Wood For Picnic Table

04/05/2015


From original questioner:

I need to make picnic table for a customer. First species that comes to mind is redwood 2 x 4s.

Any other species that would do this?

From contributor Mi


The cheapest of the cheap would be treated. Cedar and Teak would be other options.

From contributor ri


Redwood isn't what it used to be. Anything with sapwood rots just as fast as douglas fir. White oak works well. Personally, I would not want to eat off treated lumber. Also consider powder coated steel base if they want a longer term piece.

From contributor Ge


If you use treated wood, rinse off the surface of the table to remove any excess chemical. Also, the sawdust and debris must be disposed of properly and the sawdust must not be breathed, must be washed off of clothes and skin, etc. is the surface now safe to eat off of...a kid drops a hot dog on the table for a minute, etc.? I would think not, but do not know of reliable technical info about this.

Now, redwood is probably too soft for a table and seat. And remember that there are chemicals (fungicides) in wood that make wood decay resistant. Are these natural chemicals safer than what we put in the wood when we treat? Plus, many species weather quickly to a grey color, due to aging of the wood and mildew. A finish or waterproofing has some chemical concerns too. So, maybe we need a table cloth? In any case, I would use in treated wood like eastern white pine and plan to replace the wood in 10 years or so. Watch for decay around the fasteners and brackets. I wonder of wood composite products would be stiff and strong enuf and safe?

From contributor Ke


Gene, what about torrified wood? It has been around long enough now that you must have some experience with it.

From contributor Ge


When wood as it comes from the tree is not exactly what we want, we modify it. Modification includes things like drying, sawing, gluing and so on. Further, there were some old processes for modifying wood (and a few new ones too) that changed the properties. We have wood that has acetic acid added (Accoya-TM), wood that is heated (torrified; Masonite is a heated product), wood that has chemicals added such as polyethylene glycol (PEG), monomers of styrene or other simple chemical that form a polymer within the wood (example is the hard wood-plastic knife handles), and wood that has various wood preservatives added to prevent rot (decay). Sometimes we add water repellants. Cement and wood are combined (HardiBoard-TM), and sometimes metal and wood are laminated or combined. And sometimes various wood species are combined (for example, plywood or laminated veneer lumber [LVL]). Certainly, there are other marriages of chemicals and materials.

Wood for years ago had natural decay resistance that is better than the wood grown and harvested today. Trees were larger and older, providing different material. Oftentimes, the structural use of wood was not considered to be for centuries, but rather for decades or even less (for example, log cabins were usually temporary, or short term, housing). So, today, the consumer demands have changed. (Example: I am changing four windows in my home that have rotted after 23 years.) Finally, I have seen architects and designers using wood and wood products in situations were other, wood or non-wood products could perform better (such as for house siding).

The bottom line is that if you can define the properties that you want in wood, there is a wood species or wood product that can furnish those properties.

Terrified wood is indeed one of those special products that has different properties and that may be a good substitute for "natural" wood.

From contributor Ke


"terrified wood"- I like it already.

My limited research tells me that terrified wood has had the s--t scared out of it, has lower strength properties, produces fine dust, glues poorly and is said by the sellers not to rot or move around. Accoya sounds somewhat more attractive as a possibility for painted exterior millwork (can we get a balsamic vinegar odor as an upgrade?). I am going to ask for a sample from the regional supplier, but I would like to hear more from folks who have a history of using it.