Manufactured Homes and Attached Structures-Part 3

In this post let’s talk about some of the other structures commonly attached to many manufactured homes, starting with garages:

Home being prepared for a garage attachment in a factory.

A few years ago, HUD started taking a hard look at garage attachments and they were very clear in stating their requirements. Simply put, HUD requires that if a manufactured home with an after-market garage attachment must be designed for such attachment and that the manufacturer should request a letter of “Alternative Construction” (click here for more on Alternative Construction). This Alternative Construction (AC) letter is required to establish a process to assure that these manufactured homes (with an attached garage) will meet all applicable codes and still provide safe, durable and high-quality housing as expected under the program. Here are a few of the code requirements that must be considered by the manufacturer when designing a home for garage attachment:

  • That neither of the required 2 egress doors enter into the garage.
  • That no windows are located in the garage attachment wall.
  • That there is a fire rated wall assembly (and door) separating the garage from the living space of the home.
  • That there is a separate GFCI protected circuit to serve the garage.
  • That the addition of the garage does not impact any exhaust fans (such as range hood) air intakes (such as furnace or fireplace), plumbing venting or roof venting.
  • That the manufactured home is designed for the added weight of the garage. 

    This garage attachment was the cause of several safety related code violations.

HUD does NOT address the need for a carbon monoxide detector which is generally required under state and local building codes when any home has a garage attached. Even though the HUD Code does not provide for CO detectors, I strongly recommend one be added to every home with a garage.

 

This addition led to several code violations.

If you are considering adding a Florida room, three-season room or similar addition to a manufactured home, with the exception of the fire rated wall assembly and door, every other point raised above regarding garages must be considered. Bottom line, have the manufacturer design the home for the three-season room before you proceed!

This added roof didn’t account for the penetration in the valley! The potential for a leak is great!

 

Solar panels add unintended weight to the home!

Lately I have been seeing a lot of manufactured homes with solar panels installed on the roof. I am a big fan of alternative energy solutions, but again, we need to ask ourselves if the home is designed for the added weight. My research shows that a typical solar panel adds about four lbs. per square foot onto the roof of the home. A typical manufactured home roof truss is designed for a dead load of eight (8) PSF. That eight pounds dead load is so the roof truss can support the weight of the ceiling board, insulation, roof decking, underlayment and roof shingles. While four extra pounds may not seem like much, it exceeds the allowable dead load of the roof by 50%.

Again, make sure the home is designed by the manufacturer for the additional weight of roof mounted solar panels.

On a positive note, I have been seeing some DAPIA approved designs from a few manufacturers that are a little more flexible then previous designs when it comes to certain added structures (primarily extended or attached dormers). Be sure you read the fine print on these designs, and keep good records of the construction. Remember, the devil is in the details!

This might be a topic for a future post!

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Manufactured Housing-Different From The Rest

I recently was contacted by a real estate appraisal company from Michigan that was in a heated dispute with a property owner regarding their factory-built home. Was it a modular home or a manufactured home? The homeowner claimed is was a modular, while the appraiser disagreed.

A steel chassis does NOT always mean it is a manufactured home.

This appraisal company had over 30 years experience, yet had never received any training specifically on manufactured housing. Most training courses will include a few slides that basically say that if a home has steel chassis (or frame) attached to the floor joist, it must be a manufactured home. As you know, that is not always the case. 

Now, don’t think I am criticizing real estate appraisers. I have seen tax assessors make the same mistake. In fact, not just appraisers and assessors, but code officials, zoning officers, banks and home inspectors as well. This leads me to ask, why are so many housing professionals misinformed regarding manufactured housing? 

I visited several web sites to see what they say regarding the differences between manufactured and modular housing, and found most of the information on the web is more focused on marketing as opposed to structural features and building code differences. To make things worse, too many industry professionals do not have a clear understanding of the differences, and play fast and loose with the terms manufactured, mobile, modular, etc., causing further confusion.

