Corrosion on jacks under manufactured home

[Bill Anglin]

Manufactured home was set in 2008. The home is set on a full cement pad with a vapor barrier over the top. The base of all of the jacks are corroding where they are in contact with the vapor barrier. White efflorescence type powder was observed on the vapor barrier as well throughout most of the crawlspace. It is well ventilated through the vinyl skirting. Any ideas on what causes this condition and/or how to correct it is greatly appreciated.

[John Kogel]

It gets cold enough under there for water to condense on the cold steel and run down to rust the base.
They want to reduce the air flow under there in the winter, open vents maybe in the late spring.

[Mark Fisher]

It gets cold enough under there for water to condense on the cold steel and run down to rust the base.
They want to reduce the air flow under there in the winter, open vents maybe in the late spring.

That doesn't account for the efflorescence, unless this is by the coast and that is salt residue. Actually, I don't see what could account for "efflorescence" on the surface of the vapor barrier since there is no masonry/mineral material adjacent to most of it to be the source of the calcium salts.

Whatever the cause, that is some major damage in a fairly short time.

[H.G. Watson, Sr.]

WAG/requiring investigation, Automatic Dishwashing machine and/or Clothes Washiing Machine Discharge, drainage/waste plumbing leaks, caustic or acidic cleaning products, can produce same in short order.

What was the condition of the DWV system? Note corrosion above struts.

[John Kogel]

Good points.
Efflorescence comes from concrete as a rule, so I would call it something else. Dried soap suds is certainly a possibility. The spilled water would accumulate around the stands where the vapor barrier is pressed tight to the slab. Yes, detergent would help corrode steel.

I carry surgical gloves in my bag, not that I wear them much, but a sample in a glove or baggy could be a good idea sometimes.
If you could mix it with a bit of water and shake it up, that would tell you right away if it was soapy. No, I don't watch CSI, but I must have seen that somewhere. :D

[Mark Fisher]

This 'case' has piqued my interest. From the pictures, it seems:

1. Condition appears to be present throughout crawlspace;
2. Residue appears to be waterborne deposits left after evaporation;
3. Residue is located on top of vapor barrier which was placed on top of a concrete slab on grade;
4. Jack 'stands' are placed on top of vapor barrier and are presumably anchored to the slab, or hopefully, a pier.
5. Residue 'spots' or patches visible in field of vapor barrier are mostly isolated, meaning surface water levels were not high enough for 'flow' patterns;
6. Severe deterioration at base of jacks indicate long term/continuous exposure to water.

Based on these observations, I would propose that:
1. Surface/above grade water source unlikely or pooling/flow patterns would be evident from a source location.
2. Continuous nature of exposure at jacks indicate that moisture source is the concrete. This accounts for the metal deterioration and the residue/efflorescence there, but not for the residue in the field of the vapor barrier (assuming that the VB is reasonable intact).
3. The continuous capillary action via the concrete indicates that the slab probably does not have a vapor barrier UNDER it, and may or may not have a gravel base. These two components of slab-on-grade construction are there, in part, to be a capillary break in between the soil and the slab.
4. If there are piers, which would not typically get gravel and VB, there is a good chance that the anchor bolts (or other metal reinforcing) did not have adequate clearance from the soil (3" minimum for all steel in concrete adjacent to soil) creating a path for moisture as the steel degrades.

In other words - the jacks are shot and need to be replaced, but the cause of the deterioration needs to be resolved or the new ones will fail as well. If the embedded anchorage has also been compromised, major repair/replacement of the piers may be necessary. Underslab dewatering may be necessary to reduce moisture source (perimeter 'foundation' drain, possibly even a sump pump) since existing slab appears to have excess moisture levels (use your moisture meter to confirm). Of course, ensure any surface water sources are not present (DWV leaks, exterior runoff).

[Dan Harris]

Manufactured home was set in 2008. The home is set on a full cement pad with a vapor barrier over the top. The base of all of the jacks are corroding where they are in contact with the vapor barrier. White efflorescence type powder was observed on the vapor barrier as well throughout most of the crawlspace. It is well ventilated through the vinyl skirting. Any ideas on what causes this condition and/or how to correct it is greatly appreciated.

Lime or some other chemical in the soil ??

[Billy Stephens]

.
Any ideas on what causes this condition and/or how to correct it is greatly appreciated.
.
Water and lots of it. Improper drainage water collects after rain . Correct drainage .
.

[Randy Mayo]

Bill,

Is there a possibility a water softer was added and drains under the mobile home?

