Anyone have experience with Accoya?

[John TenEyck]

I'm debating using Accoya for an exterior door project, on my own house to be specific. That door faces due North but gets afternoon sun as the porch overhang is not that great to the West. It's not the worst situation, to be sure, but there is some exposure. There will be no storm door. The alternative I'm considering is Sapele, but the data for Accoya looks really good. Construction will be one piece stiles and rails and floating T&G panels.

I'm looking for your experiences using Accoya. Machining, gluing, finishing, the good, the bad, how much you paid for the grades you bought, and would you use it again? Pretty much anything you care to share. Thanks.

John

[Kevin Jenness]

The shop I used to work at started using accoya for painted exterior work 5 or 6 years ago as an alternative to the African "mahoganies". As far as I know the only species available around here (through Rex Lumber) is flatsawn Radiata Pine. All the stuff I have seen is a dull gray, fast-grown with wide rings, rather ugly and not suited for clear finish. It comes flat and stays flat, is knot-free, machines ok, is very thirsty for glue but glues well if you sozzle it. Has a bit of a vinegar tang due to the acetylization. Not sure of pricing, I seem to recall about $6-7/bd ft but assuming it performs as advertised long term it is a good value. No problems in the field that I am aware of, and I have asked, but it hasn't been that long.

[Joe Calhoon]

One of our local suppliers started carrying it a few years ago and I tried 500 feet and built a few doors just to see what it was like. My experience was about the same as Kevin’s. These doors went to project here high in the mountains with bad exposure. I think it has been about 3 or 4 years but no idea how they are holding up. Probably should make a trip up to see. Since then the supplier quit carrying it. It gets real expensive to order it in shipped common carrier.

I network with a few door and window shops around the country using it and most like it. One oddity is all the Accoya I have seen in the US and Canada have dark streaks running through it making it unsuitable for stain grade. By contrast all I have seen in Europe is clear creamy colored. Makes me think we are getting B grade material. We went to an Accoya seminar at a German shop that uses it a couple years ago and the Accoya rep there was baffled about this and didn’t believe me till I showed him pictures. It is widely accepted in Europe now.

You do have to be careful to use stainless fasteners and back prime anywhere non stainless hardware like multipoints are used. The corrosive properties and wondering about long term affects of the fine sawdust are something to consider. You are not suppose to use TB 3 with this but know one east coast shop that does with no issues.

Pictures from my shop

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From a UK shop we visited that was using Accoya.
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Outside the German shop.��

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[John TenEyck]

Thanks Kevin and Joe. Joe, those pictures of Accoya in your shop give me pause; it's pretty ugly compared to the nice linear grain of the stuff in Europe. That's what my expectation is, I'm going to ask for some samples before buying any. I'd like to use a semi transparent finish like Sikkens Cetol so any wild grain would show through. Your comments about corrosive effects on non-stainless fittings is greatly appreciated, too, as I am thinking of using a multi-point lock set.

John

[Kevin Jenness]

John. if you find a source for attractive accoya I'd like to know. Good luck.

[brent stanley]

Here's a bit more material on the history of Accoya over here. There's some mediocre stuff bouncing around the US, and who knows where it ended up. https://www.greenbuildingadvisor.com...a-miracle-wood (https://www.greenbuildingadvisor.com/article/the-rise-and-fall-of-a-miracle-wood)

Upper Canada Forest Products in Canada distributes and sells it out of the Toronto area warehouse, and it's the product produced in the Netherlands. Roughly $10/BF. Sierra is their name in the US: https://www.sierrafp.com/products/lumber/accoya/

B

[John TenEyck]

Thanks Brent. UCFP is only about 50 miles from me over the border. I'm not sure I can bring lumber in from Canada, but it's worth a call to find out.

Kevin, I'll let you know how it turns out.

