horizontal strips in walls are ????

[waitingtohear]

I have a 1969 Champion single wide mobile home.

All that makes up the original walls are 1/8" panel boards with R-9 fiberglass batting, a thin sheet of plastic, then the aluminum siding of the outer wall.

I am replacing the original 1/8" panel boards with 3/4" thick wallboards, then putting new 1/8" decorative panel boards on top of those for the interior room.

My question is, the wall studs are 16" apart and of course go vertically. But there are also 3 rows of horizontal stips that are about 1.5" wide and are about 2 ft. and 3 ft. lengths. They are nailed to the vertical studs. (a notch in all the vertical studs allows the horizontal strips to go across them which creates a flush framing surface so wall panels can lay flat against them.)

What is the real purpose of these horizontal strips and is it dangerous to remove them? I assume they are only there to keep thin panel board stiff and from becoming warped over time.

But since I'm swapping them out with thick wall board, are they even necessary any longer? I want to remove at least one row across the entire wall so I can run some network cable through those pre-made notches in the vertical boards.

[HouseMedic]

I might be wrong but I think if you put the 3/4" drywall up you better make sure it will handle the weight. The outside walls of older mobiles have an outrigger that sticks out to hold the wall up. Most don't have a frame that goes all the way around the full outside perimeter. Those horizontal boards are stiffeners (lack of a better word) they help keep the wall straight and true. I guess this helped a lot when moving down the road so the walls would not rack out of square.

Ron

[Greg]

As Ron said, they are there to help stiffen things up. 3/4" is over kill, I would go with either 3/8" or 1/2" if you are going that route. Weight is always an issue you may want to consider some perimeter blocking for added support, Excessive weight WILL bow the floor joists down over time.

Again if the ground freezes in your area expect some cracking at the seams if you use drywall unless you are on below the frost line footers.

Greg

[waitingtohear]

Now that there are some replies to my questions, it's normal that new questions would arise from the responses as well as some confusion:

1)

I have to correct what I said before. I'm not using "wallboard" or "sheetrock", I"m using 3/4" OSB gypsum board.

2)
HouseMedic mentioned that if I don't have a solid frame all around the sides, I could have issues with the weight of the new OSB gypsum boards.

I do believe I have a framed outer edge around all sides. If so, does that close the book on any weight issues?

3)
Greg mentions that if there is no framing, that perimeter blocking would be the cheese. I assume that means putting some cynder block stacks around the outer sides every 6 ft. would work?

4)
Greg also mentions using thinner boards. I didn't want to get into the reasons I'm using the thicker stuff, but I guess I shall mention that I'm using them for better sound resistance. ( I know there's other ways I can do sound resistance with thinner boards, but I've already bought the boards and I don't have time to re-work the ideas)

5)
I'm still confused on the overall responses about the horizontal strips. Do they keep the walls stiff in any way that helps the vertical studs also, or are you guys saying they help with keeping only internal wallpanels stiff?

(if they help overall also with the vertical boards that make up the framework, then I would have to wonder why they don't do this in stick housing also)

6)
On Brewiss's response, I really couldn't follow the wording. Since I"m upgrading the interior walls with OSB sheathing, which I assume will not have trouble keeping "stiff", then I don't see why to keep the strips. I really didn't understand the mention of "use pro's because the walls are already weakened". The vertical framing is in great shape, I have no bends in the ceiling or floors. I had someone check the outside and they made sure it was leveled. They said there was no need to add any additional support in any areas. This is also a 42 year old mobile and I am a handyman who, with the right input from others, gets good results from any job. Using Pro's would defeat
my purpose of doing the work myself to save time, money and gain more knowledge for my next job, since I do all my own work on 3 different homes.Any updated or new responses is greatly appreciated. You guys are swell for taking the time.

Keeping it real,

DT

[DaveyB]

I am part way through completing the lattice screening around my home, so the following is relevant to your project.

The screening comprises of 4' x 8' plastic sheets of 1" x 1" lattice, about 1/8" thick. I found that, if installed vertically and screwed in top and bottom only, they developed a great deal of bellying fairly quickly (dependent on the ambient temperature, and this is Arizona!).