[Gregory Booth]

...........doesn't look like vented skirting to me. How is it well ventilated? What's the exterior grade look like? Venting should be open year-around.....Greg

[Bill Scott]

I have inspected hundreds of manufactured homes and have never seen a head scratcher like this. It appears from the photos that ventilation is obtained from the perferated vinyl skirting which is common for manufactured housing and can not be restricted under normal conditions. The source of the effloescense is puzzeling. If it should occur, it should be on the underneath side of the vapor barrier and not the top unless there is penetration of the vapor barrier. There must be a different source. I agree with Mark Fisher's analysis of the problem and the corrections recomended, however, if you are not a structual engineer then I would advise you to tell your client to hire one and let the engineer be on the hook for the corrections needed. My caveat to all inspectors is that if you have ANY questions about structual integrety of the subject property that you must advise the client to hire a structual engineer. Otherwise you better have deep pockets.

[Billy Stephens]

Hard to tell but it appears not all of the jacks are corroded. Just the ones water would pool around and take the longest to dry after a rain.

[Dan Harris]

I have inspected hundreds of manufactured homes and have never seen a head scratcher like this. It appears from the photos that ventilation is obtained from the perferated vinyl skirting which is common for manufactured housing and can not be restricted under normal conditions. The source of the effloescense is puzzeling. If it should occur, it
My caveat to all inspectors is that if you have ANY questions about structual integrety of the subject property that you must advise the client to hire a structual engineer. Otherwise you better have deep pockets.

I'm not sure that I would recommend a structual engineer. I dought an engineer would cut the underbelly paper unless he noticed moisture stains/damage to the paper, or bowed floor joists or flooring .. I would likley state, determine and correct the source of moisture that's damaging the piers, and replace the piers.

[Mark Fisher]

Hard to tell but it appears not all of the jacks are corroded. Just the ones water would pool around and take the longest to dry after a rain.

There are no flow lines to indicate surface water movement. And efflorescence is formed by moisture migrating through a calcium source (masonry, limestone, etc.) and depositing mineral salts on the other surface when the moisture evaporates. Rain water surface discharge can't be the source of the efflorescence.

If it is efflorescence.

[Jack Feldmann]

Is there a swimming pool nearby?

[BridgeMan]

Another good argument for requiring either reinforced concrete or CMU stemwalls under manufactured homes. Many states (and I think, HUD) require them.

[H.G. Watson, Sr.]

In the second picture, I note the breaks/separations in the underbelly liner, the either splash zones from activities below or dripping from above with similar deposits, deposits below in-line with breaks in the underbelly lining, and most suspicious in that second picture - the broken metal strapping no longer securing or supporting the suspected building drain/building sewer (lateral) laying upon the plastic - and its cleanout l- all of which appears likely to be unprotected from freezing.

Perhaps a problem with the DWV/sewer drainage occured, blockage, freezing, etc. and some spillage occured?

From the looks of the pattern of the collections and the installations I suspect the ring-like deposit patterns caused from moisture dripping from above (condensation, leaks, etc.), and evporation. Directional Pattern of areas of accumulation seems to coinside with surfaces/edges/openings/seams above.

The residual residue might be from contamination/clean-up/deodorizing efforts related to same (perhaps rodded via cleanout, etc.), not completed or improperly remediated (i.e. not flushed, neutralized). Perhaps the occupant utilized chemical clog-busters first, drainage was acidic or caustic, salt ladden, etc.

It is an area not devoid of moisture (condensation, etc.), air (ventillation), and unconditioned.

I also note in that second picture, two large "chunks" of white material sitting upon the "barrier" in the middle foreground, appearing not unlike dried out dessicant material ('damp-rid', etc.), styrene insulation, or gypsum/plaster.

http://www.inspectionnews.net/home_inspection/attachments/structural-components-home-inspection-commercial-inspection/26393d1343529740-corrosion-jacks-under-manufactured-home-p7260066.jpg

[Billy Stephens]

I also note in that second picture, two large "chunks" of white material sitting upon the "barrier" in the middle foreground, appearing not unlike dried out dessicant material ('damp-rid', etc.), styrene insulation, or gypsum/plaster.
.
Or Toilet Paper.:eek:
.

[Gregory Booth]

.............as I questioned before, it does not appear to be vented (perforated) skirting. This is most likely a simple case of poor ventilation and too much moisture. Too bad the OP can't be bothered to respond to questions by folks trying to help......Greg.

[Dan Harris]

.
Or Toilet Paper.:eek:
.