John

[lowell holmes]

I made my door to replace one that was damaged by splitting. It is a raised panel door with leaded glass panels in the upper portion of the door.
I thought I would share an innovation I came up with for the raised panels. They are double panels. They are 7/8" thick and I put polyethylene sheets between the two panels so the outside panel can expand and shrink from the sun and then cloudy days. The door is several years old and holding up well. I make them using fir lumber.

[Joe Calhoon]

There are several dealers for Accoya, we got ours from National Wood Products. I know some shops buying from Rex Lumber on the east coast.
https://www.accoya.com/where-to-buy/united-states/

Brent, was the Accoya you got from the Canadian dealer good color?

I dug out the samples from the presentation in Germany. A lot of shops there use Accoya for the outside cladding of windows and doors with 3 layer laminated scantlings. This makes a outside surface that holds paint well. With this you also avoid the corrosion of hardware since nothing screws into that layer.

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[brent stanley]

There are several dealers for Accoya, we got ours from National Wood Products. I know some shops buying from Rex Lumber on the east coast.
https://www.accoya.com/where-to-buy/united-states/

Brent, was the Accoya you got from the Canadian dealer good color?

I dug out the samples from the presentation in Germany. A lot of shops there use Accoya for the outside cladding of windows and doors with 3 layer laminated scantlings. This makes a outside surface that holds paint well. With this you also avoid the corrosion of hardware since nothing screws into that layer.

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I didn't get any in the end Joe. I couldn't justify a $1000 minimum order just to satisfy my curiosity, so I wanted to try and find a few people interested to go in together, but just had too many things on my plate. I'll likely get back to it some time. It seems like it would be a decent way to use mediocre, fast grown softwood from plantations and rapid second growth. Normally that material performs poorly with respect to rot, but if this process could change that, it could be interesting. As I understand it, the raw materials come from New Zealand (it would have to be treated for bugs there first) shipped all the way to the Netherlands, processed, then shipped to North America. No wonder it's so expensive......surely a plant in North America could produce it cheaper......

A neighbour of a client saw a wooden door I made on a historic designated home in town and wants a wooden door for their house with a lot more exposure......maybe it's a opportunity to go buy some and give it a try? Painted both sides so appearance doesn't matter that much within reason.

Did you use a water based finish on any of yours? Just wondering about grain raising etc. Did you do a moisture check from the supplier?

I don't mind trying new stuff with my own wallet within reason, but the minimum is a little steep.

B

[John TenEyck]

Joe, would you recommend doing that same three layer approach with a door, with the Accoya only on the outside? I was thinking of using solid stock, but actually am not keen about having Accoya on the inside so a three layer construction would allow me to use a different species. But the question is "Will that construction be stable.".

John

[Joe Calhoon]

Seems like it would be risky With Sapele as that species moves a lot. I have experience with split species on doors but never with Accoya. Sipo is a lot more stable and that would be my choice for a Mahogany - Accoya door. At that point though I would just go all Sipo Mahogany. I still see Accoya as only paint grade.

I see Munchinger offers split scantlings up to 145mm wide for doors with Accoya-Spruce and Pine. Interesting that they mention the dark streaks in Accoya. So maybe not all clear there either.
https://www.muenchinger-holz.de/fileadmin/user_upload/PDF_Downloads/delivery-programme/Modifizierte-Ware-en/muenchinger-lieferprogramm-accoya-en.pdf

[Joe Calhoon]

I didn't get any in the end Joe. I couldn't justify a $1000 minimum order just to satisfy my curiosity, so I wanted to try and find a few people interested to go in together, but just had too many things on my plate. I'll likely get back to it some time. It seems like it would be a decent way to use mediocre, fast grown softwood from plantations and rapid second growth. Normally that material performs poorly with respect to rot, but if this process could change that, it could be interesting. As I understand it, the raw materials come from New Zealand (it would have to be treated for bugs there first) shipped all the way to the Netherlands, processed, then shipped to North America. No wonder it's so expensive......surely a plant in North America could produce it cheaper......

