A couple questions for the step van guru's

[Road Dawg]

First off, I want to say thank you for all the warm welcomes. I'm new to the forum and have no RV experience. I'm not new to camping. Grew up in the Pa. mountains on a farm but know nothing about RV's. My wife and I are building out a 89 Grumman step van to go full time when I retire (hopefully real soon). I will start with window and insulation questions. From what I've read, it is recommended I use RV windows with the rounded corners to prevent stress risers. Being a blade smith I can understand that. Do I need to keep the windows between the vertical structural ribs? and will I need to reinforce around the hole? How thick can I go with the insulation using RV windows? I want to do this build the right way to minimize problems down the road. Thanks ahead of time for any help!

 

[66788]

First off, I want to say thank you for all the warm welcomes. I'm new to the forum and have no RV experience. I'm not new to camping. Grew up in the Pa. mountains on a farm but know nothing about RV's. My wife and I are building out a 89 Grumman step van to go full time when I retire (hopefully real soon). I will start with window and insulation questions. From what I've read, it is recommended I use RV windows with the rounded corners to prevent stress risers. Being a blade smith I can understand that. Do I need to keep the windows between the vertical structural ribs? and will I need to reinforce around the hole? How thick can I go with the insulation using RV windows? I want to do this build the right way to minimize problems down the road. Thanks ahead of time for any help!

I have a 1990 Grumman Olson that I am building and mine has no vertical ribs.  I am putting aluminum ribs in to aid in holding the 1 1/2" polyiso insulation.  I also have a few RV windows that will go in.   They are 1 3/4 inch windows, so 1 1/2 inch polyiso is ideal.   Its a good idea to frame them in with 1 1/2 square wood (hand sculptured corners made from plywood) and square pine for the straight runs.   This allows a good seal between the window and the outer skin, as well as the inner skin.

 

[akrvbob]

When I put windows in my cargo van, I found it easiest to stay between the rib, mine were 24 inches so I got 18x36 vertical windows--I;ve never regretted it.

You can cut the ribs but then you've got to put back in something to give them their strength. I've never done it but if I did I'd do it just like I was framing a house and put in the extra studs to carry the weight to the ground.

For insulation I think your best bet is polyiso, which is a type of styrofoam that comes in 4x8 sheets. Minimum of 1 inch and the more the better.
Bob
Bob

 

[highdesertranger]

it is easier to stay between the ribs if you have them. but you can cut them to install the window if you need to. do like 66788 said and frame around the window with wood. if you need to cut a rib tie the rib in top and bottom with the wood frame. highdesertranger

 

[flying kurbmaster]

I am no guru but I do have a Grumman Olson Kurbmaster and I installed two windows in it and four locker doors which are just like windows, the way I did it is I only used 3/4 inch insulation with a plastic on one side and a reflective foil on the other, ( I advice going thicker on the insulation) I glued the insulation to the wall then the paneling to the insulation, I don't have vertical ribs, I have tow horizontals one inside and one outside, I used the inside one to hold the panellng in mechanically then my cabinetry attached to the floor to the inside ribs and ceiling hold the rest of the paneling mechanically no framing around the windows, I cut using a jigsaw through the alluminium, insulation and panelling in one go, then built a ring for the inside as my windows came without the ring, I used butyl tape to seal the outside and screwed the flange to the alluminium with a few small stainless steel screws. then I screwed the ring from the inside to the channel on the outside section sandwiching it all together and holding the panelling at the same time, it is working fine no need to overbuild it has been like this since 2011 many thousands of miles. no problems. on the locker doors I did the same thing but without the inside ring only a few screws(four)
here is what they look like

 

[Road Dawg]

Thanks for the replies ya'll. I guess Lowes or Home Depot would be the place to get the Polyiso. Using Polyiso would I need a vapor barrier on the inside? Thanks again for the help!

 

[Road Dawg]

I am no guru but I do have a Grumman Olson Kurbmaster and I installed two windows in it and four locker doors which are just like windows, the way I did it is I only used 3/4 inch insulation with a plastic on one side and a reflective foil on the other, ( I advice going thicker on the insulation) I glued the insulation to the wall then the paneling to the insulation, I don't have vertical ribs, I have tow horizontals one inside and one outside, I used the inside one to hold the panellng in mechanically then my cabinetry attached to the floor to the inside ribs and ceiling hold the rest of the paneling mechanically no framing around the windows, I cut using a jigsaw through the alluminium, insulation and panelling in one go, then built a ring for the inside as my windows came without the ring, I used butyl tape to seal the outside and screwed the flange to the alluminium with a few small stainless steel screws. then I screwed the ring from the inside to the channel on the outside section sandwiching it all together and holding the panelling at the same time, it is working fine no need to overbuild it has been like this since 2011 many thousands of miles. no problems. on the locker doors I did the same thing but without the inside ring only a few screws(four)
here is what they look like

Looks like a great setup. Hope mine turns out that good!

 

[masterplumber]

most of the polyiso already has a vapor barrier built it - that is the plastic coating on the one side and the foil on the other. I have a cargo trailer - not a step van, but the window in insulation technics are the same. I kept my windows between the wall stud, but filled the stud bay with plywood in the area I wanted windows. I made the plywood 3 1/2'' above and below the window openings so I had backing to nail trim and screw in curtain rods. Since my walls are 1'' thick I just glued 2 layers of 1/2'' plywood together. Once I had it all in place I cut through the plywood and aluminum siding in one shot with a circular saw from the inside. It worked like a charm and gave me a good solid base to mount my windows to. Mine don't have an inside ring so they are held by multiple screws from the outside.

 

[Road Dawg]

most of the polyiso already has a vapor barrier built it - that is the plastic coating on the one side and the foil on the other. I have a cargo trailer - not a step van, but the window in insulation technics are the same. I kept my windows between the wall stud, but filled the stud bay with plywood in the area I wanted windows. I made the plywood 3 1/2'' above and below the window openings so I had backing to nail trim and screw in curtain rods. Since my walls are 1'' thick I just glued 2 layers of 1/2'' plywood together. Once I had it all in place I cut through the plywood and aluminum siding in one shot with a circular saw from the inside. It worked like a charm and gave me a good solid base to mount my windows to. Mine don't have an inside ring so they are held by multiple screws from the outside.

Thanks masterplumber, sounds like a good way to do it. I also want to be able to trim the windows out and I'm sure my wife will appreciate being able to hang curtains.