If you are happy that the frames have been treated with preservative, how about clear or 'natural' Sadlin Exterior Advanced Woodstain. It is like varnish but allegedly a better technology, microporous, so allowing the wood to breathe and resist flaking. My only other tip is to sand off any sharp edges on the frames as coating often start to flake off at a sharp edge. Just a few passes with some 120 grade sandpaper would be better than nothing, you don't need to remove much wood at all, it won't notice visually. Andy.
What would be the best kind of finish to use on new oak window frames. Painting them is not an option as the wood look is required. I do not have a clue whether the frames should be oiled, varnished or whatever and what would be the best products to use?
As soon as you recieve them from the factory put a coat of 50:50 varnish and meths or rubbing alcohol on them.
This will help preserve them from contact with water, iron and grubby paws, all of which will stain them. If they are already on site, sand them down to remove all such marks and stains and paint them with the above mixture.
Once in situe, further coats of a slightly stronger mix will ensure their good looks will be maintained.
Clear preservative might be used first. If it is heartwood it is not really necessary. Do not put anything on top of preservative until the wood is thoroughly dry. Whiter outer wood must be treated in the same way as any other hardwood as it is no more insect or rotproof than they.
I used a woodstain - bugger me - can't remember the name - but its not Sikkens or Ronseal, and its fine inside, but UV and rain is messing up parts that get a beating outside.
Ah Sadolin. So don't expect Sadolin to last under pressure.
Thers a real problem with oak: Stick too much on and it looks plasticky. Not enough and teh water gets underneath it and blows it off.
I can't see why a woodstain is necessary cos oak is a pleasant enough colour without staining and will weather to silver within a few years
I can't see why preservative is necessary or 500 year old oak timber framed houses would have fallen down centuries ago
So I'd be tempted to put nothing on the frames. You could ask for advice on the 'period property' pages cos I spex they will be able to give you the pros and cons, but what I certainly wouldn't do is to bung something on in a hurry and regret it afterwards
Anna
~~ Anna Kettle, Suffolk, England |""""| ~ Lime plaster repairs / ^^ \ // Freehand modelling in lime: overmantels, pargeting etc |____|
Wayne oak is susceptible but heartwood is quite good at standing up for itself. However most ancient oak timbers were creosoted and covered with pitch or some other standard preservative.
500 years ago a tree cultivated for the purpose it was eventually felled for, would spend a few years pointing downstream in a clean, fast river. This would wash out all its sugars and starches. It might then have been buried in mud. Quite elabourate techniques were used in the good old days. None of them involved rushing them through a bakery.
What would be saved buy not using preservative? Ten or twelve quid?
I suppose I assumed that joinery would be made only of heartwood, just so it doesn't twist and warp, which is important for opening window frames
My experience is in using oak for massive timber framing. Timber framers today don't use timber which has been preserved, or soaked, or buried in mud. What they do like to use is airdried oak, not kiln dried
maybe preservative will clog up the pores so the timber can't breathe properly ... maybe it will become impossible to get the silvery weathered oak effect ...
Anna
~~ Anna Kettle, Suffolk, England |""""| ~ Lime plaster repairs / ^^ \ // Freehand modelling in lime: overmantels, pargeting etc |____|
Ther is a difference brtween being rained on a bit and being permenently damp Anna.
Oak rots over 20-30 year period if very exposed.
My extenla cills are showing signs afrtre a couple of years even WITH varnish on.
Internal tmber farmes stay dry and don't need anything really, but again, if damp gets in, so does rot and death watch. You can examine the pile of old oak timbers down my garden if you need convincing. We burnt the worst ones.
I think its bad advice. Oak rots. Period. Unless its kept dry, and exterior frames do not stay dry.
If you want teh silvery wetahering, leave it in te sun and don';t put anything on it, and watch as teh silvery eathering gradually changes to deep scoring weher teh softer parts rot away.
Alternatively limewash it and hop the bugs don't like the taste.
Oak is a combination of soft & hardwood as I recall, and it is the softwood which can (more easily) rot - hence the "weathering". o Hardwoods like Iroko & Teak are very oil heavy o The oil has to be stripped (Meths) before you can paint them
Green oak also likes to change size, shape.
