When choosing materials for the house we have considered the obvious factors such as durability and price, but we also care about whether or not the material is natural. After we had decided to build the house on concrete piers and post bases we started thinking about what wood we should use. In so many ways, we are absolutely against pressure treated wood. Why? Well, pressure treated basically means treated with poision. It means that the wood has been treated with all kinds of chemicals to stand up to moisture and insects. And seriously, poisonous wood can't be healthy for you, right! - especially not if it's in contact with you. Overall we think that people use pressure treated wood way too carelessly, not realizing what it's actually made of. We've seen posts online where people let their kids play with old pressure treated wood leftover from some project. Please don't. And don't even think of sanding old boards down to use for something else without masks, gloves and goggles! It's full chemicals, it's not healthy. Sure, regulations might say that when used properly, pressure treated wood poses no health hazards, but how often have safety commisions realized things after the fact - "oh by the way, we have now realized all that wood that everybody built stuff with years ago is really dangerous." You just never know.
So, after that rant, I guess I wanted to say that whenever possible, we like to go with natural. Natural materials and old fashioned techniques. Things that have been used and tried and relied on in the past.
With the idea of pressure treated wood in the back of our heads we started to look for other options. We looked into cedar since cedar is naturally water and insect resistant. But, do you have any idea how much 4x8x12 (or two 2x8x12) cedar beams costs? A lot. Way, way more than pressure treated wood. Plus, cedar is not really as strong as Doug Fir, and these boards were going to provide the base for the whole house. Then we thought of using regular fir boards that we could paint or treat in some way, but after realizing that the boards would still be at risk of termites, we figured that might not be the best idea either. So finally after several ifs and buts, we settled on pressure treated wood for the main beams. At least this way, this wood will only be used at the very base of the house, and hopefully all those chemicals will keep the boards rot-and-termites free.
For the beams we went with pressure treated 2x8x12's doubled up across three piers. The height of the 2x8's and the 12 inches of ground clearance from the piers gave us at least 18 inches off the ground to start the floor. Eighteen inches is a standard in many communities to ensure the proper distance from ground to untreated wood. That gave us the opportunity to use untreated wood for the entire floor.
So that's the materials we're going for: pressure treated for the base, untreated fir for the joists and floor panels for the subfloor. As we continue building up, we hope to use natural whenever availability and price permits, and maybe even find some old beautiful wooden windows and doors to incorporate into this structure.
of course we're not doing this, but isn't this idea kind of neat!