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Solid wood beam with significant crack split or checknig (C) Daniel Friedman Evaluating Cracks & Splits in Wood Beams or Posts
Cause, Effect, & Dealing with Checking or Splits in Wood Beams or in Solid or Milled Log Home Walls

  • CRACKS CHECKS SPLITS in BEAMS, LOGS & POSTS - CONTENTS: How to evaluate cracks or splits in wood posts, beams, or logs such as in a log home. Guide to Diagnosing & Repairing Leaks & Other Problems on Modern Kit Log Homes. Guide to Identifying, Diagnosing & Repairing Older & Antique Log Homes. Log caulk, spline, gasket, and coating product guide for log houses. Log checking, cracking, shrinkage, & Leaks in log houses and log siding. Window & Door Installation Details for Log Homes can prevent later leaks & Damage
  • POST a QUESTION or READ FAQs about splits or cracks in wood beams or in log home log walls
  • REFERENCES
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This article defines, illustrates, and explains the cause and significance of splits or "checking" in wooden posts, wood beams, or in logs and beams used in log home structures.

Checking or splits in wooden posts, beams, or in solid logs used to construct both antique and modern log houses worry homeowners even though usually they do not present a structural problem. But checks in structural wood beams as well as checks and splits in logs used to construct log homes can result in water or air leaks into the building.

Our page top photo shows the author's precision probing device exploring checking (also called splitting or cracking) of a structural wood beam in a pre-1900 home that had been moved to a new concrete block foundation. As solid wood beams and logs cure, shrinkage produces not only checking (large cracks that are normal and are not necessarily a problem) but also an actual reduction in log or beam diameter.



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Evaluating Splits & Cracks in Wooden Beams, Posts, or Logs

Extreme bend in a wooden post at a basement stair (C) Daniel Friedman

[Click to enlarge any image] Above: a bending, cracking, and failing wood post by the stairwell of a pre-1900 home in New York.

This article describes splits that are found in horizontal wooden beams (photo above), vertical wood posts, and in logs used in log homes. While extreme loading can cause a wood beam (or more rarely a post) to split and would indicate a sign of impending disastrous collapse, usually the splits or cracks found in wooden posts and beams are due to shrinkage as wood dries, occur along the grain, and do not raise a structural concern. An example is seen in the checked beams of our ceiling beam photo above and another example shows up in the cracks or splits in the logs of a log home discussed below.

Article Contents

Splits & Cracks, Sags & Failures in Wooden Beams

Splits in a ceiling beam (C) Daniel Friedman

While extreme loading can cause a wood beam to split and would indicate a sign of impending disastrous collapse, usually the splits or cracks found in wooden posts and beams are due to shrinkage as wood dries, occur along the grain, and do not raise a structural concern. An example is seen in the checked beams of our ceiling beam photo above and another example shows up in the cracks or splits in the logs of a log home discussed below.

When a wooden beam is failing from rot, insect damage, or excessive loading, it may also split but you'll see that the split is very different, showing visible breakage of wood fibers and sagging in the span of the beam.

Sagging wood beam in an old barn (C) Daniel Friedman

Above: there is a bit of sag and some checking in the wood beam above the yellow arrow in our photo. A closer look will be needed to see if this beam is actually failing. In wood-framed structures, leaks, rot, and insect damage play important roles in the failure of wooden structural members. In older structures such as the post and beam framed buildings shown above and below, failures at connections can lead to structural collapse even if the rest of the wood framing member is intact.

Wood beam failure (C) Daniel Friedman

Above: this wooden beam is failing and collapsing from insect damage and possibly rot.

An Owner-Builder's Guide to Shrinkage In Log Home Walls

Log splits or checks in a log home

[Click to enlarge any image]

Log homes will shrink considerably in wall height as the logs dry during the first one or two years after construction. This is so even in factory cut "dry" logs which may have absorbed moisture in transit or on site, and it is even more true if the logs used in construction were "air dried" or were used while still "green".

The more moisture that was present in logs at the time of construction of a log home, the greater the amount of shrinkage that will occur in overall wall height, and the larger and more extensive will be the checking cracks that occur in log walls.

Usually the crack in the wood beam or solid log radiates from the outer surface of the log towards the log center; it is not common for a log or beam split or crack (or checking) caused by the drying process to pass beyond the center of a log or beam. However more severe splits and cracks can occur in a wood structural member, even passing through its full diameter, due to structural loading or damage.

This series of articles provides information on the inspection and diagnosis of damage to new and older log homes and includes description of log house and log siding insulation values and alternatives, and also a description of the characteristics of slab-sided log homes as well as all other types of log home construction. We include illustrations of log structures from several very different areas and climates in both the United States and Norway. Our page top photo shows a modern kit log home constructed in New York State.

