Hi Jan,

I agree that thin strips and fiberglass can result in a strong deck. My concern about the strength of the wood is due to the grain pattern.

For example, if you take a board and cut off 1/8" directly across the grain, the fibers are only 1/8" long and can be broken (separated) very easily. If you would cut an other 1/8" strip exactly with the GRAIN (not necessarily along the length of the board because the board will probably not be cut "straight" to the tree's growth) the strip, with all the fibers intact will be many times stronger.

If the trees grew perfectly straight and the boards were ripped exactly along the grain then 1/8" strips would half the strength of 1/4" strips. It is more likely that there are waves in the grain (knot areas) and the boards are not cut true. The thinner you cut a strip, the more chance there will be that the grain will run out (cross from top to bottom). That is why plywood is so strong, with the layers glued together there is not a single grain path through the material.

Locally (Ontario, Canada), our spruce can have a great variation in its strength - you can see that in the growth rings. For cutting thin strips select wood with more rings per inch to give you a better tolerance to grain run out.

While I am rambling on about wood grain I might as well add that selecting and cutting wood to the grain pattern allows you to make components (like deck braces) thinner or from a lighter (weaker) wood with out loss of strength. Wood cut with the grain can also be formed easier. I steam bend my cockpit rims from a single piece of ash with great results.

Why my infatuation with grain patterns? I make "primitive" wooden bows out of logs - if you violate the grain the bow WILL fail. Some of my "character" bows look really weird because the limbs of the bow twist and curve to follow the grain - but you should see them shoot!!

I hope this is of some use. Good luck with your project.