wood mosture in LVL material

General Inspection Topics General Inspection Discussion
1

I did an inspection on a large new house that had major vented crawlspace moisture problems. The floor system has regular lumber and engineered lumber. The readings varied greatly but some areas had up to 28 percent. The builder had some fans installed to dry it out some and then had a sealed crawlspace installed. I went back for a reinspection and found a very humid sealed crawlspace with the supply air duct not yet installed. The regular wood had dried to 15-17 percent but the lower flanges/chords on the I-joists that have LVL type material were 20-26 percent still.

The builder disputed this and said LVL material will read higher moisture.
The builder hired an engineer that checked the whole installation but refused to check or report the LVL moisture levels because “his meter was not accurate for that”.

I check these materials all the time and have no problem, in fact, I find the LVL to be a drier product to start with but once it gets damp it takes longer to dry out than regular wood.

This crawlspace simply needs a dehumidifier for at least the time it takes to get all the wood below 20 percent. The builder does not want to install one since code does not require it.

Anyone ever see any pin type moisture meters that can’t check LVL material?

2

There is actually a formula that should be used on any engineered lumber, I read about it years ago in an IAQ maganize, but nobody I know really uses it, but your reading would not vary not more than two percent from that formula. I feel nobody needs to get that technical. In your situation, it is damp enough and mold growth can occur at that high of a moisture content. Lumber such as that have air gaps which can fill with moisture and makes them hard to dry out. I even heard that some molds love eating the glue but I never could find a study on that.
All wood need to be dried out to 12% + or - 4% . If you know a water restorer in your area that is IICRC S500 certified, you can have him or her write you a letter on the correct moisture contact. It is best since you are not certified in water restoration not to comment on moisture percentages. I myself use a GE Protometer that has the green, yellow, and red scale for I do not have to note exact percentages. My Industrial Hygienist taught me that, because he says if you ever go to court one of the first things the other side is going to try to prove is the inaccuracy of your meter.
If you have any more questions, please fell free to ask.

3

The reason I think two percent of wood moisture variation is close enough is; if one day you take a moisture reading on a piece of lumber and the air is dry then come back next week after steady rains, the moisture content will rise at least that much. But it all depends on your climate, states like Arizona are basically dry all the time so I would never except to see more than a one percent variance. That is if taking in the same exact spot. A piece of wood itself can naturally be more than a four percent moisture difference in different areas.
What I mainly do is compare the moisture content of one material in one area to the same material in an area that I know is dry.

4

Sounds like you made the right call. You’ve given your client the info they need. Now it’s between your client and the builder. I wouldn’t get involved with a running dispute with a builder/homeowner without compensation for consultation costs.

5

http://eng.ecohome.by/articles/laminated-veneer-lumber-lvl/

Advantages of LVL:

Portable: The set for a future wooden house is delivered to the building site.

Rapid: Technologies used for LVL allow shortening of assembling time; the assemblage may take only 3-4, provided the foundation is ready.

Moreover, LVL does not need a lot of time for shrinkage; therefore less time is spent on getting a turnkey house.

Affordable: There is no need for exterior or interior finish of the house made of LVL, which makes the project less expensive.

Quality: The heat loss of a wooden house with 200mm wall thickness equals the heat loss of a red-brick house with 1000mm wall thickness.

Weather-proof: Material for LVL is processed with special equipment which makes LVL deformation-resistant. Seasoned wood, processed in the right way, preserves its qualities after repeated cycles of freezing and thawing.

Comfy: Wood is hydroscopic so that wood will adjust to the relative humidity if the environment, either absorbing water vapor from the atmosphere or evaporating moisture into it. The walls of the house are amber-colored which creates an atmosphere of comfort and warmth.

Fail-safe: Due to the low weight and firmness of constructed houses they show resistance to earthquakes and other natural calamities.

Durable: The wooden houses created by our experts with the use of high-quality materials can be used by your family at least for 100 years. If necessary you can substitute not only upper, middle or lower parts of the walls, but also the foundation itself.

Environmental-friendly: Wood is a natural material. The wooden house has higher heat insulation value than conventional construction; moreover it is energy-efficient since you need less energy to rise the temperature in the house.

LVL production techniques:

• First of all the logs are bucked in order to relieve the stress, then they are tested for defects.

• Then the material for LVL is dried in special drying cabinets until the moisture content reaches 8–12%. The low moisture content is the reason of the minimal shrinkage of the houses made of LVL. Before processing, bold timber is tested for moisture content. The timber, which does not satisfy set standards, is not used further on.

• Bad twigs are removed. The sorter marks good and bad parts of the timber. Then the bad parts are removed and the good parts are joined by shoulder tenons.

• The adhesive is applied on the billets of LVL and they remain under pressure until cure. As a result the boards (so called lamellae) of up to 12m in length are produced.

• After that in the special hydraulic press the lamellae are glued together with the use of ecologically friendly adhesive of high European quality, this adhesive does not affect on the wooden property to “breath”. There are can be 2–5 lamellae in one beam; the maximum width is 240mm. The lamellae which have rings are applied to each other in reverse, which makes LVL beams very strong.

• Lamination, sawing of dap, is the major thing which affects the quality of assembly of the future house. LVL is cut into the units of the right size which are specified in accordance with the elements of the log-house, and then special holes for wire and dowels are made.

• Every LVL unit is tested and marked. The house is assembled within 1 or 2 months on the factory abiding by the highest standards of quality.