1978 Toyota Chinook floor rot

[zero]

I just started tearing apart my 78 Chinook. Had a few "soft spots" in the floor. I removed everything to get a better look. I found around 1/4 of all the floor completely rotted out. Mostly around the outside edges where you would not notice by walking on it.

This Chinook has a floor material I've never seen before. Plywood on top but the bottom area is honeycombed and all wood where it lays against the aluminum skin. Or at least it was. Looks like a bee-hive made out of paper mache. I've seen modern synthetics that look similar, but I've never seen it in wood.

What is this stuff? I'll post some photos later. Right now I'm trying to figure how to replace the floor "in place" and not taking off the frame.

[WME]

Its not wood, it is paper honeycomb. Very common in the old days as packaging cushion. Supposedly by soaking in resin it would be waterproof. Of course a small spot missed in the coating process and it would dissolve when wet..

[zero]

Here are some photos. The front of the Chinook has an aluminum square tube at each front corner that runs vertically from the roof down to the floor. It then is supposed to be bolted to the wood base. After pulling the carpets up I found both front corners completely rotted out. Same goes with other areas. Didn't seem all that bad when the carpet was hiding it all.

Honey comb stuff

Fridge compartment . .

What’s left of the 5/8” plywood at the entranceway . .

[Totem]

my 86 sunrader had a similar wax/resin injected honeycomb insulation material under the fiberglass of its roof when I removed the vent and installed the rooftop AC. Looked very similar.

Mine also had a thick rubber liner spanning the entire RV area after the cab all the way back to the rear protecting the floor wood from the road and moisture. Do they all have that rubber mat like mine does? seems its a very good protector. All holes cut into it have been extensively sealed/caulked/greatstuffed on mine. no rot.

[zero]

my 86 sunrader had a similar wax/resin injected honeycomb insulation material under the fiberglass of its roof when I removed the vent and installed the rooftop AC. Looked very similar.

Mine also had a thick rubber liner spanning the entire RV area after the cab all the way back to the rear protecting the floor wood from the road and moisture. Do they all have that rubber mat like mine does? seems its a very good protector. All holes cut into it have been extensively sealed/caulked/greatstuffed on mine. no rot.

my 86 sunrader had a similar wax/resin injected honeycomb insulation material under the fiberglass of its roof when I removed the vent and installed the rooftop AC. Looked very similar.

Mine also had a thick rubber liner spanning the entire RV area after the cab all the way back to the rear protecting the floor wood from the road and moisture. Do they all have that rubber mat like mine does? seems its a very good protector. All holes cut into it have been extensively sealed/caulked/greatstuffed on mine. no rot.

I've only had two Sunraders apart. A 1983 and a 1984. No rubber liner in either. I'm sure the "Great Stuff" wasn't OEM. That "stuff" is open cell and soaks up water like a sponge. Useless for long term use on an RV. If using spray foam, closed-cell is needed.

Just about all the RVs I've worked on had many staples coming in from the bottom-outside that piece the aluminum skin and cause leaks from underneath. Maybe when new the underside was sprayed with some sort of sealant?

I guess there are at least two schools of thought for an RV floor. If you seal it tight then any moisture that gets in there is trapped and has to cause rot.

Or - you can leave the bottom with small vents so it can drain and get some air - but that also causes leaks from the bottom up. No matter how well sealed on the bottom, there is always going to be some moisure coming in from leaks above (roof and/or sidewalls).

In my experience where I live, I've never pulled apart any RV that was more then 10-15 years old that didn't have rot starting somewhere. I will say though that the Sunraders are one of the best built RVs I've ever come across.

I don't believe any RV is designed to last very long. Obviously, some do but it takes a lot of care and repair

[Totem]

Great stuff cures with moisture and is polyurethane based and a great expansion sealer. You are just dead wrong on saying it attracts moisture through it.

It quite effectively seals out moisture. If yours is "soaked like a sponge" its obviously been crushed and expanded a few times to wick or submerged. The liner under my rig is a rubber mat, not sprayed on as mentioned.

I used to use great stuff to seal the hard tops on my Jeep CJ's front top windshield gasket as a matter of fact; NEVER was it wet when I would pry it off to put the frog top on in the summer. It would take all the Michigan fall/winter rain and snow like a champ and at high speeds driving into it.

Messy, yes, soaks like a sponge? no.

[zero]

Great stuff cures with moisture and is polyurethane based and a great expansion sealer. You are just dead wrong on saying it attracts moisture through it.

I didn't say it "attracts" water. I said it soaks up water when the external waterproor barrier-layer is penetrated. I was also speaking generically which I guess I should of avoided. Many people use the name "Great Stuff" generically for other brands of spray foam just as many do for "Kleenex" or "Band-Aid." To qualify my statement - when "Great Stuff" first came out it was based on open cell polyeurethane. Now it's closed-cell. So yes, the newer closed-cell formula does not soak up water and yes, the older open-cell does. Many of the spray foam "in a can" polyurethane or latex foam expanding foam sealants are still open cell. But yes - last I checked the brand "Great Stuff" is now a version of closed-cell. I had to rip out lot so Great Stuff (yes the actual brand) out of several exterior places and it was completely water-soaked like a sponge. That was here in NY where we get worse winters then anywhere in Michigan does (except for a few area in the UP).

In open cell spray foam insulation the bubbles are cross-linked or connected by air pockets. In closed-cell they are not. Even the big insulation companies spray foaming entire houses are still using both (open and closed). Closed cell is much better and also more expensive.

[Totem]

Yeah I only use great stuff brand always have. closed cell it is. quite similar to gorilla glue in makeup. the stuff under my rig is the new kind, not the rockwool type.. someone put effort into it. I believe they may have even lifted the camper off the chassis and put that rubber liner in too. Maybe that's just how the Monterey Leisure guys built them that month as opposed to the California sunraders. I know mine has no hidden rot as of 2 years ago when i gutted it. It was thick marine grade plywood that had a fiberglass coating over it. rock solid.

[zero]

Yeah I only use great stuff brand always have. closed cell it is. quite similar to gorilla glue in makeup. the stuff under my rig is the new kind, not the rockwool type.. someone put effort into it. I believe they may have even lifted the camper off the chassis and put that rubber liner in too. Maybe that's just how the Monterey Leisure guys built them that month as opposed to the California sunraders. I know mine has no hidden rot as of 2 years ago when i gutted it. It was thick marine grade plywood that had a fiberglass coating over it. rock solid.

I'm trying to figure what to use on my Chinook right now. Total original floor thickness is 1 3/8". I know in the past I've built a lot of boat transoms that were 1 1/2" thick by gluing two sheets of 3/4" marine-plywood together. In an RV, I'm not sure the marine plywood is worth the extra expense and special ordering. It is no more rot resistant then standard CDX you can buy at Home Depot. Just better quality with less voids and fillers. I was also considering "foundation-grade" 3/4" plywood as a bottom layer and some standard 5/8" CDX on top; Foundation grade 3/4" CDX is pressure treated, rot resistant and kiln dried. It also has to be special ordered and is pricey.. Another option is the plastic waffle-type board made by 3M called Nida-Core. That stuff is REAL expensive and it all has to be special ordered and truck shipped in my area. It also cannot be direct screwed into. On an RV there are often many things that get screwed into the flooring. So if i used the pricey Nida-Core, I'd need a laminate of real wood glued over it.

Unlike the Sunader that I assume does not need the floor for structural stability - the Chinook relies on the floor to hold up the sidewalls. On mine, both sides sunk. I've got them jacked back up and I'm going to add some aluminum C channels to help take the stress. But still - a good weight bearing floor is needed. Note sure if a layer of half-wood and half-foam like a Sunrader uses will suffice. After tearing into this Toyota Chinook, I am amazed at how poorly it was designed.

If someone actually stocked the pricey Nida-Core, I might try it. But shipping charges make it very expensive.

http://nida-core.com/english/

[Totem]

Marine grade ply is algae and mildew resistant. CDX will go green and moss over faster than marine grade when exposed to sun and light without care lying horizontal. in your case wouldnt matter as it gets no sun/light agreed. why not just do what ML did and glass some regular ply?

[zero]

Marine grade ply is algae and mildew resistant. CDX will go green and moss over faster than marine grade when exposed to sun and light without care lying horizontal. in your case wouldnt matter as it gets no sun/light agreed. why not just do what ML did and glass some regular ply?

Foundation grade CDX is also mildew/mold resistant and more more rot resistant then standard marine plywood. Years ago I used to buy standard "wet" pressure treated 3/4" plywood and pay to have it kiln dried. That was before they started making "foundation grade" stuff that comes already dried. It's about $60-$70 per sheet.

At this moment, that is my plan (resin/glass over plywood). But I'd like to get some insulation in there. That would require some sort of wood "sandwich" floor with a layer of foam or polysi in the middle. The way Sunrader did it looks pretty good. Thin sheaf of plywood at the bottom, then foam, and then the heaviest plywood.

It may sound like I'm over-thinking this but - I'd like to do it once and never have to think about it again. I also don't camp much in severe cold so maybe insulation isn't a huge need. Still, I'd like to have it if I can design it in. Unlike a Sunrader, I don't trust foam in the floor anywhere near the perimeter due to its low compressive strength. As I stated earlier, the Chinook has what I call a design problem because the perimeter of the floor bears all the weight of the sidewalls and roof. Most other RVs I've worked on had skeletons of steel or aluminum tubing (and some had wood framing) to hold the weight. As it left the factory, the Chinook does not even have any metal support running sideways to support the floor. I don't know what those guys were smoking when they designed it. I'm adding in three 6 foot long aluminum supports made from aluminum channel - 3" with 1 1/2" sides and 3/8" thick. Only 8 lbs. each so it won't add much weight.

[linda s]

If you completely cut the floor out of a Sunrader the shell will fall to the ground. No fiberglass on the bottom. Only that funny sandwiched floor glassed in at the sides.

Linda S

[zero]

If you completely cut the floor out of a Sunrader the shell will fall to the ground. No fiberglass on the bottom. Only that funny sandwiched floor glassed in at the sides.

Linda S

I had the sidewall torn apart on a Sunrader a while ago. It had aluminum tubes in the side the wall holding up the sides and roof. But - I can't say I know what they attached to on the bottom. Are you saying they attach to the floor and have no other support? If so, that is how my Chinook is designed.

[linda s]

That's what the brochure says and it was confirmed to me by a guy who calls himself Sunrader Bob. He's done quite a few major restorations on these rigs and is pretty well known on most of the toyota motorhome sites. Scroll down on this and see the diagram and explaination

http://f1.grp.yahoofs.com/v1/QOPlUPwNfz1TnDkNfKUzpYpfa6vb-Wx4v5sgpULvXQtYPok_n0a_uYDNwQccug0E_sKGSDhsRlWD_HOH8kxfIdI8D1diSaw/Coach%20Manufacturer%27s%20Information/Owners%20Manuals%20and%20Brochures%2C%20Etc./Sunrader/Sunrader%20Brochures/SunraderClassics.pdf

Linda S

[Derek up North]

FWIW, He also calls himself a PITA.

[linda s]

FWIW, He also calls himself a PITA.

Yes and you two are so much alike he could be your BFAM

Linda S

[Derek up North]

I'm taller though!

[Dolphinite no longer here]

jdemaris,

Looks like you have a mess on your hands, but not an impossible one. Although I've never torn into a Chinook, I've ripped into literally thousands of wooden boats in my thirty-some years as a shipwright specializing in wood boat repair and the best fix was always to rip out the rotten junk and put in new wood. Don't mess with trying patch in good wood around the old. I'm sure you've already thought of this but I think the best fix would be to figure out how to jack the coach up off the floor, get rid of all the old wood floor and lay down a new floor.

As far as wood choices go, most any plywood will work as long as its sealed well, both sides and all edges-even with just a couple of coats of paint! The wood that's exposed to the underside of the coach can also be coated with that black rubber-like goo that comes in a spray can. You can get it at NAPA.

John

[zero]

jdemaris,

Looks like you have a mess on your hands, but not an impossible one. Although I've never torn into a Chinook, I've ripped into literally thousands of wooden boats in my thirty-some years

We think the same. I too have ripped apart many boats over the years to replace floors, stringers, and transoms. Many fiberglass boats have a horizontal seam like the Sunrader motorhome. I've split many in half to work on. With this Chinook - I got the entire body on jacks right now sitting a few inches off the truck frame mounts. I got to tell you that the floor in this thing is more miserable then any boat I've torn apart. It's 1 3/8" total thickness and is three layers all glued together. Bottom is (or was) 3/8" plywood against the aluminum. Next layer is 3/4" wood framing and it is NOT a rot resistant wood. Looks like common spruce. Then top layer is 1/4" plywood. With the middle layer with framing - the voids are filled with a cardboard-like honeycomb material. When this stuff is all glued together it is miserable to tear up and remove. But, I'm working at it with a saw and prybars. If any wood framing goes back in it's going to be white oak or white cedar. Don't know yet.

[Totem]

Awesome link thanks Karin!

[zero]

The floor on the Sunrader is a stressed skin insulated panel....

I built a house with SIP ten years ago. All sidewalls, foundation, and roof structure was SIP. I don't think that's what the Sunrader used. I saw one (1983) with a hole cut through the floor. Had a sheet of 1/8" plywood on the bottom with a sheet of 3/4" styrene over that and another sheet of plywood on top. No rbbed reinforcement and no polyiso inside.

The Sing panels you posted a link to would probably be great except for a few possible problems. SIPs are usually pre-engineered. I.e. all the cutouts and areas where fasteners need to be use are preplanned and engineering into the one-piece assembly. In this Chinook there are two wheel-well cutouts and a curved front. There is also no room to get a one piece assembly in there unless I remove the entire sidewall and roof assembly first. I'm hoping to avoid that. The original floor structure looks as though it was built in place and IS sort of a engineered panel 1/4" plywood on the bottom. The a framework of 3/4" thick spruce boards in perimeter and in areas that need to be screwed into. The framework was all glued to the bottom plywood. Then the top layer of 3/8" plywood also glued. All the voids between the wood framing were filled with glued honeycomb material (instead of polyiso like in newer SIPs).

I'm going to call the Sing place and get more info.

I'm also considering trying to make a structured panel in place with Okoume marine plywood, white oak ribs and sprayed-in polyiso. That or marine-grade Douglas Fir plywood that is CCA treated and kiln dried after the treatment. Commonly used in the decks of pontoon boats.

I see that a 4' X 8' sheet of the Sing SIP panel if 1 1/2" total thickness weighs 55 lbs.and I'd love to have that weight saving.

A 4' x 8' sheet of Doug Fir marine plywood, 3/4" thick weighs 75 lbs.

A 4' X 8' sheet of Okoume marine plywood, 3/4" thick weighs 55 lbs.

[zero]

.

Here is a local company in Washington state that I am familiar with.

http://www.singcore.com/

Thanks for the link. Do you know if they custom engineer panels with all the curves an cutouts needed - or do they just sell in sheets? I read through their Website and looked at their order form but am still not sure. Can't seem to get any idea on pricing either.

[zero]

.

From all the research I have done on the subject it is very difficult to control spraying in your own poly filler

I've installed spray-foam in residendtial construction. There is always excess and it is shaved off when cured. So yes, I agree it would not work well with a "built in place" floor. At least not with my limited skills. If I used foam, it would be "pour in", not spray. It's commonly used in boats for flotation purposes. It's closed-cell and expands 30X. That would me that for me to get a 1/2" thickness, I'd have to accurately pour 1/30th of a 1/2". Again, I doubt I can do that.

I am probably going to use the polystyrene "blue board" at 1/2" thick. I got the entire floor out last night and now know for sure - I cannot get a new floor in as "one piece." It has to be built "in place."

My plan so far. I am going to built a aluminum channel grid-work under the floor to better support it - especially seams. It will only add 25 lbs of weight. Total floor thickness must be as original - i.e. 1 3/8" total. I am going to use some sort of 5/8" plywood on the bottom and then build a 1/2" thick framework of wood (glue and screwed to the 5/8" plywood). The wood framework will go anywhere that stuff from the top has to be screwed down into it. On top of that a final layer of 1/4" A-faced plywood also glued. Main thing now is to figure what plywood to use. I really wanted treated rot-resistant wood as the bottom layer but I don't think I can get it in 5/8" thickness. Pontoon boats use 3/4" douglas fir that is treated and then kiln dried afterwards and polyester and epoxy resin bonds to it. If it was available in 5/8" it would be my choice'

I agree 100% with the "blue board." But since it comes in standard thicknesses - I have to work around it with what's available in plywood to come up with that 1 3/8" total. The other slight issue is the wood framework. The original was a cheap softwood. Probably spruce. It was rotten all over. I like to use something stronger and more rot resistant. I was considering white oak - but that stuff is murder to put screws into without predrilling. It is natually rot resistant. I could also use white cedar. I'm still thinking about it.

The original floor was 3/8" plywood on the bottom, then 3/4" thick spruce framework, and then 1/4" plywood on top. If I copied that setup, I'd need 3/4" foam as filler and insultion to meet the total 1 3/8".

[zero]

All the contemporary marine plywoods seem to be imported and they are metric sizes. Try your configuration using a conversion calculator working with a combination of the metric plywood sizes and the inch dimensions, work in decimals to make the math easier. Don't forget that you will be adding extra depth due to adhesives and also some amount of warp of plywood panels. You may also want to add a layer of fiberglass over the top inside the coach. That will make it easy to mop up after spills and leaks. If you did a fiberglass layer over a nice looking plywood you might not even need to put down carpet or any other flooring over the plywood.

There are a lot of rot resistant wood choices. Black Cherry, cypress, southern pine heartwood and a whole host of new sustainable hardwoods being imported from South and Central America. Your best source of information for a suitable wood will be from the wooden boat building newsgroups.

I am using Western Red cedar to replace the particle board framing that was used in the cabinets and also as the cleats that support my dinette seats in my 1980 Sunrader. I have also used it around the hatch areas where the particle board had been damaged over time by water. I only select boards that have very tight grain, not the big grained stuff you find in fence boards. Being in Seattle it is relatively easy to find that kind of cedar and I can hand pick through stacks of it in various dimensions at the local Home Depot Stores. This is actually the best time of year for finding the good stuff as the stacks are not already picked over. I have the best luck with quality tight grained cedar in the 2 x 2 pieces.

I just had a 20 foot Glastron boat split in half. Clamshell design like a Sunrader. Under the floor it had three 18 foot long 1" X 8" wood stringers embeded in the fiberglass hull and all rotted out. I went on a search for some 18' white oak boards but had no luck (naturally rot resistant). I was just getting ready to cut down a white oak and mill it myself when the local mill got sawing some white cedar (also naturally rot resistant). I coaxed the guy to mill me some 18' boards. Not my first choice since cedar splinters so easy - but good enough.

