I’m hoping some of you guys are online. We’re getting ready to buy lumber for a shed, and we need opinions.

We have a 11.5’x16′ concrete slab that has a little 8’x8′ slab “addition” on one end (long story!). Planning to build a main shed over the large section with a smaller shed over the 8×8 section – all as one building. The small shed will either turn into a sauna or a little garage for a motorcycle. The larger building will be a workshop area with a loft. Both buildings will have cathedral ceilings with a regular gable roof – large beam with bird’s mouth cut rafters at a 12/12 pitch – like the old days before trusses. The weight of the loft will be supported by the walls, not the roof.

Here’s my question: How large should the ridge beam be that spans the 16′ with NO center support (like a center post) and how large should the beam be that spans the 8′ section? The local truss company wants to sell us a 1 3/4″ beam by 14″ for the large section at a cost of $200. The local lumberyard suggests an LVL engineered beam that’s 1 3/4″ x 11 3/4″ for about $70. The truss works is notorious for “overbuilding”, so we don’t exactly trust their quote of what we need, but we don’t want a sagging roof, either. As for the ridge beam on the 8′ section, we’ve been told that a 2″x8″ would do, but we’re thinking a 2″x10″ would be better. We are in NW Wisconsin, and we do have a snow load to consider, plus the roof will be 50 year architectural shingles that match the cabin.

Suggestions appreciated!