Wood Choice for Reproduction Windows

Spanish Cedar, White Oak, and Cypress are options that come to mind for a durable exterior application. and January 23, 2014

Question
The picture below is a wall/window section, interior on the right, exterior on the left. The window is a stained glass unit for which I need to reproduce parts (for lots of windows), and in the case of four windows, reproduce the entire frames. When completed, all of the windows, the repaired and the new, will be completely covered with new storm glazing which will be inside the sill, but well away from the wood frame. I'm not entirely sure how the venting will be done (by others), but the windows will be vented (see drawing). Windows are all well above the ground, and face in all directions.

I am not responsible for the painting of the replacement parts on the largely sound windows or the complete frames. However, everything will be finished appropriately. Given the storm glazing, the painted wood will not be subject to impact moisture, but obviously will to humidity, temperature fluctuation, and sunshine. And while the storm glazing will be removable, I think it's a safe bet that a regular painting/upkeep schedule will not be adhered to.

What are your thoughts on the species for both the replacement parts and the new window frames? I had been planning on poplar, given its cost-effectiveness and readily-available supply, but 90+ percent of my career work has been for interior applications. Recent research tells me poplar is not going to be a good choice for exterior (albeit protected) work. Do I need to look further for, say, Douglas fir?

Just to be clear, I'm not looking to get by on the cheap - this job needs to be lasting - but cost is a definite consideration.


Click here for higher quality, full size image

Forum Responses
(Architectural Woodworking Forum)
From contributor J:
I would suggest you look into white oak. Not the cheapest date, however very weather resistant, tough, easy to machine. Knowing maintenance won't be high on the customer's list, it will surely last a long time and no phone calls.


From the original questioner:
I thought white oak, too, then rebutted the cost. For the smaller sections, it might be feasible, but when it comes to doing the four complete frames (mostly glass, yes, but there are two that measure 60" x 26'-4", with the other two a couple feet shorter; the top sections on all of them are nearly the same, though), I'm going to blow my budget. With all the glue-up involved (lots of turning and shaping, etc.), there's a fair amount of material here.

I am pretty sure the existing 120 year-old wood is fir. I have a capital in the shop now, and after stripping, I'm fairly certain of it. So fir was a reasonable replacement wood I thought (after my blunder planning with poplar). I have used cypress for a couple outdoor projects, and no surprise, it's held up beautifully without any treatment or paint, and cedar has weathered likewise. I was concerned about these being too soft, though, and then I also need to think about how available it is locally. I do have a bit of time if I need to have something shipped in, but then I'm back to the budget.


From contributor D:
We do a lot of historic restoration. The Doug fir of today is not like yesteryear. We are restoring a 100 year old round cupola on the CT coastline, and Spanish cedar is the wood we would always use for jobs like that, although we used cypress recently and everyone was quite happy.

From the original questioner:
I have messages out now to two suppliers asking for quotes on white oak, Spanish cedar, cypress, and mahogany. I got to thinking about the budget more. For the replacement parts I need, and for much of the ornamental work for the new windows, shorts are a definite option, so I'm hoping to save some cost there.

Speaking on the four new complete frames, now, what are the thoughts on using one of the exterior species listed for the outside face, and using poplar for the inside? The window faces are mirror images - all the same ornamental work on the inside as the out. I'm not sure why there would be any problem, but want to make sure I'm not overlooking something. Further, I'm not entirely sure how the windows go together (they'll be pulled sometime next month, I'm told). Might end up with a split-jamb type of deal.


From contributor J:
I like cypress, but sadly for you it is not common. Here in NC it is very common and relatively inexpensive. About 2 bucks a bd ft. Nice, clear, lightweight, works like cedar, lives in the swamps so it doesn't fear water. It is soft like cedar. If you know about the bd ft you need, maybe it is worth it to ship it north.

From the original questioner:
Oh, it's common enough. I previously thought it was reclaimed river bottom logs, but I can get it here just fine. The last I worked with it was about 11 years ago, I think. I reproduced a sharpening horse/stand (owner had the stone, but the original stand was shot). I didn't do a thing to it regarding paint or sealer. Last time I saw it (last year), it hadn't even silvered that much. Looked very much like the day I delivered it. That lumber I got from a rack in an outbuilding at our family farm. Not sure how old it was at the time. Plenty.

I got a quote today, and asked for the highest price (that is, lowest quantity pricing): $2.68 for 4/4. She told me she has good stock, too, and that she sells a lot of it to another customer doing historical restoration on shutters, balustrade, and the like. I'm planning on going that route. Just need to write up the change order, though I'm not sure the architect even specified species.


From Professor Gene Wengert, forum technical advisor:
As it appears that the wood will not be subject to rain wetting, yellow poplar should be fine. Note that if you use a species that changes size a lot when the RH changes, you can potentially crack the glass, unless the piece is designed to accommodate movement, which is rare. So, if not yellow poplar, then choose a lower movement wood. Spanish cedar is a good choice. Incidentally, did you know Spanish cedar is not a cedar? It is a leaf tree, so it is a hardwood. So is balsa wood.

From the original questioner:
Spanish cedar not cedar... Yes, I found that elsewhere while looking over choices. Regarding movement, is cypress going to come and go a lot? I am using poplar for the interior facing parts. The outside and inside are mirror images, and while we aren't entirely sure how they go together (the windows to be replaced have yet to be pulled), at present I am imagining a split jamb scenario. Whatever the case, the stained glass will be mounted in the poplar portion, that is, favoring the interior. Thanks, Gene!

From the original questioner:
Dr. Wengert, I just watched the multi-part moisture content video presentation. What a great resource! I appreciate you making that available. And thank you for the vote of confidence regarding the use of poplar for the frames.

The method the glass studio uses for installing their panels in a case like this is small cut nails or tacks for pointing, and silicone for glazing the panel into the wood frame. I plan to allow 1/8" on all sides, provided this corresponds closely enough with the existing. That is, my new frames have to fit the opening the old ones come out of, and the stained glass panels will change in size only fractionally. Actually, they should get smaller since they'll be disassembled, cleaned (new glass where broken pieces are encountered) and then put together again from scratch with new lead. I would presume they'll be nice and tight, no sag, etc.

Is 1/8" on all sides of the glass reasonable if I am using poplar for all parts, interior and exterior? Or does that matter since the glass studio tacks in points all around? I believe the silicone will provide enough flex for humidity-induced movement in the wood, but will the points be a potential culprit in potentially freezing the panel? I'll talk to the glass studio, too.


From the original questioner:
Update after speaking with the glass studio: Non-round panels will be installed without pointing; caulk and wood stop to the interior. Rabbets in existing windows are exceptionally wide, I am told, so the new work (if replicated) will allow for plenty of movement in both wood and glass, without fear of cracking. Of course the leaded panels by nature already are more moveable than large panes of clear float glass, for instance.
Related Articles