Timbers for external use

[Arthur2]

Hi all. Can most any timber be used for weather exposed situations providing it is well treated with preservatives? And also, that it is of a heavy enough section? eg, timber panelling from 6mm ply is a bad choice?

Thanks.

Arthur

[stuart noble]

What's the application? Anywhere where water sits for long periods will rot regardless, which is why fence posts rot before panels, even though they're many times thicker.

[Arthur2]

Panels in lower half of sidelights for front door frame.

Arthur

[stuart noble]

I've seen t&g used for that sort of thing but, whatever the finish, it always rots at the bottom, especially if it faces the prevailing weather

[Rednadnerb]

This is something I have been wondering as well. The barge board on my sisters 12 year old extension is completely rotted away. The woodwork on our 100 year old house is slightly rotted in some exposed places. Teak never seems to rot. When you pick up a piece of wood, how do you know how resistant to rot it is?

I don't know the answer but I would never use kiln dried wood outside however much preservative was applied to it.

[The Medway Handyman]

I think there is a section about this on the Wiki thingy?

[Piers Finlayson]

There was this informative post recently:

[Arthur2]

the prevailing weather has been kickin the crap out of my front door since I moved here more than 17 years ago. The door looks like shit but while the paint on the frame is kaput, the frame is solid. And thats despite the frame verticals extending down to the door step. The paint is several layers deep. What preservatives did they use in days of yore (30/40/50 years ago) ?

Arthuir

[Dave Liquorice]

How big are the appatures? 6mm ply won't stand a kick and could prove to be an easy means of entry...

[The Medway Handyman]

Good point.

I was watching one of those 'how easy is it to burgle your home' shows a while ago, where they had an ex burgular showing how easy it was.

Back door to the house had all the correct locks etc. Half glazed door, bottom panel was plywood, a couple of kicks & it was wrecked.

[Arthur2]

I was only mentioning 6mm ply as an example of what not to use in a round about way. I will use timbers of at least 18mm thickness.

Arthur

[mail]

Dear Athur Answers to your questions

1) No Supplementary point - treatment with preservatives is a complex subject and the only treatment that will out live you would be tanalith and that is unlikely to be suiable or your door panel so your best bet is to choose the correct species and type of timber AND the supplemaentary treatment process which also will involve surface coatings 2) No 3) yes - a bad choice

Piers has kindly helped by posting my last effort on the subject - which after you have read it - feel free to come back to me with some more specific suggestions involving species, proposed treatment and surface treatment - I can commment Chris G

[Andy Dingley]

Timber species that don't need applied preservatives will generally outlive those that had preservatives applied.

As a good starter, larch is cheap and long-lived. For any more detail, tell us what the application is.

[Arthur2]

Thanks, Chris. The door frame has red hardwood verticals from a timber yard

I am using mahogany for the horizontal pieces. (This is my ship and I'll sail it any way I want) The panels for the lower half of the sidelights 260mm x 1100mm, will be mahogany...probably joining two 150mm wide boards of 20 - 25mm thickness.

I hope thats easy to follow.

Thanks again.

Arthur