Mobile Home Roof Over Manual
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Many mobile homeowners attach porches and additions onto their mobile homes incorrectly. It’s not usually a detrimental issue, thankfully, but an incorrectly installed mobile home addition can pose problems. In this article, we are going to cover mobile home additions as thoroughly as possible. We’ll cover the advantages and disadvantages of adding to your mobile home and all the basics of building an addition or porch onto your mobile home, plus a few more important things you should know.
There are a few basics you should know before you decide to build an addition onto your mobile home.
The top priority for any homeowner considering an extension to a mobile home is to understand that the extension must not be connected to the existing structure. This implies that the extension should be constructed independently with its own footers. This ensures that the load of the new construction is evenly distributed into the ground rather than onto the original home.
A mobile home addition must move freely from the home itself. Porches, decks, and additions must have their own foundation or footers so the structure can shift independently of the home. The addition is simply ‘butted up’ and attached to the mobile home, and ‘sealed’ so nothing impedes the separate movement.
In other words, an addition should have at least 4 footers, one at every corner to transfer its weight to the ground. If you only see two footers at the ‘end’ of the addition (the side opposite the home), then it’s probably wrong and should be checked by a licensed profesional.
To put it simply, you aren’t attaching the addition to the home at all, you are building extremely close to the home and then sealing the crack between the home and the addition to prevent air and moisture leaks.
An addition needs a completely separate foundation from the home. And, like any structure, the footers must be placed below the frost line to keep them from shifting when the moisture around the cracks in the ground freeze causing the footers to heave and bow.
There are poured footers, cinder blocks, slabs, and piles. Footings for a mobile home addition should be determined by the depth of the frost line of your area, even if your home does not have the frost line footers so that shifting is minimal.
Here’s a map showing the frost line depths for the US:
Footers are installed below the frost line so that the addition doesn’t sink or shift.
Additions to manufactured homes are not often seen as an ‘improvement’ – meaning it probably won’t increase the value of the home in most cases. It won’t change the classification of a manufactured home from personal property to real estate unless the home is permanently installed.
A big disadvantage of building an addition on your mobile or manufactured home involves financing and insurance. It may be harder to obtain both if your home has been modified in any way. If you didn’t get the proper inspections and permits you may run into serious issues if you try to sell the home later down the road.
Some state mandates override local and county regulations when it comes to manufactured homes. Research properly for your location before you begin planning a mobile home addition. With some locations, you could run into so much red tape that the project ends before it even begins.
With all that said, mobile home additions are perfect projects for families that need a larger home but you must get permits and inspections done before, during, and after the construction process. Read about one manufactured homeowner’s experience while building an addition onto his single wide. He failed to get permits and inspections done and paid a price when he sold the home.
Sarah and Justin Wartick built an addition onto their 1985 Liberty single wide. You can see how they created the footers right up against the home and then framed the floor of it out (they were test framing the top in the first image). The second image shows the walls and roof have been framed and the floor joists being laid.
These next two images are the interior of the addition. The image on the right showing the door with the two steps is where the mobile home and the addition are attached. Technically, this is the only place the two structures meet other than where the roof and the siding are ‘sealed’ together.
There are some great online resources about mobile home foundations. This guide about manufactured home foundations and supports is invaluable.
For information about general construction footers, Front Porch Ideas and More has some nice illustrations that show the poured concrete and pier footings.
There are new products hitting the market to aid in DIY footings such as these square foot concrete forms.
You want the mobile home addition to having framing that is equal to or better than the framing that your home has. Of course, you’ll need to follow your local code.
Below shows a mobile home addition being framed out by SM Construction.
A great blog called Dovetail Blog shares its mobile home addition process in detail. It’s a small addition but the end results are beautiful:
As you can see, they used poured concrete footings and extended the roofline down to the addition, keeping the pitch. The addition looks to be used as an entryway that houses the stove and is a few inches lower than the home, except for a platform that the stove sits on.
Here’s the interior of the home:
You’ll have to determine the size of your opening from the home to the addition. Doorways are easier to close up should the home ever need to be moved or the addition removed.
If you do opt for a wider opening between the home and the addition you will need to consider support issues for the opening. Wider openings, where studs would need to be removed, will likely require support beams. That’s not the smartest move for mobile home perimeter walls because those are your load-bearing walls. In other words, keep the opening small so that it’s easier to seal around the home and to keep from needing to support the perimeter wall with a beam.
As stated previously, basic mobile home additions are not completely attached to the home. They are simply butted up to the home and then sealed all around to prevent leaks.
