Remember Me? What's New? Page 1 of 2 1 2 Last Jump to page: Results 1 to 15 of Thread: Pergola beam size?? Pergola beam size?? I'm designing a pergola for my house and could use some insight on the size of beams required for safety and to eliminate sag. I'm planning to use 2x6 rafters spaced 16" OC. Due to the size of the existing concrete patio the 6X6 posts will be 14' apart on the long sides, and 8'on the other sides.
What size beam do I need to span the 14' posts. Can I use 2 2X10's, each one bolted to the side of the posts?
Span Tables for Pergola building
Would it be better to sandwich the two 2x's together then set it on top of the notched posts? Google Sponsor Google Sponsor.
Join Date Jun Posts In my first effort I used 2 x 10 cedar beams glued and bolted together. Looked great - about 20 years later we got home after a night of heavy wet snow to see that the thing had partially collapsed.
Turned out the wood had rotted around the bolts. When we bought this house in Lethbridge - it had and still has a classic open pergola roof sunroom at the back.
It has 2 x 10 beams and they're fine but. Two years ago I had to shore up the walls, remove the deck, dig out the muck underneath, and replace the foundations with 6" concrete posts dug and hammered 3 ft down, then put new floor beams and deck. All new information says you should not bolt beams to the side of your posts.
You should place the beam directly on top of your post. So notch the post and set the doubled or sandwiched beam directly on top of the notched post Doubled up 2 x 10 will give you 15'8" according to the span chart I ran. See the photo. Join Date Jan Posts Find a real lumber yard and ask them for help. They size the laminated beams you use to carry the load when you eliminate a wall.
What is going on top of the 2x12's? I would set my posts on 12' centers and cantilever 4' on each side. I would also sandwich a 2x12 on each side of the post. There actually is enough information in your question but there are many online beam span charts. Here is one. Hope it helps. Make sure there is no earth to wood contact on your posts and you will enjoy your pergola for decades. There's not quite enough information here to give a definitive answer, but for decks, a rule of thumb is when supporting joists that span 12 feet, a double ply beam can span in feet a value equal to its depth in inches.
Thus, a double 2x12 beam could span 12 feet - with 20' beams, posts at 10' might look the best. That said, this is typically applicable for a deck with 10 psf dead, 40 psf live. Depending on your loading and design, this may or may not be applicable.
If you were to cantilever the beam beyond the posts, you might get away without center posts at all, but at significant risk to warping, bowing and potential instability. It all depends on the rest of the design. This can also be very dependent on local conditions - hurricane-prone areas will be very different from others. Standard disclaimers apply - Check local building codes, talk to an engineer if needed, this advice is only worth what you are paying me for it, do so at your own risk, etc, etc Sign up to join this community.
The best answers are voted up and rise to the top. Home Questions Tags Users Unanswered. Asked 5 years, 1 month ago. Active 4 years, 8 months ago. Viewed 45k times. There was a similar question a few weeks ago which was answered with the uri of a calculator for this purpose.
The android SE app makes tracking that down awkward, but it's probably the right answer for this question too. Active Oldest Votes. Troy Emmett Troy Emmett 79 5 5 bronze badges. Ben Ben 1, 7 7 silver badges 13 13 bronze badges.
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Feedback post: New moderator reinstatement and appeal process revisions. Linked 1. Hot Network Questions.Wondering how to measure for a pergola? Choose the location and get an idea for the amount of space you would like to use for your pergola.
Will your pergola be attached to your house or other structure or will it be standing alone on an existing or to-be-built patio? Some customers prefer not to attach the pergola, but install it freestanding immediately next to the house or other structure.
How much useable space would you like inside the posts or between the wall and posts, and how much overall roof coverage would you like to achieve? You may need a specific amount of space inside for patio furniture, planter boxes, outdoor kitchen components, a hot tub etc. Look at the space you have and consider how much room you would like inside the posts and under roof.
The overall dimensions of our pergolas determine the size of the roof structure. The inside area is always a bit less as explained above. Once you have an idea of the location and amount of space you plan to use, now you can take measurements to determine the actual size kit that you will be ordering.
Using a tape measure, pull your first measurement from the wall where the pergola will be attached to the spot where you would like the outside edge of your posts to land.
This is Measurement A. Then, add the overhang to that measurement.
Patio Roof Maximum Beam & Rafter Spans
Take note of this measurement, as this will be the first number in the size pergola you choose. For a freestanding pergola, the difference is that the Rafter is not attached to a wall, so there is overhang on both sides.
Using a tape measure, pull your first measurement from the spot where you would like the outside edge of one set of posts, to the spot where you would like the outside edge of the other set of posts to land. Rafter and Beam Overhang by Pergola Style. This is Measurement B. Then, add the overhang on each end to that measurement. Take note of this measurement, as this will be the second number in the size pergola you choose.
We offer posts with standard lengths of 8 feet, 10 feet and 12 feet, and can customize post lengths upon request. When trying to decide the length of pergola posts needed for your wood pergola kit, there are a few things to consider.