Now, to muddy the water even more, we are dealing with “tiny houses” which are a completely different product! Why do they use the word “house”? Calling them “Tiny Campers” would be more accurate. But, as it stands they also add to the confusion. 

A tiny home is not a Manufactured Home!

So, what is so different about a manufactured home compared to other housing? And who should be responsible to assure that manufactured homes are not confused with other housing types? And does it even matter?

Simply put, modular homes are generally built to a state specific building code and are not intended to be moved after the initial installation.  They are considered real estate and must be placed on a permanent foundation on privately owned land. And like it or not, some producers design and construct modular homes that leave a chassis in place, even after it is placed upon the foundation. But the intent is that the modular home will never be moved after placement.

As you know,  manufactured homes are built to a national building code. However each state has their own set of requirements (or lack of requirements) regarding assesment, classification, zoning, lending, sales, etc. Many states consider manufactured homes to be vehicles, registered or titled through the state Department of Motor Vechicles (DMV). Therefore, like a “vehicle”, manufactured homes are considered “personal property”. Which means instead of a low interest rate mortgage, purchasers must either pay cash or take out a high interest rate “chattel” loan.  

This home on private land will likely never be relocated.

So why are manufactured homes considered vehicles? Because by definition, a manufactured home must be permanently transportable. It doesn’t matter if the home is placed on a full basement, masonry crawl space, piers or slabs. A manufactured home must retain the ability to be moved from one location to the next. It may not always be practical, but the on-going ability to lift the home from the foundation, re-attach tires and axles, hitch and lights for transport is required.

For a manufactured home installed in a leased land community (park), a chattel loan makes sense. But today, many manufactured homes are placed on private land with permanent foundations. For these situations, a chattel loan is not the best option.  The owner of the manufactured home would have to work with their state DMV to retire the registration or title and establish the home as “real” property, and therefore qualify for a mortgage.

I hope this helps you better understand the mortgage/chattel loan issue. Banks are reluctant to lend money to a structure that could potentially be towed from the building site.

So, can you blame an appraiser who looks in the crawl space and sees a steel chassis and assumes it is a manufactured home?  

I don’t presume to have all of the answers to this decades old problem, but I do think that understanding the requirement of transportability is important. I also believe that there are some simple steps that all of us can take to help educate those in the housing industry as well as the home buying public:

  • Use the correct terminology. If it is a Manufactured Home, call it a Manufactured Home!
  • Earn the confidence of other housing professionals. Start sharing how this program is regulated, and that there is oversight to protect the consumer and the public.
  • Consider sponsoring a training session in your area for code officials, assessors, appraisers, or other housing professionals.
  • Teach the consumer that at some point the home’s label and data plate will be important and should be preserved.
  • Invite housing officials to your trade show, retail center, or to visit an installation site.
  • Become your area’s manufactured housing expert. 

The Manufactured Housing Program is likely the best kept secret in the housing industry. To encourage the industry to grow, we need to get the rest of the housing industry to better understand what makes our product different.

Do Manufactured Homes Really Need Two Exit Doors?

Every time I talk with a group of building code officials, the issue of exit doors comes up. Most code officials are familiar with the requirements of the International Residential Code (IRC), which only requires one egress (exit) door per home. Many code officials mistakenly think that as long as the manufactured home has one landing and/or stairs that provide a single way of escape from the home, the code has been satisfied. The problem is, when it comes to the design of a manufactured home, the IRC is the wrong code! Instead, The Manufactured Housing Construction and Safety Standards (HUD Code) requirements must be followed – and are different from the IRC. Every professional installer needs to understand the differences. Manufactured homes are designed with two egress doors to allow occupants to escape the home in the event of fire, an intruder, a violent situation, or any other emergency.  

To make the situation worse, installers often permanently disable any exit doors where they didn’t install a landing or stairs. This is an extremely dangerous and risky practice that impedes the ability to escape the home. I know professional installers worry about increased liability, and blocking emergency escape paths puts installers at the greatest risk of all!  So, let’s examine this issue and try to better understand.

