What wood to use for park bench rebuild project.

[dbhost]

I recently salvaged a garden bench from a neighbors heavy trash. It's one of those benches with the cast iron ends / legs, and wooden slats for the seating surface. I was able to manage to save a couple of the original slats for hole spacing for the bolts, as well as for sizing of the replacement pieces. And I am making good progress with the Evapo Rust. Boxes of 10-24 x 1.25" stainless phillips head screws, lock nuts and flat washers have been sourced and stand at the ready for the project. Now I need to figure out, what sort of wood would be best / most cost effective to replace the original slats with...

The entire thing will be painted, but when completed, it will life its life on a bed of crushed gravel under my magnolia tree. So exposure to the elements, particularly sun, heat, humidity, and rain are going to be major factors for this bench...

The slats will be fully painted and pre drilled prior to assembly to eliminate the possibility of moisture migration to some uncoated piece of wood...

I am honestly leaning toward using pressure treated SYP. It's cheap, readily available, and stands up to the elements well. But my concerns are, with this being a bench, and with me being a rather substantial guy, is would pine be sufficient for a seating surface? And would the PT stuff hold paint well?

What woods would you suggest for such a project?

[JimD]

I would use the southern yellow pine, pressure treated. Plain southern yellow pine would be a decent choice too. It is relatively strong and decently weather resistant. PT takes paint well once it is dry. The typical stuff from the big box store will need to dry for a week or two to take paint properly. Strength should be fine if you are selective. Knots from dead limbs (detectable by the black ring around them) and splits are to be avoided.

The chairs, footstools and table on my open deck are all PT pine painted. They need repainted again now but the wood is fine and the paint held up for several years. In direct sunlight, that's all I expect. I also made the screen panels on my screen porch of PT pine. That was in the winter time and the wood was dryer. The paint is holding up better maybe partially because the wood was dryer or perhaps because it is a little less exposed due to overhangs.

Jim

[chopnhack]

Having used PT SYP in Florida I will tell you this...

Even after dry, primed and painted the wood still moves... You may require frequent patching and repriming and painting. It's just a fact of the material. I have both a mailbox post and a raised garden box made of the stuff and primed and painted, the mailbox post got a semi-transparent stain (IMHO its paint) and within a year in the elements the wood "opens" up and the grain "comes" through. I have toyed with the idea of sanding it down again and spreading on some bondo, lol but I haven't done it yet.

[LCHIEN]

Maybe try some TREX, that plastic synthetic wood. Machines well I hear and will last a long time. Just a suggestion.

[dbhost]

I actually considered TREX, but seriously doubt TREX can handle weight without excessive flex.

[pelligrini]

Do you really want to paint it?

If I was going to spend a lot of time cleaning up the iron and redoing the slats I'd probably go with white oak and a penofin finish. I belive the oak would be a bit stronger than PT SYP too.

[Cochese]

If you are going to all the trouble of fixing it up, might as well spend a few bucks on teak or cedar.

[tommyt654]

Considering Texas ranks 10th in the country in forest products I would think there's no problem with variety. SYP is popular and cheap, but the arsenic used to treat wood is nothing I would care to have touch my skin even after painting the chemical can leach threw. I would lean towards red or white oak readily available and very strong.Looks great painted or stained or just a clear-coat. Redwood could be another possibility to consider if available.

[chopnhack]

Considering Texas ranks 10th in the country in forest products I would think there's no problem with variety. SYP is popular and cheap, but the arsenic used to treat wood is nothing I would care to have touch my skin even after painting the chemical can leach threw. I would lean towards red or white oak readily available and very strong.Looks great painted or stained or just a clear-coat. Redwood could be another possibility to consider if available.

I thought they banned CCA in early 2000's? What you say about the leaching is true, but I don't think they use that in the states anymore. I think they use some other copper molecule.

[LinuxRandal]

I think it is ccq now, instead of cca. (unless they changed the formula again)
I understand the reasoning for pressure treated, but I think I would go for white oak (more water resistant/pore differences, then red oak).

[LCHIEN]

true, CCA with arsenic is no longer used in the treatment of pressure treated pine anymore and hasn't been for years. Since 2004 hey have used alkaline copper quaternary compounds (ACQ) which has no arsenic.

