Plywood Panel Backer Board

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infinity

infinity

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When installing a piece of wood for a panel below grade, how many guys use pressure treated wood in contact with a block or concrete wall? Recently we starting using pressure treated plywood strips behind the 3/4" plywood boards since a building inspector said that the strips (insect resistant, i.e. -termites) were required where the wood contacts the block wall. Anyone else hear of this?
 
First this is an electrical issue not a building issue.

Ask him if he knew that a wood structural panel itself meets the 'nominal' definition of a vapor retarder.

What code did he cite? None!!!

Crap crap crap. Unless the wall are DAMP all the time. I mean DAMP.
 
SECTION 320 PROTECTION AGAINST TERMITES

320.1 Subterranean termite control.

In areas favorable to termite damage as established by Table 301.2(1), methods of protection shall be by chemical soil treatment, pressure preservatively treated wood in accordance with the AWPA standards listed in Section 319.1, naturally termite-resistant wood or physical barriers (such as metal or plastic termite shields), or any combination of these methods.

SECTION 319 PROTECTION AGAINST DECAY

319.1 Location required.
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.
 
jxofaltrds said:
SECTION 320 PROTECTION AGAINST TERMITES

320.1 Subterranean termite control.

In areas favorable to termite damage as established by Table 301.2(1), methods of protection shall be by chemical soil treatment, pressure preservatively treated wood in accordance with the AWPA standards listed in Section 319.1, naturally termite-resistant wood or physical barriers (such as metal or plastic termite shields), or any combination of these methods.

SECTION 319 PROTECTION AGAINST DECAY

319.1 Location required.
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.
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Sounds like it's required according to the information that you've provided.
 
infinity said:
Sounds like it's required according to the information that you've provided.
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Yes. Sounds. Look at my first post. "wood structural panel itself meets the 'nominal' definition of a vapor retarder."

The code also says that you can put vinyl siding over OSB. But if you read the fine print in the chart takes you to an ASTM standard the prohibits that.

But we are not talking about framing, walls, studs, joists, we are talking about a panel 'board'. That is outside the building inspectors jurisdiction. IMHO.
 
480sparky said:
Most building codes require lumber in direct contact with concrete floors/CMUs to be treated.
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If that lumber is part of the structure of the building.

The plywood back panel is not part of the structure and as Mike notes is outside the BIs authority.


I would use PT cause I am just that good. :grin:
 
It the wood panel and the strips are installed in a damp location (which by description of the OP it is), the panel is securing/supporting the panel, then it becomes part of the structure. The building official has every right as a CEO to require the wood to meet the requirements.

I have a number of photos where the wood supporting electrical equipment located in the basement on an exterior wall, is decayed and the wiring method is holding the equipment up.
 
jxofaltrds said:
First this is an electrical issue not a building issue.

Ask him if he knew that a wood structural panel itself meets the 'nominal' definition of a vapor retarder.

What code did he cite? None!!!

Crap crap crap. Unless the wall are DAMP all the time. I mean DAMP.
Click to expand...

If that is the case then serious consideration should be taken about the use of dry location only wiring methods and enclosures also.
 
Pierre C Belarge said:
It the wood panel and the strips are installed in a damp location (which by description of the OP it is), the panel is securing/supporting the panel, then it becomes part of the structure.
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I STRONGLY disagree with that ... did I mention strongly? :grin:

The building official has every right as a CEO to require the wood to meet the requirements.
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Nope.

I have a number of photos where the wood supporting electrical equipment located in the basement on an exterior wall, is decayed and the wiring method is holding the equipment up.
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I have no doubt of that at all, but good intentions are not code.
 
Pierre C Belarge said:
It the wood panel and the strips are installed in a damp location (which by description of the OP it is), the panel is securing/supporting the panel, then it becomes part of the structure. The building official has every right as a CEO to require the wood to meet the requirements.

I have a number of photos where the wood supporting electrical equipment located in the basement on an exterior wall, is decayed and the wiring method is holding the equipment up.
Click to expand...

