Thread: Allowable Settlement?

I inspected a home two weeks ago that had what I considered some significant settlement. I called for a foundation contractor to evaluate and determine appropriate repairs. Some of the support columns in the crawlspace had daylight underneath them and most of the interior doors had been trimmed to allow them to close.

The response from the "expert" said that they found that the home had settled in the center 5/8". According to their senior engineer "the allowable settlement in a residential home is 1.5" over 20 ft". Anyone ever hear of this? I can't see anyone accepting that much settlement in a home. I would think that most people would notice that much settlement in a room or rooms.

What do guys think?

//Rick

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Originally Posted by Rick Bunzel

According to their senior engineer "the allowable settlement in a residential home is 1.5" over 20 ft".

I ain't buyin' that.

That means I could have "normal settlement" of 3 inches across my living room/great room? I would not want that, heck, if I had that kind of settlement I'd have to turn it into a skate boarding park.

5/8" over a 20' or 22' wide house isn't bad, not great but common enough. Anything up to 1/2" 3/4" doesn't worry me too much depending on what I see in the basement. Talking vintage house of course, NC is another story.
I did a house the other day, 22' wide, ~ 1.5" - 2" drop in the middle. It's a bit much and all too noticeable.
Because of the type of construction we have in a lot of our vintage houses, mid span drop is a common issue.
i.e. 22' wide house, 6x6 or 6x8 midspan beam, 6x6 posts
The beams are usually fine, age typical cracking, but fine. The bottom of the posts are usually rotted a bit and crushed down from the load. Thats where the drop comes in.
The stupid thing about the house the other day is someone installed a new 8" steel beam and 4" steel posts with footings right next to the old defective wood posts and beam. Really nice steel work. Unfortunately they didn't jack up the middle as part of the job.
I would ask Mr. Expert for some sort of engineering documentation for his claim that 1.5" - 2" is OK.

Originally Posted by Jerry Peck

I ain't buyin' that.

That means I could have "normal settlement" of 3 inches across my living room/great room? I would not want that, heck, if I had that kind of settlement I'd have to turn it into a skate boarding park.

Agree.

If the engineer had described the movement as "common" for the age and construction of the home, but not necessarily requiring remediation or stabilization; then that might have been something that I could have agreed with. 1 1/2" of shift is enormous and visually unsettling even over 50'. I've never seen anything remotely official describing 1 1/2" in 20' as "acceptable" or any other similar term.

fairly standard TX 10yr warranty verbiage pg 8-9
http://www.2-10.com/Builder/CMSPages...1-f1ee9851845f

WA NAHB 3rd edition
http://www.leg.wa.gov/JointCommittee...Guidelines.pdf

The code up here in Canada allows for a maximum deflection of 1 / 360... For a 20' joist or beam, that would be a maximum allowable deflection of 2/3 of an inch. Anything over that would mean "excessive deflection". It doesn't necessarily mean that it MUST be corrected... it can certainly be called as being "serviceable", as we can't expect all older homes to meet the current requirements of the building code. Some good judgment need to be used. It may not be in any danger of collapsing, but yet, it still has excessive deflection.

Originally Posted by Markus Keller

I would ask Mr. Expert for some sort of engineering documentation for his claim that 1.5" - 2" is OK.

I's add to that by asking for a sealed report from a PE at that organization. See if they are willing to put their ticket on the line behind what they have said......

Originally Posted by BARRY ADAIR

fairly standard TX 10yr warranty verbiage pg 8-9
http://www.2-10.com/Builder/CMSPages...1-f1ee9851845f

WA NAHB 3rd edition
http://www.leg.wa.gov/JointCommittee...Guidelines.pdf

I've never held much regard for quality control documents that are developed by the parties to be held to certain standards. A quick skim of the WA state document shows what happens when you allow foxes to guard the hen house--concrete footing cracks up to 1/4" wide are allowed with no repairs required, while finished grade (backfill) settlement adjacent to foundations only has to be corrected if/when it exceeds 6".

"We want to be home builders, as long as we're allowed to do it sloppy."

This is jogging a memory loose. I think that 1 1/2" standard might come from the insurance industry and the 1 year homeowners warranty on new homes, or similar. If I remember right, I thought there was language about repairs to drywall cracks on ceilings and corners not being covered if the floors/ceilings did not sag more than 1 1/2 inches at center.

I could be way off, but it sounds familiar, as I remember a builder joking about how the 1 year warrantees were a waste of money and a scam in his opinion, with such outlandish requirements on sagging, thought he said 1" over 15', which would be 1 1/2" over 22.5'???

Always read the fine print.

Am I the only one who sees a difference between deflection and settlement? Deflection is movement due to flexing of a member, settlement is due to failure of the soil to support the load. A half-inch of sag on a 15 ft. joist is not nearly as scary as a half inch of settlement on a new building.

Originally Posted by Matt Bezanson

Am I the only one who sees a difference between deflection and settlement? Deflection is movement due to flexing of a member, settlement is due to failure of the soil to support the load. A half-inch of sag on a 15 ft. joist is not nearly as scary as a half inch of settlement on a new building.

a) One could have settlement of the soil under the slab and no deflection (the slab settles the same all over).

b) One could have settlement of the soil under the center of the slab and have deflection (the slab settles at the center where the soil is no longer providing the required support for the slab.

b) above has both settlement and deflection, while a) only has settlement.

Originally Posted by Rick Bunzel

I inspected a home two weeks ago that had what I considered some significant settlement. I called for a foundation contractor to evaluate and determine appropriate repairs. Some of the support columns in the crawlspace had daylight underneath them and most of the interior doors had been trimmed to allow them to close.

The response from the "expert" said that they found that the home had settled in the center 5/8". According to their senior engineer "the allowable settlement in a residential home is 1.5" over 20 ft". Anyone ever hear of this? I can't see anyone accepting that much settlement in a home. I would think that most people would notice that much settlement in a room or rooms.

What do guys think?

//Rick

I thought that "standard" may have come from the NAHB Residential Construction Performance Guidelines, which could also be called "a book of reasons why your problem is not covered by the warranty". It usually list large tolerances. However, under Section 2-2: Observation: The foundation is out of level. Performance Guideline: As measured at the top of the foundation wall, no point shall be more than 1/2 inch higher or lower than any point within 20 feet.

As an engineer I try to determine why something has settled and whether it is likely to continue. Sometimes 2 or 3 inches of settlement is not a big deal if its been stable to many years. 1/2 inch of settlement can be a big deal if its still moving.

It is all relative to the home in question.

An inch and a half in 20 feet is absurd..

Now an inch and a half. of up a little here and down a little there across that 20 feet does not add up to too much in the visual. Sometimes it is total movement, the ups and downs, that really amount to nothing. A straight run of 1.5", not acceptable.

Now what were the measurements when the home was new? I guess no one will ever know and maybe there has been extremely little to no movement over time.

I inspected a home in Flower Mound Texas that visually you could tell has a slope to it from back toward the front. Until measurements were taken no one thought the entire front of the home at almost an even straight slope was........6 inches. Yes the entire lot was filled and the rear of the lot was the original height and the ground work never prepared properly and over time just like a wet pile of clay slowly sank from rear to front 6 inches. The home was 70 feet from front to back. An inch in twelve feet or so was noticeable but nothing to the degree of the total. A twelfth of an inch per foot. Not overly noticeable.