Even so the main worry about CCA was leaching arsenic into the ground from buried prolonged ground-contacting parts of the wood... not a problem with a bench.

http://en.wikipedia.org/wiki/Chromated_copper_arsenate

[JimD]

I have a bench that is probably quite similar. Surprisingly, the original slats on the back have rotted and failed while the seat is OK. It's in an area where I do not really need seating so I haven't fixed it (at least that's my story and I'm sticking to it). The wood was some kind of hardwood that doesn't grow here.

It's true that PT wood doesn't much care for sunlight and trex flexes a lot. I used Trex on my outside deck because I did not want the huge splits PT develops. Painted I have not had that kind of performance. The two chairs on the same outside deck are OK to sit in, at least for me, but could use repainted. I guess it depends some on how picky you are. What I think is OK could be considered not OK by others. If you do not want to see some splits, then you should at least use clear SYP. It should be strong enough and it weathers fine painted. My exterior doors are hung in finger jointed jambs. Where somthing softer, I think maybe spruce, was the bottom piece, I had rot and had to replace. Where SYP is the bottom piece, no problem. These contact concrete so it is a worse situation than the slats on a bench would be.

If you use SYP, PT or not, I would either put a coat or two of shellac on it before paint or use Kilz. The original works better than the latex but I usually use the latex. SYP is bad for bleed through, at knots and otherwise.

Jim

[tommyt654]

I stand corrected, but still wouldn't use any lumber products that come in contact with humans on a regular basis for anything other than ground contact as even the ACQ is basically a chemical used to stave off fungus and insects(you want that leaching thru to your skin) and the like, better off with untreated lumber and a good coat of oil based paint if necessary or as some suggested a latex(I prefer the oil as it last longer)., from wiki, Alkaline copper quaternary

Alkaline copper quaternary (ACQ) is a preservative made of copper, a fungicide, and a quaternary ammonium compound (quat) like Didecylthyl Ammonium Chloride, an insecticide which ALSO augments the fungicidal treatment is a wood preservative that has come into wide use in the USA, Europe, Japan and Australia following restrictions on CCA. [6] Its use is governed by national and international standards, which determine the volume of preservative uptake required for a specific timber end use.

Since it contains high levels of copper, ACQ-treated timber is five times more corrosive to common steel. It is necessary to use double-galvanized or stainless steel fasteners in ACQ timber. Use of fasteners meeting or exceeding requirements for ASTM A 153 Class D meet the added requirements for fastener durability. The U.S. began mandating the use of non-arsenic containing wood preservatives for virtually all residential use timber in 2004.

The American Wood Protection Association (AWPA) standards for ACQ require a retention of 0.15 lb/ft3 (PCF) for above ground use and 0.40 lb/ft3 for ground contact.

Chemical Specialties, Inc (CSI, now Viance) received U.S. Environmental Protection Agency's Presidential Green Chemistry Challenge Award in 2002 for commercial introduction of ACQ. Its widespread use has eliminated major quantities of arsenic and chromium previously contained in CC

[dbhost]

Okay so no Pressure Treated stuff...

It's looking like White Oak would probably be best. I saw the recommendation for Cedar and had to control an outburst of laughter. Cedar is nice for certain uses, but for putting my fat tail on, forget it!

So I am guessing I would need stain or oil finish of my choice, followed up by either Spar Varnish, or Spar Urethane as either of those should remain flexible enough to allow flexing of the slats when weight is applied...

[pelligrini]

I haven't used it (yet), but I've read about and seen firsthand some good results with using some of the penetrating oil finishes that penofin makes. The spar products would remain flexible, but being more of a film finish they might be susceptible to scratches from metal rivets on jeans and stuff in pockets. With the Spars you mentioned, refinishing is a lot more difficult. An oil can be re-applied without the need for sanding.

Last year we had a high end wood door & window manufacturer stop by our office with their trailer. The trailer was built as a showroom with all their doors and windows making up the sides. I think their shop was way out west. I was pretty impressed with the oil finishes on the teak woods that were exposed to a lot of weather.