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Thread: Manf. Homes
06-11-2012, 08:33 PM #1
What do you guys do on manufactured homes with respect to siding/window design issues?
These things come out of the factory w/o Z-metal flashing on band boards and over windows.... and most come with composite siding which we all know basically sucks. Also, many have the composite siding run right into the ground as skirting. It's not "structural" but will sure rot quickly.
So, do you take the "system is performing as intended" approach and say nothing? Or, do you detail all the shorcomings compared to "best practices" and write-up all the lack of flashings and other details?
I've gone back and forth over the years and can see the argument for both. I've just had a run of manf. homes the last few weeks and thought I'd see what the majority opinion is.
06-11-2012, 09:11 PM #2
Re: Manf. Homes
If there isn't any noticable damage, I just figure it is what it is and they aren't going to change anything.
On the windows if the caulking is in good shape I don't say anything, other than recommending re-caulking if the caulking cracks.
Wood siding in the ground?
Here if the home is ground set the siding is often buried in the concrete slabs, [ usually a carport on one side and a patio on the other, and 3'ish sidewalks on the front and rear of the home,] if so I mention that the moisture will damage the siding , and recommend keeping the gap between the siding and concrete sealed to prevent water damage to the siding.
On the homes that are above the ground and they use the same siding for skirting , and install it against the ground I recommend raising it to keep it above the finished grade. Most of the time they do use treated wood for the bottom board.
I guessing I see termite tubes on apx 70% of the homes with the siding against the ground,
Last edited by Dan Harris; 06-12-2012 at 07:19 AM.Phoenix AZ Resale Home, Mobile Home, New Home Warranty Inspections. ASHI Certified Inspector #206929 Arizona Certified Inspector # 38440
06-12-2012, 08:27 AM #3
Re: Manf. Homes
The windows are used in a Manufactured Home are listed for this purpose and must be installed per the listing. These windows are designed differently from site-built windows, designed specifically for this type of installation. There should be no problem in that they do not match what you are used to seeing in a site-built home. If they are leaking, yes, point that out as needing repair.
As for the hardboard siding, and haven't seen much of that siding being used in the last several years; too many field problems for manufacturers. (Actually put several out of business.)
But if you come across a home that is sheathed with hardboard, I would scrutinize it carefully. Any little break on the outer finish is critical (true of site-built as well). The problem is any little break in the outer finish lets water get it and soak the interior of the board. This always results in the board deteriorating. Any break in the finish, expecially if any is warpped, needs immediate repair.
In the Manufactured Housing Industry, the usual method of repair consists of one or two coats of quality oil-based paint and re-nailed at any area that's "slightly" buckled. Large warping will need replacement.
Also, we have discovered that the board fails more frequently on the east side of the home. I believe this is related to moisture collecting to the back of the siding, turning to frost (or ice) during the cold nights and then being warmed quickly from the sun at morning. (The other sides would warm more slowly allowing the moisture to be released slower. Did a research project for HUD years ago and seen this over-and-over traveling through Wisconsin.
As for using hardboard as skirting, this material should never be in contact with the ground. Not even close to it. The critical point on hardboard is the places where the finish is broken. And as the edges are raw, water will soak right in like a sponge.
In the factory when they install hardboard, they are required to seal all edges and repair any nails not driven deep enough or fill any nails driven too deep. We are very through in inspecting these areas as they have so many problems in the field. (As a thrid party inspector, we are required to check every square foot of surface, every nail). Any open edges, not sealed, ESPECIALLY if in contact with the ground, is a disaster waiting to happen.
I would make this a glowing error on my report. Perhaps the present owner used hardboard as a cheap "quick, fixer-upper" and didn't want to forgo the cost of real skirting material. (They make special skirting, usually of PVC for this.)
I would inform the potential buyer that the skirting will deteriorate and they will be forced to remove and replace it. It should last a few years if kept reasonable dry, perhaps three.