There are a variety of ways to seal the connection between the home and the addition. To seal the gaps between the home and the addition you can use weatherstripping, flashing, backer rod, caulking, and lumber. A backer rod is just a fancy name for round foaming that can be used as a membrane between the 2 structures.
There is a popular way to attach the siding of the home to the addition. Attach a 1×6 board to the home vertically so the addition will butt up against the middle of that board. You’ll attach another board with a lip to the side of the addition. Then, add weatherstripping and screw the lip of the addition to the board on the house – this brings the addition toward the home and helps seal it without overly damaging the home.
These questions were asked in the comment section of our very informative article about building mobile home additions found here.
Flashing and vinyl siding will cover it all up.
To connect the addition to the mobile home if the addition is lower than the roof on your home, you will need to use flashing to seal the gap between the home and the addition’s meeting points.
For a metal roof, you would tuck a single length of 18″ flashing, that has been bent to the needed angle, place the flashing under the homes roof edge and over the addition roof.
Attach to both with screws. Using 2″ neoprene flashing tape is always a good idea, and always seal the screws with weatherproof caulking (neoprene based).
One note about the flashing, you want as long a piece as possible, but you don’t want it too long. If the flashing is too long, it can cause cracks.
If the addition’s roof is higher than the roof on your home, you add the flashing under the lip of the roof of the addition and over the roof of the home (the opposite of above). This creates what roofing professionals call valleys and are problematic areas on any home. Special care should be made to keep water from sitting in the valley that is created.
The graphic below is based on a graphic found on Mobile Home Repair that shows a concept for sealing a mobile home addition. The top drawing shows a cap built on the home (labeled Alum Cap) and a piece of wide weatherstripping folded over to make a bulb shape and screwed into a board on the top edge of the addition.
The bottom drawing in the image above is showing the home and addition from the top, looking down. A flexible vinyl with fiberglass insulation is used to seal the sides of the addition to the home. It allows the needed movement required if your home is not set on a permanent foundation that is set below the frost line – the best method to prevent shifting of a manufactured home.
If the 2 roofs are at the same height, you just use flashing. Screw and seal.
When planning structural modifications or additions to a mobile home, especially those involving metal frames or support structures, understanding welding techniques becomes crucial. Mastering welding positions—such as flat, horizontal, vertical, and overhead—ensures that welds are strong, secure, and compliant with building codes. Whether you’re installing a steel foundation, reinforcing skirting, or crafting custom frames for extensions, proper welding enhances the durability and safety of your addition. A complete guide to welding positions empowers DIYers and professionals alike to work more efficiently and confidently on mobile home projects.
Below you can see a mobile home addition that passed inspection and can be found on The Inspector Blues blog.
It is independently supported, has wired smoke detectors, an exit, sits on an 18″ grade, and is built with pressure-treated wood. It may not be great looking but it had what it needed to pass its inspections and current codes are not lax at all.
Here’s a park model manufactured home getting an addition built onto it. Notice how they’ve done the roof:
Another park model manufactured home addition and carport built by HorseFly Construction:
The next photo shows a huge addition built onto a double wide manufactured home by Addon Rooms:
We’ve featured a few mobile and manufactured homes with additions:
The Directory of Mobile Home Manuals may help you find more information about your specific builder’s suggestions about mobile home additions here.
Here is a great resource from HUD about manufactured home foundations that explains everything.
The basic concept of mobile home additions is to keep the addition separate from the home, while still allowing a connection that is weatherproof and leak proof.
Inspectors and building consultants are available at your local and state agencies, use them to your advantage. You want a safe, long-lasting addition that will make your homework better for you and your family.
If you have any questions, please comment below and I’ll try my best to find you an answer. As always, thank you for reading Mobile Home Living!
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Hello, my name is Kim. My husband and I are discussing building a bedroom addition to our double-wide manufactured home for our oldest daughter. While the structure would be separate we would extend the heating duct from our kitchen to the room. Would that be an issue? While my husband is capable of adding the duct work, would it cause problems if he did it himself rather than hiring a licensed professional?
Hi Kimberly,
I'm not very knowledgeable about HVAC but I'm pretty sure it's usually not a problem to extend the ducting from your heating unit as long as it can handle it (there's a fine line between a furnace that is too small or too large for a home and both are not energy efficient). As far as hiring a licensed professional, it's all about your location. I'm all for DIY but legally I need to say that you need to follow all laws in your town. In some cases, it may be cheaper to install a separate unit in the addition because hiring a pro is pretty expensive. You can get a wall mounted heating unit for $300 - 800.
Best of luck!
