ground contact lumber

[n15533]

any alternates to PT for ground contact lumber.  for sill plate on concrete and want to use timbers I have not use a bunch of PT

uh...paint on in particular, like anchorseal, coppercoat, etc

[Andries]

Welcome to the Forum.
If you go to your profile and add more info such as where you live, the answers to your questions will be better. 
First suggestion: You can spray on Timbor or Solu-bor, two similar products, both contain borates.
It'll kill termites and other bugs. It'll soak into beams to give them some protection.

[longtime lurker]

Copper napthenate. It's a brush on, available in retail volumes, and won't leach out like borates will. Nisus corp is the manufacturer - I'm sure their website will have retail stockists or a contacts page for where to get it.

[GeneWengert-WoodDoc]

Pressure treatment assures that chemical goes deep into the wood.  Surface treatments do not go deep.  A nail or screw or crack or drilled hole or end split or a cut end and similar all expose wood in the interior of a piece of lumber.  The depth of treatment with PT minimizes the risk from such exposure of the interior, while non-PT does not provide such protection.

Note thaT PT sawdust and cut off ends and similar must be disposed of properly.  This is true for any treated wood.  Borates are fairly safe, but require soaking to get deeper penetration.  With some species of wood, however, even soaking will not get deep penetration.

The question boils down to an evaluation of the chance of failure and the cost of such a failure.  If a sign post fails, the subsequent cost is small.  If a fence post fails, and a few cows get out onto a high speed road, the cost is high.  If a piece in a house fails, the cost can be very high, especially if it is a deck and there is human injury.  Wood in a dry basement on a concrete floor has little risk, if the ends are treated separately.

[Don P]

for sill plate on concrete

Actually for sills, which is a non ground contact, out of the weather use, where the sill is not in direct contact with the concrete, separated by sill seal or similar, naturally durable species or borate treated woods are approved by code.

[bushhog920]

Copper Naphthenate 8% (68% by Volume) Concentrate from Poles, Inc

[Bandmill Bandit]

Larch/Tamarack is one of your best choices for wet locations and ground contact. Ive yet to find any thing better including pressure treated lumber.  

[Crusarius]

I have gotten in the habit of using composite decking to isolate any wood from the ground. Not really cheap but works quite well and does not rot.

[GeneWengert-WoodDoc]

Research has shown that second growth of some species does not have the decay resistance and/or insect resistance of the virgin growth.  So, today's wood is often not as resistant as the older books have for older wood.  Unfortunately, the old info is sometimes used today for today's wood, unknowingly.  

Perhaps more important is that sapwood has no appreciable decay or insect resistance...virgin or second growth.  This is an issue with many so-called "naturally resistant" species, as today, with smaller trees, sapwood is present in a lot of lumber pieces.

For these two reasons, PT lumber that is properly treated, as indicated by an authentic stamp or label, will outperform naturally resistant North American species.

[Mad Professor]

Put your sill plate on top of a piece of 2 X pressure treat.

[GeneWengert-WoodDoc]

When building in the termite zones (mainly in the South), we are concerned about termites that come through the ground, rather than the flying termites we have in many tropical countries. As many people know, these ground-contact or subterranean termites can enter a home or other building through a minute crack in the foundation or even by a nud tunnel between the ground (moist soil preferred) and untreated wood.(or wood without natural resistance, including sapwood of all species). The termites prefer wet wood, as their jaws are not strong enough for really dry wood.  They must have a connection, therefore, to water.  So, we often see them around incoming water pipes that have condensation in the humid summer, or areas with poor drainage from rain water, and so on.

So, in the South, we need to use various techniques that our northern neighbors do not have to use.  Using PT lumber for a sill plate is fine indeed, but these termites are able to build a tunnel over PT wood to nearby untreated wood.  So, using PT wood in contact with the ground is wise, but that is not enough if the rest of the wood is untreated.  Inspectors will look for these tunnels.  

Sometimes a builder will use a metal termite shield (flashing) between the contact of PT wood with untreated wood.  Sometimes in lower risk situations untreated wood in contact with PT wood is sprayed with a surface preservative to make any termite tunnels too long to reach untreated wood surfaces.  Of course any insecticide must be safe for the occupants.  And it is not uncommon to see in the Southern risk areas that the entire basement or first floor framing of a building is using "YellaWood" (R) or similar.  Basically, untreated wood cannot be in contact with PT wood without some special care.

[Magicman]

 

 



 



 

PT stops rot/decay, not termites.  Metal flashing all of the way.

