Maybe.

Flat or cathedral ceiling? What type of insulation? What size are the framing members(wall studs/roof joists). Roof framed using trusses?

If the answers to the above questions are 2" by 4" and trusses, there should be enough support. If the answers are smaller framing, then no.

No.

HandyMac, thank you for your response. It's a cathedral ceiling but I don't know about the roof specs or insulation. It's a Bonnavilla house, and they have not responded to my questions.

I doubt there is sufficient support for much more weight, unless you redo the roof with one layer of shingles. Most mobile homes(designed with springs/axles installed for transport as opposed to modular homes which need a trailer to transport) are built as light as possible. Meaning 2" by 2" or 2" by 3" wall studs and thinner roofing members than usual.

Reason? Mobile homes do not have to meet residential building codes so are kinda on their own as to how strongly built they are. I've worked on mobiles where wall studs were 2" by 3" and 24" on center. The hardboard wall panels literally held the walls together.

Never got into roofs, but cannot believe they are much stronger.

My educated guess would be if there is too much weight, the ceiling will begin to push the walls apart. And collapse is not out of the question if left without some kind of repair.

HandyMac, I suggest you educate yourself by reading the standards for manufactured home construction, particularly the standards used in stick-built housing that are included. Here is a link to it: Manufactured Home Code

The home in question is a mobile home. Mobile homes are not covered by that code. The problem is semantics. I have worked on factory manufactured stick built homes and mobile homes. There is no comparison other than they both have walls, floors, and roofs.

Often, the term 'manufactured home' is used in reference to mobile homes. That is not false, but is a play on terms.

Mobile homes have not been manufactured since 1976. Guy said his home is a 1986 model, so it IS a manufactured home and the code does apply. People still refer to manufactured homes as mobile homes, even though they are not. You are apparently one of them.

What is a manufactured home?

A manufactured home (formerly known as a mobile home) is built to the Manufactured Home Construction and Safety Standards (HUD Code) and displays a red certification label on the exterior of each transportable section. Manufactured homes are built in the controlled environment of a manufacturing plant and are transported in one or more sections on a permanent chassis.

What is the difference between manufactured and modular homes?

Manufactured homes are constructed according to a code administered by the U.S. Department of Housing and Urban Development (HUD Code). The HUD Code, unlike conventional building codes, requires manufactured homes to be constructed on a permanent chassis. Modular homes are constructed to the same state, local or regional building codes as site-built homes. Other types of systems-built homes include panelized wall systems, log homes, structural insulated panels, and insulating concrete forms.

https://www.mobilehomesell.com/mobile-home-construction-standards/

The HUD standards mentioned in your link are the HUD standards to which I linked. There is no separate standard for mobile homes versus manufactured homes. It is the same standard.

They still call them mobile homes. There is no law making any term illegal.

I’ve got a 1972 double wide, and after everything I’ve researched this house seems to be fairly renovated or it was built with upgrades off the rip I’m not sure but it does have 2x6 walls and floor joists and the truss system but they’re made up of 1xs. My question is will I be okay to add the 1x7x3/4” tongue and groove boards across the middle section of the house?

You may need an engineer to do the math regarding load and safety.