 

blocked door 1

How can someone escape through this door?

The HUD code at 3280.105 requires that every manufactured home:

  •   Have two exterior doors, remote from each other
  •   Establish a maximum 35’ path of travel from each bedroom to reach an exit door.
  •   In single section homes, the doors must be at least 12’ apart, in multi-section homes, at least 20’    apart.
  •   Must not be in the same room or group of rooms.
  •    May not open into a garage or other similar structure.
  •   May not be located where a lockable interior door must be used in order to exit.

(see 24 CFR 3280.105 for the exact requirements)

Even though the IRC (or other state or local code) is preempted from the design of the home, professional installers must reconcile the HUD requirement with the state code. The IRC-R-311.3 says that each door must have a landing or floor on each side, not less then the door width. Also, the stair geometry (rise and run of the stairs) must also comply with the IRC or whatever code the local authority has adopted.

 

blocked door 2

A landing and stairs are needed here!

Basically, every manufactured home is designed with an exit or egress system that assures that there is a continuous and unobstructed path to the outside of the home. The system relies on a minimum of two exit doors that allow occupants to escape from the home in any given situation. There are no exceptions to this important safety feature. No one, including the code official, may authorize anything less then the code requirement.  

If you are an industry professional that sells/installs manufactured homes, be certain that you fully understand the code requirements for emergency escape doors. Be certain that every home is completed in a manner to offer the occupants each and every safety feature that the code requires. And finally, if your local building code official does not understand the Manufactured Home Construction and Safety Standards, share a copy of 24 CFR 3280.105. This issue is too important to ignore.

We will explore more on this issue in our next post.

 

How to Train Your Code Official

The one thing that all manufactured home installers and retailers have in common, is that they are all impacted by the state or local building code officials and their approach to manufactured housing. Whether a code official oversteps his authority by requiring unnecessary code provisions, minimizes his role by simply issuing permits and occupancy certificates without any oversight, or if they don’t issue building permits for manufactured homes at all, our work is impacted and far too often, negatively.

Code officials that do not understand the manufactured housing program, ultimately add unnecessary costs to the home and limits our ability to provide high quality, durable, safe and affordable housing.

Today, I want to talk a little about what installers and retailers can do to educate code officials and as a result, better position the manufactured housing industry for the future.

The first thing to remember is that the vast majority of code officials receive no formal training in regards to the manufactured housing program(s). Except for the few states that specifically require code officials to receive training on manufactured homes, very few code officials understand manufactured homes. The industry does a poor job explaining how the manufactured housing program works on behalf of the state/local code enforcers. As a result, we are left with a patchwork of requirements which often result in inferior installations, and also undermine the overall affordability of manufactured housing.

To compound matters, installers, retailers, and manufacturers are reluctant to have business-like discussions with code enforcers and as a result, nothing changes. The industry folks I talk with generally adopt one of two extremes when it comes to this relationship (neither of which is correct). Either they object to the code official simply entering a manufactured home, or they are of the opinion that it is easier, cheaper, or faster to just do everything the building code official asks.  No matter which approach you take, it ultimately supports the notion that either we have something to hide, or that the construction and/or installation of manufactured homes is substandard and needs the code enforcer to improve on the homes design.

Here are a few things that installers and retailers must do to start to get code enforcers to view manufactured housing for what it is: sophisticated, code compliant, safe, high quality, durable and yet affordable housing.

Stop using the term “mobile home”. If it was built before June, 1976, fine, call it a “mobile home”. But today we produce and install “manufactured homes” and the differences are significant. If you want state and local code officials and the home buying public to think that the industry of today is producing and installing the same product that we did over 40+ years ago, then keep using outdated terms. But if we ever have hopes of getting people to understand that the manufactured home of today compares favorably to every other housing product on the market, then we must use proper terminology. 

