wood in contact with CMU wall

[dcredskins]

If the CMU wall is interior wall, and I have wood ledger board attached to it, does the latter have to be treated? However, I understand if the wall is exposed to ground, it can absorb moisture, and the ledger board needs to be treated. Is there any reference that talks about this?

 

[csd72]

The IBC calls this up. It specifies that timber in contact with concrete must be treated.

CMU would be even worse as it is more porous.

 

[MiketheEngineer]

Sorry - CSD is correct - must be treated if in contact with concrete...

 

[dcredskins]

I agree. However, the CMU wall I am talking about is interior. It is not exposed to outside atmosphere or ground whatsoever. The CMU wall is inside and wood ledger board is attached to the top of the wall. Hope this clarifies my concern.

 

[concretemasonry]

Most people make the same mistake about the wood/concrete connection. The rediculous extreme is an interior wall on a multi-story concrete structure that could concevable be required to use treated wood (and special fasteners) on a restroom in the 50th floor.

If you do some looking, you will find that it generally refers to wood that is attached to concrete that is in direct contact with soil (ground moisture).

There are some very simple and obvious soultions like a moisture break between the CMU wall and the foundation that is below grade. You could have even more serious concerns if it is a poured wall instead of CMUs.

 

[dcredskins]

concretemasonry,

So, you are saying, if we can make sure that the moisture does not get into the interior concrete walls or CMU walls or elevated concrete slabs, the wood that comes in contact does not have to be treated.

 

[youngstructural]

There are plenty of sources of moisture inside a building, including condensation and steam, but perhaps most obviously pipes...

There is good reason to treat any and all timber in contact with concrete, whether it is cast insitu or masonry type, and no matter the location. Remember how long your structure is meant to last...

Just my 2c,
Cheers,

YS

B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...

 

[DonPhillips]

IBC 2304.11.2.3 Exterior walls below grade. Wood framing members and furring strips attached directly to the interior of exterior masonry or concrete walls below grade shall be of approved naturally durable or preservative-treated wood.

IRC R319.1 Location required. In areas subject to decay damage as established by Table R301.2(1), the following locations shall require the use of an approved species and grade of lumber, pressure treated in accordance with AWPA C1, C2, C3, C4, C9, C15, C18, C22, C23, C24, C28, C31, C33, P1, P2 and P3, or decay-resistant heartwood of redwood, black locust, or cedars.
1. Wood joists or the bottom of a wood structural floor when closer than 18 inches (457 mm) or wood girders when closer than 12 inches (305 mm) to the exposed ground in crawl spaces or unexcavated area located within the periphery of the building foundation.
2. All wood framing members that rest on concrete or masonry exterior foundation walls and are less than 8 inches (203 mm) from the exposed ground.
3. Sills and sleepers on a concrete or masonry slab that is in direct contact with the ground unless separated from such slab by an impervious moisture barrier.
4. The ends of wood girders entering exterior masonry or concrete walls having clearances of less than 0.5 inch (12.7 mm) on tops, sides and ends.
5. Wood siding, sheathing and wall framing on the exterior of a building having a clearance of less than 6 inches (152 mm) from the ground.
6. Wood structural members supporting moisture-permeable floors or roofs that are exposed to the weather, such as concrete or masonry slabs, unless separated from such floors or roofs by an impervious moisture barrier.
7. Wood furring strips or other wood framing members attached directly to the interior of exterior masonry walls or concrete walls below grade except where an approved vapor retarder is applied between the wall and the furring strips or framing members.



Don Phillips

http://worthingtonengineering.com

 

[apsix]

"There is good reason to treat any and all timber in contact with concrete"
The extension of that argument is that all interior timber should be treated; sorry, I don't agree.