Help with attaching plywood deck to Yakima Roof Basket

[VJP5]

I need some advice as I am over my ski's on this one. I will also preface that I am a belts and suspenders guy when it comes to these types of projects. I tend to overbuild everything.

This is also not about weight. I understand the dynamic and static weight limit concerns and will be well under the limits for both moving and parked.

My concern is with the flooring.

I have added a Yakima Roof Basket to my tintop. It's sitting on 4 sets of crossbars (it's only 74" long and 48" wide). I want to add 3/4" plywood to it so we can use it as a deck, as well as for packing some odd items when going camping. As I see it, there are 2 ways for me to affix the deck to the basket.

Option 1 - U-Clamps, plates and lock nuts. These will have to be about 4 1/2" long and can mount to all 4 crossbars. This is likely the most secure, since those crossbars aren't going anywhere, but could also be overkill. I am thinking about 14 of them. 4 on the front, 3 on the two middle bars, and 4 on the back crossbar (about $60 in galvanized hardware)

Option 2 - small clamps attached to the 1/2" bars of the basket. I would still use bolts and lock nuts and could easily use about 30-40 (about $45).

Am I way over thinking this? The cost difference is insignificant, so it comes down to safety. The last thing I want is a sheet of plywood popping off the roof while driving.

If you've done this before, what did you use? Is there a better, third option?

Sorry for the crude photos, but hopefully you get what I am trying to do. Thanks in advance for your help.

Vince
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1988 Vanagon Wolfsburg Tin-Top - "Elmo"

[vanagonjr]

I know you said you overbuild things, but consider that the plywood isn't really supporting the load - the basket itself is. The wood is only stopping things from falling through the cracks per se.

Therefore, 1/2", or even thinner, will do the job.
Are you leaving the plywood up there more or less permanently?

If not, I'd go with door skin (or <1/2") and zip tie it in, as the load on top being lashed will hold everything in the basket, including the wood floor.

Then when finished with your trip, cut the zip ties, and easily move the thin wood to your shed, basement or garage.

Elsewise, I'd be using 6 of those clamps, 3 on the front and 3 on the rear.
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John - 86 Wolfsburg Westfalia "Weekender"
Flint reversed 1.8T W/Passat 5-Speed
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FAQ thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=525798

[VJP5]

When we're camping, which is maybe once a month, you are correct in that the load will help keep it in place. But its primary use will be as a roof deck, which will be left on permanently. One of the benefits of living in SoCal is there are plenty of places to drive around to catch a good sunset. My wife and I will eat dinner 'on the deck' as the sun goes down. No worries about fighting for space or trying to get an unobstructed view. it is just a great place to relax

It also works as a great place to spot where the waves are breaking for surfing. I'll even get up there to watch others surf if I'm too tired.

So my primary concern is driving with no load bearing weight on it.
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1988 Vanagon Wolfsburg Tin-Top - "Elmo"

[panel]

If you went with the 2nd option using the conduit clamps you could always line them with rubber to protect your new rack.
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My '65-Subaru EJ20 Turbo conversion

[VJP5]

Agreed, I would absolutely use rubber to protect the bars.

My main concern is safety, as this is my daily driver and 90% of the time there will be no weight on the decking.
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1988 Vanagon Wolfsburg Tin-Top - "Elmo"

[pnwkayaker]

I think both would work fine, but personally, I'd go with u-clamps:
- easier to install and remove, they can drop from the top instead of pushing from the bottom (gravity is a great helper)
- they can distribute the load at a pass-through hole more easily (you'd need to add multiple washers and such using the other method to distribute the load at a hole)
- less number of u-clamps (14 u-clamps vs 30-40 small clamps is not overbuilt in my book)
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87 Syncro Westy EJ25 ("Tardis")

Seattle Meetup at Marymoor (link)
A collection of Simple Useful Mods (SUM) (link)

[Crooked Designer]

I have my solar panels held on to the roof rack with 6 u bolts. (like your Option 1) I also put 1/8" pieces of rubber between the panel box and the rack bars. I've had it up there for 3 years now and it's incredibly solid.

