![]() ![]() ![]() As a result, engineered lumber is more consistent and has more load-carrying capacity and spanning ability than regular sawn lumber.” This manufacturing process enables G-P engineered lumber to resist shrinking, twisting and warping. “We combine high-grade wood fiber with specifically formulated resins to produce virtually defect-free engineered lumber. ![]() Georgia-Pacific says of their engineered LVL’s: This makes the LVL extremely strong in one direction but not in the other. It is an engineered beam made up of multiple plys of wood, much like plywood except that all the strands are oriented in the same direction. The structural ridge is made up using an LVL, or laminated veneer lumber. Our example below is calculated using the Georgia-Pacific "Engineered Lumber Residential Floor & Roof Systems Product Guide." See below for a free download of this booklet. Some roofs will also require collar ties between opposing rafters, and hurricane ties between rafters and wall plates. Steel strap ties are often specified, but wood side-pieces extending up alongside the ridge beam from the ridge supports or columns also can be used.ĭon’t forget to secure the base of the support columns also to resist uplift forces. You must provide adequate tie-down connections between the ridge beam and its supports. For speed and efficiency when nailing joist hangers, you need to pick up either a positive placement nailer or just a simple palm nailer.Ī requirement for proper ridge beam design that must be taken into account is resistance to wind uplift force from rafters. Of course, there are special nails for these types of hangers: 1 1/2" long 9-gauge galvanized nails that won't split out the opposite side. Using bottom rafter hangers, I'll generally hold the rafter in position and nail it through the top edge to hold it, then install the hanger by pushing it up flush on the bottom and nailing. One issue can be that your ridge beam may not be thick enough for two hangers meeting on top. Then I can work my way along dropping the rafters into place and nailing them through the hanger. If I'm using top rafter hangers I'll install them 24" o.c. There are a couple of ways to hang the rafters from the ridge beam: from the top and from the bottom, using two different types of rafter hangers. It's also a good idea to install several matching pairs spaced out along the ridge beam span in order to keep it straight, then go back and fill in the remaining rafters. Try to balance the installation by matching rafters on both sides as you work along, rather than installing all of the rafters on one side first. This can be tricky since each rafter will push on the ridge beam with its own weight, and this can push the beam out of line. Once you have the structural ridge beam set up, it's time to install rafters. A structural ridge can be used when installing structural insulated panels, or SIPs on a cabin roof. This is required for roof slopes less than 3 on 12 by the International Residential Code (IRC) and International Building Code (IBC) and also on a cathedral ceiling such as often used in log cabins. The roof loads are carried by the LVL (laminated veneer lumber) and transferred down the load path via end supports and posts.ĭon’t be confused by the two similar terms:Ĭonventional construction of a gable roof or A-frame roof uses a ridge board and this is primarily for ease of construction it gives you something to nail the ends of the rafters to while assembling your roof.Ī structural ridge beam, instead, is used when the high ends of the rafters require independent support. It is also easier to assemble by installing the ridge beam and then hanging the rafters from the beam and can span long distances. Using a structural ridge beam for your log cabin roofing is much stronger and more stable than a conventional ridge board held in place with rafters. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |