[heynow14]

Hi all!

New guy here. I’ve undertaken a fairly (for me, anyway!) ambitious project of building a 6’ octagon which houses a center Weber Grill for on-the-fly grilling and imbibing. It’s built 100% out of Cypress which I’ve read to be a great choice for outdoor furniture. I’ve covered it in 5 coats of Epifanes Clear Gloss and then 3 coats of Epifanes Matte. I’ve gone out of my way to not skimp or cut corners. I’ve got a TON of money in this project and even more time. It was completely wrapped and looked amazing in the workshop. I took it out to the back yard and that’s when things went south…quickly.

The weekend I brought it out was a crazy heatwave and further, over the last month it’s been out, it’s splitting all butted board seams AND starting to develop a few internal cracks mid-board. The table top consists of 8/4×8” Cypress and all boards are just looking ugly and I’m starting to worry about overall integrity at this point. Odd thing is that the base is 100% perfect…not even one seam is separating.

This is leading me to believe that the direct sun on the table top is just accelerating the expansion and likely the drying of the wood. The temp I am getting on the table top in sunlight is 160+…not good, I know.

My question for the pros here: What’s my play to get this table top back in shape for the long haul? Do need to wait another month and see if the expansion stops? At that time do I fill seams and cracks with epoxy resin and just sand the hell out of it and refinish? Luckily, I inserted biscuits every 15” or so in all of the butts and I think that may be really helping at this point.

The pics attached show the expanded seams. These do not really illustrate how bad it’s become. Before it found it’s way outside, I had a hard time finding the butt seams…it was that clean…

Please lend some advice and info to the guy who didn’t let the lumber acclimate in the heat before I went crazy with the tools…

Thanks much,

Nick

 

[Steve Neul]

From what I can see in the picture the glue joint doesn't look like it was exactly straight to begin with. The boards need to fit together nearly perfect without any clamps on it. Did you use an exterior glue such as Titebond III? To fix it I would take the edgebanding off and rework the joints on the top and reglue it. Filling the gap with epoxy will just be a temporary fix. It would have been better if the top didn't have the edgebanding on it. That way it would be allowed to expand and contract. It's possible the edgebanding could have caused the joint failure. As far as the finish I'm not sure I would have put eight coats on. It would have been better to go thinner with it and apply a fresh coat every couple of years to renew it.

 

[heynow14]

Thx for your reply. The Cypress was S4S before glue up so all glued edges were perfectly square. I used TiteBond so the glue is weatherproof and with the finish that went on there was next to zero chance that the seams would be open to the elements...until the heat expansion took over. I'm just not sure I can get everything apart to re-work it all. Where the glue is good, it's rock solid. Taking a saw to the table doesn't seem to be where I should head...but what do I know!!??

:blink:

 

[Tony B]

My best guess is that the edge banding was the leading cause of failure preventing the wide boards from expanding and contracting. Keep in mind that when 2 boards are glued up it becomes one wide board.It is also possible that the cypress was not dry enough. Generally, cypress has a high coefficient of expansion which is why it became a popular boatbuilding material in the south. It expands and contracts quite a bit with moisture content. The sun hastened things a bit.

 

[Dave Paine]

That is a very large surface on the table. There will be decent movement even indoors, but outdoors it will be even greater movement.

Use this link to determine the overall movement.

http://www.woodbin.com/calcs/shrinkulator.htm

I am not sure if this can be fixed.

The very high temperatures on the top of the surface and lower temperatures underneath the surface will cause a lot of stress. I would expect to see more cracks and warping over time.

 

[HowardAcheson]

I agree, the construction has numerous cross grain situations. You can't solidly attach a long grain board to an end grain board. The changes in relative humidity will cause the boards to expand and contract in the across-the-grain direction. The solidly attached ends will not be able to move and something will have to give. The normal results are failing glue joints and/or warping.

Sorry, but there is no good fix for the problem but if you saw off the perimeter banding thereby eliminating the cross grain joints, you might save it. But, you have to figure a way to close up the open joints.

 

[heynow14]

Thx guys - I was afraid I'd hear such things. Lessons learned, I suppose.

So, if you're me, how do I proceed? Unwinding and separating the boards and reassembling with a gap is not possible since I dropped pocket screws underneath and covered with wood inserts. Undoing all of that is not possible. Other ideas? This is just a killer after all of this time and expense...