However, using that method for what you're going to be using as flooring, I would probably think about how to attach it without bolts coming up through that flooring to avoid giving yourself something to trip on. If I were you, i would probably consider something like the electrical conduit solution, but attach to the basket before you put the basket up top. This would allow you to put some flush mount bolts down through the floor and bolt them on from the bottom.
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'85 Westy full camper, Subaru 2.5L, 5 speed SubiGears + 5speedbus shifter kit

[0to60in6min]

I'd treat the wood well (staining?) and leave it permanently. It will create an airflow and help cooling down the van... similar to the Land Rover roof... 

[VJP5]

[DuncanS]

9 mm Okume plywood fastened down with 3M 5200 and nothing else. Once cured if you try to lift the ply with a crane, the whole van will come off the ground. No fastenings at all.

[calo1956]

Awesome van and roof rack setup! Have fun camping with it. Aside from the attachment method, I would question why use plywood, personally I would go with a solid wood.
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Enjoy the ride....
72 bug
80 westfalia

[DuncanS]

And while you're at it, weld some proper sized tubing onto the basket so you can sport an umbrella up there for sun protection and coolth.

Skip all the wild paint work and graphics and just have a couple of chairs and the umbrella. Although this does have some qualities.

Just noticed the difference in the way the rear fender wells and the firewall are designed for the splitters and the T3. Wish ours were like the splitters so we would have more interior storage capability.

[Steve M.]

Having had plenty of expereince with plywood on the roof rack:

1.) Do not permanently mount it. It is wood and will deteriate/rot over time and require replacing.
2.) Use the "U" shaped brackets. Those longer brackets will distort the framework by pulling the metal tubing out of shspe.
3.) Before mounting get all your holes drilled for the u-shaped brackets and then use Thompsons Water sealer on the plywood making sure it gets into every hole to soak into the raw wood exposed by the drilled hole.
4.) Use stainless steel stove bolts and nyloc nuts with washers coming down through the top so the bolts do not stick up into the cargo area.
5.) Do not paint it. I used the best quality Behr exterior paint on my first sheet of plywood thinking it would last for years. Did all the proper prep work to paint it and it only lasted 6 months before starting to peel off in strips. It looked like palm leaves blowing in the wind going down the road. Since then I have only used Thompson Water Sealer and the lastest sheet has been on the roof rack since 2016. Reseal it every year.
6.) You only need 1/4" thick marine ply. The framework under it is going to distribute the loaded weight. Weight is your killer and the thinner you can go is best. Even think about 1/8" sheet of aluminum if it is less weight.
7.) The temperature difference between the bare roof and the shafe underneath the plywood is going to be about 15-20° cooler in the shade.

Nicely painted waste of time and money to remove it 6 months later. Slots cut inyo along the edges are hand holds for when climbing up there and also double as places to use ratchet straps for cargo.

Road grime will blacken it.
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[Steve M.]

[DuncanS]

Steve--Not a fight here, but a few defensive thoughts on my ply post.
1. Okume ply is marine and will not degrade for the life of the van
2,3,4 NA
5. Use only marine oil paint with a primer first. Interlux Bilge Coat is really tough and will stand up to traffic. I recommend it for porches. And recoat as needed. Paint the underside too. But after the ply is on. Take the rack off and paint then.
6. I agree on thickness. The 9mm has extra cores so more better for the abuse and very little extra weight.
7. You are dead on. Absolutely. White is the only way to go. Any scuffs or stains are above eye level and can be repainted when they become objectionable.

The ply can be removed, but only by destruction if no longer needed or a different idea.

Duncan

[syncro surf]

Duncan - as a boat guy I expected you to recommend Starboard/Seaboard HDPE type material. Fit it and forget it. Too expensive? I haven't used it for anything but it seems like a good application for it.

[VJP5]

[VJP5]

[pemz0r]

I would use a bunch of rubber hose clamps. I don't like the sight of "U" bolts.

This is how I mounted my solar panel. The best part, is that the rubber gets sandwiched between the the metal bar and the solar panel for some sort of anti vibration.

https://www.amazon.com/LOKMAN-Stainless-Cushioned-...4&th=1

[Steve M.]