Log Checking or Splitting - Are Log or Beam Splits A Structural Concern on a Milled Log House?

Log checking, long horizontal splits in the log surfaces, will appear on both inside and outside surfaces of log walls and may vary considerably in width (hairline to 1/2") and length (a few inches to several feet). (Photo courtesy Arlene Puentes.)

Checks in logs (or other large timbers) are rarely a structural concern, but they may become a leak or rot problem.

Checks are only a cosmetic concern unless they are taking in water and therefore risking leaks into the building interior or causing rot or inviting insect damage, as we discuss below

What Other Problems Might Be Caused by Checking and Splits in Log Walls

Checks and splits in the upper radius of log walls on the wall exterior are of more concern than checks and splits in the lower half of these walls.

Checks in logs leak into the building (C) Daniel Friedman

Checks even in the lower radius of log walls - that is just below the center or outward-most face of the curved log face may also be a problem if they occur in a position and shape to send water running down the log wall into the log interior.

Checks in logs leak into the building (C) Daniel Friedman

Rain or melting snow sending water into these checks can cause these problems:

So as our photo (above left) shows, even a structurally harmless shrinkage crack or check in a log wall can lead to an interior leak if the window was not properly constructed. This particular log check reached to the center of the log and bypassed the caulk that the builder had placed around the window frame on the log wall exterior.

Checks in the lower radius of the curved outer face of a log wall and checks in weather-protected location are unlikely to cause damage and are only cosmetic.

Tips for Avoiding Leaks at Splits & Checks in Log House Walls

Evaluating Splits or Cracks in Posts

As long as they can be characterized as typical wood-post or wood-beam checking, those splits found in vertical posts are not a structural concern. Placed vertically the post is in compression. Checking cracks in a post such as the 6x6" pressure treated deck post shown here are not going to be flagged as a concern by your building inspector, deck builder, nor other experienced field investigators.

Watch out: While checking-cracks in a vertical post are harmless, as we illustrate just below, overloading, rot, insect damage, or side-loading can indeed cause failure of a wooden post and risks catastrophic building collapse.

Collapsing wood posts in an old NY Barn (C) Daniel Friedman Taurozzi

In this photo we have a set of old locust wood posts that are bending and breaking as the whole building is collapsing. The root problem in this wood structure collapse-in-process is the inwards collapse of the concrete foundation wall.

Reader Question: how dangerous are these cracks in the posts supporting our deck?

Checking cracks in a deck post (C) InspectApedia Hector

2016/05/11

I sent picture of my balcony [above and below], and I would like your opinion about the post in the picture it is 5.5”x5.5”. It has a crack 1/8”,I don’t know how many year has been there .The dimension of balcony are 10’x10’ x10’ high - Anon by private email

Reply:

Tall deck of unknown safety (C) InspectApedia.com

With the WARNING that nobody can conduct a proper safety inspection by email, and that other defects such as improper fasteners or improper construction can certainly cause a fatal deck collapse,

The crack in your photo in the center of a 6x6 pressure treated post is common, it's called "checking", and it has no structural significance at all. Search InspectApedia.com for "checking in wood beams" to read details and to see more examples. Thanks for the photos - those may help other readers as posted here - keeping you anonymous of course unless you want to be identified as a technical contributor.

Watch out: Stay safe, don't fall off that ladder, and be sure that your deck was properly built with proper structural connections at all points, particularly to the building and between deck and posts; it should have had a building permit and a CO inspection.

Common causes of deck collapse include

Those are not details one can see in your photos. Less often (I think) decks collapse due to rot that in turn may be aggravated by improper construction or improper flashing.

Also be sure that the deck guardrails are safe, secure, well fastened, and at proper height and spacing. See GUARDRAIL CONSTRUCTION, STAIRS.

See DECK COLLAPSE Case Study for a detailed example of what can go wrong that causes a dangerous deck collapse.

Also see DECK FLASHING LEAKS, ROT Case Study

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Continue reading at ENERGY EFFICIENCY of LOG HOMES or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see DECK COLLAPSE Case Study

Or see DECK POST CONSTRUCTION

Or see FRAMING DAMAGE, INSPECTION, REPAIR - home - for advice on looking for damaged, unsafe wood structure framing

Or see LOG HOME GUIDE

Or see ROT, TIMBER FRAME for a discussion of the cause and prevention of log checking during log or timber dry out, and for a case study of rot in timber frame construction.

Or see ROT, TIMBER ASSESSMENT

Or see SHRINKAGE & HEIGHT CHANGES, LOG WALL

Or see WOOD STRUCTURE ASSESSMENT - home

Suggested citation for this web page

CRACKS CHECKS SPLITS in BEAMS, LOGS & POSTS at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

INDEX to RELATED ARTICLES: ARTICLE INDEX to BUILDING STRUCTURES

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