There are different treatment specifications depending upon the use:  LINK

[Don P]

Termites are another problem, I've had them tunnel over locust and white oak, too hard for their jaws, in order to get to easier wood. They can come up through unfilled block totally hidden and know how to hide from easy inspection. A termite shield does not necessarily stop them, it simply makes it easier to see the tunnel as they run around it. Any punctures, laps, abutments to old work, etc are vulnerable. Aluminum and PT are incompatible, the copper in treated (the green) and aluminum create a battery that pinholes the aluminum in pretty short order. Piers, the backside of stairs, porches, posts, garage door framing, etc, are all hidey holes for the little buggers, they don't advertise their presence. On one job I poured footings and they had tunneled across them by the next morning, I called in the big guns to poison the perimeter and took a week off. I found the nest at the frost line in old foundation rocks later, which is typical. On another they were running the roots from the outside mint bed back to the house. Remove all organic matter and wood debris from crawlspaces, they sniff out decaying organic matter and are attracted to it. In some places of heavy infestation, especially with tropical drywood termites, all structural framing is borated lumber. This will work with subterranean termites or any wood ingesting insects as well. That is not a casual level of borate though and it will not work in ground contact or where there is a "sink" that the borate can leach into. It works well for protected wood such as sills and structural framing. I have used it to successfully evict them and powderpost from old houses.

[Mad Professor]

I'm too far north to have termite issues.

But, it's good to have learned about the problem, and solutions.

[Don P]

There's a termite probability map, as well as a bunch of useful stuff, in chapter 3 of the IRC;
https://codes.iccsafe.org/content/VRC2015P2

They are interesting creatures. I could dump a colony of subterranean termites out on a wood floor and they would all be dead by morning, they must have a path back to moisture. That is the purpose of the mud tunnel. Drywood termites can fly into a wall and move in, they can survive on the moisture in the wood, they are in Hawaii and have begun moving into the deep south. Termites never sleep, they are on 24/7 from birth to death. They have the ability to convert cellulose to digestible food, we could learn a thing or two from them.

[longtime lurker]

One thing I've learnt from this thread is most y'all know very little about pressure treatment. A lot of people get hung up on the process - pressure treatment isn't that complex, and while there are other ways to impregnate wood with preservatives it's the easiest and fastest for cost effective industrial application. Wood preservation technology is an entire field all of it's own, and I could probably write 100 pages on it and I'm no expert... so this will be very abbreviated and very general...


Pressure treatment is one of the range of methods to get preservative chemical into wood. Note thats INTO not on... a spray with borax is not treatment. P.T. is just an application method - the effectiveness of pressure treatment is in the chemicals used, not the process itself. There are a range of chemicals suitable and the nature and the retention level of those compounds in the wood after treatment is what determines its effectiveness. LOSP can only make H3 level protection. CCA can be used lightly to get H3, or with stronger treatment solutions can be taken to H4/5/6 levels of protection. It's all about what you use, and how much of it okay.

With pressure treatment we place lumber into a chamber and pull a vacuum  When we pull a vacuum it removes all the air from the cylinder but it also sucks water from between the wood cells in the outer layer of the lumber.

We then flood the chamber with solution and apply positive pressure. Flooding alone has an effect similar to spraying it on - it just coats the outer layer of the wood. The positive pressure however forces the chemical into the cellular structure and replaces the water removed by the negative pressure cycle.

We hold it under positive pressure for a period of time, depending on the treatment solution and the desired protection level that will vary. 

Then we release the positive pressure and drain the solution back out of the treatment vessel.

Then we pull a negative pressure again to remove excess solution.

The result should be that all sapwood is now fully impregnated with solution, and the outer layer of heartwood... in hardwoods at least it does not treat beyond the surface layer of true wood. I dont know much about pressure treating softwood species.

What you've done is create a  barrier layer - or envelope treatment - of treated wood around an untreated core. the effectiveness of that barrier will depend on the type of chemical used.

Pressure treatment with borax is still prone to leaching - but its a nice user friendly environmentally safe option for non exposed lumber.

Mostly pressure treatment however is used to get more stable preservatives in place. These range in effectiveness... and also in environmental and user safety issues. These things are poisons - they are designed to kill living organisms - and some degree of caution is required in their use. As with most poisons the better it is at killing undesirables like fungui, bacterial, and insect pests the better it is at killing other living things like people as well.

IMHO the best wood preservative ever is CCA. Copper chrome arsenic is a relatively safe solution to treat your lumber with, it gives long lasting protection against insect and decay organisms, is stable and not prone to leaching from the wood.... and everyone freaks because its got arsenic in it. You would need to eat about 14lb of CCA treated wood to have a health issue, but people flip over it so it's falling from favour.

With structural and other external hardwoods the current favourites are all copper based salts. I'm most familiar with ACQ, but theres Copper azole, CuHDO, and a few others. Copper is a very good wood preservative that resists decay, and additional salts are included in the various formulations to act as insecticides etc. As mentioned above it also is copper and can have an electrolytic reaction with other metals, such as aluminium and zinc galavanising compounds used on fasteners.  However this damage to fasteners has to be weighed against the extended life span provided the wood from treatment.... woods treated with the copper compounds last on average 5 times longer than untreated wood.