Accept that you as the installer are the primary source of information for the code official. If you start to improve the building permit application process, you can begin to drive your code official to better understand our program. For example:

  • Provide a copy of your installer license with every installation. The code official is the first line of defense in stopping unlicensed installers. Presenting your license with every permit application, supports the notion that only trained professionals should be installing manufactured homes.      
  • Provide DAPIA approved details (from the installation manuals) to the code official to used to conduct the inspections.  Single page, unapproved pier (or footer) prints do not illustrate that the real installation drawings and details have already been reviewed and approved. Far too many code officials don’t understand that the plan review has already been performed for them!
  • On the other extreme, it seems that too many people just give the code official the entire installation manual and expect them to make sense of it. We should organize the DAPIA approved designs needed for the installation so that they are easily followed. Utilizing a cover sheet is one way to do that. This not only educates the code officials, it is a great tool for installers as well. Click here for a sample that you can use: MH Building Permit Coversheet
  • Be present at the inspections. There is no better time to provide training than this. Bring the DAPIA approved designs (and maybe your copy of the Manufactured Home Construction & Safety Standards) with you and whenever a question is asked, refer to the designs or standards.

 At this point, I know many of you are thinking that you would rather not make waves, and that the code official won’t listen, and a ton of other reasons as to why you prefer the status quo. But, like it or not, the industry is changing and what worked for us in 1976 is not going to work tomorrow.

I was encouraged to learn folks from HUD and SEBA are speaking at a national meeting of code officials in September to discuss installation.  I have been conducting code official training for the past several years, and I can tell you, they are receptive to the message when we present it properly.

Bottom line is that either we start driving the state/local code officials to understand and respect our program, or manufactured housing will go the way of typewriters, telephone booths, and record albums.

 

Let’s Talk About Spacers and Shims

A few weeks ago, we looked at pier cap blocks, so now it makes sense to talk about spacers and shims.

Just so we are on the same page, a spacer can be used to fill in the space between the cap block and the frame (chassis) if that space is more than can be shimmed (1″). Sounds simple enough, right??? Well think again.

Double block pier, concrete footing under the ground vapor barrier, double 4″ solid masonry cap blocks, 2″ hardwood spacers and hardwood shims. Nice job!

The Model Manufactured Home Installation Standards describe a spacer as “Hardwood plates no thicker than 2” nominal in thickness or 2” of 4” nominal concrete block…”. (3285.304(c)(3)). But the individual manufacturers’ installation instructions often provide more options, and sometimes confusing details.

Most manufacturers allow 2” x 6” hardwood spacers. One spacer for single stack block pier, two spacers for a double stack block pier (one per cap block). If you stick with this, you will be in good shape.

 A recently revised instruction manual now defines a spacer as “hardwood, southern pine, or Douglas fir larch dimensional lumber 1x or 2x (2 layers maximum)”.  This is the first time I have seen pine in the same category as hardwood, not to mention allowing the spacer to be 1” thick. So, for those of you that like to use 5/4 pressure treated decking boards as spacers this appears to be one of the first DAPIA approvals for this method.

2″ hardwood spacer on a 4″ solid masonry cap block. Too bad the strap is loose.

When checking your installation manual, look at both the table and the text. Many instructions will specify “Nominal 2” thick boards” in the Pier Minimum Specification Table. BUT, if you turn to the text at “Install Shims” generally on the next page, they allow hardwood or concrete, not just 2” thick boards.

spacer text

Pressure treated hardwood dimension lumber is mentioned in a few manuals, but I have yet to see pressure treated hardwood. Maybe it’s a regional thing, but where I come from, hardwood is not pressure treated.

I even saw a few manufacturers’ installation instructions that don’t mention spacers. Just be sure to double check with your manufacturer to be certain that you are following their instructions.

When it comes to the overall size of the spacer, most pier illustrations show a 2” x 6” spacer board. While the installation instructions don’t specify the length of the spacer, the illustrations appear to show them the full length of the pier cap (16”). 

