I'd love to lower the foundation, but at what expense? Going lower on the foundation would have meant double the drilling since now I'm exposing more ledge area and it's more solid. 1.9 Lateral restraint of roof beams 9 1.10 hemical resistance 9 1.11 Durability and exposure to moisture. In areas with mild climates, patio roofs are generally designed for loads of 30 psf (pounds per square foot). That got me an extra foot in the basement, to a 7' ceiling if I used 2x8's for joists. An essential part of planning a patio roof or gazebo project is determining the number, size, and spacing of rafters, beams, and posts, according to the loads they will carry. I spent a week drilling holes (130) in the ledge and pouring in Dexpan to break it up to the point where a small hammer on a skid steer could bust it out. Blasting is not an option due to cost, and I doubt that any demolition person would do that when it's right next to another structure. 32' thick tongue and groove sheathing (exterior glue), installed with long edge perpendicular to joist length, staggered one joist spacing with adjacent sheets, and glued to joists with construction adhesive. When we dug the hole, we hit ledge at 6 feet down. Residential Floor Span Tables OneHour Fire Resistive Assembly FIRE ASSEMBLY COMPONENTS 1. I may keep the 8' LVLs and use them to stiffen the floor in the older section.Īs for 'refusing' to drop the foundation, or raising the floor: It would be better to say I'm having to make choices. This will still be much better than the house I'm adding on to where the floors are carried by 2x8's sitting on horizontal 4x4's resting on piers every 6 to 10 feet. He said that if I used a triple 12', then the floor would be perfectly stiff, but the double would be fine. Said that if I put in a center post, I could stay with the 8', but I don't want that. For the initial calculation, F can be estimated at 1,000. F stands for the beams fiber strength in bending, which depends on the species of wood. In the example, the beam spans the 10-foot width of the roof. L stands for the span of the beam, in feet.

I dropped in on them this morning and after looking it over and doing some calculations, they said I needed to swap out my 8' LVLs for 12'. Fill in the parts of the formula that are already known. Listed are 46 tables based on common loading conditions for floor joists, ceiling joists and rafters. I'm getting my materials from Hancock Lumber in Conway, NH. Simplified maximum span tables for selected visual and mechanical grades of Southern Pine lumber in sizes 2×4 thru 2×12.

Lvl roof beam span tables