Treat exterior decorative wood beams

[drublic]

Hello trusty DIYnot forum.

First time post go easy on me. Just bought a house and popping my DIY cherry.

I have wooden beams on the outside of my house and need to treat them. You can see from the pics they are pretty weather worn. They seem to be creased and cracked in places.

I was going to buy a tin on ronseal wood stain and give it the once or twice over.

Do I need to do anything else? Does it need sanded or prepped?

View media item 81692
View media item 81693
View media item 81694
Going to try and do it myself. Wish me luck! Any tips?

 

[JohnD]

Are they purely ornamental, or do they hold the house up?

Press any suspect areas, especially towards cut ends, with a chisel-tipped screwdriver, to test for rot or worm (don't use anything pointed, as the marks will look like insect damage)

 

[drublic]

Purely ornamental, they seem to be bolted on the outside of the concrete. Will test for rot tomorrow evening.

I should note it's a listed building in a conservation area; AFAIK replacing things is a last resort after exhausting refurbishment.

 

[AronSearle]

They look fairly well done for "mock Tudor" beams, and they don't look decayed, though follow the above advice and test.

There are signs of the timber weathering, so you will want to sand them, otherwise the new coating will fail early. A stain type product will be suitable.

Pay particular attention to the ends of the verticals, as due to the way they butt the horizontals, water is more likely to get into the end grain (though any end grain area is key). If they are easy to remove without upsetting the render, I would remove them so as to fully preservative treat and seal the end grain.

 

[foxhole]

I would apply teak oil first, then your stain, sills will need double the coats of any vertical surface.

 

[AronSearle]

Would an oil not stop the stain being taken up properly?

 

[JohnD]

you might also try a water-based shed and fence stain. These leave a waxy water-repellent decorative film, the big advantage is that they are very easy to apply and recoat, no sanding needed, you just clean with a stiff brush. Depending on exposure you may get more than five years between treatments.

timber preserver like Cuprinol will soak in and delay decay. They also make spirit-based preservative stains. Spirit treatments have to be fully dry, and preferably weathered a bit, before applying paint, oil or stain.

 

[foxhole]

Would an oil not stop the stain being taken up properly?

No it dries and behaves like oil based paint, the majority is absorbed by the timber.

 

[AronSearle]

Hmmm, paints sit on the surface, oils are meant to absorb into the fibres, paint would stop uptake of the stain.

 

[foxhole]

Hmmm, paints sit on the surface, oils are meant to absorb into the fibres, paint would stop uptake of the stain.

Stain just sits on the surface, it peels with age like gloss.

 

[AronSearle]

Hmmm, paints sit on the surface, oils are meant to absorb into the fibres, paint would stop uptake of the stain.

Stain just sits on the surface, it peels with age like gloss.

There are different stains, most erode, some are more surface based.

They would peel rather than erode if a finish is put under them first.

:roundabout jpeg: