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Best cheap treatment for exterior wooden deck, posts, etc?


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jojogumabew

Hi, I would appreciate some help in how to treat the exterior wood so it lasts as long as possible, preferably with a way that's not so toxic and not too expensive.

 

We're now doing the exterior wood work for our house in batangas. Our house is half concrete half wood.  The exterior wooden portion has a wooden deck and balcony made from mixed recycled hardwood (yakal, guijo, dungon, molave) and the exterior wall will have burnt cedar cladding (sho sugi, it's a japanese technique that supposedly extends the life of the wood to 60-80 years). 


To prevent mold/termites:

1) For the interior wood, I am using propylene glycol + borax + boric acid (if you google this diy recipe is easy to find).. This is supposed to be a minimally toxic, effective anti termite mix according to my internet research. Also before pouring the slab we put plastic/polyethylene sheets with lots of borax. The problem with this mix I understand is epoxy paint will have a harder time bonding to the wood. However the glycol is supposed to draw the borax, boric acid into the wood.

 

Anyway, I really hate the standard termite poison they use here which they inject into the house. It's a blue green powder which smells really toxic and the smell persists for months. 

 

Borax seems to work well. I bought a load of wood two years ago. We sprinkled borax on the soil and on the wood and lay it down fully exposed to the weather. We are just starting to use the wood now for our new house. Two bottom planks have some termite marks just on the exterior but everything else is good.

 

This is not an expensive treatment. 

 

2) For the exterior wood - I am planning to use ethylene glycol (similar to propylene glycol but toxic if ingested) + boric acid + borax. This is supposed to not just prevent termites but also stop mold/fungus. I understand you need to reapply the treatment every so often (couple of years?) if the wood is exposed to driving rain. Ethylene glycol is moderately toxic especially to animals because supposedly it's a sweet alcohol. But I read that if you mix it with borates they won't eat it.  

3) For further protection (UV, etc) and for the burnt cedar (from what i read and saw on youtube you need to put a finishing oil), this is actually where I wanted some help. Our foreman uses old motor oil. He is a very talented bantay (caretaker) of a rich guy who is our neighbor. He built a similar house with a lot of wood. They have wooden doors and windows and a large wooden deck. While mostly this is under a roof, it is almost totally exposed to the rain and wind during habagat. The house is over 20 years old and the wood looks 98% new. He's only replaced a couple of planks for the deck. He has a number of tricks which really make the deck last longer (using spacers etc). We're doing those as well.

 

However, I read that used motor oil is carcinogenic so I don't really want to use it. It also smells bad and doesn't dry. I don't know if unused motor oil is any better. 

I've read about using sadolin yacht/spar oil (which is really expensive in truvalue - P3-4k per gallon). For the burnt cedar, on youtube they use boiled linseed oil/tung oil. I've found some locally available linseed oil varnish which I am sure is much cheaper.

 

http://www.centurychemicals.com/details.asp?productid=12

 

If this is shiny, I plan to mix w talcum powder if I can't find a flatting agent.

 

 

I've also read to use polyurethane and or clear epoxy paint but my wife says this is the most expensive finish you can think of.

 

So far, I've been applying #1 to the interior wood. Will do #2 for sure for the exterior.

 

Am leaning towards the linseed oil/varnish thing but need to check out pricing. But since it's local, it's probably not going to be too bad.

 

 

Anyway would appreciate some advice on this? If possible with brand names of products and where to buy and approximate cost (sorry I know this is quite a lot to ask).

 

Thanks very much

Edited by jojogumabew
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Knowdafish

 

I am using propylene glycol + borax + boric acid

 

At what ratio? What percentage of each are you using, and where did you find you ingredients? 

 

At Handyman here in Dumaguete in Robinson's Mall they sell Solignum (expensive) and another stain. Both brands come in  clear and brown that supposedly prevents termite damage and repels water etc. I wonder if they also contain a UV inhibitor? One used to be able to buy a UV inhibitor additive to add to paint etc in the U.S., but I don't know if it is still readily available. 

 

The cheapest termite repellent I've heard of (and never tried) is to soak (especially bamboo) your wood in salt/ ocean water for a time and then let it dry thoroughly before use. 

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jojogumabew

At what ratio? What percentage of each are you using, and where did you find you ingredients? 

 

At Handyman here in Dumaguete in Robinson's Mall they sell Solignum (expensive) and another stain. Both brands come in  clear and brown that supposedly prevents termite damage and repels water etc. I wonder if they also contain a UV inhibitor? One used to be able to buy a UV inhibitor additive to add to paint etc in the U.S., but I don't know if it is still readily available. 

 

The cheapest termite repellent I've heard of (and never tried) is to soak (especially bamboo) your wood in salt/ ocean water for a time and then let it dry thoroughly before use. 

 

Hi fish

 

For glycol + borax + boric acid - 1 gal:3.5lb:3.5lb approximately. You have to heat this for the crystals to dissolve 260F (which i think is glycol boiling point). Then you can dilute 1:1 w water. You can google the exact formula, it might be 3.3 or 3.5 lbs. Btw, this is still experimental for me so please do this at your own risk and do your own research.

 

I bought the three items from a chemicals supplier here in Manila (atkinson). I just send my driver. I think its P650/gallon of PG, and maybe 300 per kg for Bx and Ba. The ethylene glycol i got from another supplier (allison?).  If you are in cebu, I would just call chemical suppliers in the yellow pages which is how we found these guys.

 

For toxicity, I just compare them based on what I read in wikipedia. We've used solignum before but this seemed more cost effective and less toxic to humans. Propylene glycol is used in soap etc so it's not toxic at all. Bx and Ba are minimally toxic.

 

Ethylene glycol (used in antifreeze) is moderately toxic so I am planning to be more careful in applying that.

 

As far as soaking wood/bamboo in salt water. We've tried this. I suppose if you soak it long enough it can work. However, we had some wood that was soaked a couple of times for an hour and still go eaten by bukbok. If you nail the wood, it will be more prone to rusting.

 

I'll check out the UV inhibitor.

 

Thanks

Edited by jojogumabew
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