If that is the case every staple, conduit clamp, clip, etc. supporting a wiring method is also part of the structure. The wood panel is for supporting electrical equipment and does not otherwise provide any structural purpose. If anything 110.3 may be the rule here, but it kind of leaves the decision to the installer and ahj as to whether or not it is suitable. Does the plywood (treated and non treated) have a listing? How about fasteners used to support the plywood?
 
infinity said:
When installing a piece of wood for a panel below grade, how many guys use pressure treated wood in contact with a block or concrete wall? Recently we starting using pressure treated plywood strips behind the 3/4" plywood boards since a building inspector said that the strips (insect resistant, i.e. -termites) were required where the wood contacts the block wall. Anyone else hear of this?
Click to expand...

I just pulled down the 2000 CABO One and Two Family dwelling Code.( not sure where the newer code book is right now ). But it is addressed in the building code.

The electrical inspector probably couldn't write up a violation but the building inspector could so in the end a violation is a violation.

Is it really that big of deal???

The reason for useing pressure treated strips behind the non-treated plywood is that the new pressure treated lumber is very corrosive.

This is just my opinion but I don't think that everything that an electrician needs to know can be found in the NEC. I "think" that it's important to be familiar with any codes and building practices that you may come in contact with. This would include all local building codes and common practices.

But I do admit that much of this has nothing to do with the NEC.
 
kwired said:
If that is the case every staple, conduit clamp, clip, etc. supporting a wiring method is also part of the structure. The wood panel is for supporting electrical equipment and does not otherwise provide any structural purpose. If anything 110.3 may be the rule here, but it kind of leaves the decision to the installer and ahj as to whether or not it is suitable. Does the plywood (treated and non treated) have a listing? How about fasteners used to support the plywood?
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That is how I see it as well.

If I screw a picture frame to the wall is that now 'part of the structure'?

If that panel backboard was covered buy the building code it would also specify the size, the strength and types of wood allowed along with how it would have to be fastened.
 
growler said:
I just pulled down the 2000 CABO One and Two Family dwelling Code.( not sure where the newer code book is right now ). But it is addressed in the building code.

The electrical inspector probably couldn't write up a violation but the building inspector could so in the end a violation is a violation.

Is it really that big of deal???

The reason for useing pressure treated strips behind the non-treated plywood is that the new pressure treated lumber is very corrosive.

This is just my opinion but I don't think that everything that an electrician needs to know can be found in the NEC. I "think" that it's important to be familiar with any codes and building practices that you may come in contact with. This would include all local building codes and common practices.

But I do admit that much of this has nothing to do with the NEC.
Click to expand...

So lets say hypothetically you do a service upgrade and you use a wood product that does not comply with the building code should that service pass inspection anyway?
 
I really don?t see what the problem is, it?s not an NEC code thing it is a Building Code issue.

We are generally not at liberty to install into other possible BC violations.

By BC around here one cannot put simple non treated wood down on concrete at floor level (street level) or on sub basement floors; I don?t think it?s a stretch to say that also includes under grade walls.
 
kwired said:
If that is the case every staple, conduit clamp, clip, etc. supporting a wiring method is also part of the structure. The wood panel is for supporting electrical equipment and does not otherwise provide any structural purpose. If anything 110.3 may be the rule here, but it kind of leaves the decision to the installer and ahj as to whether or not it is suitable. Does the plywood (treated and non treated) have a listing? How about fasteners used to support the plywood?
Click to expand...

iwire said:
That is how I see it as well.

If I screw a picture frame to the wall is that now 'part of the structure'?

If that panel backboard was covered buy the building code it would also specify the size, the strength and types of wood allowed along with how it would have to be fastened.
Click to expand...



Not really, the wood is what the screws and straps, etc... are FASTENED to.
In other words, the screws, etc... are the fasteners, the wood is what the screws, etc... are fastened to.

Rebuttal please ;):D
 
kwired said:
If that is the case every staple, conduit clamp, clip, etc. supporting a wiring method is also part of the structure. The wood panel is for supporting electrical equipment and does not otherwise provide any structural purpose. If anything 110.3 may be the rule here, but it kind of leaves the decision to the installer and ahj as to whether or not it is suitable. Does the plywood (treated and non treated) have a listing? How about fasteners used to support the plywood?
Click to expand...

YES they do. There is a listing and an installation requirement for just about every building material out there. You are not going to find it in the NEC because the NEC is only concerned with the materials that are directly related to electrical. This does not mean you can ignore the building codes or the requirements of the other materials. I would bet any one here who thinks other wise doesn't have a copy of the building code or any of the other standards that are referenced in it.
As to the comment on the "fasteners" there is a standard for those too.
 
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