With the Chinook - I finally figured out what I'm going to do. I discovered that in my barn I had two sheets of 1/2" CCA treated southern-yellow-pine plywood that is over 10 years old - i.e. it's dry. Note that it seems just about every Chinook I've seen has "sag" problems. The sides of he fiberglass body sink due to hanging well beyond the truck frame and little support. So, I made a grid of aluminum support that are rubber mounted to the truck frame. I'll post some photos later. Worst part was the price of aluminum -it's getting like gold. Each 6 foot piece of channel aluminum cost me $50. The bottom will be the 1/2" treated SYP plywood and the side facing the road will be sealed with epoxy. Next layer is 1/2" blue-board styrene. Then the top (floor) will be treated 3/8" Douglas Fir (marine grade) type A/B and kiln dried after treatment. That was hard to find since it's mostly available down south or in Canada. Lowes sells it for $27 a sheet down south and getting it in NY is costing me $70 per sheet. The "sandwich" will have framing amidst the 1/2" foam anywhere things need to be screwed from the top. The 1/2" framing I'm sawing out of treated SYP lumber.

[zero]

Here’s the original floor before I tore it out. The sides that hold the weight of the Chinook camper body are slumped and drooping. I’ve seen this in just about every Toyota Chinook I’ve seen. No support other then the wood floor to bear the weight.




Another Chinook problem area. The front of the Chinook body just lays on top of the Toyota truck cab cut-out. This one has started to collapse. Not from rust – just inadequate design. I added a 6 foot wide aluminum support that is rubber mounted to the truck frame.



As it came from Chinook – just four of these held the entire Chinook body to the truck frame. ½” bolt, rubber biscuit, and a stack of plywood squares. I added three more mounts and made new support blocks.



This is a corner support. There are four of them. The Chinook body has four, i.e. one in each inside corner and they originally bolted to the wood floor via two ¼” bolts. The steel support runs inside the wall up to the roof.



Note a how rusty the bolts are



After stripping all the wood I could, I had to fold the aluminum skin to make it small enough to get out the door. Some of the old 3/8” plywood was glued to the aluminum.






New front support I made. 6 foot aluminum angle-metal attach at three points to Toyota truck frame via three rubber cushions.





New aluminum grid work I’ve installed to hold up the new wood floor and better support the Chinook body. 3” wide C-channel, 3/8” thick.


Seen from inside cab . .



Seen from back door . .

[zero]

You don't have the aluminum touching against the steel right? You have not talked about how you can't have those two metals in contact with each other. It is important to edit your posting to emphasize the dangers of doing that or you could cause issues down the road for another reader who does not have that kind of knowledge.

Every piece of steel that is touching aluminum is epoxy-painted and a piece of thin plastic is used as an "electrolysis barrier." Any steel connector bolts have stainless-steel washers that serves as inert protection between steel bolts and aluminum. I'm more concerned about the aluminum touching the copper-azole treated wood. The wood will be encapsulated with epoxy and also a thin plastic liner. The electrolysis problem only occurs with bare disimilar metals and moisture present.

Aluminum touching steel is not exactly a "danger" unless in a critical area that gets wet a lot. Look at just about any modern auto engine and they've got steel bolts threaded into aluminum all over the place. I had to pull the engine out of my 2005 Subaru recently (for a new clutch) and the steel bolts holding the engine to the transaxle had caused a lot of corrosion. On my Chevy Suburban with rear AC - there's a 15 foot aluminum line that runs under the truck and is clamped to the frame with plactic-coated steel hangers. The plastic chipped off and the steel ate right through the aluminum lines. To be fair, we have lots of water and road salt here that helped it rot.

[Dolphinite no longer here]

Jdemaris,

I've been looking over the photos of your rebuild of your Toyhome and I gotta' say it looks bulletproof. You do good, thoughtful work! The last post I saw was dated 12 January. Any further progress?

John

[zero]

It's going slow. Takes a lot of time since each all the wood has to be cut, fit, and coated twice with epoxy, bolted in, and then joined to the walls with epoxy and fiberglass cloth with at least two coats of epoxy. The bottom floor that faces the road is now all in and bolted with stainless-steel carriage bolts. Things will go a bit faster now that that part (the worst) is done. 1/2" foam goes in next with 3/8" marine-grade treated Douglas Fir A/B plywood on top.

[zero]

And a few more . .

[sdboltdude]

looks like a big project going good!<br />great job

[Dolphinite no longer here]

Well, looks like you done good, there! That floor and support system will be bulletproof and very pretty. Where did you get the auxiliary fuel tank and how big is it?

John

[zero]

Well, looks like you done good, there! That floor and support system will be bulletproof and very pretty. Where did you get the auxiliary fuel tank and how big is it?

John

Jeep CJ3 tank is 15 gallons and a perfect fit in the original spare tire location. I didn't want the spare there anymore anyway.

[MontanaChinook]

I found some rot in my Chinook. Drivers side, front, under the window that had been leaking. I'm sure, after reading this thread, that its probably more extensive than just that area ... but the rest of the floor looks really good. I'm in no position to get into a full restore and remove the entire floor. You boat repair people ... I know it depends on how bad the rot is, but if its around the mounting bolts up behind the drivers seat, and all the other mounting bolt corners are solid, what do you think is my best bet? Seal the leak and move on, or is there a reasonable way cut out and patch that section? Nothing is so bad that any one is going to fall through the floor, I just don't like that its rotting around the mounting bolts and seatbelt bolts. I'm sure that aside from the wood being rotted, my bolts look just like yours ... only one corner, but maybe not super safe ... I think I'd just like to reinforce that area, somehow.

[zero]

I did not have a thorough understanding on the Chinook floor construction until I ripped mine all apart. After doing so, and looking closely at several other Chinooks - my take on it is this. The floor is contructed like a bridge made from toothpicks. There are no main or centralilzed supports. It's an "all or nothing" sort of construction. I've seen many Chinooks suffering from the sidewalls of the camper sinking and drooping. I don't see how any rot as you state can cause any immediate or catastrophic failure. Just a slow one over time. The condition of your's could be checked with a straight-edge put sideways across your camper floor to see if the floor on the both sides where it meets the sidewall is no longer in the same plane as the central parts of the floor - i.e. cockeyed and slumped.

I've noticed that on a few pictorial "essays" on the Web when someone transplants a Chinook body off of one truck and on to another - steel crossways supports are usually added. Maybe because the sagging got noticed when the body was removed?

If you've got a corner that rotted and all else is fine - and some sagging has begun - I'd stick a metal support under it. Then you could tear out whatever rot is in the corner and fill it with a wood-repair system that can be poured in. Doing so will not bring back the structural integrity but will seal it and stop more rot from progressing. Installing one sideways metal support would not be difficult. If you used a 6 foot long piece of 3" aluminum C-channel - it only adds 3/8" of an inch to the height. Since the Chinook body is sitting on little wooden supports that are about 1 1/2" tall - all you need to do is saw off 3/8" from the support, slide the new aluminum piece in, put the two big support bolts back in and it's all fixed. Won't slump anymore. My Chinook had some much rot on both sides - such a quick fix was not my choice.

By the way, if you find that no slumping has occured - then you can assume there is not enough rot so far to ruin your "toothpick bridge." If that is the case, seems just cutting the rot out and pouring in some wood-repair epoxy will do the trick.

[MontanaChinook]

Thank you! And I don't know how different the newports are from the regular chinooks...I'll do some measuring. Visually, it all looks good with no noticeable slumping, but I'll measure to make sure.

I know you're a member of the yahoo chinook users group. I've got a ton of photos of the project up there under Zachs Newport project, or something like that..