I ask questions occasionally as Your blog covers questions I have rolling around in my head on a daily basis. I will probably have to take over ownership (and payments) of a 96 Fleetwood doublewide home. It was once a beautiful home but is now in sad shape. The question involves the roof line. You know how they are usually built with a separate pitch over the front door? The little triangle gable (entry pediment)? The design is flawed. The water during heavy rains wraps around and under the eave and will/has rotted it. I ponder something daily. Can that be easily removed? And just have the normal roof pitch all the way down the front of the home? I actually do not favor the look of the entry pediment. And adding a porch onto it multiplies the "ugh" factor. The roofing has reached its life expectancy limit and will need replaced very soon. If it is an uncomplicated task then I would love to remove it. The front door is set back a little so there will be no real need for the pediment especially since I will more than likely have a gutter ran the length of the home. If you know any instances of this being done I would sure love to hear about it. Thank you! Love the site. Keep up the good work!
My doorway is similar. Luckily for me it hasn’t caused problems with the rain but it does cause other problems. For example I changed the mobile home door to a standard door. However, because of the entryway/indenture. I can’t put a screen door or glass door on. The screen/glass door wouldn’t open completely. It would hit the top of the entryway/indenture. I’m afraid to modify it because I’m not sure how it will effect the structure and possibly cause major problems later. If anyone has any ideas it would be appreciated.
Hi Lisa,
It's best to either special order the door or modify the door yourself instead of the home. Maybe you could make it open the opposite way for enough room?
Hi Steven,
I know exactly what you are talking about but I cannot recall ever seeing one removed. On all the roofing jobs I've seen they always leave them.
I honestly have no idea how to answer your question. There would be a structural modification to the roof (which is how manufactured homes derive most of their structural integrity) so it could potentially mess some serious stuff up if you don't do it correctly. Sorry I can't help more - it's a really good question but one that is way above my head.
Best of luck! Let me know how it goes if you decide to do it!
Crystal,
Do you know where I would find information about replacing a window with a patio slider door?
Hi Linda,
You'll probably want to look for the door manufacturer's manual. Other than that, I'm not sure as it would be based on design. Sorry.
Hello Crystal,
I am Planning on adding on to my manufactured home and i have some questions.
First of all i love you're site it has been amazing reading thru all of these posts!! I own a home that is 13'-6" by 66' and i want to add on to the back side going 16' by the 66' so my home will be 29'-6" by 66'. I plan on butting up to the original and keeping the addition a seperate structure. Now here is by question, is it ok to build a whole new roof truss going off of the front of the manufactured home to the back of the addition? Thank you for your help!
That sounds like a great addition - you're gonna have so much more space! To be honest, I don't know the answer to your question. Roofing is always the trickiest part because each state/city have different rules. Sorry I can't help!
hi my wife and I have a trailer home ( mini-home ) we call it and my wife is in a wheel chair, we were thinking about adding a piece to the front and going the whole length of the trailer with a piece about 10 or 12 feet wider to make room for her in the wheel chair because right now she has issues with the accessibility to our bedroom which is on the end and also the washroom which is also located towards the end and our hallway needs to be widened. on the opposite side is our oil furnace and as well as our washroom that we recently done and two other rooms one we use for a small spare bedroom and a storage room as well as our small linen closet and our washer and dryer, we do not want to disturb this side because we feel it would be better to widen our trailer on the opposite side especially where we have all ready spent $5000.00 plus on our washroom. So we are deciding on adding a piece so we can have a roll in shower with tile that she can roll right in as well the hallway would be widened which would make the accessibility for her a lot easier. we would like your input any suggestions for a floor plan would make it great. thanks and hope to hear from you real soon.
Hi Chad!
Adding an addition will be expensive but possible. When I priced our addition plan (8 feet wide by 24ish feet long) I came up with around $2500 in materials with 2 cheap windows and the bare basics on everything with no plumbing or electricity factored in. I never checked on labor because we were going to do it ourselves. In the contractor's world, you usually get a minimum price of $110-150 per square foot on additions (in my area anyway, CA would be a lot more).
You may want to look into knocking the walls back in the hallway to give her more room. This wouldn't be as expensive but you'd lose some space in the rooms (but gain it in the hallway). Depending on your home's layout you may want to look into extending the rooms out to the exterior wall and getting rid of the hallway completely, too. She could just move through the rooms and not be restricted by a narrow hallway.
Best of luck!
hi crystal , I am wondering if you have any in formation (plans) on slideouts partically
manual pushout pull in types ? sincerely deb
Hi Deb,
I'm sorry, I don't. Slide-outs are more of an RV thing nowadays (even though they got the idea from the old mobile homes). Google RV blogs and or RV Slide out info and you'll probably find something to get you started. Best of luck!
