Hello!
I have a question regarding pressure-treated wood;
I discussed with a carpenter about using pressure-treated wood NTR A in a construction above ground. Only parts of the construction would come in contact with soil or vegetation, and the carpenter believes that all other wood can just as well be of lower "pressure grading" (AB or B) since NTR A is designed to withstand the bacteria in soil that cause rot. "It's only in contact with soil that NTR A is better," claims the carpenter. "NTR AB or B has the same resistance above ground as NTR A," he maintains.
Is that correct? I thought that NTR A has better rot resistance in all situations, so to speak. Even if NTR AB holds up reasonably well, NTR A lasts even longer... (yes, I know that NTR A should only "be used" in contact with the ground).
Anyone know?
/Micc
I have a question regarding pressure-treated wood;
I discussed with a carpenter about using pressure-treated wood NTR A in a construction above ground. Only parts of the construction would come in contact with soil or vegetation, and the carpenter believes that all other wood can just as well be of lower "pressure grading" (AB or B) since NTR A is designed to withstand the bacteria in soil that cause rot. "It's only in contact with soil that NTR A is better," claims the carpenter. "NTR AB or B has the same resistance above ground as NTR A," he maintains.
Is that correct? I thought that NTR A has better rot resistance in all situations, so to speak. Even if NTR AB holds up reasonably well, NTR A lasts even longer... (yes, I know that NTR A should only "be used" in contact with the ground).
Anyone know?
/Micc
A is protection class 4 and AB is 3. There are probably 1-5 if I'm not mistaken...
The higher the protection class, the better. I can't really go into more detail than that, you'll have to try reading standards or hope someone else can elaborate!
The higher the protection class, the better. I can't really go into more detail than that, you'll have to try reading standards or hope someone else can elaborate!
Well, my basic idea has been that the better the protection class, the better. But this carpenter means that the protection in NTR A-classified timber primarily applies to "rot created by bacteria in the soil." Sounds strange, I think...
If you look at NTR's list of approved preservatives, you can see that almost all products can be used for both class A and class AB, with the difference being that the wood should contain about twice as much product in class A. So the idea that it would be about two different types of preservatives effective for different environments seems to be incorrect.
https://assets.website-files.com/595cf666695a72458025adb0/5be3f627e6dd260c6a39bcad_approval list 95_.pdf
https://assets.website-files.com/595cf666695a72458025adb0/5be3f627e6dd260c6a39bcad_approval list 95_.pdf
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