Design and Construction Problems

SETTLING-RELATED PROBLEMS

Many of the design and construction problems unique to log homes are related to settling of the log walls, most of which takes place in the first 2 to 3 years depending on wood species and climate. Tidewater red cypress, for instance, may take 5 years to dry. Accommodations must be made for settling in any home system or component which will not move with the wall as the wall settles.

FRAMED PARTITION WALLS

Two problems must be dealt with when interior partition walls are conventionally-framed

1. a space must be left at the top of bottom of the wall to allow for settling. This is usually accommodated for by installing extra wide trim which covers the gap and is designed to slide past the wall covering material.
2. Where partition walls butt log exterior walls, log walls are usually notched to accept the partition wall. Scribing and notching drywall around logs is an improper method of making this connection.

                                                                                                      Courtesy of Husky Logwork

In the photo at the left, an older manufactured log home had scribed and coped drywall. Beacause all settling was complete, this was not a defect, just poor workmanship. The photo on the right shows a common method of dealing with this condition.

WINDOWS and DOORS

The minimum amount of space which must be left above windows and doors to allow for settling will vary with the amount logs are expected to settle.

Handcrafted homes built using scribed green logs typically require 5 inches or more. Wall built using Kiln-dried logs may settle very little.

Manufactured log homes typically need less settling space and often have very little. If the home is newer and you see no allowance… call it out anyway and let the seller prove that it’s not necessary. If an inspector fails to comment on it and the home settles, the inspector may be liable. The

This photo shows trim designed to slip as logs settle.

SETTLING SPACES

The amount of settling experienced by log walls in a home can vary anywhere between 5 inches and 0.  Inspectors have no way of knowing how much settling space space is properly required in any particular home. At best, they can only describe what they see and do their best to educate their clients about the problems connected with settling in log walls.

Furtunately- since for most inspectors, most of their work consists of existing homes-  settling is mainly a problem with new homes. The newer the home, the greater the possibility for problems related to wall log settling.

The ICC 400-2007 Standards on the Design and Construction of Log Structures gives formulas for calculating settling which lie beyond the scope of any home inspection. Inspectors attempting to calculate settling in order to make a more accurate recommendation regarding settling space adequacy are increasing their liability.

Inspectors should not recommend a minimum dimension for the settling spaces above doors windows and partition walls in any particular home. They should simply state what they find, and educate their clients.

VERTICAL PIPES and CONDUIT

Plumbing waste pipes and conduit installed vertically should be installed with slip joints to allow for loss of wall height. Inspectors will often not be able to confirm that these measures have been taken and that information should be mentioned in the report.

Water supply piping can be routed between floors using soft copper tubing. A pipe is bent into a loop which expands as walls settle.

STAIRCASES

Staircases which bear upon a floor will have problems with treads and landings developing a slope as the upper floor moves closer to the lower floor during settling. Staircases in which stair components both rest on the floor and attach to the log wall may have an even more complicated situation to deal with.

Staircases which self-adjust as settling occurs are available for some situations. Others may require adjustment occasionally.

Inspectors should comment on out-of-level treads or landings, risers which vary more than the allowable 3/8 inch and conditions in which no problems are apparent in the staircase, but no allowance has been made for settling in a newer home.

CHIMNEYS

Chimneys at log walls may need to be constructed in a manner which leaves them free standing. Any connection to logs may cause damage as the walls settle. Inspectors will need to examine conditions at individual homes and comment as necessary.

CABINETS

Base cabinets typically rest on the floor, but the countertop backsplash may be a problem if it’s been installed to fit tightly against wall logs.

ROOF GABLED ENDS

Roof gabled ends in log homes are often conventionally-framed.

The problems with log-built gabled ends is that as they settle, the roof changes pitch. In thinking about the roof framing, you can ignore everything below the level of the top plate log, the top wall log on which the bottoms of roof framing rests.

If the peak of the roof is 8 ft. above the plates when the home is first constructed, imagine what will happen as the gabled ends begin to settle. In a home built from green logs, the gabled ends might lose 6 inches in height over the first 3 years. What would happen with the roof framing? If the gabled ends lose 6 inches in height but all other roof framing stays where it is, eventually something has to bend or break.

In homes with log gabled ends, inspectors should examine roof framing carefully where it connects to the gables.

Veneer siding is available to match common log profiles. Here are int. and ext. photos of the same gabled end.

POST ADJUSTMENT

Log home design often includes posts which support horizontal loads. If the other end of a horizontal framing member is supported by a wall which undergoes settling, screw jacks must be installed so that occasionally adjustments can be made at the post to keep framing level. Screw jacks are usually hidden behind trim and may be installed at either the top or bottom of a post. Common areas for this condition are porches, lofts and stairwell openings.

Inspectors seeing this condition can check for proper adjustment by measuring between the floor and horizontal member at the wall and at the post. Neglecting to make adjustments may cause damage or gaps in framing. Upon finding homes in which screw jacks have not been adjusted, check for damage where horizontal members bear on wall logs.

HAS it STOPPED SETTLING?

As mentioned in the settling section, settling will be complete when the wall logs have reached equilibrium moisture content (EMC) with the homesite.

 Inspectors should not try to determine whether logs in a home have finished drying/shrinking by using a pin moisture meter. While the surface of the log may have reached EMC, the interior of the log will dry much more slowly. Reading the moisture content on the surface will not reflect accurately the overall moisture content of a log or provide useful information about how near the walls are to completing the drying/settling process.

It's a good idea to ask if a written log has been kept of settling adjustments. Some log home manufacturers provide a settling log or recommend their customers keep one. Examining the settling (written) log may give an inspector a better idea of how far along the home is in the settling process. 

NARRATIVE LANGUAGE

Some log homes may have accomodations for settling which are not visible after home construction is complete. Inspectors should refrain from including narrative language in inspection reports stating that "No accomodation were installed...". Inspectors should word narratives to read "No accommodations were visible...".

INSTALLATION DEFECTS

Notice anything odd about the way logs were installed in the photo to the right? It's easier to see in person, and once you're aware that this can happen, you'll be watching for it when you inspect your next manufactured log home.

The wall logs were installed upside down with the groove facing up. Any water getting past chinking will be trapped between log courses, dry slowly and provide good conditions for decay to take place.

CORNER NOTCHES

Inspectors will see many types of corner notches. Because the same type of notch may have a different name in a different area, and because inspectors will see corner notches for which no name extists, inspectors are not required to idientify corner types.

Corner notches should be tight and should be self-draining.

LOG EXTENSIONS

• Overly long extensions are exposed to increased damage from  weather, sun and impacts.
• Extensions should not trap water between rounds.