I built a dining room table for my daughter from Poplar lumber that was approximately 8 years old and had a moisture content of 9%. Unexpected shrinkage (by me) has occurred evidently due to the wood continuing to dry out due to dry natural gas heat. I cannot get a new RH reading as she lives 7 hours away. Question / issue: I understand the shrinkage of the top as it has reduced each half of the table has reduced from 24 inches to 23 5/8", Skirt staying 24" (in total 48" to 47 1/4"). The leaves have reduced from 12" to 11 13/16" (skirt staying 12") My question concerns the skirt did not shrink causing the skirt ends to hit before the top edges close, leaving a ~3/4" gap. 1) I can remove the skirt and trim back to match the table, but I am concerned that when the gas heat is turned off in the spring, the table top will grow and the "cut off" skirt will not come together. Granted it is better the top to close than the skirt, but I would prefer the top and skirt to stay together. The climate is Arlington Va. where AC will be used in the summer. So what do you think? Would you expect the top to grow in the spring? Please assume good home construction and HVAC operation. Other Options? Please note the pictures are before unexpected shrinking. thank you.

View higher quality, full size image (2016 X 1512)

View higher quality, full size image (2016 X 1512)

Your lumber is air dried apparently. This means it has not been dried enough, and it has not been 'set' to where it does not move as much as air dried. Kiln drying does not stop movement, but it reduces it from air dried.

It is not heat or the type of heat in the house, it is the wood trying to dry out. This will not stop, despite what you do with the apron.

Thank you for the prompt response and the kiln vs. air dry. I realize that the physical temperature does not affect the wood as much as the relative humidity in the house. My experience is gas heat will tend to dry the air out more that a heat pump which is common where I live.

I have to shorten the skirt/apron to get the table to close. Any other suggestions for correction of the problem? thanks

The answer to your question is yes, expect the top to expand in the summer as the relative humidity rises. It will not expand to it's original dimension though.
The skirt can be mounted with fixed screw locations at the top joints and slotted screw holes towards the ends (you now know how much movement to allow for)
You will have to live with the gaps from the skirt on the leaves after trimming back to the winter extents of the shrinkage.
On the good side, the top didn't split from being restricted by the screws.

Many tables are purposely built with the skirts too short to start with leaving a gap of about 1/4" between skirts. A trim piece is added to the end of the skirt face to hide the gap and allow for wood movement. The trim needs to be wide enough to attach to one skirt, hide the gap in winter, and overlap the skirt beside it. The trim is usually about 1/4" thick. The covered gap acts as a slip joint to accommodate seasonal wood movement.

Wood only (normally) shrinks across the grain and not lengthwise. So the shirts will shrink is width and thickness, but only a small amount that will be hard to measure.

If the shrinkage was slow, then it will come close to recovering in the more humid summertime a/c conditions. It may not totally recover, but close. The reason for less than 100% is due to the hysteresis effect. It causes a different final MC when going from drier to wetter than from wetter to drier.

Of course it's going to expand in the spring, that's what wood does. Shrinks in low humidity and swells in higher humidity. The top and skirt ends can stay together if you hard fasten it by the ends of the skirt, and then allow the rest of the top to float and slide over the other end of the skirt. FLOAT is the key word. Fasten it hard and both ends and you get a couple more pieces in the top when it splits the next time it shrinks. Do some research about the material. Wood movement has been a know issue for centuries. Probably when the first slab doors fitted too tight when built, wouldn't open in the spring, and they could see light through the cracks in winter.

Knowing that wood moves, I find it helpful to plan ahead. If the top to apron connection was through tight fitting screws where the apron /top come together in the middle, but elongated or other fastening methods which allows the expansion and contraction to transfer to the overhanging ends wouldn’t show.
But then I can’t tell how those angular struts are fastened.

One issue with a table with the grain running as shown is that the leafs will not fit as tightly, but will have a small gap at the ends or in the middle.

MOST of that UGLY movement CAN be adjusted for in the designing for movement...RULE # 101 WOOD MOVES...Learn the directions and design for it.....IF you'll anchor solid to skirt at the split open section only and design for float/slide towards the ends towards legs around the skirt then when top shrinks and expands it will do it at end of table and not at the sliders not interfering with that joint as those are large panels. The leafs need to be anchored tight in the center of them and float both edges with skirt even or a touch short in my opinion at the time as you IF it loses moisture it will shrink approx 1/8-3/16" and I'd personally rather my top meet than my skirt so the crack will always be hidden below view. JUST my wood experience opinion.

IF a person learned the art of building with green uncured wood (this is a knowledged filled area MOST don't learn or understand which involves movement and designing for it, BUT 98% of "craftsmen" NEVER learn it....) their dry wood building would NEVER have any flaws as they would KNOW what the wood IS going to DO and already preplanned for it. Wood lives forever and is a living, breathing, moving product....IT'S ALIVE !!!!!

Check out my website www.tsmfarms.com ...it hasn't been updated for a while as my construction business has been GREAT!!!! You'll see I'm VERY familiar with wood and it's movements. EVEN old true timberframers knew wood movement and most designed for it to last centuries.

Tennessee Tim gives excellent advice. Ring from TN myself, I know that most of us in TN are way above average.

One trick to consider, if the look does not bother you, is to make a slight grove in the top when the leaves join. This channel will make any gaps less obtrusive and obvious.

Isn’t that what I said first? Thanks for agreeing!
Arkansas

LOL!!! Kieth and a few others, I'm truly SORRY!!! I OWE ya'll an apology, I typed a answer without reading the responses first (actually this evening) (that's what happens reading web late at night after a long day).

My answer should've been:.... there's been good offered and I agree with those on being tight at main leaf edge and skirt ( closed table center) and float out towards the ends. I had NO intention of overriding of any correct info.

SO I'll "second" the ones above!!!