I was wondering if you have any advise for taking out the 20foot section on the exterior wall in our kitchen and living room. We already have an addition there as a porch. I would like to take out the wall and make our living and kitchen space larger. We have a single wide. Also any advise on moving breaker box, furnace and water tank. I would like to add a laundry/utility room. Thank you
Hi Lyndsey,
That's way over my head! Regulations are different but I'm pretty sure there is a ratio they use to determine those types of projects (total length versus total removal). You can't lose the integrity of the home and that is derived from the roof down so the walls are vital. Keep in mind that for additions, you'll need the new structure to be completely separate from the home itself.
You will want to get an engineer involved. Every homeowner that I've seen do this has had issues eventually because they enforced the home like a site-built and not the manufactured home that it is.
Best of luck!
Hi,
We put our MF home on the market and it sold in four days. It was built in '92 and at the same time a 21/2 garage was added. We are the third owners and had no problem getting appraised properly and getting a conventional loan when we bought in 2003. NOW the appraiser won't recommend the lender loaning the funds to the new buyer because he doesn't know if the integrity of the home has been compromised by the adding on of the garage though there have been no issues with the home during these 24 years since it was built. They want to see permits/plans/whatever that are now in storage by the county where it was built.
Are MF homes unable to be sold that have additions in Wa. State (Kitsap county)? We're told we will need an L&I inspector out here to look at it though we needed no such thing 13 years ago.
My question is, if they can't obtain the plans, will the inspector know if it's a worthy structure and we would be able to sell then? Thanks.
Hi Sue,
It's 100% dependent on the city or county laws. In the last decade just about every town, county, and state have initiated many new laws and regulations to create revenue (and jobs).
Kinda sounds like they are concerned that your addition is bearing on the manufactured home and they want to make sure it was constructed properly (as a completely separate and freestanding structure from the home).
You'll want to hire an inspector that is qualified on manufactured homes (they're out there, just a little hard to find).
Here's a very informative website written by expert mobile home inspectors. There's tons of great information!
http://www.mcgarryandmadsen.com/inspection/Mobile_Homes.html
Best of luck!
Hi,
Wanted to let you know after getting an Engineer to inspect and approve the garage (24 years later!) we were able to close on our home.
The lender was satisfied with his report, which he said it was done properly. He couldn't believe he was needed in the first place!
Just another way for the bureacrats to squeeze more money out of property owners and get their noses in our business, if you ask me.
Thanks for your time.
Great news Sue! Congratulations! Please keep me in mind after you get all settled - I'd love to see/share/feature your new home!
Hi! Do you have any before and after pictures of added additions? We are considering adding square footage to our bedroom by knocking out the exterior wall in our bedroom and also adding a new bathroom. We will turn our existing master bath into a walk in closet. We are also thinking about lifting the pitch of our roof and adding a new higher metal roof. Any info would be much appreciated as we are both nervous about this undertaking. We have also considered just removing our double wide from our property and building a new stick built house but we are thinking a renovation and adding additional square footage would get us what we need. With as much as we'd like to do, I'm not sure which way would be more cost effective though :)
I am thinking of doing the exact same thing...did you do it and if so how did it turn out? Any wisdom would certainly be appreciated!
Kristin
Hi Kristin,
Between the articles and the comments you should have a good start on how to build an addition. Be sure to take photos so we can add yours! Best of luck!
Hi Loree,
Unfortunately the only addition images I have are at this link: https://mobilehomeliving.org/?s=additions
There's a single wide that shows before and after images but that's about it. I have a hard time finding images of mobile homes (which is why I started MHL - I wanted to see actual photos of our homes and not all site-built homes..lol).
Sorry I can't be more help!
I have been living in a mobile home park for years and made additions to my mobile home. Now 30 homes are being EVICTED with 90 day notice due to owner selling land for state construction. I have to remove my mobile home from rental lot but doing so will leave 75% of the front of my home exposed due to the addition. Any advice?
Hi Frank,
I'm so sorry you're dealing with this! Parks are closing at an astounding rate all across the country and there are little protections for the lot renters. I hope they are giving you a fair price for your trouble.
As long as the home didn't lose any structural integrity (none of the perimeter studs or framing was removed during the addition's construction) you should be able to move the home - you'll just need to brace it and put plastic wrap on the door openings during the transport. To move the addition you will need to have a flat bed transport and they will need to jack the addition up and slide it onto their bed (much like they do large pre-built buildings and garages).
If the home's framing was modified, you'll need to get an engineer in there to take a look. I hope it all works out well for you! Please let me know how it goes!
You may need to