A neighbour of a client saw a wooden door I made on a historic designated home in town and wants a wooden door for their house with a lot more exposure......maybe it's a opportunity to go buy some and give it a try? Painted both sides so appearance doesn't matter that much within reason.

Did you use a water based finish on any of yours? Just wondering about grain raising etc. Did you do a moisture check from the supplier?

I don't mind trying new stuff with my own wallet within reason, but the minimum is a little steep.

B

These went to 2 jobs, customer was finishing the one in the pictures, paint I think. The others I believe got Sikkins 23 in a gray to match some other parts of the house. Sikkins is one of my least favorite finishes.
It does work well with the German and Italian exterior water base finishes. We made a small sample and it finishes fine. There are procedures with these finishes to counter grain raising.


I would think one of the benefits of Accoya is holding finish well with its low movement.

[brent stanley]

These went to 2 jobs, customer was finishing the one in the pictures, paint I think. The others I believe got Sikkins 23 in a gray to match some other parts of the house. Sikkins is one of my least favorite finishes.
It does work well with the German and Italian exterior water base finishes. We made a small sample and it finishes fine. There are procedures with these finishes to counter grain raising.


I would think one of the benefits of Accoya is holding finish well with its low movement.

I've never really had a problem proactively dealing with grain raising on any water based finishes, I was just wondering if the processing made it more immune to that or not, but it seems not. In my research into the stuff it seemed ideally suited to exterior, painted products with the rot resistance in tandem with the paintability. If someone could make it look nicer, it would be even more appealing....

[Joe Calhoon]

I just used some Accoya I had left to replace some rotted out Ponderosa sills on my retail building. Did one in Sapele also and primed with Sirca water base pigmented. Will get the finish on when it warms up. I probably won’t live long enough to see how they do...

[John TenEyck]

I wasn't thinking of using Sapele as part of that construction, more like pine. But now you've got me thinking about Sipo, or Sapele, my original alternative, because if you think Accoya is a paint grade only product then it's not going to work for what I want to do. I always appreciate your advise, links, and insights. Many thanks, Joe.

John

[Joe Calhoon]

I've never really had a problem proactively dealing with grain raising on any water based finishes, I was just wondering if the processing made it more immune to that or not, but it seems not. In my research into the stuff it seemed ideally suited to exterior, painted products with the rot resistance in tandem with the paintability. If someone could make it look nicer, it would be even more appealing....

I might be off base here but I seem to remember one of the European suppliers of water base finish saying you could skip the impregnating coat with Accoya as the water will not penetrate it. I might not be right about that and will check my notes.

[Joe Calhoon]

Another link for door parts
https://holz-schiller.de/?p=accoya_tuerfriese&s=profi&l=EN

[Bill Dufour]

Sounds like this Accoya is a process not a wood type. Monterrey pine is a weak easily rotted wood so it seems like a poor starting point. Similar to the poor species used for rot treated lumber. They are using cheap, fast growing wood that no one would buy if they knew what species it really was.
Bill D.

[Livingston Johnston]

Ive used Accoya on a few door jobs that have high exposure and I have been really happy with it. It is really stable and machines easily as well. Customers really like to hear about the 50 year rot warranty. In Canada, I can only get it from Upper Canada but they seem to have good stock.

[John TenEyck]

Sounds like this Accoya is a process not a wood type. Monterrey pine is a weak easily rotted wood so it seems like a poor starting point. Similar to the poor species used for rot treated lumber. They are using cheap, fast growing wood that no one would buy if they knew what species it really was.
Bill D.

If you didn't know the cost, and one wood was more durable and required less coating maintenance than most others which would you choose? Now someone tells you they cost about the same. Which would you choose?

John

[John TenEyck]

Joe, I looked up the shrinkage values for Sipo and Sapele and they are within something like 0.1% both radially and tangentially. Both are quite a bit higher than True Mahogany. And everything is a lot higher than Accoya. Does your experience suggest the data for Sipo and Sapele are not really that close?