While talking about skirting, it's not really needed. It does not help to keep the home warmer (unless they is a real problem with the insulation in the floor, or tear in the underfloor material). But if they do install skirting, it MUST BE VENTILATED. Same as crawlspace in the IRC, at a minimum. This seems to often overlooked. The more ventilation, the better.
One other critical point, drainage. I've inspected homes in the field and found standing water under the home. Took humidity reading inside and one home was hitting 50%!
All water must drain away from the underside of the home. Big red flag if you find evidence of standing water. Causes all kind of problems with the floor systems. Also can cause causes problems with the foundation and uneven settling.
One last item I would advise to check for. On a Manufactured Home, the home has permanent, federal certification attached to it in the form a a small, 2"x4" red metal tag. This is located at the back ("tail-light end") of the home, approximately one foot up from the floor and one foot in from the road side. (Sometimes may be present on the rear sidewall, mostly in double-wides as they are shipped without siding on the ends).
This certification tag is sometimes removed and discarded (usually if the siding has been replaced). Without this tag, the home *cannot be sold*.
If the certification label(s) (one for each floor section) is/are missing, the present owners will have to secure new certification, which will take additional time and money.
06-12-2012, 09:56 AM #4
Re: Manf. Homes
I have limited my inspection practice to manufactured/modular homes. Most of my business is for new housing or inpection requests for foundation certification.
The first thing you must determine is if the house is a manufactured home or modular home. Manufactured homes must have the red HUD tag on the the home, generally located on the rear of the structure. This denotes that the structure is built to HUD code, which is entirely different from CABO or IRC codes, and has a independant third party inspection to verify the consruction of the home. Some things they do I don't like but that's the way it is. Most modular homes are built to IRC codes and that is where most inspectors are familar with the code. MOdular homes do not have the red HUD sticker (metal plate) attached but have a "data plate" located on the interior, usually a paper 8x11 paper stuck to the wall in an interior closet. This will allow you to determine to code standards you can judge your inspection by. On HUD code houses, about the only thing you can call out is lack of water intursion protection (caulking, etc.).
From the floor level to the ground is where you can get into problems. The home must have drainage all around the home, 5" slope over 10'. The skirting enclosure must be of substantial material not subject to rot and wind resistant (FHA standards). Composit or cement board skirting directly on the ground will not cut it. Use the same standards for ground clearance as CABO or IRC. FHA requires the skirting must be supported to frost level. Ventilation requirements are based on same formula used in conventional foundation systems. Vinyl skirting is the most common in my area and weed eaters will do a number on it. Any vinyl skirting with holes should be called out for replacement.
What type of foundation system does the home have? Manufactures have different spacing requirements for the support piers (blocking) for their homes but none that I know of allow spacing greater than 8' OC. The support piers can be placed on ABS pads or side by side cap blocks forming a 16"x16" pad and stacked up from there. Over 32" high will require double blocking. Earth anchors for tie downs are acceptable for conventional loans but not for FHA loans. You need to know who will be lending on the home and the type of loan involved. Not only the buyer but the lender will be relying on your expertice, so protect yourself. Note that within the last few years the anchoring requirements have called for double anchoring on the ends for shear forces in both directions of the axis of the home.
Modular housing, both on frame and off frame, use IRC or CABO codes for support piers and exterior support. On frame modulars have same anchoring requirements as HUD homes (8'OC) and are set in concrete to frost level.
Manufactures will void their warranty if any attachment to the home is not self supporting. Therefor, decks can not be attached with ledger boards to the box band of the home. It must be free standing or self supporting. Any carports, garages, covered porches or decks or awnings must be self supporting. The codes for the construction of decks, garages, etc. are the same as CABO or IRC.
Be sure that the scope of your inspection services is spelled out in your agreement. Since most of the inspections that I do are on new housing, any defects on the interior are covered by the manufacturor or dealer and the form and verbage that I use covers me (HUD-92051).
