24"x12" on the same building I had other footings that were 7'-0"x7'-0"x24". That is the difference in a footing carrying 10k and one carrying 125k. You are putting a home that weighs 100's of thousands of pounds on ground that used to hold grass or corn. Look at it this way, a man weighs 200 pounds and trys to walk across a snow bank with his shoes on, he sinks. Now the same guy walks on the same snow bank with snow shoes on, he stays on top.

Now, the majority of your settling will happen after your first frost cycle or after your first winter that a home is complete. After that time it should be minimized.

It looks like the OP house has been there for some time and now it has started to settle, water tables can rise and lower, but his house should equally settle at this point not causing much for problems. I would check around the house and make sure that something outside hasn't happened where one side of the house is taking more water than another part and is making that part stay wetter so the soil isn't as stable. I only mention this because I had a home owner that decided to make a rock bed for flowers on one side of his house for his wife. He dug down about 6" and out about 3' on two sides of the house, virtually making a moat. Then proceded to complain about his sump pump running constatntly during heavy rains and his french doors sticking that were on that side of the house.

 

[wssix99]

Against popular assumptions here, a house will settle. Unless you know how to change physics, your home will settle.

Right, it all depends on the designer's grasp of physics. If the weight of the dirt removed across the footprint of the footing is more than the weight of the house, then the building one move a single tick. (God and Mother Nature would have taken care of any compression/settling long ago as the weight of the dirt compressed the layers below.)

Expansive clays swelling with water are another issue, but it depends on what part of the country you live in: http://jbanta.wordpress.com/2007/10/14/expansive-clay-soils-map/


If the foundation is moving, a level across the ceilings and floors should tell the tale.

The driveway is another deal, because it doesn't have a foundation. Water can upset it tremendously. If the driveway doesn't drain properly, ice can form underneath and cause it to heave.

 

[jktruck150]

Clay soils can be subject to shrink/swell variability and maybe the recent dry spell you mentioned has allowed some shrinkage to occur. It is very difficult to provide good advice because soil conditions are very site dependent as you can imagine.

Clay soil can be very sensitive to water content, so keeping the soil well drained around the footings is important.

This is VERY much the case. If anyone is wondering, check out this website about soils.
http://websoilsurvey.nrcs.usda.gov/app/HomePage.htm
Click the Start WSS button, and navigate to where you are building. Highlight the area using the AOI button at the top. Then use the Soil Data Explorer tab at the top to examine a soil for its capabilities. Remember, soils maps are not accurate to the inch. You should get a map that displays like the one below. The red means high shrink-swell (i.e. bad!). The box is my future house...go figure.

Proper water drainage and proper prep work are both key to maintaining a foundation. A 1,000 dollar investment in gutters could save you a 10,000+ foundation repair bill!

 

[Falcon67]

Cool deal. Our house and future shop area comes in at "yellow" - .35 shrink-swell, low strength (0.01). Interesting - they are building a house next door and the "footer" - such as it is around here - is barely 12" wide by maybe 6~12" deep around the perimeter.

 

[Full Size 66]

My neighborhood is not available on that site.

 

[Highbeam]

It should be, my site was certainly available and I am in the south puget sound area. I am a civil engineer and use this site for info, it replaces the old soil survey books that were extremely dependable. Almost magical really, how could they know where the soils change so well.

 

[jktruck150]

It should be, my site was certainly available and I am in the south puget sound area. I am a civil engineer and use this site for info, it replaces the old soil survey books that were extremely dependable. Almost magical really, how could they know where the soils change so well.

All they did was digitize the soil maps, and then link each soil with the description. All the hard work was done in the 50s when they had to map it all out. Dig a hole...determine the type of soil, and determine what topography and area that soil covers.

If the information isn't available on the website, go to your County USDA office, and they should give you the information you need. Any good engineer/home builder should look at this information beforehand.