Cleaning up the balcony after building

Paula enjoying the sun on the new balcony

You may remember that we put in our balcony when we finished plastering and painting the outside of the house. There are 43 larch planks (not sure how thick - at least 30mm) with bevels on the top (presumably so nobody slips if they are wet). Larch is quite a nice timber to look at - a kind of orange/red colour. The timber is hard as iron - particularly the heartwood that we went for (hoping it will keep for years). It was delivered and installed untreated.

Filthy dirty planks

Since then, months have gone by - in which we plastered the inside of the house, painted the inside of the house and did hundreds of other jobs. All this time, the balcony was being (mis)used as a kind of storage space or dump for materials. It also got very dirty. Working boots, shoes, spilled drinks, paint - the whole lot. Having moved in, it was getting to be time to do something about the mess - particularly if we wanted to take advantage of our balcony with glass roof in spring at all.

I started off sanding on the east side. It was taking ages. The timber really is hard as iron and sanding it wasn't doing any good - at least not with 60 sandpaper. Anything rougher tended to scratch the timber without actual doing the sanding job. That's when I decided to go get the electric hand sander I used for the beams in the kitchen and in the bedrooms. The reason I didn't start with it is because I was afraid the circular motion would scratch against the grain of the timber. The electric band sander (which always sands with the grain - unless you are very stupid) wasn't working. However, I reckoned I'd need until Christmas to sand it all with sandpaper, so I decided to give it a try.

It worked perfectly! With light paper (120), the sander took off just the dirt and pencil marks (from where I marked in the line so I'd know where to screw down the planks). The timber looked a lot less red afterwards, but at least it was clean. Very clean. I still had to sand the rills in the timber with sandpaper. Luckily enough, there was just loose dirt in there and very little dirt that actually had to by sanded off. All in all, the sanding took about two days.

After sanding, I gave the boards a coat of this stuff. Now this is the strong fungicide that we used for the exposed timber in the roof. It ain't cheap but it is very effective. It soaks into the timber quite quickly and should prevent any black fungal growths. Apparently larch is very resistant against rot and fungus anyway - even untreated. I had the fungicide left over anyway though, so I decided it's better to be safe than sorry. Even though the balcony has a glass roof (i.e. it is not completely exposed), I do notice that some condensation drips down - especially in the morning - and the wind can blow rain in too.

After the fungicide came the real fun with linseed oil. Since painting almost all exposed timber inside with linseed oil, I have become a big fan of this stuff. It has a huge advantage over standard varnish in that it actually soaks into the timber rather than forming a sealing coat on top of it.
For a floor, it made sense to do it this way - varnish might look great for a couple of months· but eventually feet and weather combine and it starts to flake, making it look terrible. Oil doesn't have that problem. Every so often I can just scrub it clean and put another coat of oil on top. Oil also has the benefit of allowing the grain of the timber show its colour again. Have a look at the "before/after" photos below.

The boards on the left are sanded but not treated with anything

Finally finished treating. The further away boards are still wet