LOSP is also popular - its a clear, light organic solvent applied to finished (dressed) lumber similar to kerosene and does not have the copper green/brown colour to it so it retains the natural colour of the wood 

The most effective treatment IMHO is still Pentachloride, but its going the way of the dodo. Penta is basicly a way to make DDT stick to wood, and it has all the risks of a persistent organochloride included. It does what wood preservative is supposed to do - kill things that eat wood.



Back to OP's original query...
Copper Napthenate is a copper based antifungal & insecticidal preservative chemical. The nature of it however is that it is not an aqueous solution - that is unlike most of the above copper based preservative compounds it doesnt dissolve in water. This is both good in terms of leaching resistance to treated lumber in situ , but it makes it uneconomical to apply in the volumes suited to industrial pressure treatment where water is used to dilute the chemicals for use.

Copper napthenate however does mix with a range of organic solvents. In practice it is usually used in conjunction with kerosene (LOSP) or a preservative oil... you dilute the concentrate with kero and then brush it on. Kero, as with most organic solvents, is happy to soak into lumber... so you paint on your mixed CuNap/kerosene solution which soaks into the wood (into not on again), and than as the kero dries the copper compounds are left behind. Several coats will be required to get enough to form an effective barrier envelope however.
It's good, it works, it's not unduly risky in terms of exposure either during application or after, it gives a high degree of protection for an extended period of time, and you can apply it without the need for a treatment plant. 
That makes it a winner for backyard use where you arent trying to treat lumber by the ton

[tule peak timber]

Pentachlorophenol, mans best friend for wood. But as you stated the chemical, as well as me ,are one of the Dodos, in many ways.....

[longtime lurker]

Penta is banned here now, has been for 20 years. But... Best wood preservative ever. I can't buy Penta, I can't use Penta... But it is legal to import wood treated with Penta M( go figure). My local shire (county) imports some of their bridge girders in ex the west coast for just that reason... They'll be there long after my ACQ treated wood fails, even though my species are more naturally durable.

Had a discussion with someone a while back about CCA and they got to the "what if my dog or child eats the treated wood" line of reasoning. My answer was well it's supposed to kill things that eat wood... Teach your kids and dogs not to chew the furniture... wasn't appreciated. :D

[tule peak timber]

Actually one of my sales arguments, but what if your kid eats the furniture.....unreal......

[GeneWengert-WoodDoc]

CCA was banned in the US quite a while ago, except for a few special uses.

A treating process that starts with an initial vacuum is called the full cell process, while one that adds pressure first and then the solution is called the empty cell.  Both finish with a final vacuum.

I would add to the previous discussion that the effectiveness of a treatment is dependent on the chemical used, AND THE AMOUNT in the wood, along with the depth of penetration.  For example, ground contact PT wood has more chemical and is deeper.  Of course, as the amount of chemical goes up, so does the cost of the treated wood.

There are many backyard DIY treatments, but they are not as effective as PT.  I can remember on the farm we took a 55 gallon drum, heated a preservative solution in it and then put the ends of fence posts in the solution.  The heat drove off some water in the wood and expanded the air in the wood, so we could see bubbles rising.  Then, as the solution cooled, the air left in the wood contracted, pulling some preservative solution into the wood.  The poles dripped like crazy when we lifted them out and if we put them in a hole right away, I am sure the soil was treated too.  What was left in the drum was now a mix of water and chemical solution, but was not string enuf to do another batch.  I do not recall how it was disposed of.  Obviously, human and environmental safety was not a huge consideration.

Creosote pressure treated railroad ties with creosote are another issue indeed.

[Woodpecker52]

I use coppo green wood preservative, got at Lowes online about $26 a gallon, also can coat the bottom with an black asphalt based paint, found it at tractor supply about $18 a gallon,  it says to use with posts in contact with ground but I used it to treat oak timbers under shop floor in 1986 and nothing has touched them and still looks as solid as they day I painted them.  You do need to metal flash any wood to concrete contact like magic man says.  This is the best barrier for termites in the end its all about keeping things high and DRY in the south, if it gets wet it is going to rot and a good wide lipped metal barrier stops a multitude of problems.

[barbender]

I'm sure glad we don't have termites up here. There are definitely some benefits to our bitterly cold winters😁 I was surprised when one of my aunts that lives in north central wyoming told me they had termite damage in their home. I didn't realize that little boogers made it that far north- and they get some nasty winters too.

[RichTired]

The first fence posts I installed on my property over 40 years ago were post that I soaked in a 20 gallon drum full of creosote.  Left them in a day or so and put them in the ground wet and dripping.  Most lasted 35 or more years.