Smaller kits generally look better with a shorter post. But, keep in mind things like ceiling fans or other accessories, head room for tall people, standing up in a hot tub or dancing on tables!Pergola beam span 18 span tables for 8 x12 x24 western red girder span chart bunace seasoned softwood floor joists for pergola beam span calculator pergola beam span calculator. Diy pergola guide seasoned softwood floor joists for balconies and decks revised measuring pergola dimensions learn the standard span tables for deck joists beams and flooring giving pergola beam span table beams our maximum from center span tables for 8 x12 x24 western red cedar this pergola.
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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.
In areas with mild climates, patio roofs are generally designed for loads of 30 psf pounds per square foot. For heavy roofs or in areas with substantial snowfall or winds, call your local building department for code requirements. The tables below give maximum spans for rafters and beams. The figures are based on quality materials. For lesser grades, spans should be shorter.
Keep in mind that these are maximums—in other words, shortening spans slightly will result in a more solid structure. Find out the loads your overhead must bear, and then determine the rafter sizes.
Next, calculate beam placements and how best to coordinate them with the rafters. Keep in mind that these are minimums for the spacing indicated—you can select larger sizes to handle excessive loads or for appearance. Of course, beefier sizes also increase your lumber bill. He has also authored, edited, or produced more than 30 books in the home improvement space.
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How to Measure for a Pergola and Determine Rafter Length
Maximum Rafter Spans for a Patio Roof. Maximum Beam Spans for Patio Roofs. Search for:. Affiliate Disclosure HomeTips articles may contain links to Amazon. Search Expert Articles Search for:.I like the balance of macro work digging holes, cutting timbers and micro work awesome layout tricks, scroll cuts.
You can see them out the window, when walking in from the driveway, or as you mow the lawn. And while the pergola explained here is built as a stand-alone, weaving one into an existing patio or sitting area is also ideal. A pergola is practically the definition of a luxury item, and budgets usually enable me to use nice materials and take the time required to build them well. A key element to building this kind of project as a freestanding unit is full-size templating.
I use it to mark layout, confirm proper sizing and location of the structure, and to anchor the posts. When it comes time to trim the structure I can leave the sandbox or remove it. There are four design rules I like to follow, otherwise pergolas can be more of an inductive seat-of-the-pants rather than deductive following a prescribed plan process.
The girder should be 80 inches minimum from the ground, the same as an interior doorway. Finally, for cantilevering past the posts, my feeling is that anything less than 12 inches looks less than graceful. The pergola shown here has inch overhangs. If you have to nestle the unit in a small space like a backyard nook, site lines from the house, interior windows and other egress points should be investigated and considered. In a larger space, working in basic units 8 feet, 10 feet etc.
And, I build in design elements so that I can make on-the-fly tweaks to the basic design as the unit comes together. More on that later …. Rough-siting the structure is typically basic. Since this pergola is nestled in a corner, my rough layout was pretty much done for me by the existing fences on the adjacent properties.
Nevertheless, I spent considerable time measuring from known control points located on the property. With the level surface prepped I could proceed with final—or micro—layout. Without so much obstruction, hacking out a reasonably small trench in the grass with a mattock and shovels would have been my excavation process.How to Build a Pergola - Mitre 10 Easy As DIY
I also like to build my stuff as square as possible, so instead of running strings all over the place that would inevitably move and otherwise infuriate me for marking post holes, I built a big box out of 2-by-8 stock—the sandbox—that acts as a full-size template for layout and securing posts. Next, I square it up and brace each end with an A-brace—a diagonal in each corner and a spreader to connect them.
Before positioning the box for final layout, I hacked out roughly an 8-inch wide trench about 6 inches deep, which I then half filled with gravel. With a full-size template that I could easily move, I re-measured from the property lines and the house. To ensure that I could tweak one corner of the box without moving another, I positioned sticks between the outside edge of the box and the straight run of fence.
When the sticks touched the fence, I was parallel to the property line in the East-West axis and I could make the final adjustments to the North-South axis more accurately.Forgot your Password? We welcome your comments and suggestions.
The material will be pressure treated pine. I want to limit the support posts to 4 and need to know the maximum span between the posts to avoid sagging. I am planning on using 6" x 6" x 12' posts set in concrete. I can inset the posts about 1' from the corners to lessen the span to give me about 13' on the front and back beams which will be 2x8x16'.
These beams will be supporting 2x6x12' rafters on 16" centers. I can double the 2x8x16' beams and rest them on top of the posts. Will this be prone to sagging? If so, would a 3rd 2x8x16' sandwiched and bolted or 45 degree corner bracing help? If not, would you have any other suggestions other than adding another support post?
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How to Build a Pergola
Find all posts by Randy Received 4 Votes on 4 Posts. Welcome to the forums! Burying post in the ground will shorten the life of the pergola. You should, instead, dig 12" footings to the frost line in your case probably a foot or so and pour footings in sonotubes. Then apply Simpson Strongtie post bases, either prior to the concrete setting, or after it sets, depending on which base you choose. Then your posts will rest off moisture laden ground and will be fastened to the post bases.
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