Despite my best efforts to prevent them (end sealers, controlled humidity, etc) I know that checks in timbers *WILL* happen.

Fom a structural standpoint it's not the end of the world when it happens and if I stand back and look at the some of the patterns of the checking, there's a certain beauty in it. However, my preference would be to have little or no checking.

So, when checking *DOES* happen is there anything I can to live with it?

Should I spray a Timbor/Borax solution in there to keep insects from nesting?

As part of the finish, should I fill it in with a wax based compound?

To control the checking, should I cut a kerf into the face of the timber that doesn't show? (Similar to what's done with a slab of concrete)

If I see that my timbers are drying out too fast, is there any value in spraying the timbers with water to reverse/minimize the checking? (of course being careful to make sure that I'm not encouraging mold growth)

Other things I can do?

Thanks in advance,

-srj

Hi nvh-srjones,

Get used to it... ?

Yes, this is abviuosly good idea.

I do not see much sence in filling cracks since they will continue spreading part. I've seen it before and it just does not look right.

It is definitely good practise if

• the timber has hidden face
  
• your engineer takes it in consideration

Even it might help, I suggest a covered storage where you can control and continuously reduce humidity.
Michal

Some species tend to check much more than others; I have seen Hickory split almost, and entirely, in half, I've also had difficulties with excessive checking in boxed heart Ash, and tend, now, to avoid using either in any structure which will be closed, and, heated.

Other than this, checking occurs. It is a natural function of wood, the releasing of tensions. It is true that the Japanese method of kerfing a stick does help to channel the checking, I saw this first hand on a one month trip to Japan a few years ago. There were also a number of examples where the checks were filled with strips of wood, What comes to mind are two, enormous, Rounded posts which stand at one of the entrances to the Meiji temple in Tokyo.

Ponding also lessens some of the stresses created by drying, and reduces checking. As does a consideration for when the trees were felled, even, How they were felled.

How far you wish to go to eliminate checks is certainly up to you. Traditional crafts, from all heavy timber cultures, have dealt with, and surpassed this issue. In the granduer of those structures left behind for us, checking is not likely to be one of the first features to be seen, or to be commented upon.

Kerfing a timber to draw the checking to that side is interesting. Does anyone have any thoughts on either the depth of the kerf required to be useful? Perhaps more than one kerf? Any engineers out there care to comment on this practice? I wonder if a few 3" deep saw cuts on the outside of an 8x12 would hinder it's ability to take a load.

A single kerf, not more than 1/3 the timber depth, in the center of the timber face, would be my suggestion. It should be ok to use the same kerfing on the top surface of beams, if they are going to be covered by flooring.

If the member is kerfed it should also be wedged (in the kerf)during the initial drying process. The wedges should be snug and adjusted periodicaly.

Hi John,

Why would you do so? I remember doing this to split the beam completely.

Michal

Thank you everyone for your replies. I didn't think the kerfing question would go anywhere, but there's certainly some wonderful comments here.

A little more info about my project. I'm using DougFir boxed heart. Cut in Winter/Spring 2003, milled fall 2003, planed Winter 2004 and sat covered and stickered until Fall 2004. Very little checking so far, compared to the checking I've seen in hardwoods, I should consider myself pretty fortunate.

Timberbe, said something interesting:

"Ponding also lessens some of the stresses created by drying, and reduces checking. As does a consideration for when the trees were felled, even, How they were felled."

Ponding is out of the question for me, but I'd like to know more on your thoughts of When and How the trees were felled.

I read in Steve Chappell's book, A Timber Framer's Workshop,

"Ideally, tress should be fell in the winter months, when the sap is down. According to timber folklore, the best time is during the full moon in February" (p. 147)

I'm not sure if this would apply to Douglas Fir, but just for fun I cut a load timbers this year....during a full moon...in February. We'll see how it goes.

Regarding the "How" trees are felled, could you elaborate a little bit here too?

I've been careful not to drop the trees directly onto anything in it's path because I know the tops (or middle) will snap. However, I suspect that stress fractures may develop when a tree hits the ground.

The traditional Japanese technique of placing a kerf or sewari works most effectively in a boxed heart timber or a round. In either case, the kerf extends all the way to heart center. Wedges are placed at 18" intervals and periodically tapped further down to keep a snug fit. By using this method not only will checking be virtually eliminated but the timber will be dry significantly faster. Almost 2X good luck