Roof pool

[Carterjon]

I have a 84 motorhome, previous owners said it sat for 11 years.

The roof is sagging a bit, maybe half an inch at deepest, as a result, rainwater/ A/C pools up on top. And I am worried for the snow. I can put a tarp on it for now. It doesnt seem to leak yet, but I am sure it is just hidden.

How bad is it, from scale of totaled to diy fix in garage?

Also, how can I be sure the right sealant to get. It has aluminum pieces. Thanks, I am broke and cant pay a better dude than me. Might as well try or nothing.

[Kirk W]

It is very difficult to say without seeing what you have but if the roof has actually begun to sag I would think that would mean structural issues in the roof trusses that may be far more costly to repair than the RV will ever be worth. If you can post some pictures that would help us give you an opinion. What make & model of RV is this?

[Ray,IN]

I  agree with Kirk. Unless  you are handy with framing/construction and already have carpenter tools and machines, and can DIY, the expense will be far more than the value of the MH.

For instance, up the  road from my house is an older( 1998?) gas chassis 34' MH for sale @$12,500, that appears in excellent condition just driving by it.

I expect the price of materials to replace a MH roof and structure will cost near that amount today.

Edited December 2, 2022 by Ray,IN

[Carterjon]

Thank you for the reply, It's an 84 itasca motorhome, I know that's a big deal, so I just try to see if there's a good way to fix it

[Kirk W]

Have you walked on the roof? If so, when you do so does it feel solid or seem flex? 

To determine what is happening I would first remove the air conditioner so that you can examine the structure around where it is mounted. I believe that the roof you have is basically flat and some water pooling on that type of roof is normal but an inch deep does seem like a lot. If there is no sign of any water damage or water staining on the ceilings, you may not have a problem at all. You could probably also see what the support structure is like if you remove the ceiling material. That would probably be easier than to remove the aluminum and less expensive to repair. Do you have any pictures of the roof and/or the ceiling?

[RV_]

You likely have more than just some minor damage. However, having torn up my interior and redone a booth into a custom counter and computer printer nook in both my fulltime rigs and then replacing the Rubber roof (EPDM) on our last 28 foot Sunnybrook I can tell you that if you have a tall enough garage or shop to work in the work is more tedious than difficult. If you can cut wood no larger than 2X4 and usually smaller, and can watch videos and learn to lay down the rubber roof adhesive and stretch it just right or to seal the aluminum metal roofs with Parr Bond or other materials. Just never use silicone anywhere on your RV. That clear stuff around the top of window seals is not silicone it is usually par Bond. Having said all that preparation will make it a project you can be proud of but if you can't afford the repair materials then get another. You will need roof material, several specific sealants, but until you rip in you don't know how much. We are off the road now after years of full timing in various fivers, and decades of part time camping previously in one canvas old Coleman popup (Hated - it kept the mosquitoes in!) 7 Superstock VW Westphalia campers I restored myself, a 36' HitchHiker fiver with a metal roof I had to repair and major leak damage requiring removing the slide and replacing about 8 square feet of the floor, a 36' Challenger fiver with a lot wrong I fixed, a 28' Sunnybrook fiver with a roof needed but no wood rot surprisingly, and a Scamp fiver that needed new vinyl flooring. These things are basic and experts not needed except for electrical mods, gas mods. The wood and roof are really basic for someone with a compound miter saw and good blades, a tool to shoot whatever your frame was put together with, screws, and the usual drills, pry-bars, impact drivers.

Strong suggestion. go through this page of Youtubes all the way down and pick out what you need to know and watch making notes of materials and tools needed and costs of them:

https://www.youtube.com/results?search_query=Sealing+a+new+aluminum+RV+roof

Then this for a quick view of how the roof are built:

 

ParBond info: https://search.brave.com/search?q=Parr+bond&source=desktop 

It's not rocket science, very doable. If you choose to.

Safe Travels!

 

Edited December 3, 2022 by RV_

[Carterjon]

Can you see the sagging part? 

[Carterjon]

Thank you for that information RV_

[Kirk W]

11 hours ago, Carterjon said:

Can you see the sagging part? 

From the picture it doesn't appear to be significant. It is normal for flat roofed RVs to have some water pooling which is the reason that most RVs now build with a slight curvature in the roof. If there is no signs of water staining inside then it probably has not been leaking. Did you remove the air conditioner to coat the aluminum roof with something? 

[RV_]

16 hours ago, Carterjon said:

Thank you for that information RV_

YW. Sorry but it is hard to tell any sagging in a picture. You mentioned it wasn't leaking, so since you seem new to RV structure and repair I would take it to a couple or three RV dealerships/RV repair shops and get estimates for what they think needs to be done and the costs. Or if they think it is fine. Then if you need to fix it you will know the costs for them to do it and can check on materials if you are handy.

Keep posting as you go with what you find. 

Edited December 5, 2022 by RV_

[Ray,IN]

A picture is actually worth a thousand words.

From the picture, there is a workaround. With the A/C removed from the roof, the luan underlayment may be lifted some. Determine that maximum distance, then cut 2"x2" tapered shims to fit between the roof underlayment and existing rafters. Two shims per rafter(one for each side) so they may be inserted with as much length as possible.

One you have proper fitment, they may be glued in place.

This will create a slight crown to the roof when properly executed.

Now you must make a decision whether the effort is worth the price of the MH..

Edited December 6, 2022 by Ray,IN

[Carterjon]

Yes I did remove the air condition before

[Carterjon]

Thank you so much for you guys' advices, due to my lack of hands-on skills, I have now decided to take it to the dealer to have a look

[Ray,IN]

If the dealer quotes less than $3,000 I'll be surprised, that is assuming it's done correctly.

Edited December 7, 2022 by Ray,IN

[Clydro]

I had a 1984 Winnebago Chieftain with the same problem.  At the time I contacted Winnebago and they told me that the issue was caused by the weight of the AC unit and insufficient structural support.  On their suggestion I put two pieces of 3/4” plywood between the AC and the roof, attached it with bolts and fender washers.  I also used Eternabond tape to seal the boards to the roof.  It worked just fine, no more leaks.