While there appears to be variation in the materials prescribed by different manufacturers, make sure to stay away from plywood or OSB! These materials will delaminate rather quickly and will certainly cause problems.

When it comes to shims, the installation instructions are more straight forward.

Use proper size spacers and hardwood shims! Not cedar shims like this!

Hardwood shims, 4” x 6” x 1” thick, must be used in pairs, and cannot occupy more than 1” total between the cap block (or spacer) and frame (I-beam). And like the spacers and cap blocks, a double block pier would require two sets of shims, one set atop each cap block.

Plastic Shims

Most manufacturers allow for plastic shims of sufficient capacity. I believe that plastic shims are a great choice for piers in porch areas, where water can pass between the decking boards and lead to premature decay of wooden shims. Also, the plastic shims are grooved so that they cannot slip apart. Again, I did see one manufacturer allows southern pine or Douglas fir shims in addition to hardwood. But generally plastic is the only exception to hardwood shims.

Hopefully, this post will encourage you to examine your current practices regarding spacers and shims, and to be certain you are following the manufacturers’ installation instructions. If you have questions, call the manufactuer’s Quality Assurance Manager and ask him to clarify their requirements.

Let’s talk about: Alternative Construction

Last week during a discussion in an installation training class, it became obvious that too many installers and retailers aren’t being informed about Alternative Construction (AC) and On-Site Completion (SC) and what this means for the manufactured homes that they install and/or sell.

So, lets take a look and see if we can shed some light on these issues, starting with Alternative Construction.

When a manufacturer intends to produce a manufactured home with a construction aspect that does not meet the Manufactured Home Construction & Safety Standards (MHCSS), but will perform at least equal to the MHCSS, they can request HUD allow such construction.

Let me give an example:

Say you want the manufacturer to construct a home for your customer that has tankless water heaters instead of the typical storage type water heater.  Since the MHCSS doesn’t provide for a tankless water heater, the manufacturer needs a special approval from HUD to omit the storage type water heater and replace it with the tankless type. That approval is called a Letter of Alternative Construction (or an AC letter).

Here is another example: your customer needs a shower that is designed for wheelchair access. The MHCSS requires a minimum 2” dam (or threshold) to keep the water from running onto the floor, making it impossible to access the shower with a wheelchair. The manufacturer can request an Alternative Construction authorization from HUD to provide a shower without a 2” dam, designed to facilitate wheelchairs.

Accessible Shower

 In both of these cases, the home will not meet a specific requirement of the Manufactured Home Construction and Safety Standards, however they both will perform equal or better than the actual code requirement.

DAPIA approved floor plan for a home with garage attachment.

 Currently, one of the biggest requests for AC letters is when a manufactured home is designed for the attachment of a site-built garage. There are many issues of code compliance that must be examined when designing a home for garage attachment.  Issues such as the path of egress (exit) from the bedrooms, impact on lighting and ventilation in the area where the garage is attached, additional loads on the structure of the home, and electrical considerations, to name a few. But the omission of the exterior covering (siding) for the application of gypsum to provide the needed fire separation is where you will find the need for the AC letter.  On a side note…the MHCSS still does not address carbon monoxide alarms! If you are selling/installing a home with a garage attachment, talk to the manufacturer about a combination smoke/CO alarm or an added electrical outlet where you can provide this important safety consideration.

Through the years, the most common use for an AC letter has been a home with a hinged roof, usually a 5/12 roof pitch or greater (this never made sense to me, but that is how they handled hinged roofs). Today most manufactured homes with a hinged roof are being constructed under the new On-Site Completion Process, which we will discuss in a our next post.

 Here are a few “take aways” for retailers and installers when it comes to Alternative Construction.

  •  A manufactured home covered by an AC letter is determined to perform equal to or greater than the MHCSS requirements.

Typical notice to consumer of Alternative Construction.

