Problems with wood expansion during winter

[Paul Macias]

Hi All,

I've run into a new problem this wet winter in Northern California. In October, I milled/cut legs and rails for my daughter's loft bed and completed those mortise and tenon joints. Then I got busy and had to set it aside. In December, I took down those parts with the intention of picking up where I left off, and due to expansion from moisture (lots and lots of rain already) the joints wouldn't fit. So, obvious there: wait till late Spring on the loft bed.

However, in the meantime I have cleaned and milled some old doug fir (that I actually ripped out of the front porch when we bought our property), and I've cut to dimension parts to build my daughter a desk (trying to make-up for the delayed loft bed :)). But here's my question: Should I cut joinery and glue up right now, given my experience with the bed parts? In other words, if you have contraction after glue up, would this compromise the joint?

I haven't run into this before. Do any of you have this dilemma? Due to moisture/rain-based expansion, do any of you have to avoid certain stages of woodworking in the winter?

My shop is two-car garage, but it's porous. Would buttoning up the structure actually change the humidity in the shop?

Thanks

[David Bassett]

... My shop is two-car garage, but it's porous. Would buttoning up the structure actually change the humidity in the shop?

I don't think you can close it up if it is a garage. (By code.) You are required to have a certain amount of ventilation for car fumes, especially if attached to a house, and other things, e.g. water heater or furnace pilots. I'm not sure what the specific requirements, or how you might make it "not a garage". Check your local codes or with an inspector before you make big plans.

PS- I'm replying to only this part of your post. I'm actually looking forward to responses to the wood movement and joint strength.

[Chris Padilla]

Hi Paul,

As long as the wood is acclimated to your shop/climate and has reached the generally accepted 6-10ish % moisture content, you should be fine to build whenever. It is possible your wood wasn't acclimated properly or that perhaps you are using different wood or different orientations of the wood. For example, quarter-sawn won't move as much as plain-sawn in the same wood species. Also, your nicely orthogonal and square M&T joints might not be so after expanding and contracting on their own for a couple months.

Had you not gotten side-tracked after cutting the M&T and put them together right away, odds are decent you would have been fine.

Also, wet winters are the norm for us here in Northern California despite what has happened the last couple of (dry) winters. I've lived here for 17 years and haven't had any issues using my typical hardwoods of maple and walnut but then again I don't leave such joinery unconnected for long periods of time because they never seem to fit if left unattended.

It is like planing wood and exposing a fresh surface. Some folks say to use it right away and other say to let it rest and adjust in case it goes out of flat in which case you'll need to plane it again. I say if your MC is correct and the wood has been dried properly (no case-hardening), it should be fine when cut. But wood is a fickle medium and things go awry all the time with this natural building material!

[David Gutierrez]

Not true there is no code requirement for ventilation in a garage because you should not be running the car inside a closed garage.

[peter gagliardi]

The simple answer is that joinery should be glued within 24 hours of being cut, regardless of the weather.