 

[GeorgeC]

Thx for your reply. The Cypress was S4S before glue up so all glued edges were perfectly square. I used TiteBond so the glue is weatherproof and with the finish that went on there was next to zero chance that the seams would be open to the elements...until the heat expansion took over. I'm just not sure I can get everything apart to re-work it all. Where the glue is good, it's rock solid. Taking a saw to the table doesn't seem to be where I should head...but what do I know!!??

:blink:

Steve asked if you used TiteBone III. You replied you used TiteBond. Which one did you use.

George

 

[GeorgeC]

The only way you will have a decent looking table is to totally disassemble. Also lose the paint. Cypress does not do well with paint. You may have to plane a small amount off the top.

It will take some work but you can remove the pocket screws. Just drill out the wood plugs if they are glued in. If not glued then just pull. They were unnecessary because you glued.

You can salvage most if not all of your lumber.

George

 

[Dave Paine]

So, if you're me, how do I proceed? Unwinding and separating the boards and reassembling with a gap is not possible since I dropped pocket screws underneath and covered with wood inserts. Undoing all of that is not possible. Other ideas? This is just a killer after all of this time and expense...

I can appreciate the time and expense.

As GeorgeC stated, it is technically possible to dis-assemble, just a lot of work.

If you do not dis-assemble, I think the consensus is that this cannot be fixed. Attempting to fill the gaps will be temporary at best.

So if dis-assembly is off the cards, I think you will have to accept how the table looks. There may still be more movement.

 

[heynow14]

It's not painted, it's stained and then cleared with Epifanes. Removing the edge banding is doable. I'll try that and see what I can come up with.

Thx again,
Nick

 

[heynow14]

Upon thinking about this:
I’ve got an octagonal apron which is helping with the rigidity underneath. In an effort to maintain the apron could I approach this as follows:
1. Cut off edge banding all around the octagon
2. With universal blade, cut through all butt seams (and pocket screws) to add expansion gaps everywhere.

I’d likely have to add in additional lumber underneath to add support but this approach may save me from having to completely disassemble and tear out the apron which is structurally sound.

Thoughts?

 

[Dave Paine]

I would just remove the banding at the moment and see how much more movement is in the boards, then decide on whether you can accept the table in that state, or whether you need to dis-assemble.

If I were to dis-assemble, I would try drilling out the plugs so I could remove the pocket screws.

You can get a blade to cut the wood and the screws, but that will leave part of the screws in the boards which will rust.

How about some pictures of the present underside of the table.

 

[heynow14]

I'll take some underside pics this evening. One wise move I made was to use stainless pocket screws so that may help things if I leave them exposed.

 

[TimPa]

it is a nice table, and a bigger lesson. personally, I would bring it in immediately, lose the edge band. then rip at the failed glue joints, (all joints if you didn't use tbIII) or some even pattern. machine grooves into the edge, and install floating splines (similar to tongue and groove). ease the edge if desired. then slot your fastening screws, and let her float.

 

[heynow14]

Can you expand on floating splines? I know something would be needed at the outside perimeter but wouldn't a spline just put me in the same predicament I'm in now with limited expansion ability?

 

[Steve Neul]

I think the top can be glued together in one piece but you can't just take S4S wood and glue it together. The boards need to be edge jointed on a jointer so they fit together nicely before clamping. You can put an apron under the top as long as it is not glued on. If you would run a dado on the back side of the apron and mount it to the top with some table top fasteners it will allow for wood movement. http://www.rockler.com/product.cfm?page=784

 

[HowardAcheson]

The primary cause of your problems are the multitude of cross grain construction in your project. You must use construction practices that allow the boards to freely expand and contract with changes in relative humidity. The perimeter border is a cross grain situation on all the boards in the field of your project. If the movement is restricted it will lead to splits, glue joint failures, warping and other damage which is exactly what you are seeing.

The only way to salvage the item is to cut off the perimeter trim so that the boards can freely move. Your table will be smaller but it will be able to react to changes in moisture.

 

[TimPa]

Can you expand on floating splines? I know something would be needed at the outside perimeter but wouldn't a spline just put me in the same predicament I'm in now with limited expansion ability?

implied to be not fastened tightly, i.e. with glue along both entire edges. maybe some dabs in the center to hold in place. when large areas need covered, and some pieces need to remain in place (around the grill), i like to use tongue and groove. the t&g concept allows each board to expand and contract individually.

or, you can re-glue back to whole, make sure your fastening is set to float, and ensure your cutout is extra large to accomodate any expanion around the grill.