Fuming a green oak frame

[Alex F]

Hello folks,
I am in the process of building a fairly large oak frame extension to my property. The oak frame has been erected and the roof will be completed shortly. I am interested in making the oak look older, more aged in colour and my reason for posting here is to see if anyone can advise on the process. The area of the building is about 650 sq ft with high ceiling. I understand the chemical used is amonia. Here are my questions if anyone has some advice:
1) Can the amonia product be easily purchased?
2) How does one use the amonia? The building will be sealed as much as practical from the elements and rest of the building. Do you just let the amonia evaporate in containers placed in the room.
3) How much will I need?
4) How long does the process take?
5) is there a risk of the building smelling of amonia for a continued period afterwards?
6) The oak partically weather from being outside for part 5 or 6 months. Should it be sand blasted 1st?
7) I'm not interested in using any stain products but if there were another chemical that had a more natural reaction from the wood I would be interested to know of it.
Any advice much appreciated.
Thank you.
Alex

 

[biffvernon]

Hmmm...sounds pretty dodgy. Oak fuming is usually done in small quantities in a sealed box, not a whole house!

 

[Penners]

I entirely agree with Biff. To fume an entire extension with ammonia sounds (a) incredibly difficult and (b) extremely dangerous. Here are some facts from authoritative websites:-

Inhaled ammonia fumes are highly toxic. They can be a potent asthma trigger. Skin exposure extracts water from the cells causing an inflammatory response which damages surrounding tissues. Ammonia is is considered a possible carcinogen by the World Health Organization.

Ammonia fumes are very irritating and corrosive to the eyes, nose and airways. Fumes may cause a burning sensation, coughing, wheezing, shortness of breath, laryngitis, rhinitis and watery eyes, even at low levels. People with asthma or other respiratory problems may be especially sensitive to ammonia fumes, as may individuals with corneal disease, glaucoma, or severe liver damage.

Eye contact may cause severe eye burns, blindness, cataracts and glaucoma. High exposure to ammonia fumes may also cause temporary blindness and eye damage.

Skin contact with low ammonia concentrations may cause skin irritation; high concentrations will cause burns and open sores if not washed away quickly.

Breathing concentrated ammonia fumes may cause headache, loss of sense of smell, nausea, vomiting, increased heart rate, and high blood pressure. Breathing in very high levels may cause pulmonary oedema, a medical emergency, with severe shortness of breath and a buildup of fluid in the lungs.

Oak fuming is invariably carried out in the open air, with the oak members being stacked together and enclosed in a temporary polythene 'tent'. As your construction has already started, it is obviously too late for this to be done, so I really do suggest that give up on the idea.

I have used new green oak in several house repair projects, and I consider it to have a beauty of its own. Its colour will slowly grow darker and richer as time passes, so you can witness and enjoy the maturing of your new oak frame. It is also extremely satisfying to see the difference between the original contruction and your new oak work, highlighting the contribution that you have made to the history and development of the house.

Personally, I wouldn't consider for one second doing what you propose, particularly for such a relatively trivial reward.

Please excuse my bluntness, but I feel it is very important to emphasise the dangers of your idea.

 

[Alex F]

Thanks for your comments. It may be a non starter of an idea. I won't be taking unecessary risks. However I know some of the oak frame companies do it and from what I can gather they do it post erection. For example Oak Masters website FAQ's is the following extract:

"Q: How do you achieve such a rich hue in your oakwork?

A: The fuming process is peculiar to the use of green oak in construction. It is a specialist method which speeds up the aging process of the wood, and causes a richer, nuttier hue in the finished product. In the case of a single oak beam this process can be completed before delivery. However, where an entire oak frame is concerned it is often more advisable to fume the building post-erection so as to ensure an even finish. "

The room is no different from the frame being inside a tent. There are not walls yet other than polythene panels.

I would think in the light of the dangers of the chemical it would need to be done by someone with experience and suitably qualified.

 

[middi]

the simplest and best way to make new oak assume that golden, mellow, old look is to limewash it when is still green an the " shaking" ( natural splitting) process has started ( this process usually starts when the green, new, oak is about six months old).

2/3 months later wash off the lime ( sponge and water), the tannic acid in the oak would have reacted with the lime resulting in that lovely "gold looking" surface.

It works extremely well with no real risks.
( if you are the patient type, don't do nothing because 3/4 years down the line it will assume that old look anyway)
Middi

 

[FamilyWiggs]

the simplest and best way to make new oak assume that golden, mellow, old look is to limewash it when is still green an the " shaking" ( natural splitting) process has started ( this process usually starts when the green, new, oak is about six months old).

Middi, for once non siamo d'accordo, the simplest and best way is to wait a couple of decades, as Penners suggests!

And he should know, he's seen a few! :wink:

 

[Keithj]

Agree with all the above. Absolutely do not mess with ammonia in that way - the stuff is evil! If I were going to treat timber with ammonia, it would be outdoors in a sealed space - probably with the timber stacked and spaced to allow the treatment to get to it. Even that, I would not do myself. I value my health!

We have a fair amount of green oak in the repair work on our house. You can tell, now, which is the green oak because it's precisely cut where the old Tudor stuff is much more "approximate"; it's shrunk leaving 1mm gaps all round; and it doesn't have that silvery sheen that the older timber has (where the vandal who "restored" the place 15 years ago hasn't painted it black).

We were told 3 years approx for the new wood to go silvery. At the moment, it's at the "leaking tannin onto the limewash" stage, so we have glorious tobacco coloured streaks on some of the walls.

 

[middi]

I must admit the natural , and my prefered, way when building with green oak is is to do nothing to " age" it. Maybe a bee waxing a couple years down the line for internal exposed beams etc.

As to externally exposed beams, it is a waste of time doing anything to them at all, after two or three years it will start to obtain that natural silvery grey anyway.

( I do agree with you FW, to ignore Penners view on ANY subject one would do so at their own peril. He must be the OLDEST of us all :wink: )

( Contributor, CONTRIBUTOR....... what was you all thinking)

Middi

 

[tobydog]

This is our extension one year on. The thick oak cladding was a golden honey colour when it went on but you will see that it's already starting to take on the silvery look. This is more evident where the rain and general weather has got to it. Inbetween the two structures and in other sheltered areas it hasn't changed that much yet.

 

[Alex F]

Hello

The oak left alone is fine and will look great in any case but I happen to prefer the appearance of aged, used more weather oak more than the golden colour oak new freshly cut or freshly sandblasted ( as many do to clean it up), and hence my search for information on how to achieve this process. It will take many years to visibly see a change in the colour of the oak inside (externally it will change colour to a natural silver in very little time). In an ideal world I would leave the frame open to the elements for two years and then finish the job. I guess I want something different and like a bit of experimentation!

With regard to your lime wash suggestion middi, I have considered using lime wash and am keen on lime generally as have used us on most walls in the rest if the house. When you use limewash with the oak do you dilute it? How easily does the limewash come off with water and sponge? Any pictures by any chance? Presumable the segments of the white lime remain in some bit of grains etc which is part of the effect. I've used lime putty on beams before to get a thick whitened limed effect which was good but never washed it off and no longer at that property.

 

[Penners]

wait a couple of decades, as Penners suggests!

And he should know, he's seen a few!

Oh yes. Lord Kitchener and I were great mates. After dinner at Simpson's we used to enjoy a rubber or two of bridge at Boodle's with Sir Frederick Donaldson and his old friend Colonel Fitzgerald.

I was one of the few people who knew about his secret mission to Russia, but I'd have to kill you if I told you any more.