I live in Austin, and there are plenty of rotting decks here too. But its mostly from three things, that incredibly shitty water based stain sealer which is 100% useless, the use of 1" deck boards, and/or the use of soft cedar.
I replaced 2" rotten cedar which was resting on 20+ year old pressure treated (and sunk in concrete footers) decking where the structure looked like it was good for another 20+ years with 2x6 pressure treated structural lumber+yearly pressure wash+oil seal/stain put down at a gallon or so every 100 sqft with a roller. The wood is checked, but none of the checking has gone more than a 1/4 the way through and 15 years in (on the oldest version of this ive done), it looks about the same as it did at year 2. I don't see any indications it won't last another 15 years, there isn't a drop of rot anywhere.
Its probably toxic as all get out, but I don't eat off it and outside of a week or two before the sun burns all the VOCs off I can't imagine its really out-gassing much.
The biggest problem was that oil based stain/sealers were getting really hard to acquire for a few years, but even the big box places have it again if you look.
Untreated pine (along with harder teak/mahogany/etc) was used in sailing ships for hundreds of years, in some of the worst enviroments. If you pay attention, a wood deck shouldn't really be any worse than wood siding on a house.
Personally I think a large part of the problem has been those water based deck sealers/stains which despite claims of wood penetration are just thin coats on the top of the wood which don't flex/swell with the wood and quickly are doing absolutely nothing but creating a layer between the wood and the sealer for moisture/rot to form. Put another way, i've yet to see a case where the stuff won't peel off after a couple years. Its basically really bad exterior paint. OTOH, the oil based sealers are linseed/etc and soak in and bind with previous layers, so you can switch from a stain to a clear after a couple years to maintain a particular color.
Oil based stain is the only way to go for sure. And cedar is definitely part of the problem. We purchased and refinished a Rainbow playset for my kid a couple years ago. We sanded out all the rot and old stain and used a very nice oil based stain. It held up much better but the cedar parts till needed constant maintenance.
The redwood posts and beams it came with however looked new after a light sanding and staining and there was never an issue with them.
I replaced 2" rotten cedar which was resting on 20+ year old pressure treated (and sunk in concrete footers) decking where the structure looked like it was good for another 20+ years with 2x6 pressure treated structural lumber+yearly pressure wash+oil seal/stain put down at a gallon or so every 100 sqft with a roller. The wood is checked, but none of the checking has gone more than a 1/4 the way through and 15 years in (on the oldest version of this ive done), it looks about the same as it did at year 2. I don't see any indications it won't last another 15 years, there isn't a drop of rot anywhere.
Its probably toxic as all get out, but I don't eat off it and outside of a week or two before the sun burns all the VOCs off I can't imagine its really out-gassing much.
The biggest problem was that oil based stain/sealers were getting really hard to acquire for a few years, but even the big box places have it again if you look.
Untreated pine (along with harder teak/mahogany/etc) was used in sailing ships for hundreds of years, in some of the worst enviroments. If you pay attention, a wood deck shouldn't really be any worse than wood siding on a house.
Personally I think a large part of the problem has been those water based deck sealers/stains which despite claims of wood penetration are just thin coats on the top of the wood which don't flex/swell with the wood and quickly are doing absolutely nothing but creating a layer between the wood and the sealer for moisture/rot to form. Put another way, i've yet to see a case where the stuff won't peel off after a couple years. Its basically really bad exterior paint. OTOH, the oil based sealers are linseed/etc and soak in and bind with previous layers, so you can switch from a stain to a clear after a couple years to maintain a particular color.