Ask Sikkens re the best finish - and preparation o Sikkens Cetol
---- lasts 7yrs + lots of "wood colours" + overcoatable o Sikkens Rubbol (gloss) & Satura (silk)
---- lasts 6yrs + many more colours + overcoatable
---- use Onol vs Onol Express undercoat (former seems better)
Unlike cheaper overcoatable paints it does last: o Dulux Weathershield 1/2/3 seems to fail at 3-4yrs
---- Cobalt salt smelly primer + Trade Undercoat + White Gloss
---- Gloss very good for 6 months, then similar to Rubbol, then worse o Rubbol AZ seems to fail at 5-6yrs
---- used Weathershield primer + Onol + White Rubbol (AZ) Gloss
---- Gloss very good if you do it right, better than Dulux at Yr1+
---- get it on clothing and you need an angle grinder to remove it
---- less suitable for high wear areas, altho Weatherhshield shells Yr3+
If you think Weathershield preservative smells, Rubbol AZ will burn your eyeballs off for days afterwards. Horrific, looks like enamel & lasts.
Oak, colour, appearance, UV, even south-facing, maintenance; Cetol.
You may well be right, I'm not an expert. I was pointing out that varnish preservative etc might not be a good thing to use to protect it which your 'rotting after 2 years' might confirm. Limewash works well on the 500 year old Lavenham Guildhall
Agreed that trapped damp is a killer. Was your old house rendered with cement perchance? Is your window varnish trapping damp? One of the main reasons oak was used for BOTH timber framing AND for building ships is cos it can cope with being wet or dry without decaying. It is the ?only? native timber which is so robust
Ships are not dry
OKOK I'm not giv>Oak is a combination of soft & hardwood as I recall
No you recall wrong. Oak is a hardwood
That is the 'early wood' which is formed as the sap is rising. It is still hardwood
So why would the OP go to the lengths (and expense) of buying oak windows rather than the standard pressure impregnated pine. He already has good "wood colours" which presumably he wants to make the most of
Enuf. Shut up Anna and go and do Xmas shopping Anna ~~ Anna Kettle, Suffolk, England |""""| ~ Lime plaster repairs / ^^ \ // Freehand modelling in lime: overmantels, pargeting etc |____|
Yes, but thse timers dont get and stay sodden like horizontals do. Sole plates always first to go. Would expect Lavenham to be on 3rd or 4th set.
That is simply not so Anna. Its one of the best woods, but it rots nonetheless - come down my garden and look at the old timbers out of the house. They are rotting even as I write.
That old house rotted because it had roof leaks, rising damp, and water got in the walls and stayed there, and it had been horribly and badly patched. Thats why I demolished it. Only one interior wall was worth preservng, and the groundman knocked that over accidentally with his tractor.
It is
Best *british* timber IIRC tho Yew comes close. Teak is better, and cedar also has some anti-fungal properties I think.
They rot as well. Very few 300 year old oak ships around.
In laws had an old Uffa Fox built 30's oak dinghy, Thats rotted to nothing. Very sad.
Ships were tarred outside extensively, and dry inside wherever possible.
Teak became the wood of choice as it doesn't suffer so much from fungus IIRC.
No wood will survive a mixed wet and dry environment: You either go for total immersion al la bog oak, and there the peat preserves it, or keep moisture below about 20%, which os not enough to promote fungal growth etc.
What on earh do yiuy think happened to all the old oaks that fell down since the year dot? Rotted my dear. Rotted.
In this case I know I am right. Oak rots period. Ther are ways to stop it but leaving it alone in the wet ain't one.
Its arguable whether bad treatment is worse than no treatment, I'll admit.
I'm still looking for a good one. May try Sikkens next time.
Hradwood being a definition of a deciduous tree. Like balsa. Thats a hardwood too. Though not a hard wood.
If not hard wood :-)
I agree. Oak is a bastard if you want to paint. Open grain, moves like a bitch and tends to crack. never choose oak for a paint finish. Iroco et al much much better.
Wood rot in boats varies by level: o Fresh water through decks -- rot a problem o Fresh water from condensation -- rot a problem o Salt water in the bilge/keel/bottom -- far less a problem
Salt acts as a preservative.
Sikkens do a clear Cetol, and I guess Dutch Oil would be ok? The risk of picking a bad finish is real, there are some really quite putrid yellow Cetol colours which ruin the appearance.
Felt a bit sacriledge putting white rubbol on an Iroko gate, but I'd only done the frame in Iroko, horizontals were pine.
Plenty of places do let wood naturally weather: o Iroko cladding, red-cedar cladding o Red-cedar shingles
However for windows most people want absolute longevity.
Ike I think has the highest rating for wet rot tolerance, ie, stuck in the ground at high humidity & high temp. Teak, Iroko & Oak are pretty high on the list too.
Lloyds register sites should have some info on wood: o Which is best (rated) for which application o Might extend to what treatments are best
Iroko fresh from the mill can twist & crack, and Sikkens advise the higher hardwoods need care re the oil - you have to get a clean surface for Cetol/Paint to adhere.
Iroko decking doesn't need arsenic laden tannalising.
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