Reminds me of working in a large MH park with 500 plus rentals , outside of Syracuse NY in the mid 70s.
Frozen sewer lines, -30degrees for several days, the people had to flush and it had go somewhere.
I left before the spring clean up. :D

[Bill Anglin]

Sorry for the Lack of response to all of your questions. I am more busy now than I have ever been. I am reporting today and will try to answer questions the best I can. This home is located in a mobile home park. There are no swimming pools close. Although the grade is pretty much flat, there is no negative grade conditions at the exterior. The crawlspace is ventilated through the skirting and appears adequate. All fixtures were filled and drained and no plumbing leaks or evidence of past plumbing leaks were observed in the crawlspace. Grade in the crawlspace is at or above the outside grade. No water migration stains anywhere in the crawlspace. Gutters are installed at the front and back. Downspouts discharge close to the structure but there is no signs of discharge entering the crawlspace. Here are a few more photos.

[H.G. Watson, Sr.]

That patio/walk/drive paved area between the shed and the home appears higher than you indicate in your summarization. Similar conflicting appearance of the paver walk to front covered stoop and placement of landscaping boulders in uncovered garden area adjacent to home.

Suspected vulnerable intersection of gable valley, porch extension clearance, beginning of gutter in freeze/thaw events over raised deck & stair/stoop to skirted area below.

'Twas an overflow (spill-over/flood rim) event, not system piping leaking, is what was suspected/suggested, (or other over-flooding activities such as spilled bucket while washing floors, etc.) in addition to the suspected vulnerability to freezing/clogging to displaced, unprotected lateral below. (such as overflow above due to freeze or other clogging event, and possible clearance of the obstruction activity for same having taken place from below.

For example, frozen sewer, washing mchine stack pipe overflow to the floor, DW, etc. Flooding the floors above (such as too-wet/careless cleaning activities - floor washing, carpet cleaning, dumped bucket, etc.)

The drip patterns/evaporation residue below, open, bulging in liner seams, etc. concentrated collections & corrosion at support locations, led to the suspicions outlined above.

[Bill Scott]

Second thoughts on your problem. First - if you call for the peirs to be replaced (and I would) I would require them to be CMU piers since they don't rust out like the ones shown. Second - From the looks of the spotting on the vapor barrier, moisture is condensing on the belly pan and dropping onto the vapor barrier. If you can not determine the source of the moisture, either by cutting the belly paper for view of the joists and flooring (will have to repair cuts) then the moisture should be coming from an external source. This is where the engineer comes into play. Third - As Mike Fisher recommends, if the tie down anchors show the same problem as the piers then they will have to be replaced. Most engineers will be ok with expoxed in place anchors and some with expansion anchors.

HUD requirements for foundation design are site specific and are required to be done by a licensed engineer or architect. All of the ones that I have done require steel in the footings. HUD does not require a CMU enclosure of the crawl space, only that the skirting be wind resistant which means that the bottom channel be anchored to the frost line. I have been called often for engineers certification of a foundation system. I follow the procedures outlined by the engineer (RCS in Texas), forward my inspection observations and photos to the engineer and receive the certification or requirements back from the engineer. If all clear this is forwarded to the lender. If not, the requirements are met, reinspected and forwarded to the engineer for sign off and clearence. After a few inspections, you will no if the foundation will pass or not and can alert the customer to the probable requirements needed to pass inspection. As a note, after being bit by a copperhead, I am quiet leary of crawling under a manufactured home so I raise and remove a lot of skirting to do my inspections. P.S. I don't like spiders either. Oh yeah, since the subject is in a mobile home park, I am assuming that is a requirement of the park otherwise why go to the expense of a slab. Most are not poured correctly anyway to properly support the structure, IE reinforced beams.

[John Kogel]

Re: the bulging membrane - you must at all costs resists the temptation to poke the bag with your screwdriver. :D

[Darrel Hood]

I will mention an unusual but real possibility. If the home has wavy floors or rotting flooring, there may have been a ruptured waterbed at some point. Usually if this occurred, and the floors were replaced, there will be a small elevation change roughly an inch from the baseboards.

[Greg Filian]

I will mention an unusual but real possibility. If the home has wavy floors or rotting flooring, there may have been a ruptured waterbed at some point. Usually if this occurred, and the floors were replaced, there will be a small elevation change roughly an inch from the baseboards.
Is it possible that only a portion of the foundation area is on cement. Here is SoCal. it is quiet common to place a newer larger home over the footprint of an older single wide with a cement patio. Where is the home located?

[BridgeMan]

Cement (Portland cement) is a fluffy, gray powder which (by itself) has no strength, and is usually sold in bags or bulk. It is one of the components of concrete.