John

[John TenEyck]

Ive used Accoya on a few door jobs that have high exposure and I have been really happy with it. It is really stable and machines easily as well. Customers really like to hear about the 50 year rot warranty. In Canada, I can only get it from Upper Canada but they seem to have good stock.

Thanks for that info. What type of finish did you use on them?

John

[Joe Calhoon]

Joe, I looked up the shrinkage values for Sipo and Sapele and they are within something like 0.1% both radially and tangentially. Both are quite a bit higher than True Mahogany. And everything is a lot higher than Accoya. Does your experience suggest the data for Sipo and Sapele are not really that close?

John

John,
They are similar but I think Sipo more stable. I have had a couple bad experiences with Sapele for door building. I like it for windows where the sections are smaller. Unfortunately Sipo Is difficult for me to acquire in Colorado. Wish I had easy access to get Sipo from Rex lumber. Happy I live where I do though.

We have always used a lot of VG fir but since the price of that went up have been using a lot of quartered and plain sawn white oak for doors and windows. Only thing I don’t like about white oak is the weight.

[John TenEyck]

John,
They are similar but I think Sipo more stable. I have had a couple bad experiences with Sapele for door building. I like it for windows where the sections are smaller. Unfortunately Sipo Is difficult for me to acquire in Colorado. Wish I had easy access to get Sipo from Rex lumber. Happy I live where I do though.

We have always used a lot of VG fir but since the price of that went up have been using a lot of quartered and plain sawn white oak for doors and windows. Only thing I don’t like about white oak is the weight.

Thanks Joe. I was out in your area skiing several years ago. It's obvious why you are happy living there. VG fir around here costs $11/BF, if you can get it. Besides the price it's just too soft for me to consider using it for a door. I have used white oak, but it's seasonal expansion is even higher than Sapele. I saw a lot of cracked bottom rails and panels in West facing, exposed WO doors when I was out in Breckenridge last year. WO is weather resistant but it turns gray/black if the finish gets compromised. All considered, not high on my list of choices.

Have you used much Genuine Mahogany or Santos for doors? Both have lower seasonal expansion/contraction than Sipo and would appear to be good choices.

John

[Jamie Buxton]

I think accoya is a process brand name. There are other torrified woods out there. A local dealer offers torrified ash, which looks quite nice—kinda walnut brown, but with ash grain.

[John TenEyck]

I think accoya is a process brand name. There are other torrified woods out there. A local dealer offers torrified ash, which looks quite nice—kinda walnut brown, but with ash grain.

Accoya is not torrified (heated), it's acetalized (chemically treated). https://www.accoya.com/why-accoya/ But since you brought up torrified wood, have you used any for exterior doors?

John

[Jamie Buxton]

Accoya is not torrified (heated), it's acetalized (chemically treated). https://www.accoya.com/why-accoya/ But since you brought up torrified wood, have you used any for exterior doors?

John

umm.. I haven't examined the difference between torrified and acetalized, so I'm not much help here. And I don't know which of those processes applies to the browned ash at my local hardwood dealer.

[Livingston Johnston]

Paint finish. Ben Moore primer and aura finish paint

[Joe Calhoon]

Thanks Joe. I was out in your area skiing several years ago. It's obvious why you are happy living there. VG fir around here costs $11/BF, if you can get it. Besides the price it's just too soft for me to consider using it for a door. I have used white oak, but it's seasonal expansion is even higher than Sapele. I saw a lot of cracked bottom rails and panels in West facing, exposed WO doors when I was out in Breckenridge last year. WO is weather resistant but it turns gray/black if the finish gets compromised. All considered, not high on my list of choices.

Have you used much Genuine Mahogany or Santos for doors? Both have lower seasonal expansion/contraction than Sipo and would appear to be good choices.

