Walls/Floors/Ceiling

 Walls
  • Better learn the difference between laminated and pre-hung and each layer of material used. Laminated are layers of material that are glued together then pressed or vacuum sealed so the sandwiched materials hold together. Here is a good article on wall construction types.
  • Here is a good video on laminated vs hung walls by Newmar (who build with hung walls).
  • RV Living has a good article.
  • Azdel wall construction compared to Luan. Azdel is rot proof and reportedly helps avoid de-lamination and has 3x the insulation value. Lance Camper uses Azdel.
  • Walls built with aluminum. Welded joints compared to glued and screwed.  And the value of single welded points compared to double welds.
  • Pressed compared to vacuum sealed.
  • Newmar Motor Homes start with a thicker piece of fiberglass.  This brings up a good point, although I’m concentrating on construction methods for 5th wheels, there is a lot of good info about motorhome that are applicable.
  • Newmar uses a c channel wall stud which allow access for insulation compared to others that use a hollow boxed aluminum stud. One thing I like about wood studs is that wood has an R value. Also the c channel stud would allow for 16″ on center studs.  Others spread the studs out and depend on the laminating process for structure.
  •  Seek a Flex is a type of glue that does not harden. The rubber like material allows the walls to flex while moving down the road.
  • Newmar and Open Range build their walls and allow them to sit for 24 hours before moving them. So the glue sets up and has less chance of de-lamination. As of 2015.  They claim other companies walls are pinched together or vacuum sealing over just a few minutes or seconds and then moved.
  • Seems to make since that having framing around the windows, compared to just cutting out the side wall and mounting them, is the way to go. Just like in residential construction, this would give you a header to help hold the heavier double pane window in place.
  • The solid laminated side in a slide, compared to hung walls, are sturdy. Just bang your hand on the side of a slide to feel the difference. Also, having the slide made of the same material as the outside walls of the RV might mean they discolor at the same rate.
  • I’m going to have to look into back cap construction details. Watched a video that claimed on the caps where the window area is in-set it causes the air that comes around the side of the trailer to act as if pushing the trailer along. Started a forum thread to find some answers. Many say the full back cap is for looks only. But, maybe because the side walls go into a full wrapped back cap it might add some stability by locked the walls together so they are less likely to twist.
  • Notes from On the Road to Retirement Blog regarding delamination.
    • Number one gotcha is delamination!  What is delamination?  Well according to wikipediaDelamination is a mode of failure for composite materials.  So what does that mean to me?First the history: Long ago RV builders changed the way they did construction.  They began putting smooth fiberglass exterior walls on RV’s that were constructed by sandwiching fiberglass with the frame’s structure and other materials.  Each of the layers were held together with adhesives making a single bonded wall which decreased the cost of building the walls and also provided for better aerodynamics and they just looked better :).  But as time passed some had noticed the early models started having problems with the bonded layers of the wall coming apart or delaminating.So to avoid buying an RV with delamination one needs to look for evidence of bubbles or blisters on the sidewalls.  Now remember delamination is usually caused by moisture getting between the layers resulting in the bubbles or blisters.  They also may cause cracks so look for these too.   And since moisture is the culprit causing the damage look for signs of moisture leaks in and around the windows, vents and any other exterior openings.  Discolorations on the ceiling may also be a sign of future trouble.Moisture on the inside is the enemy so make sure the used RV you are buying does not have any signs of moisture on the inside.
  • From a forum response to a thread I stated: “Some basic assumptions that I have come to is woven FG is stronger than random fibers that I have seen in the Filon side walls. Epoxy is stronger that polyester. Thermoplastic adhesives are better in peel and shear which is how most adhesives fail. Side wall panels bonded in an autoclave produce a better bond than an vacuum or roller bond process that most mfg’s use.”
  • True gel coat vs fiberglass reinforced gloss gel coat. True coat color is not supposed to fade with age.  Cedar Creek and other use it, but not all.  Also, another note about Cedar Creek/DRV/Augusta RV use a hung wall as of 2016. Some say the insulation will sag. Not sure about that as it is glued in and has been used for years.  Hung walls are built up from the frame compared to laminated walls that are glued and pressed together. In a hung wall you can replace a section rather than the entire wall.
    • I’ve also wondered if smaller companies use hung walls because they don’t have the lamination equipment. But both DRV and Cedar Creek are not young, small companies.
  • New Horizons (2015) is using a laminated walls, double welded studs and blue Dow closed cell foam for insulation. That’s a very nice wall!
  • Note sure if it’s true or not, but this is what Evergreen has to say about vacuum vs pinch laminating:
    • Walls, floors and roofs are vacuum-laminated to improve adhesion and drastically reduce any instance of delimitation that is so common in pinch rolled systems. Vacuum laminating works by forcing the glue down into the form. This process provides better glue penetration and coverage and ensures better adhesion. In addition, once the part comes out of the machine the glue is already cured or hardened. This means that the wall system will hold its shape much better during the balance of the construction process. Humidity and moisture is controlled in this process speeding up the curing process and improving consistency. Pinch rolling is a technology from the 70’s.  In this process, glue is applied to the parts and a press forces the two pieces together. Glue seeps out of the sides of the part causing waste (bad for the environment) and it is very difficult to remove all the air pockets. It is these air pockets that cause delimitation in ordinary RVs. In ordinary RVs, the adhesives are air-dried which takes longer, and the parts also lose their shape easier because the glue is wet longer. Vacuum laminating equipment costs up to five times more than pinch rolling equipment. This explains why very few RV manufacturers use it. However, EverGreen RV is about quality and durability and the end results are well worth the investment.
  • Some say vacuum bonded laminated wall is best. If a manufacturer does not advertise their walls are vacuum bonded it’s because pinched bonded walls are cheaper. Also you have to look at how the slides and floor are handled.
  • Decals. Calendared has 3-5 years life span, Cast has a 5-9 year life span. These are two types of vinyl letters.
  • Wall type and insulation seem to run together.
  • How is the vapor barrier handled – if at all. Such as DRV with thin foam board behind studs between interior wall.
  • Regarding outside storage doors with slam latches. I prefer doors that don’t require two hands to open such as the ones that swing out rather than up. That way we can open the basement doors with hands full. Then again, swinging them out might get in the way of something you have setup outside.
  • Full body paint looks great for years but as a trusted source says 

Floors

  • Need to research using plywood for subfloor compared to OSB and marine grade products.
  • What is rubber backed flooring.
  • Watch for the insulation, stud spacing and sub-floor thickness. Home construction uses 5/8″ tongue and groove with floor joists on 16″ centers. Floor joist thickness makes a difference also. Don’t want to walk on a springy floor.
  • Prefer not to have the floor vents exposed like we have now, but any angles in the vents if routed through cabinets will cut down on efficiency of air movement. But will also help with sound isolation.
  • Marine grade vs plywood. Is it worth the cost and weight?
  • Link to Dyna Span, used in the Montana (5/8″) and others. 25 year warranty.
  • I’ve been in trailers where the floors are spongy rather than solid. I’d also be concerned with what sub-flooring is used in case of water damage that might swell the flooring. Then again, weight is a factor.

Ceilings

  • Study just like floor construction.

 

2 thoughts on “Walls/Floors/Ceiling

  1. Looking for a reliable unbiased source for travel trailer ratings as in best construction. Doesn’t seem to be easy to find. Consumer Reports has nothing. There’s lots of most popular best selling. I’m looking for best construction. Thanks for your help. Rick J

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    • That’s for sure Richard. I finally had to start researching each major part of construction for individual information. Then decided to keep my notes on a blog page to refer back to. Hope my information helps a little.

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