Wood Window Frame Rot

[ajk1]

An architect is claiming that the original 50 year old wood window frames are rotting. He has made no tests and he wants to replace all the windows and frames as part of a general renovation of the building. The windows are punched windows - that is, narrow and tall winddows at regular intervals along the wall. I am doubtful of his claim, as he has made unsubstantiated claims in the past that he has backed off from. Is there a test for rot, other than the knife point penetration test? No tests at all have been done to date, not even the knife point penetration test.

Questions:

1. I seem to recall reading that there is a drill bit test where the drill dust is checked for rot by some chemical test or physical test. Is there any such test, and if so, what is its designation?

2. How long can wood window frames be expected to last if properly manintained by periodic re-painting and re-caulking?

3. How often should they be repainted in the Toronto climate? Every 10 years?

Perhaps it is a good idea to replace the windows and frames, but if so, we should do it for the right reasons. I don't know if a modern frame is as good or better as a wood frame. The existing windows are double glazed. I suppose I should post the relative merits of this on a mechanical enginering forum, but I am most interested in ways to detect rot, particularly if there is an ASTM or like standard method, and the expected life of wood window frames.

 

[a2mfk]

I think this is a good post for the Building Engineering forum.

I don't understand how the architect is claiming there is rot damage when it sounds like there is no indication thereof?

You may want to start with a moisture meter probe of the window frames, which will at least give you some information about the current moisture level of the wood, and if that would support microbial growth. However, that doesn't mean there was not rot damage in the past and that source of moisture was somehow removed and now the wood is dry(er).

I found this site on older windows that is obviously biased towards preservation, but has some good info nonetheless:

http://www.preservationnation.org/i...ings/weatherization/windows/#replacement-hype

Also, I have been reading several articles challenging the notion that replacing older windows (mostly talking about residential) is the great money saver that many people have been touting (perhaps the window industry the most). The actual economics in most cases may not work out for the average homeowner. Now, for a commercial building, especially one that is institutional, this may require some more detailed analyses of replacement cost vs energy savings. What many are saying is if you want to invest in energy efficiency of your building, there are better places to start that give you more bang for your buck, such as attic insulation, sealing around other windows and openings, etc.

http://www.houselogic.com/home-advi...e-old-windows-with-energy-efficient-models/#.

 

[ajk1]

a2mfk - you know how some architects say anything to justify what they want to do - hence the claim of rot. The sites that you refer me to seem more oriented to residential. Thanks for the idea of posting this question on the building engineering forum. I'll try that. Thanks.

 

[dik]

It's a simple matter of taking a core (wood plug drill bit) and sending it to a qualified lab for microscopic examination... relatively inexpensive and quick.

Dik

 

[TomDOT]

I can tell you that the modern aluminum window frames in this building are purely terrible (thermally speaking) - in the winter, they are routinely 10F colder than the glass, when the outside temperatures are only 40F below the room temperature.

 

[IRstuff]

Wood frames in windows can hypothetically last for decades in a well-maintained and un-harsh environment. That said, not everyone is willing to pay for, and have the time for, maintaining a building to its pristine and as-build condition. A further consideration is energy-efficiency, for which a wood frame window is the least best option. There was a brief fling with aluminum frame double-pane windows, but that's gone by the wayside in favor of vinyl-frames with with aluminum reinforcement. Initial and replacement cost for vinyl windows could be expensive, though

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[ztengguy]

How is a window related to a structural engineering issue? If he wants to replace, let him. The owner can decide if its within his budget.

 

[ajk1]

ztengguy (Structural) - the building is a place of worship and this may not be the best use of funds if not required. There may also be heritage aspects involved. The owner is a committee that has little or no technical expertise in wood. I am involved with the committee and have experience in timber design and its properties. By the way, there are a lot of elements in any building that are not normally designed by a structural engineer, but then go wrong and it then becomes apparant that had a strcutural engineer reviewed it at the start, he would have recognized the potential problem and been in a position to give advice to avoid the problem.

 

[ajk1]

IRstuff (Aerospace)- these are double glazed with wood frames. Is that not good thermally?

ztengguy (Structural)- Whatever is eventually done, it should be done based on accurate and true advice, not on misinformation and speculation with no basis in fact. If the frames are not rotting, we should know that. We may still decide to replace, but we should be sure that we are doing it for the right reasons, and that we are not replacing with an inferior product. This has already happened in another item in the renovations carried out to-date, and then the new item had to be ripped out and replaced.

 

[ztengguy]

If your on the committee, isn't it up to you guys to question the architect to show where the rot is, not just a blanket statement? Then have a couple window companies out, and get a second opinion. Go out with a screwdriver and prod around....you will know if its rotten or not. If not, carry a 2z4 with you, and if the screwdriver sinks an inch in the window, see what force it takes to drive into the 2x4. Rot is easy to find, hard to fix.

 

[ajk1]

Yes, that's my point. I have do the screwdriver test on other structures, but I knew there was a more preccise test and "dik" has helped me by reminding me what it is.