Many people view manufactured housing as substandard. But I have built a lot of homes over the years but have never built one that you could haul down the road at 50 mph and it wouldn't fall apart. To me, the newer homes are engineering marvels and when set up and maintained will last as long as site built. You are going to see more and more modular housing on the market as well and I have not seen one yet that will not surpass any site built home.
Hopefully, I have given you some things to look out for or consider in your inspection process. I would be happy to share my experince or knowledge with any of you. I can be contacted at firstname.lastname@example.org or at my home office at 405-386-4545. Have a great day and God Bless the USA.
06-13-2012, 06:36 AM #5
Re: Manf. Homes
Wow! Great info guys! I inspect a lot of modulars but rarely do manufactured (mobile) homes. I inspected a manufactured home a couple of months ago. The realtor specialized in selling these and about halfway through the inspection, she asked me how many of these I do. I replied that I rarely inspect these. She smiled and said that she could see that.
I asked her if there was any problems or recommendations about my inspection. She said that I was doing a good inspection, but her regular inspector who specialized in mobile homes did his inspections very different and had very different commentary. I'm still not sure what to make of that.
06-13-2012, 01:11 PM #6
Re: Manf. Homes
If you are going to continue top inspect Manufactured Housing, there are several key differences between conventional housing and Manufactured Housing.
A good place to start is by reading the "Factory and Site-Built Housing: A Comparative Analysis" put out by the NAHB Research Center and is available through HUD User.gov. It can be downloaded here:
Factory and Site-Built Housing: A Comparative Analysis | HUD USER
It will describe the basic differences between site-built and factory built housing;
or, the "Home Builders' Guide to Manufactured Housing"
Home Builders' Guide to Manufactured Housing | HUD USER
<Q> This Guidebook provides conventional builders and land developers with an introduction to manufactured housing, focusing on differences between manufactured and conventional homes that are likely to be encountered in practice<Q/>
The HUD code went into effect on June 15, 1976. Mobile Homes built prior to this were built to specific state standards; and will bear their labels. After this date and they will have the red certification labels I wrote about in my previous post. Make certain these little red labels are on the home, and I would note the label numbers in your report for record purposes.
Now, the most important (besides being built to different codes as Bill described), is the installation.
Modulars are almost always installed on conventional foundations. The foundation and installation will be subject to the AHJ so it should meet the local codes. A standard site-built type of inspection is all that's required.
Manufactured Housing however is sometimes installed by untrained individuals (varies by state) and often leads to problems after installation. And even with experienced individuals, the installation is sometimes done in a inferior manor.
So the first place to start is by learning the installation requirements. States have different amended codes for installation, but often these can be found on line.
For starters, you could download and read the following manuals:
"Permanent Foundations Guide for Manufactured Housing": Permanent Foundations Guide for Manufactured Housing | HUD USER
"Guide to Foundation and Support Systems for Manufactured Homes"
Guide to Foundation and Support Systems for Manufactured Homes | HUD USER
"A Review of Manufactured Housing Installation Standards and Instructions"
A Review of Manufactured Housing Installation Standards and Instructions | HUD USER
Manufactured Home Installation Training Manual
Manufactured Home Installation Training Manual | HUD USER
Additionally, you could consider enrolling in an on-line course on installation. The MHI has such a course.
Manufactured Housing Institute-Education, Accredited Community Manager, Professional Housing Consultant (PHC®) Designation Program, Online Training, MHEI® Board of Directors, Seminars
(this is really designed for those who are actually installing the homes, but would prove useful to anyone inspecting installations as well).
To give you a better idea of what's involved, here is a reference for the State of Wisconsin's "Manufactured Home Installation Manual" (could prove to be useful):
After installation, a close inspection of the wind hold-down is next important. Most often this completed with steel strapping material to specifically designed ground anchors. These often need to be adjusted annually from frost/freeze heave. (Same is true for the concrete pilings under the home.)
