What determains the span spacing, and the size of lumber to be used. I will be building a 40' long by offsetting 14' and 12' back yard patio cover. Other than code requirements, is there a general rule out there on size of lumber, spacing of rafters, and size of decking. Here's an example of what I am looking for. If I use 2x6's on 16" centers, VS 2x8's on 22-24" centers I will save $50 for just the trusses (or runners) using the 2x8's. Could I possibly go with 2x6's on 24" centers if I were to increase my decking to either 5/8's or 3/4? I am looking for a general rule of thumb rule here on what tells me I can increase span, enlarge lumber and save $ doing so, but maintaining the stregnth and durability in our TEXAS wheather. BTW; I will be installing a metal (steel) lifetime roof on top. And Yes I want to walk on this overhang with out feelling that spongee week feeling.
Here's what I would like to do: 2x6's on 24" centers, with decking 5/8 to 3/4, paper then metal roofing.
One more question, I live in Dallas Tx. area. If I am going to enclose the lower surface area of this patio cover, (hide the rafters), does anyone out there think I still need to use PT wood rather than reg. #2? My general rule is if it's exposed go with PT, if its covered and protected from weather go with reg #2. Just wondering about the moister in the air absorbsion as far as long lasting... Any info will be greatly apprieciated...
Here's what I would like to do: 2x6's on 24" centers, with decking 5/8 to 3/4, paper then metal roofing.
One more question, I live in Dallas Tx. area. If I am going to enclose the lower surface area of this patio cover, (hide the rafters), does anyone out there think I still need to use PT wood rather than reg. #2? My general rule is if it's exposed go with PT, if its covered and protected from weather go with reg #2. Just wondering about the moister in the air absorbsion as far as long lasting... Any info will be greatly apprieciated...