joining boards together ??

[Mike Jones NM]

In a normal situation I would probably use a joner and glue it up. However I need to join together 2 pieces that will be over 14 feet long, 4 inches thick and more then 24 inches wide. The final board will need to be able to support some weight on the outside edge so it has to be pretty dang stout.
My first guess is to run both pieces through the jointer and then use LONG lag bolts through the back (blind side) to pull/hold it together.
Any other suggestions??
Thanks

[David Epperson]

(2) 14' 4x12s are pretty stout to begin with. But what about a series of dovetailed butterfly "splices" part way through from the bottom, every 6" to 12". Not sure if that's the correct terminology, but I've seen the technique used to "pull" checks back together in "natural" rustic furniture.

[Jim Becker]

A scarf joint would likely be the "normal" way to join them, but you mention weight bearing. Please explain that in more detail.

[Mike Jones NM]

Ok, let me see if I can get a little more specific here.
This will be mounted to the outside of a house, horizontal under a set of windows to make a shelf.
I have no idea how it is to be mounted as I run the mill and do the wood work, how it gets mounted to the house is the problem of the contractor.
It will be routed out and a piece of 1 inch thick 14 foot long granite will be set in it.
The owners do not want any support such as legs etc. showing from the outside.
I can only cut 25 inches thick on the mill and no way can I find a single tree that will be a consistent diameter tree to make it a one piece. I.E if I start with the butt end at 25 inches by the time I get to the 14 or so feet I will have lost at least several inches. SO I have to go with 2 pieces joined together.
Hope that is a little clearer.
Thanks

[Jim Becker]

Mike...be glad you're not the contractor! That's a LOT of weight to carry and with "no visible means of support"?? Sheesh!

At the very least, I think you're going to need to join the boards using stout lose tenons. If you cannot supply a 14' board of that width, then maybe the design needs to consider that before the material is source. Maybe that needs to be the contractor's problem, too?

[Mike Jones NM]

Jim, ANYTHING I can pass on to the contractor at this stage of the game I will LOL. THis is going to be an interesting "little" project. Has been on going for a year now and we are down the the "little" stuff.
Thanks for any thoughts
Mike

[glenn bradley]

Sounds like someone wants something a little unrealistic with that mounting description. You could use a spline (a big one, 3/4" x 4" maybe) or tenons as Jim describes. I think something like that will be your best bet but I would discuss the means of support with the installer to get a better idea.

[David Epperson]

OK. I'll admit to being a complete Noob at the woodworking, but as a mechanical engineer the reasoning for this type of construction escapes me. Why go to all the effort to build a 2 piece glue up, just to rout it out and hide the fact that it's a two piece glue up? Particularly since the grain is not going to be running in the strongest direction to begin with. Seems to me (and I know this is the contractors delima not yours), that a cantelevered beam set through the wall every 16" to 24" would serve to support this "shelf" much better, and still not be visible. And these could be integrated into the shelf you are building, and infact help to hold it together. All the "joints" are going to be covered with granite anyways. If there's a good reason for it, I wish someone wold 'splain it to me. Cause I don't get it.:D

[Joe Chritz]

The GC needs to call an audible and pass this one.

Assuming that slab is 1" thickx20" widex 164" long that is around 350 pounds.

8/4 or 10/4 material will hold the granite fine as it falls to the deck when the attachments fail.

You could hold some liability if you do any of the work on the piece. Personally, my free $.02. Get a waiver signed or supply the rough wood and let the GC worry about joining it up.

Support that 24" wide plank with 16x16 corbels every 3 or 4 feet, properly secured through blocking from inside and it will outlast the house.

Good luck

Joe

[John Downey]

If it were my problem to solve (and I'm thankful its not :D), I think I'd be looking at using LP gluelams instead of screwing around with real lumber. Epoxy or urea formaldehyde to do any gluing and bolts to hold it together. You don't mention if its to be painted or not -- I shudder to think of the problems if they want a clear finish. And how high up is this going? If its overhead you may have to get engineering on it anyway -- building inspectors can be funny that way (I had to get engineering on a stone foundation, but if I had done the same thing with CMU's no engineering needed :confused:)

[Mike Jones NM]

I really like the idea of the gluelams but that won't happen. This entire project has been done with trees I cut from the property and have run through the mill. Log, walls, log siding etc. SO going to the gluelam won't fit the "rustic" look.
As for the liability I work as the manager for the property owner not doing this as an independent source so any liability will fall back on the owner but that was one of my concerns.
As for the height off the deck it will be just below window height so that food can be passed out the windows in the kitchen to the folks at the hot tub/deck!

[Jim O'Dell]

WOW, some house!! I can't imagine any easy way to hold up just the granite, much less a 24" wide 4" thick hunk of wood. (Will this wood be dried in a kiln, or is it to go up wet?) I'd think if some 4 X 4 material could be anchored through the walls, 16" OC, and building structure to make a shelf, then the granite could be attached to them, and a skirt applied at the edge to make it look like it was solid 4" thick wood the granite was sitting on. But then if the house is beyond the framing point, this could be a real chore to cut into the logs (log veneer or true log construction?) and be able to make a structure and be able to secure the 4 X 4's to create the shelf. What ever the design/implementation, don't forget to take pictures to show us!! Jim.