In your case, the original 1/8" wall facings would not be strong enough to stand up by themselves, hence the horizontal pieces of wood (which would equate to "laths" in a roof) to provide anchor points between the top and bottom and prevent the bellying effect.

Given that you are replacing these boards with material that is capable of standing up by itself, you probably don't need the laths. Thing is though, since they are already there, why not use them? As you mention, they are recessed into the vertical struts and so flush with the inner wall surface. By using them rather than discarding them you can ensure that joints between wall sections are uniform, even if the mating edges of the boards don't land on a strut!

I'm not too savvy on the weight aspect of the boards, seems to me that going from 1/8" to 3/4" is overkill though. You mentioned sound-proofing as part of the reason - if you are trying to kill outside sound from entering or internal sound from leaving then I would reduce that thickness and add in some acoustic baffles into the wall behind the boards - thinks egg-trays for example! Since you already have the 3/4" boards though, that is kinda moot!

As far as running network cable is concerned. I wouldn't use the notches to run them - one misplaced nail to hang a picture from could ruin your connectivity since the cables are directly behind the wall board. I'll assume that the vertical struts are 3" or better deep. Drill a hole 1" dia though the center of the strut and insert a piece of 1" dia rustproof metal pipe in the hole. The strut will retain its load bearing capability since the weight will be imposed on the pipe which will transfer it to the wood below it. Next, run some (preferably orange) 3/4" dia hose through the holes from entry to exit of the cables, and run your cables through the hose. Drilling into the wall for any reason, if you start getting orange flecks, you have hit the hose and still not damaged the cables.

In the event that a cable is damaged in any way (or upgrading to fiber optic - you never know), it is a simple matter to pull a new one through the hose (taped to the end of the old one) instead of tearing the wall apart to rewire it! While I lived in Mexico, I found that most houses there are wired in this way - why electricians here staple the cables to the sticks is beyond me, it just doesn't make sense!

There again, living in a desert, it astounds me that 95% of the houses are wood frame, and all that wood has to be imported to the state, while bricks are a local resource - that's another story though!

One other thing you may want to consider, since you are cabling networks - add a 110 block and a 66 block to the distribution center, and run all the cables through it. This makes re-routing a cable a simple punch job instead of a re-cabling job. I did this in a previous stick house and was able to send any phone line or network connection to any point just by re-punching the blocks.

Hope that helps some!

DaveyB

[waitingtohear]

I have the cat5 cable issue all worked out. Really looking for follow up to my other questions, hopefully by the original responders to clarify their thoughts...

[flcruising]

Could you rephrase your questions to be more concise? You guys are using alot of words for each post and it makes finding and answering questions too time-consuming for an online forum. But that's just me. Forum posts that are too long are often overlooked more than you realize.

[waitingtohear]

Be more concise???
Did you see how I seperated each question for easy response to whichever you have information about?

Also, the longer the post, the more info it contains to explain the needed knowledge. The short answers are the ones that require more follow up questions.

But that's just me....

anyhoo, still looking for response to the 6 questions above.

[JD]

Waiting-, I wouldn't get too testy with people that are trying to help me, out of the goodness of their hearts. You are getting some pretty good info about your plan, as in 3/4" OSB is overkill and maybe a weight issue. Why take time to remove lath if they are not in the way or causing problems. I dunno, maybe a void in that lath strip gap is not such a good thing. Like DaveyB was pointing out with the metal pipe in a drilled hole, it offers support for the missing wood. I will attempt the 6 questions.

1. What you have is probably 3/4" OSB since gypsum board is wallboard and is sometimes called sheetrock. Oriented Strand Board is wood, sort of.

2. Water damaged rim and floor joists could certainly have problems with the additional weight, but even factory framing in good condition is not intended to support the additional weight. The problem is the support comes from the piers at the I-beams and there is no support under the rim joist to hold up additional weight added to walls and or roof.

3. Perimeter blocking is usually spaced a bit further apart, I think at 10', with including additional piers under the king studs to doors and large windows. Keep in mind that any time you add more than 2 rows of piers to any single unit, that you are also creating a situation where releveling the home frequently is important. A straight line being held up by two points of contact is easy. A third row must be in line with the other two or your could be stressing your home.