John

John,
Door longevity depends on a lot of factors and don’t think you can judge any particular species by just looking at doors in the field. How it’s made and finished, how it’s maintained after a few years and exposure can determine the longevity.
no experience with Santos but used a lot of Genuine Honduran Mahogany up until it became hard to get. It was my favorite for sure.
Here is a pair of mahogany doors we built for a local historic hotel in town in 1980. 39 years ago. I took this picture about a year ago.
this is East facing with a small awning above. The owners maintained it well. I have other doors around in Mahogany, Oak and Fir. Some nice and some showing a lot of weather depending on the maintenance.
the South American Mahogany available now in my opinion is not so great. We used some on a window and door job 4 years ago and no comparison to the old Honduran Mahogany. Of course all Mahogany, especially African can vary depending on how it is processed from he mills.
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[Kevin Jenness]

Accoya does not use torrification, or heat, rather it is a chemical process using acetic acid to achieve a similar result. Don't ask me to explain the particulars. Accoya is a brand name referring to the process. When I first looked into Accoya it seemed that a number of species were being processed, but as far as I know only Radiata pine is available in my area.

For exterior millwork with "natural" wood Honduras mahogany ( Swietania Macrophylla from Central/ South America) is hard (impossible) to beat, but difficult to justify due to cost and rarity. The resource has been effectively mined out. I did make a door recently with mahogany faced rails and stiles laid up on a sapele laminated core and solid mahogany panels and moldings, but that was a premium project.

Imagine being a cabinetmaker in 18th century Europe when mahogany was first imported in quantity from the new world. Here was an easily worked, beautiful stable wood that did not have to be glued up for width- effectively plywood, only better, much better. I bet they went to bed happy men, dreaming of ready-mixed glue.

In my fading memory, I assisted my neighbor and colleague 35 years ago with a 30 door project all in solid mahogany , from Peru I believe. Several thousand board feet arrived, 8, 10 and 12/4, the largest planks over 36" wide and I don't remember anything less than 10". We roughed it out, stickered and remilled it, beautiful stuff. Try and find anything like that now. When the white elephant they were installed in was deconstructed due to excessive maintenance costs several years ago the doors were parted out and looked as good as new.

Accoya is what's left, grab it while you can.

[John TenEyck]

umm.. I haven't examined the difference between torrified and acetalized, so I'm not much help here. And I don't know which of those processes applies to the browned ash at my local hardwood dealer.

Ash is one of the species used for torrified wood and, as far as I know, pine is the only species sold as Accoya. What you've seen must be torrified wood.

John

[Jamie Buxton]

Ash is one of the species used for torrified wood and, as far as I know, pine is the only species sold as Accoya. What you've seen must be torrified wood.

John

Do torrification and acetylization achieve the same resistance to weather and bugs?

[brent stanley]

This guy uses Accoya for a few projects as well if anyone wants to watch it being machined. Even made dominos with it: https://www.youtube.com/user/Ollybrad2k10

Good channel besides that as well.

B

[John TenEyck]

Do torrification and acetylization achieve the same resistance to weather and bugs?

Accoya claims 50 years against rot. One of the torrefied sites I looked at claimed 25 years. I don't recall seeing any real data on dimensional stability for torrefied wood, only that it's more stable than wood that has not been roasted, while Accoya posts a pretty complete data package for their product. If you are looking for a dark color the torrefied products look like a good choice.

John

[Joe Calhoon]

I think at this point Accoya is a better bet than thermally modified wood. I played around with some that a timber distributor sent to us and the results were pretty disappointing. Ripped out some glass beads and they curled up like spaghetti. According to a wood scientist I know this is a tricky process to get right with some mfgs better than others.

For me seeing how the glass beads behave is always a good indicator of stability. Accoya was not bad in this respect but not as good as White oak, tight grain fir or Sipo. Khaya being the worst I have ever experienced.

Another feature of Accoya that I find a plus is the availability of thicker 10 to 16 quarter stock that would eliminate any laminating for thicker doors and windows. None of the distributors I have contacted had those thickness but Accoya information says it is available.

[John TenEyck]

Your experience and insights are always appreciated Joe. Thanks very much. As pretty as the toasted ash looks, I'll scratch it off my list of candidates for exterior doors.