[Steve Schoene]

This piece needs, apparently, to look very heavy, but why does it need to be so heavy. Can't you take these timbers, resaw them into planks, and build them into a box. The box would then attach to the house by slipping it over a smaller beam bolted to the studs. That way having a bunch of very sturdy bolts, into every stud to hold the inside "support beam" to the wall won't be visible. But when the outside box is slid over the support beam it can be attached with much smaller lags to hold it in place. Bolts from the top would be covered by the granite. The joints on the box would be very hard to see. The one on the top would be covered by the granite, and the one on the bottom would be low enough that one would have to be on hands and knees to see it under the shelf. The ends could be more challenging unless the shelf runs into a wall or the like.

Question--however built from solid wood, how does the granite top accommodate the seasonal wood movement? Contractors concern again, but....

[Eddie Darby]

Skip the real granite and go with a Faux Finish that imitates granite.

[Randy Klein]

Just throwing this out there, but what about a torsion box instead of solid wood? Then support "things" can be built into the torsion box as it is designed, plus will weigh alot less than solid wood.

[John Downey]

This entire project has been done with trees I cut from the property and have run through the mill. Log, walls, log siding etc. SO going to the gluelam won't fit the "rustic" look.


Ahhhh, the plot thickens... given that info, I'd start favoring the torsion box idea that Steve and Randy both suggested. Might even be less work, but better use some good glue on the miters! That should also take care of wood movement problems. Then the only bad headache is how to finish the silly thing and not have it all come apart in 5 years when they don't maintain the finish!

[Mike Jones NM]

Ok, appreciate the ideas folks. I have been brain storming most of the day on this and have come to a possible solution that takes care of the problem and the securing it. See what ya think.
Taking a piece of 1/4" X 3" X 14' steel plate
Inlet the 2X6 studs on the inside of the wall (about 3/8" or so) so the plate will fit flush with some welds on the inside.
Every 18 inches drill a 3/4" hole in the plate.
Weld 3/4" gas pipe into each hole (pipe long enough to insert into the wood shelf about 18 to 20 inches outside of the house)
Put together the 2 planks that will make up the shelf by what ever means??
Drill holes in the wooden plank to match the pipe coming through the wall.
Lag bolt the steel plate to the studs inside.
Slide the shelf onto the pipes, drill a couple of holes in the bottom of the shelf and into the pipe and run a couple of screws in to secure the shelf to the pipe.
The weight issue on a joint will be pretty much a non issue since the entire shelf will be supported by the sections of gas pipe through the center and all the weight will be held by the 2X6 studs.
There will be no exterior support visible.
Will it work??
Thanks

[Chris Schoolland]

I'd propose making a steel frame out of beefy square tubing that has integral L-brackets lag-bolted or SDSed along side the studs inside the wall. Then clad the frame with wood or let it into the bottom of your beam. Angle braces could even fit in there invisibly if they're kept within the wall, which would be very strong--especially in a 2x6 wall. All this to say that with proper support your joinery is less critical.

Interesting problem!

CHRIS

[Alan Turner]

Mike,
I have done a number of shelves where the owner wanted the shelves to "float" with no visible means of support. The solution I use is to have pieces of plate steel, generally 3" wide, 1/4" thick, fabricated, with drill rod welded to the plates at a 90 degree angle. The plates are then through bolted to the sides of each of the available studs, and the shelf/plank is drilled to accept the drill rods. I have never had a problem with this. However, the largest ones I have done have been about 12' long, 2" x 14 or 16" wide, in cherry. The drill rod was inserted to a depth of about 10" or so, as I recall. I think I drilled 1/2" holes, and used 15/32" drill rod. These were all interior applications.

The exterior aspect of your job, plus the extraordinary size, adds some features that are important. The wood will move more than the KD wood I used. And weather will cause additional wood movement, esp. since you are starting with wood that is not dried, as I understand it. I think I would consider stainless for the steel, although that would be quite expensive, but cheaper than rebuilding.

If the granite is to be let into the wood, then there will be water collection, and so weep holes will be needed. Epoxy is your glue of choice here. Leave a bunch of room in the recess so that when the wood shrinks, it does not pinch the granite and split the wood.

The glue up should not be a major problem. Loose tenons will give you your registration, top to bottom, for the glue up. Dominoes would be perfect for this as they are quite tight in the mortises and will give you good registration, but a slot cutter in a router would work as well.

Good luck; this is an interesting project.

[Roger Savatteri]

.....a fourteen foot, 4'' thick, 24 ''wide structure bolted to a side of a house to then hold a granite slab, with no visible means of support......not to mention the potted plants placed on that will then add to the weight.

.....my thoughts tend to go with a structual aluminum frame with 3'' square tube, bolted first to the side of the house, then wrapped in cedar. (think of a structure looking like a ladder) I would consult an engineer regarding the weld joints and weight stress, etc.

.....it is after 3 in the morning, so that's about how far i could go right now.

all the best,
roger

[David Epperson]

The weight issue on a joint will be pretty much a non issue since the entire shelf will be supported by the sections of gas pipe through the center and all the weight will be held by the 2X6 studs.
There will be no exterior support visible.
Will it work??
Thanks
Well yes and no. That's a lot of weight and you are still working in the weakest dimensions of your materials. I'm still afraid that with your pipe supports fastened onto the wall at 90 degrees that you are going to see quite a bit of sag. If it were me I would feel a lot better about adding some upward angle to the pipes and supporting the shelf from at least 6" to 12" below the shelf. And the torsion box idea would lighten this load by quite a bit.
You could perhaps prestress you pipe supports but someone would have to run the deflection numbers pretty accurately to come up with the needed angle to weld your pipes so that they would "sag" back into square.