Plywood glassed right to roof?

[Barbara]

Does anyone know about the roof construction on an ‘84 Sunrader?  There is no insulation and looks like plywood was fiberglassed directly to the roof shell.  It seems the original rear vent was replaced later with an AC unit. Probably due to lack of support, water and weight, the roof has sagged.  Does anyone have a suggestion on how to go about removing the plywood from the fiberglass so I can get the roof back up to an arc?  

I don’t know if it was Linda S. or another post, but I vaguely remember reading about a certain year Sunrader where the plywood provides the roof support and should NOT be removed?  Any advise or link to a previous post is welcome!  The pics show two edges where roof meets plywood;; one on the vent hole and the other at the ceiling  transition.  Three layers: fiberglass, plywood, and veneer

[linda s]

Yes it's a compressed composition panel which I think was glued to the ceiling and it does add strength. Removing the whole thing and fiberglassing multiple wood strips works but it's obviously a huge job. Later model Sunraders came with ceiling beams that supported the weight of AC units and strengthened the roof. Adding one would only require you cut out part of the ceiling panels. Is your Sunrader a shorty or full sized. The full sized ones had  2 beams the shortys only one. Still not an easy job but don't have any easy solutions to offer you. By the way my shorty Sunrader came with a cutout in the cabinet door to allow you to open it near the air conditioner. Mine may have some slight sagging but nothing I worry about. Your air conditioner cut out looks to be in very good shape. No noticeable water damage at all. There is an edge on the roof too so I'm thinking yours really hasn't sunk that much. I would love a picture of your whole roof. But if you must here are instructions to build a roof beam

From Gail Frasier who used to be the finest Toyota motorhome restorer anywhere and her husband Jon Gail has passed and we all miss her   MATERIALS: One good quality straight grained red fir or spruce 2x4 8 ft long (or equivalent), with no large knots, 8 ft of 1 1/2" by 1/8" steel bar, primed and painted, Two 5/16" by 3" lag bolts with wide area flat washers (fender washers), several #10 by 1" wood screws, construction adhesive, and silicone caulk to seal outside when done.   Make a cardboard or paper pattern of the curvature of the roof where it is best preserved, usually at the front or rear where sagging has not occurred. Trim the 2x4 to fit snug from wall to wall then trim another 1/4 " off one end. Next transfer the pattern to one edge of  the 2x4 and saw the curve on a band saw so that you get an even cut.    Cut the metal strap to a length that will allow full coverage of the curved edge of the 2x4 plus bending over both ends. Drill 3/16" holes every 12" or so in the strap and countersink each hole so that the heads of your wood screws will be flush when installed. Form the metal strap to the shape of the wood piece and bend it down over the ends for a tight fit. Do a trial fit to the motor home and adjust as needed. Mark the strap at the center of each end of the truss and drill a 5/16" hole at each of these marks through the metal only. These holes will be the anchor points for the ends of the truss. Now run a bead of construction adhesive along the curved edge of the board and install the strap with wood screws making sure everything is properly aligned as you go. Next, drill a 1/4"  pilot hole into the wood at each end where the previously drilled larger holes are located.    Apply construction adhesive to the top of the truss and raise it into position inside the roof at desired location. You may need to force it up with bracing between the floor and the truss to get it into position. Measure the distance from a reference point on the motor home to the center line of the truss on each side of the vehicle. Next drill a 1/8" pilot hole from the outside through the fiberglass at each point making sure these holes coincide with the holes in the end of the truss. Once that is established you can drill the pilot hole out to 5/16" to install the lag bolts. Use rubber gaskets or sealant under the flat washers. Also cover the bolt heads with sealant or other waterproof cover. Now you can install upholstery and modify your upper cabinets to accommodate the truss.     Linda S

[Barbara]

Thank you Linda S!  You are a wealth of information.  It is a shorty (I’m assuming 18’ is the shorty).  I posted a pic yesterday of the roof sag under the topic “Roof Sag -fix or not?”  where it shows a measurement of the droop.  It’s worse when there’s weight on it.  I’d like to keep the AC rather than replace it with a vent, but I worry the rain will pool and become so deep it’ll get beyond the pan and gasket?  Here in the Pacific NW we get a ton of rain.  

I’m not sure if this will show up as a response to you...I hope so... am still trying to figure out how to use this website.  Thank you kindly for your info.  I’ve been checking back like crazy hoping someone would reply.  

 

[linda s]

Yeah I saw that pic but it don't really see a curve in the roof going to the front I'm guessing bathroom vent? Like I said there is an edge that's higher than the main section of the roof. Pooling can be easily solved by parking on a slope. It rains here on the north California coast too but your AC seal does just that. It seals the AC to the roof. New one shouldn't leak. If you ant to PM me click on the L where it identifies who posted and it will take to my profile. From there you can message me

Linda S

[RobotRichard.79DoLL]

I haven’t read the relating posts don’t know what’s been said and I have a Toyota Dolphin 1979 (78 4Headlight) so my experience might not be exactly helpful. What I did was instead of removing the pieces like I thought of doing at first till I followed them naked ceiling and realized they are the support so I cut some wood to the exact length and added it, thusly adding to the original support design just with more umph. Downside extra weight of materials and the orginal in my case is also pretty wrecked so really it doesn’t add much of any worth, upside, added support of two sticks are better than one and what not even if one stick is a zombie. The curve poses more issue, but there are definitely some woods you could use like a very hard wood, very thin like you would see boats made of and some half dome roof farm structures use similar stuff. You could make it look nice by putting it on the visible side of the ceiling even if you want, I’ve used a bit of choice walnut here and there in my rig, but might not look as good with a light ceiling. Anyways that’s  my .02, add and make rad.