Manufactured Homes seem to subject to moisture problems more then site-built due to bad under-floor drainage.
"Moisture Problems in Manufactured Homes"
Moisture Problems in Manufactured Homes | HUD USER
may have some useful advice.
If your in a high-wind area, such as Florida, a review of the specific state requirements would be helpful.
I wouldn't concentrate on learning the specific code for Manufactured Housing. The homes are throughly inspected in the factory by the manufacturer (the current federal QC regulations are very severe), then by an independent third party and finally overseen by HUD through its agent; IBTS.) In a general sense, the home should comply with every item in the code, when it was manufactured.
As far as the code goes, the structural plumbing and energy aspects are very specific to Manufactured Housing. Electrical is mostly HUD code, based on the 2005 NEC. (The HUD Code will governs if they differ.)
You can find the HUD standard for Manufactured Housing at:
PART 3280—MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS :: PART 3280--MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS :: CHAPTER XX--OFFICE OF ASSISTANT SECRETARY FOR HOUSING--FEDERAL HOUSING COMMISSIONER, DEPARTMENT OF HOUSING AND UR
The following Manufactured Homes Inspection Checklists may also prove helpful:
"Manufactured Home High Wind Inspection Checklist"
the HUD "Inspection Checklist" (Office of Public and Indian Housing):
"General Walk-Through Inspection Checklist for a Manufactured Home"
(this is a good one to check out)
City of Abilene's "Building Inspection Division Hand Outs Mobile Home Inspection Check List"
Building Inspection Handouts
City of Tallahassee's "MANUFACTURED HOME INSPECTION CHECKLIST GENERAL CONDITION STANDARDS"
(also a good checklist)
Good luck in your business.
06-13-2012, 04:27 PM #7
Re: Manf. Homes
Once again, thanks for the great info. I have some late night reading to do
06-13-2012, 07:10 PM #8
Re: Manf. Homes
Hi Dennis, in my area of the southwest the homes are often installed at the exterior grade with a dug-out crawl space. I occasionally see the retaining wall / skirting is treated plywood held in place with rebar. It is usually bulging or failing but apparently is allowed by local authorities. I tell clients it will eventually fail as I have seen it fail often. Is this an accepted practice?
END GLOBAL WHINING
06-13-2012, 11:14 PM #9
Re: Manf. Homes
If the home had been sited prior the current law, almost anything was allowed. I could be wrong, but I believe that under current law, if the skirting is replaced, it would require a permit and be governed by current law. Manufactured Home exterior sidewalls are designed to deflect (up to an inch or more) and if the construction holding the plywood isn't designed to carry the sidewall load, it will certainly buckle. All vinyl skirting panels fit into a special channel which allows for movement.
I think Arizona has some new installation rules going into effect this month. I'm not really familiar with AZ code, you could try contacting the Office of Manufactured Housing in Phoenix at 602-364-003 or send an email to dfbls.az.gov and see what they say.
06-14-2012, 11:03 AM #10
Re: Manf. Homes
Very solid information presented by Bill and Dennis. I would add however: don't make generalizations regarding pier spacing and footing size. Footing dimensions are a factor of loading and bearing - and this changes based upon home size, pier numbers and bearing material. Many manufacturers allow greater than 8' o.c. spacing for piers. Also, anchoring requirements need to account for wind zone, roof pitch, wall height among other considerations. New anchoring technologies are dramatically different than "old-style" strap/cable sytems. To really know if any particular home meets the required install standards, you need to reference the home installation manual, as well as the state requirements............Greg.
08-26-2012, 05:12 PM #11
Re: Manf. Homes
Last edited by Greg Filian; 08-27-2012 at 10:30 AM. Reason: Left out some information
08-26-2012, 09:10 PM #12
Re: Manf. Homes
The manufacturer provided very good instructions, but reading them would have meant bringing a flashlight.
John Kogel, RHI, BC HI Lic #47455
08-27-2012, 04:54 AM #13