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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I would have to politely disagree with the comment that non-city homeowners can do as we please and are exempt from the pure H-- of permits. I live in a rural area miles from anything, and can't even see a neighbor from my property. However, obtaining permits are a nightmare for anyone who wants to put up a shed or animal shelters, and forget letting Grandma live in a travel trailer on the back Forty like folks used to.
In the last fifteen years, our county building department staff have become beyond petty, while ignorant of basic building techniques. They get sued a dozen times a year for fining people inappropriately. Small-town nepotism insures they'll never be fired, so.....
Many people in my area go ahead and do what they have to, then worry about getting caught and fined later. Trying to do it legally often results in conversations across the Permit Department counter that boggle the mind. "I have to hire a Structural Engineer to draw up plans for a dog kennel?"
I would still recommend finding out what you are SUPPOSED to do, if the local staff is professional and knows their job. Just be forewarned that idyllic life in the country is often subject to local politics and contradictory policy, just like city government.
Best wishes to all. It's great to see so many people enjoying their mobile homes.
Thanks for the comment Lucy.
I'm sure every state is different. In all the states I've been in (WV, VA, NC, SC, FL) homeowners out in the 'country' had little to no inspections or permit requirements. I understand a lot of local governments are changing that because it is another revenue stream and we know how governments love revenue!
I'm trying to find out if it is possible to put below ground footings on the edge around my mobile home, instead of inside below the attached metal beams. the idea I had was to put a beam, either metal or wood just inside the skirting with 18 inch footing supporting the blocks or other supports for the beam. so far, I cant seem to find who would know this. If it matters, I live in the texas panhandle, just above where the map shows a switch from <6 to 6 to 18 inches. I know moving the mobile home would add $2000 dollars or more to the project.
I would appreciate if you could tell me who I would have to talk to about this.
once I get this done, I'm planning on adding several addition over the next few years.
Hi Robert,
I'm not sure I understand what you're wanting to do.
My generic answer would be that as long as your home is properly supported how your builder recommends (which is typically a pad or pier footers below the frost line and strategically placed under the chassis. The chassis' are designed for that particular home's weight and design so any modification would likely stress quickly. You can Google your make and model and see if you can find a installation manual for your home (or a similar model)
Best of luck!
Is it possible to build on top of a mobile home with a peaked roof
Hi Jim,
No. Unless you are willing to spend tons of money to reinforce and basically rebuild the entire structure you could not build on top of a manufactured home. They are simply not designed for it.
You could possibly build a completely separate structure above a home (with it's own footers, rafters, etc.) using the right architectural design but I seriously doubt an inspector would allow anything like that to be built.
I've seen some decks built above a couple flat-roofed mobile homes. They are really neat but the decks are not attached to the home structurally, they have their own footers that hold and distribute the entire weight of the deck down to the ground.
Thanks so much for reading MHL!
Do you know anything about the regulations or permit process in Pierce County, WA state
Hi Debbie, you should be able to call your court house and find out which department handles the permits. Good luck!
my husband and I would like to add on to our doublewide. Do you know of any contractors in SE North Carolina that can do this?
Hi Lori! Unfortunately, I don't. You may want to call a local mobile home supply store and see if they have any recommendations. Good luck!
Thanks so much for reading MHL!
Thanks for the info on the different ideas on remodeling. You can sit and try to imagine what it would look like, but until it is done you really don't have any ideas. Those in the for front are the ones taking the chances in the models they come up with. I personally think doing your OWN remodel is 10 times harder than having someone do it for you. You end up taking your time and changing it a 1000 times and then the frustration.............
We are In ga and considering an addition of a den/ library and a bedroom off that. Your site is helping us soon much.
Thanks a bunch!
Any info regarding adding on to a park model rv or travel trailer? Like the rules and regs if any? It's sitting on metal piers in LA County, Lancaster, Ca. Thanks a bunch!
Howdy! I'm not at all familiar with California codes but I suspect they have very stiff regulations for all building projects. Still, adding onto a travel trailer or park model would be the same as described in this article. You wouldn't attach the addition to the unit at all, it will simply be butted up to it and then sealed around the openings.
I would check your city hall or court house and see what their codes are and then go from there. As long as you don't modify the trailer or park model (other than making the hole) you should be able to do it without causing too many headaches.
Good luck and thanks for reading Mobile Home Living!
Karen, very interesting site, stopped in during my search for information about the type of addition I would like to make, but not sure if I can based on what I have read so far. I was hoping to run it by you so that maybe you could point me in the right direction.
I have a doublewide, 24X52, that is currently in a park, but fully paid for. We are in the process of purchasing land that is raw, needs to be developed, that we would like to move our home on to, and then make it bigger. I would like to have built on the lot a 18X52 modular extension, which would go in-between the two halves of my home, turning it from a 24X52 to a 42X52. I was hoping to find a company that would build the extension at the factory, set it up on my property, so that when we are ready to move we could then have the mobile home moving company break apart our home, and instead of re-joining the halves together, they would attach them to the new extension, and then we would remodel with the new floor plan that we are developing for the larger home.
My question is, do you know of any companies that would build this for us, or would we need to build it on-site ourselves? Also, I have run across some potential road blocks about how mobile homes can have additions attached, depending on the type of foundation used. Any information that you could give on this would be great. Thanks, Rodney
Hi Rodney!
I know it would be simple enough to build onto a double wide but I've never seen a double wide divided with the addition in the middle. To be honest, that's something a structural engineer would need to answer cause its way outta my league!
Double wides are essentially 2 single wides that are joined - your biggest issue would be building the middle extension properly to support the two halves in the needed manner. I would think its possible but its probably not cheap or easy - finding a contractor willing to do it would be difficult and the permits would be a nightmare in certain areas. It would probably be more attainable if you redesigned to add the addition onto the side of the home with a 'separate' roof over everything. With the right technique, the roofover could even hold a second story.
I believe anything is possible! It would definitely be different and awesome!
Thanks so much for contacting me - please keep us informed!