Screw-jacks

Why They’re Required

Screw-jacks allow settling to occur in a synchronized manner. Log homes are built using vertically placed posts, horizontal beams, and horizontally placed wall logs. Without screw-jacks, this difference in orientation would leave gaps because settling will occur in some places and not others. To illustrate: in one scenario, the end of a horizontal beam connects to the top of a non-settling vertical log post and the other to the top of a settling log wall. Without a screw-jack, one end will settle with the wall logs and the other will not, resulting in a gap between the beam and the ceiling. Placing a screw-jack under the vertical post will allow it to be lowered so the top meets the same level as the log wall, thereby preventing the gap above the connecting beam.

Parts of a Screw-Jack

Making Adjustments

Use a wrench to adjust the 2” nut. The nut may feel snug and require effort to loosen but you will soon feel and hear the post and beam settle. Re-tighten the nut so there is at least some tension on the screw-jack. Keep track of how many turns on the wrench you made as you will need to repeat for each screw-jack in the home. Ensure each screw-jack is lessened by the same amount, as all log walls settle evenly.

Where Are They Required?

Screw-jacks are required on any level with scribe-fit log walls (most often the main floor). Some homes also have horizontally stacked scribe-fit logs on the upper level (for example: gables, pony walls). In this case, screw-jacks will be required there as well. Screw-jacks are also installed when posts on the main level extend to the roof. Lastly, some designs require screw-jacks on top of main floor framed walls.

How Often Should Adjustments Be Made?

The first adjustment should be made within 1 to 2 weeks after the log shell package has been assembled with a second adjustment after installation of the upper floor framing, roof framing, and roofing. Follow-up adjustments should then be made every 1 to 2 months for the first couple of years.