4. No question.

5. I am a bit confused with the horizontal strips also. I have maybe a hundred homes stripped of siding in my time, and the horizontal strips have always been on the exterior. They are there to fasten the vertical aluminum mobile home siding to. So if yours are on the interior side, I haven't a clue. Paneling does well attached at 16" centers. Still I would leave them and use them (liquid nail and fasteners) There should be diagonal wood strips toward each end of the units to keep the home from racking, which is standard procedure on stick built homes. OSB would certainly do this job better if installed correctly, meaning straight, plumb, level and on center.

6. No question.

Well, that is the best I can do for now. Let's see where this goes.

[waitingtohear]

JD is right. They are OSB boards. Not Gypsum at all.

I will probably have to add perimeter blocking. However, I weighed the OSB board and they are 37lbs each. There will be about 3 per room for the one wall side I'm nailing these to.

So that brings up one final question, will these boards actually cause sagging at 37 x3 = 111 lbs. per room? If you compare that to other furnishings that have been butted up against the walls for years without causing sag issues, (such as beds, workdesks, weight plates and even a weight bench with barbells) I'm not sure what would make a difference.

Perhaps their are carpentry mathmatics or other gravity issues that makes this comparison useless.

Any thoughts?

[JD]

What you have may not be OSB either. OSB weighs similar to plywood, with 3/4" being around 70 to 80 pounds, depending on grade and density. Would 225lbs per room cause sagging at the rim joist? Maybe. If there are 4 rooms with 3 panels each, that is around 900 lbs of unsupported weight at the rim joist. But I have seen older mobile homes handle excess weight well and I have seen them fail. I think we warn against major structural changes without approved plans because of the severity of the fail when it happens. JMO

[flcruising]

If it's OSB, what are you going to cover that up with? Are you also going to add drywall over that? There's even more weight to calculate then.

[DaveyB]

So that brings up one final question, will these boards actually cause sagging at 37 x3 = 111 lbs. per room? If you compare that to other furnishings that have been butted up against the walls for years without causing sag issues, (such as beds, workdesks, weight plates and even a weight bench with barbells) I'm not sure what would make a difference.

The thing to consider is the additional weight of the walls when all these things are put back into the home increasing the weight on the struts that do the actual supporting. Having crawled under my own home several times, and in the past I drove semis for a living, the construction is similar to the bed of a flat bed semi trailer, but twice as wide (16' as opposed to 8'). Semi trailers have the chassis main beams positioned so that a pallet placed above them is pretty much over the center of the beam, and the stress from each side cancels itself out. Here we are discussing adding weight on the outboard side only, and with a longer strut or outrigger, so applying greater leverage to the main beam.

Obviously, there has to be a limit as to what the frame will support, but IMHO it would be better to do the research and calculations to find out rather than discover the limit by trial and error. A twisted chassis would just about write the home off completely in terms of costs of repairs!

I found information on another site (which teams the words "mobile home" with a title used in the medical profession) and says pretty much what I said above, so this isn't a new topic or a new concern. Just remember that in a manufactured home, the outriggers are designed to handle the stress of the predicted load (original walls, original roof, reasonable furniture and possible snow load), and have no reserve capacity worth talking about.

Hope that helps!

DaveyB

[waitingtohear]

DaveyB,

Yes, I get what you mean. But I keep thinking about what's already been in the home. Such as a gas stove, washer and dryer, all of which are in a row against the outer wall. so if all that weight doesn't make the flooring bend at the frames edge, why would an extra 111 lbs of wall boards? Expecially when the wall board weight will be dispursed over a large area, unlike the appliances which are dead weight all in one area. Even I weigh 250 lbs. If I sleep horizontally next to the edge of the wall in any room, I can't imagine it's going to cause an issue on the framing. With your comparison of a trailer truck, then I would also assume if you put 111 lbs. against the edge of every 4 ft. it won't cause a problem (except for actual driving of course...ha ha). So I"m wondering if anyone else is seeing the stove, washer dryer comparison as a valid point of how much weight it really would take to make the mobilehome walls sag.