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ryanwms
Jan 31, 2006, 8:38 PM
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I am going to build a bouldering wall in my backyard. I need some advice. Some of you may remember I earlier posted questions about building on the underside of my staircase. This idea was shot down in committee. :wink: However, the committee did approve the outdoor wall, and passed through the membership vote with no opposition. This brings us to now - the design stages. I am planning to build 2 walls, each 8' x 8', intersected at a 90° corner. I would like to make one of them overhang, about 15°. My initial thoughts are to use 4-4x4 posts cemented in the ground at a two foot depth - so these would be 10-foot boards. Two feet down, 8 feet up. Each of these would be 32" apart, providing even spacing across the 96" (8') wall. Would this be sufficient support for a vertical wall? To build the overhang wall, is it as simple as starting with my support posts in back, and then build an 8x8 frame and attach it at the proper angle? I saw pictures on one site somewhere of someone who build an angled wall in his basement, and used chains to hold the wall at the angle at the top, and the base just rest in the corner of the floor. Would this work in my situation? What are your thoughts?? