House leveling – crawl space – clay soil
First, I am more of a woodworker and usually hang out at Fine Woodworking. However, I am also a homeowner. We bought the house new in 2005, it is one level with a crawlspace ~ 4′ concrete foundation on the entire outside and two foundings with 2 x 4 stub walls to hold up the floor joists (dividing the crawl space into 1/3s). The soils are heavy clay in the area and expand and contract with moisture. The first year we had no visible settling. However, the second winter the drywall cracked where the walls meet the ceiling and some doorways. I did my best to jack up the floor joists and place shims between the 2×4 stub wall and the floor joists. This took care of the problem but it came back the next winter and again this winter. I am not sure why the builder didn’t use a steel I beam and post jacks (my guess is cost). However, I am sick of spending time in the crawl space with a jack and shims when I could be woodworking or doing something more productive. If you have read this far, thanks and if you have any advice double thanks.
Yes, I have called the builder, he accepts no blame. When he sold us the house, he explained the joys of one level living and not needing to go up and done steps, he didn’t mention spending my free time in the crawlspace on my hands and knees.
Any advice would be appreciated. Will I have to do this every year I live here?
Replies
pheasant..... where do you live.... what is the heating system ?
when you go down in the crawl space after it starts to drop... what do the joists measure ?
I live in north-central Montana. 12-14" a year of prec., low RH most of the year (I can air-dry hardwood lumber to 6% in a garage). The heating system is gas forces air (the duct system is in the crawl space). The joists are OSB I-beam(9.25" tall). The footings are strip footings (8" tall x 18" wide).
I don't have time to do all the requested soils test tonight. What I can say is the soil nearby is bentonite clay (old mine), often used for drillers mud. You can roll a ribbon. I will try to complete the requested soil tests tommorrow.
I landscaped the yard to avoid plants/lawn near the house and house has positive drainage.
since it's i-joist that reduces the total amount of shrinkagebut your interior wood does not want to be at 6%....i would like it to be at equilibrium.... so would your respiratory systembesides the soil tests... do some RH measurements in the house and the crawl...
and i bet you have a moisture meter..... measure your interior woodMike Hussein Smith Rhode Island : Design / Build / Repair / Restore
I have attached two photos of the crawl space. One thing I may not have mentioned is that settling seems the worst in the center of the house, which is also under the washer and dryer. The build thought the house was raising on the outside foundation and the center had not moved (he determined this over the phone, he wouldn't come and look). I still think it has settled in the center.
I do not have anything to measure RH. I will need to buy a more advanced home weather kit?
I do have a moisture meter, interior wood is 6 % or less currently, which doesn't surprise me.
Soil test. I was surprised that the soil did NOT expand. After 30 seconds most of the soil had settled but the water was very cloudy. After 3 minutes still very cloudy but you can clearly see the soil line in the jar. The water has cleared significantly after ten minutes (I can see shadows but not my hand throw the water). I will report tommorrow after 3-6 hours of settleling.
<<Soil test. I was surprised that the soil did NOT expand. After 30 seconds most of the soil had settled but the water was very cloudy. After 3 minutes still very cloudy but you can clearly see the soil line in the jar. >>How much is "most"? &0 percent? 80 percent?And the ribbon test?Seems like it might be worth your time to check your floor and see if it is in fact lower (or higher)in the middle, and if so, by exactly how much. Then check it a few more times throughout the year.If you have something nearby (light pole base near the street, manhole cover, fire hydrant) that you could use as an elevation benchmark it might be worth shooting that in relationship to a few points on the foundation as well.
pheasant...i see 3 pieces of flat stock ... the pt sill and the double plate...
they should measure 4 5/8.... what do they measure ?from the picture i can see no cracks in the exposed footing.... if the footing had sunk i would expect to see cracksif you set up a laser you cold shoot the bottom of the subfloor in the crawlspace and map the elevations for a better idea of what's level and what isn'tand the benchmark would be good for seasonal reference6% during the heating season.... i wonder what the moisture content will read in augustMike Hussein Smith Rhode Island : Design / Build / Repair / Restore
From the description of the location of the drywall cracks, a person might consider that they may be due to truss uplift and header shrinkage. Is the roof built with trusses? Must you assume that your soil base is the problem? Some shots taken with a builder's level may point out the realities, as mentioned in the above.
The roof is built with trusses. Interesting that you should mention the roof. When I first noticed that I might have an problem, I was sitting on the couch on the far side of the living room and noticed that there was a significant gap between the laminant flooring and the baseboard. I couldn't believe the walls were 'hanging' from the ceiling but near as I could tell they were. I have had some concern that the gap at the peak of the roof wasn't as large as it should be and there are no other vents. However, once I started researching adding vents everyone had a different opinion (add lots, don't waste your time, add all you want but they will not make a difference). However, is it possible that too hot of a roof is part of my problem? The roof has black shingle and I have measure the air temp at 140 in the heat of summer in the attic.
Maybe. I will tell you how to fix it, but first take some more of that clay and make me a flower pot.How old is your house?
It was built during the winter of 2004 -05, finished April 05. My first theory was that the soil got wet after they poured the footers and before they capped it, however, I would have thought the soil would have dried out in less than a year.
Any help would be appreciated.
Thanks
O.K. my first guess: could it be your floor joists? How far do they span? I'm not very familiar with those I-joists, I don't see them alot. But I do know that they have alot of play. Maybe some blocking or bridging might help.When did you say the cracking started, how long ago?
I still want to see how far out of level his floor is (or isn't).But if the floor isn't seriously deflected, then that's the most likely guess I've seen yet.I'm not gonna mess up arcflash's free flowerpot deal here. <G>
Edited 1/6/2009 10:41 pm by Catskinner
I'm home sick today so have some time on my hands... Some thoughts:
In some states, like mine for example, builders are required to supply a 10 year structural warranty. This may likely not cover cracks in drywall, but if you can show that the house is settling significantly or similar that would be considered structural. I hate to be like this - being on the other end of this thing - but if your state has a state licensure board for GCs you might want to check with them to find out what your builders responsibility are. The way we do it is we supply a 1 year comprehensive warranty and then buy a warranty through a insurance company to cover HOs for years 2-10.
You mentioned drywall cracks at the wall to ceiling intersection. Regarding truss uplift, on most modest to average sized houses the load bearing (weight) of the roof trusses is on the outside walls of the house. What we say is that the truss "clear spans" the house. If your house has a fairly simple roof this is likely the case. A pic of the house would likely tell us this. Anyway what this "clearspan" means to you is that although some cracking may be seen at the exterior wall/ceiling juncture, the cracks should only open up to actual gaps at the interior walls. You mentioned a gap at the baseboard to floor juncture. Same Q - interior partition wall or exterior wall? When truss uplift occurs, it can actually pull the interior walls up. OTOH, I have never heard of the floor system being pulled up. Ranch houses can be more prone to truss uplift because they have a larger roof than say a 2 story house of the same square footage - for example.
Personally, I think if you had soil and/or foundation problems you would see some cracks in concrete somewhere.
I think Mike is on to something with the RH, but more importantly is the moisture cycling of the structural wood components in the house throughout the yearly seasons. You have a wood moisture meter so this puts you far ahead of most people. You may want to do seasonal checks (say winter and summer - same months) of not only the CS lumber, but also the lumber in the roof trusses. Your problems could be a combination of things though.
Like others have said some additional on site investigation is needed. Catskinner took you through a rudimentary dirt analysis, (he is the "dirt guy") but I wasn't totally clear with the way you reported the results. Mainly I think he wants to know is how the saturated settled dirt level is varying with regard to the tape on the jar, but as I said, if it is a foundation/dirt issue there should be some cracking of concrete - the stuff doesn't flex. :-)
Anyway, my next step would be, as mentioned above, using a laser to really find out what is going on. Unfortunately, you will need to assume that the house was built perfectly level. I will say that most are, since lasers have been in very common use for at least 10 years. Someone mentioned a builder's level, which would work, but generally it takes 2 people to operate it and it can be a bit time consuming. What you need is a rotating laser. See attached pics. If you can't borrow one some rental stores rent them. If you rent one, the accuracy of a unit can be easily checked at a calm pond of water, (maybe hard to find in Montana in the winter :-). Another way is to check the level of the floor of a large room, and then move the laser to different locations within the room to see if the results repeat. Anyway the idea is you set the laser up roughly in the center of your area and use a tape measure to find differences in elevation. This can be done both in your crawl space to check the top and bottom of the pony walls, joists above, and in the interior of your home to check the floor and ceiling. In the pics I posted I showed a tripod and the accompanying sensor, but these shouldn't be necessary for interior use. If you look closely at the 3rd pic you can see the red laser light on both the tape measure and the white box behind. My photography isn't the best but the point is that a good laser will show up indoors without the use of the sensor. If at all possible though, I would recommend getting a automatic leveling laser. You basically just set it on a somewhat level surface, turn it on, and it levels itself. To test for check the trusses for uplift, you can measure from the ceiling down to the level plane established by the rotating laser. This would require a fairly open area of your house - maybe not smaller bedrooms, etc.
I'd be happy to stop by the house with mine, but I don't think you want to pay for my plane ticket :-).
In the pics you posted it looked like I could see the shims between the pony wall top plate and the bottom of the bottom of the I- joists. Also it looked like it was a heated crawl space. Are these correct? I think I see plastic on the ground, that being the case, how much of the dirt would you say is covered ? 100%? 90% 85%? CS moisture issues can effect a house all the way up to the roof sheathing.
Along with answering Mike's questions (essential information), take a handful of that clay under your house and put it in a glass jar, like a mason jar. Put in enough clay to fill about 1/4 to 1/3 of the jar. Tamp it down gently but firmly. Mark the level on the outside of the glass with a piece of tape.
Now add a few ounces of water and see if the clay expands.
Then add more water, to almost full. Shake the jar real well until all of the soil is swirling, then set the jar down and watch it.
Tell us how much (by percent) settles in 30 seconds, three minutes, and after a few hours.
in either case i think the answer is going to be the same.....something needs additional moisture
interesting if it's bothMike Hussein Smith Rhode Island : Design / Build / Repair / Restore
I think you're right.What I'm wondering, following your question of specific location, is if he is in North Texas or anyplace like that where they sometimes have to install a drip system to stabilize the clay.I worked for a while in North Carolina and know of sellers who would "water the lawn" real hard while trying to sell their home. Closed all those cracks right up.
i was thinking of a drip system or humidifier
i know lots of people who pretty much destroy their homes every winter by not controlling their RHMike Hussein Smith Rhode Island : Design / Build / Repair / Restore
That's certainly one of the first things he should be looking at.The other concern I have for him is why the glass jar test. What people will describe as clay soil can of course have quite a range of composition. If he has spot footings, or even a strip footing that is sitting on nasty enough clay he could be seeing a shear failure in the soil underneath the footing.Certain kinds of high-plasticity soil will squish out laterally (very slowly) from under the spot footings, it's called "soil creep". It can happen just under the spots at mid-span and not under the perimeter because the overburden of the exterior backfill is enough to restrain it.To the OP- in addition to the tests I described, please take a small handfull of soil from under your house, remove all pebbles from the sample, wet it until it becomes plastic, and see how long and thin of a roll you can form, like a potter forming clay. If it rolls out into a thin "worm" less than 1/8" in diameter and gets pretty long before it breaks, this could be trouble.
Three possibilities:
-- It's "expansive" clay soil and the soil expands when wet (and shrinks when dry).
-- The soil is freezing (you don't say where you live) and is frost heaving.
-- The footings are simply too small (or the soil they're on is poorly compacted) and they are sinking deeper into the soil.
You basically have to work out which is the problem before fixing it in any permanent fashion.
or 4th..... has a low rh and is shrinking his floor systemMike Hussein Smith Rhode Island : Design / Build / Repair / Restore
The footings are simply too small (or the soil they're on is poorly compacted) and they are sinking deeper into the soil.That was my thought, couldn't he get low enough to avoid heaving?
A deeper footing will be less subject to heaving. A wider footing will be less subject to sinking in poorly bearing or poorly compacted soils.
The mark of the immature man is that he wants to die nobly for a cause, while the mark of a mature man is that he wants to live humbly for one. --Wilhelm Stekel
So you agree it's a footing issue, at least as a first look.
nah.... the jury went next door for some drinks... waiting for some more on-site investigationMike Hussein Smith Rhode Island : Design / Build / Repair / Restore
Care for a bourbon?
I dunno. Could be truss uplift, and probably several other possibilities.
The mark of the immature man is that he wants to die nobly for a cause, while the mark of a mature man is that he wants to live humbly for one. --Wilhelm Stekel
So, what did you figure out?
Matt:
I have been on the road for work the last several weeks. So I haven't had time to work on this project. Interestingly, my neighbor stopped by tonight, his house was built by the same builder as mine. He has MAJOR problems with house movement (cracked drywall, doors that don't close, etc). His house was built a year after mine and is ~3 years old. He has hired an engineer and is probably going to sue the builder or his insurance company. I will pass on info as I find out.
Thanks for your interest.
be interesting to see what the engineer has to sayMike Hussein Smith Rhode Island : Design / Build / Repair / Restore
What has been described by the OP could also be due to truss uplift.
A laser in the crawlspace could determine the "flatness" of the floor system and the level or unlevel elevations of the footings. As well as establishing a benchmark for further movement in the foundations.
Ditto for the bottom chord elevations in the attic.
Just a thought.............Iron Helix