I am currently starting to get prices on oak beams S4S. The company charges one price for mixed oaks. Then it charges an upcharge of 18% for Red oak only and 27% for white oak only. Now do you think it is worth the cost to use only one species? For my garage I've already decided that it isn't worth the cost. However, I'm not sure about the house.

Thanks as always,
Zeke

The most important reason to choose a single species over mixed oak is mixed oak includes lesser oaks with lower design values. Refer to the National Design Specifications, NDS.

another point is that there are oaks that are not as fun to work with as red oak..... you may pay extra for wood and save time in cutting.

According to my chart of Maximum Allowable Fiberstress in Bending Values they have a species selection of "Mixed Oak" giving all oaks the same value. Definately check it out further though.
Personally I prefer to mix species up. It is a wonderful way to more fully experience and understand trees. It also creates a nice color balance.
When I lived in the East I used up to 10 species in a single frame. Now I live in the west and have less variety. I say go for the mix not because of price (although that is nice) but for the personal satisfaction of creating a Timber Frame that more fully represents the forest it came from.
-Collin

Well, I agree about the design values. However, in the frames that I have planed at this time, it won't effect things enough to worry about. I've decided to put a small (24'x24') addition on my current home. The additon will be two bedrooms. I'm also going to build one of Sobon's garden sheds. So, I'ved decided to go with the mixed oak. When we build a house, I may pay the extra for the red oak.

Thanks,
Zeke