  • Every manufactured home under an AC letter requires a notice to the perspective purchaser. This notice, as well as an appropriate checklist, and other information related to the AC process is provided by the manufacturer.
  • You can identify a manufactured home constructed under a letter of Alternative Construction by the letters “AC” which will be included in the serial number.
  • Often the home will require a special inspection.   
  • Both the retailer and installer should maintain records of compliance with the AC requirements, and a copy of any needed inspection of the completed home.

 Ok…I hope this helps. If you have anything to add, submit a comment.

In our next post we will talk about On-Site Completion.

Anchoring-Part 1-Conventional Tie Downs

Ground anchors

The other day, a professional installer wrote to me about anchoring a manufactured home. He asked if he only needed a tie down anchor at each corner of the home or if he should install one at every pier. Since neither answer is completely wrong or completely right, I thought we should start talking about anchoring and try to shed some light on this critical issue. Over the next several weeks, we’ll talk about all the various anchoring systems.

Let’s start the discussion talking about conventional anchoring systems, you know, the ground anchors with steel straps to the frame.  How should they be installed to properly anchor or stabilize a manufactured home to protect from wind storms?

 I wish there were a simple answer. At this point, I would typically tell an installer to check the anchoring charts in the Manufacturers Installation Instructions (MII), but I believe that the instructions are extremely confusing and not easily understood or followed. But if we start thinking about the basic fundamentals of anchoring equipment, it can start making sense.

Even if you use one of the alternative anchoring systems (Xi2, Vector System, LLBS, or All Steel Foundation or some other system) they generally require conventional ground anchors and straps at each corner of single section homes. So, regardless of the anchor method you prefer, you must have a good understanding of how to properly install a conventional ground anchor and strap.  Here are the fundamentals all installers must know:

  • Ground anchors are designed to be installed in the ground. Not concrete!

    This is NOT proper anchoring!

  • Cross drive anchors are designed to be installed in solid rock. Not soil!
  • Ground anchors must be installed to their full depth, and extend below the maximum frost line.
  • Ground anchors should be placed roughly under the side wall of the home (sometimes call it the skirting line) at a slight back angle (10°).
  • If you are using conventional ground anchors and straps, the first anchor should be placed within 2’ of each end of the home. There is some variation depending on the manufacturer, so check the MII for each home.
  • The anchor must be suitable for the soil where the home is being installed. We will talk more about soil holding capacity and soil classification in another post.
  • Ground anchors must be at least 12” above the water table.
  • Unless the ground anchor and the strap are in-line, a stabilizing plate is needed to prevent the ground anchor from slicing through the ground when the load is applied.
  • Poor site grading can undermine a perfect anchoring job.

    Poor site grading led to loose strap

 

And we haven’t even mentioned the straps yet!

  • The tie down strap generally attaches to the top of the frame (or chassis) I-beam, wraps completely around the I-beam, and down to the anchor. As an alternative, you could use a positive connection swivel strap.
  • Where the tie down strap wraps around the I-beam, strap protection must be provided to prevent the strap from shearing off at the sharp edges of the beam.

    Strap protectors

    You can purchase them or make them out of strapping material.

  • Strapping material must be certified to ASTM D 3953-97, and have identifying markings every 5’.
  • The strap must wrap the anchor bolt 4 – 5 times.
  • The strap must resist corrosion and weather deterioration.
  • When installing the strap, you need to pre-tension the anchor, pulling it against the stabilizing plate.
  • The angle of the strap is the most critical consideration.

    Inexpensive angle gauge to show proper strap angle.

    Diagonal straps are required in Wind Zone 1. If the strap is greater than 60°, you have not protected the home from sliding off of the piers.

 

WOW! That is an awful lot of information, so let’s stop here for now. The most important thing that every professional installer must know is to make sure that the anchoring system you’re using is consistent with the manufacturer’s design.

Start thinking about your processes for installing tie downs. Make sure to cross check your work to the illustrations and details in the installation instructions for the homes you are installing.

