# HELP: T&G planking vs plywood?



## frogger (May 7, 2007)

A tree recently fell on my house and nearly crashed completely through it. The sheathing for the roof was originally tongue-and-groove planking (it's a 1950's brick ranch with a typical sloping roof, in NC). The contractors want to replase this sheathing with plywood (1/2" CDX) because the tongue-and-groove planking is "expensive" and "hard to get". But I was assured that it is "just as good."

Is it really just as good?


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## Ed the Roofer (Jan 27, 2007)

Absolutely not.

Your T & G board decking is already 57 years old, and without a tree falling on it, it would still be in good shape not counting for any previous ongoing leaks or ventilation problems.

the plywood and especially osb board would have lost its life way before this.

Plus, the decking is nominal 1" thick and he would have to apply two layers of 1/2" cdx to achieve the same height.

It does not have to be T & G to be good. Have him use regular #2 pine, 1" x ?" whatever width boards are currently installed and cut away the tongue of the board that may interfere with a tight fit.

You do not want fresh boards to be installed too tightly though, so actually have a slight 1/8" gap on all sides of the boards.

Ed


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## AaronB (Jan 29, 2005)

NO! It is not nearly as good. 

Did your home need the T&G because of a long span?

What are the dimensions of the T&G? Is it a lambeam type of T&G or is it T&G plank?

If it is a plank, then your insurance agent should be required to replace it to match. Read your policy, and then let us know.


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## frogger (May 7, 2007)

thank you both for the great responses

I couldn't tell you exactly what kind of planks are up there now, but I'll find out in the morning. And yes, this is going through State Farm, of whom has been very good to me thus far. We'll see what he says in the morning (could only leave voicemails yesterday).

:thumbup:


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## frogger (May 7, 2007)

my policy does not give any details about construction or how construction should be done, it just says that it will cover whatever it takes to replace that which was damaged...

EDIT: scratch that, I've talked to my State Farm guy and he said that everything must be replaced with "like" and of the same quality and if the contractors cannot get a hold of "like" materials then they are to use an "exceptable substutitute" which the local building codes obviously recognize plywood as being.


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## Ed the Roofer (Jan 27, 2007)

Plywood is *NOT* an equal to 1" thick plank board decking. Plank boards *ARE *commonly available.

But, if you just want to roll over like a pussy cat, I won't stop you.

We both gave you the correct advise, and now it is up to you to put it to use.

Call up several lumberyards yourself just to see how easy or difficult it is to find 8 foot long or 10 foot long 1" x 6" #2 pine plank boards.

Ed


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## Ed the Roofer (Jan 27, 2007)

This is from the "Insurance Information Institute" which provides guidelines for all insurance companies to follow.



*HOMEOWNERS INSURANCE INFORMATION * 
 







*How is the settlement amount determined?*​







The settlement amount depends on which type of policy you have. Having inadequate insurance can affect the amount of compensation you get.

*Replacement Cost and Actual Cash Value*
Replacement cost provides you with the dollar amount needed to replace a damaged item with one of similar kind and quality without deducting for depreciation—the decrease in value due to age, obsolescence, wear and tear and other factors. An actual cash value policy pays you the amount needed to replace the item minus depreciation.

Suppose, for example, a tree fell through the roof onto your eight-year-old washing machine. If you had a replacement cost policy for the contents of your home, the insurance company would pay to replace the old machine with a new one. If you had an actual cash value policy, the company would pay only a percentage of the cost of a new washing machine because a machine that has been used for eight years would be worth less than its original cost.

Suppose, also, that the tree damaged your 15-year-old roof so badly that it had to be completely replaced. If you had a replacement cost policy, the insurance company would pay the full cost of installing a new roof. If you had an actual cash value policy, it would pay a smaller percentage of the cost of replacing it.

*Extended and Guaranteed Replacement Cost*
If your home is damaged beyond repair, a typical homeowners policy will pay to replace it up to the limits of the policy. When the value of your insurance policy has kept up with increases in local building costs, a similar dwelling can generally be rebuilt for an amount that is within the policy limits.

Some insurance companies offer a replacement cost policy that will pay a certain percentage over the limit to rebuild your home—20 percent or more, depending on the insurer—so that if building costs go up unexpectedly, you will have extra funds to cover the bill. These are called extended replacement cost policies. A few insurance companies still offer a guaranteed replacement cost policy that pays whatever it costs to rebuild your home as it was before the disaster. But neither a guaranteed nor an extended replacement cost policy will pay for a house that's better than the one that was destroyed.


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## frogger (May 7, 2007)

The SF guy is talking to the contractors about non-T&G planking to replace the broken T&G planking since that is readily available.

*Is there some kind of definitive resource that I can go to that will tell me the difference between building materials like plywood vs. plank, a resource that the contractors will recognize that will help to back me up when everyone tells me that plywood will be just as strong as plank?*


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## Ed the Roofer (Jan 27, 2007)

Taken from the articles written by Joseph Jenkins, Author of the Slate Roofers Bible.

Here is the link also.

http://www.traditionalroofing.com/TR3-readers-write.html

And here is the phrase I Googled:

Are plank boards better than plywood for roof decking?

Ed



*Reader:* "Have you ever heard of anyone running into any problems using plank board decking? I am having a small roof addition built and I want to install new slate. I'm trying to convince the contractor to use 1 inch plank board for the decking, but right now the job is spec'd using CDX plywood. I have shown him the info you have about plywood vs plank decking, but the contractor still believes the plywood will work! Yorktown, VA ​ 
*The Roof Savant:* No, I have never heard of a problem concerning plank board decking related to the material. I have heard of lots of problems regarding contractors. Plywood on slate and tile roofs is used strictly for the convenience of the contractor or architect and for no other reason. It has never demonstrated the phenomenal longevity necessary for a traditional slate roof (100 to 200 years). It will work temporarily, but it's not worth using when better materials are available for less money. It's your money and therefore your call — downgrade your roof construction to satisfy the convenience of your contractor, or build it right — once.​ 
*Reader:* I read your newsletter some months back when I was shopping for a new roof. I saw your opinion on plywood and thought, man that guy's full of it — what a blowhard! Plywood lasts forever! I've just had my mind changed — by a floor, not a roof. I recently stripped the finish flooring in my ca. 1915 house, which had an addition put on in 1965. The original subfloor is 1x6 pine, and it is still in outstanding condition. On the other hand, the addition had a plywood subfloor. Though it is still sound, you could tell it is less flexible and much more brittle than new plywood, and there was some evidence of delamination by the outside door. In a powder room in the addition, they used plywood to shim the sheetrock out, and it is brittle like an old newspaper — completely worthless. The state of the plywood all around was pretty sorry considering it was younger than I am and had been living under ideal conditions (warm, dry, and out of the sun). I can't imagine what it would be like if it had had to endure the extreme temperatures and hot/cold cycles a roof does. I guess my point is just to say thanks for such a nice and informative newsletter; you've convinced a skeptic that what you say is correct. I hope some day to own a home worthy of a fine slate roof, and you can bet it will have a lumber deck if I have anything to say about it!​


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## frogger (May 7, 2007)

wow, thank you very much!


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## Ed the Roofer (Jan 27, 2007)

You are welcome,

I hope you use this information to make the best choice now. I can't believe that someone told you either the T & G planking nor the standard 1" x 6" planking was not available.

Really, you should make some calls, to actual lumber yards, and see how difficult it would be to obtain.

Ed


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## frogger (May 7, 2007)

Issue resolved.

My insurance guy has no problem about covering T&G planking. I met the project manager onsite today and after convincing him that I knew plywood was not of equal value/strength/etc. (and that insurance will cover it) he (eventually) said 'that's fine, I'll do it'. It just may take a while because they know of people who CAN make it, but I guess don't ACTIVELY make it and have it in stock... usually. I told them if it takes longer, that's ok. He's calling around now and will let me know when he finds some because he doesn't want to do anymore work to the roof until he has the T&G on site.

My thinking is that I know the house (my first one) saved my life because of how it was built and the materials used, so no matter what, I do not want it put back together any weaker than it was.

Thank you everyone, especially you Ed. And I'd recomend State Farm to anyone (as it was recomended to me).


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## Ed the Roofer (Jan 27, 2007)

It doesn't have to be "custom made". It is available within a few phone calls.

Ed


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## frogger (May 7, 2007)

He called this morning to tell me he got them, they'll be onsite tomorrow and he's blocking 3 days starting monday to work on them.

You guys were right, thank you all. This project will take around 5 months so I'm suuure I'll be back.


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