[Erika]

On 8/5/2020 at 8:24 PM, linda s said:

Yes it's a compressed composition panel which I think was glued to the ceiling and it does add strength. Removing the whole thing and fiberglassing multiple wood strips works but it's obviously a huge job. Later model Sunraders came with ceiling beams that supported the weight of AC units and strengthened the roof. Adding one would only require you cut out part of the ceiling panels. Is your Sunrader a shorty or full sized. The full sized ones had  2 beams the shortys only one. Still not an easy job but don't have any easy solutions to offer you. By the way my shorty Sunrader came with a cutout in the cabinet door to allow you to open it near the air conditioner. Mine may have some slight sagging but nothing I worry about. Your air conditioner cut out looks to be in very good shape. No noticeable water damage at all. There is an edge on the roof too so I'm thinking yours really hasn't sunk that much. I would love a picture of your whole roof. But if you must here are instructions to build a roof beam

From Gail Frasier who used to be the finest Toyota motorhome restorer anywhere and her husband Jon Gail has passed and we all miss her   MATERIALS: One good quality straight grained red fir or spruce 2x4 8 ft long (or equivalent), with no large knots, 8 ft of 1 1/2" by 1/8" steel bar, primed and painted, Two 5/16" by 3" lag bolts with wide area flat washers (fender washers), several #10 by 1" wood screws, construction adhesive, and silicone caulk to seal outside when done.   Make a cardboard or paper pattern of the curvature of the roof where it is best preserved, usually at the front or rear where sagging has not occurred. Trim the 2x4 to fit snug from wall to wall then trim another 1/4 " off one end. Next transfer the pattern to one edge of  the 2x4 and saw the curve on a band saw so that you get an even cut.    Cut the metal strap to a length that will allow full coverage of the curved edge of the 2x4 plus bending over both ends. Drill 3/16" holes every 12" or so in the strap and countersink each hole so that the heads of your wood screws will be flush when installed. Form the metal strap to the shape of the wood piece and bend it down over the ends for a tight fit. Do a trial fit to the motor home and adjust as needed. Mark the strap at the center of each end of the truss and drill a 5/16" hole at each of these marks through the metal only. These holes will be the anchor points for the ends of the truss. Now run a bead of construction adhesive along the curved edge of the board and install the strap with wood screws making sure everything is properly aligned as you go. Next, drill a 1/4"  pilot hole into the wood at each end where the previously drilled larger holes are located.    Apply construction adhesive to the top of the truss and raise it into position inside the roof at desired location. You may need to force it up with bracing between the floor and the truss to get it into position. Measure the distance from a reference point on the motor home to the center line of the truss on each side of the vehicle. Next drill a 1/8" pilot hole from the outside through the fiberglass at each point making sure these holes coincide with the holes in the end of the truss. Once that is established you can drill the pilot hole out to 5/16" to install the lag bolts. Use rubber gaskets or sealant under the flat washers. Also cover the bolt heads with sealant or other waterproof cover. Now you can install upholstery and modify your upper cabinets to accommodate the truss.     Linda S

 

 

Hi Everyone, I was going to start a new topic, but maybe it is better to post here on this thread. The information above is extremely helpful Linda S. as I plan on making a beam for my 84 Datsun Sunrader, and will use this awesome info, though I was exploring using a carbon fiber beam. I will be installing a roof A/C and I will need the single beam for my shorty.

That being said is the rounded shape of the Sunrader roof supposed to be constant from rear to front? (pis 1 & 2) below.

 

 

 

 

 

These are a couple of side view pics from the Drivers Side (pic 3 & 4)

 

 

 

 

These photos are from the drivers side and I used an angle ruler on a couple of them to show the concave of the roof. (Pics 5, 6, & 7)

 

 

 

 

 

 

In the pics below I am trying to show the concave using a 8ft 2x4, but it had a bit of a warp as it did not sit flush against the wvwn floor, It still shows some of the concave between the edge and the center of the roof. (Pics 8, 9, 10 & 11)

 

 

These last 2 are taken from the passenger side. Pic 12 is facing the rear and pic 13 is facing the front.

 

 

 

I know these are lots of pictures, but I am trying to get a grasp of what the roof SHOULD be shaped like and how to fix and prevent the roof from sagging. Not sure if this is the standard location, but the A/C will be mounted over the rear air vent.

 

Thank you all for your thoughts an input, I sincerely look forward to the feedback, info and conversation.

 

-Erika

[linda s]

The dip around the edges is normal so I wouldn't worry about them. The Beam will reduce that slightly. The 18 foot Sunrader had one beam where the first cabinet behind the closet is. I never put one in mine because I didn't want to tear those cabinets apart. I don't have AC so it's not a big issue for me. Even though I don't have one I know where it goes and can give you measurements unless someone else here has one with a beam and can tell you. The curve of the beam is most important. You need to jack the roof up till it looks right. Standard floor jack, board almost tall enough and something at the top to protect the ceiling. Then put a straight board between the inset sections of the roof side to side. Measure from actual ceiling to board and you will have your drop to calculate the curve you need from side to side and measure distance from inset to inset side to side. I never made one so the instructions I put in from Gail are all I've got

Linda S

[Erika]

21 hours ago, linda s said:

Even though I don't have one I know where it goes and can give you measurements unless someone else here has one with a beam and can tell you.

 

Linda,

 

Thank you so much for the help. If you can please share the measurements, that would also be extremely helpful.

 

-Erika