Next week we will talk about how to figure out proper anchor locations and spacing.

The Importance of a Good Marriage (Line)!

A good marriage is critical to your emotional and financial security.  The same can be said about the marriage of two or three sections of a manufactured home. For all of the good work and craftsmanship that goes into the construction and installation of a manufactured home, I can’t help but think that the marriage line joint is the weakest link in the process. If the marriage line is not secure, level, and reasonably tight, problems are sure to creep in! Heat loss, wall and ceiling cracks, carpets and floors shadowing the seams, and doors binding can all be symptoms of a good marriage gone bad.

 So, let’s talk a little about the marriage line to make sure we are doing all we can to strengthen this weak link.

Everybody knows to remove all shipping plastic from the home. But it is especially important along the roof line as venting of the roof cavity depends on air flow from one home section to the other. Any plastic left around the roof line can restrict the air flow to properly vent the roof.

Look closely for the staple!

Inspect the marriage wall for leftover staples or nails once the shipping plastic is removed. I know they are a pain in the neck, but one staple left in the marriage line can cause big problems.

Damaged heat duct crossover gasket.

Inspect the heat duct gasket. If it is damaged, you need to replace it. Was it the shipping plastic or straps that caused the damage? If so, snap a picture and let the manufacturer know! Consider a shield made from coil stock that can be removed once the home is in place.

Look for any electric cables that might get pinched or otherwise damaged when the sections are pulled together.  Re-secure them to prevent damage.

Gasket needing inspection!

Is the marriage line gasket intact? Damaged? Properly placed?  If you read my previous posts, you should know I think this is a big problem area. Read my post from April 17, 2017 “Would You Like That Supersized?” for some other thoughts on this gasket.

Gaps between the A and B sections of a home can lead to structural problems over time. While professional installers generally don’t pay much attention to shear walls (the walls that transfer wind loads through the structure of the home to the anchoring system), it is very important to understand that in many two-section manufactured homes, all of the shear walls are found in only one of the sections. The manufacturer is depending on you to make a structurally sound joint to transfer these wind loads across the marriage line to the section of the home with the shear walls.

Wind loads are safely transferred only when you properly fasten the sections together. Basically, a structural, tight fitted joint is required in order for the home to withstand wind storm. No gaps in marriage line!

The manufacturer’s installation instructions states, “Shim any gaps up to one inch between structural elements with dimensional lumber. If any gaps exceed one inch, re-position the home to eliminate such gaps”Read that carefully. It means gaps are not permitted! You must either use shims up to 1″ or get the home sections closer.

mate line 1 gap

This needs a shim!

This is very important not just at the floor, but the walls and roof as well! Gaps between sections can cause the screws, nails, or lags to shear off, pull out, or fail at the exact time they are needed the most!

These lags should have been staggered!

Make sure to stagger your fasteners (A half/B half), and be sure they don’t split out the lumber. The lags or screws you use must properly penetrate into the receiving members by 1 ½”. You might need to use longer fasteners than the ones provided by the manufacturer.

Strapping at roof line.

If you are using straps at the roof, it is critical to remember that this joint also needs to be solid and tight. If the staple crowns or nail heads cut through the strap material, the strap won’t be able do the job that the manufacturer intended.  Make sure your fasteners go through the blocking, beams, or rails provided, and not into the truss!

Take a few minutes before your next set and double check the manufacturer’s instructions for fastening the marriage line. Take a lot of pictures, and give some feedback to the manufacturer (the Quality Assurance Manager in this case). They might be able to tweak things at the factory to make your job easier. In fact, if you aren’t on a first name basis with the QA Manager at the factories you deal with, you need to change that. These guys are a wealth of knowledge! Every QA Manager I have ever met wants to produce the best homes possible. What they are lacking is feedback from you!  

A good, strong, tight marriage line is not always easy and at times very difficult. But, with a little tender loving care, you will get that good marriage line, and we all know, a good marriage is well worth any price!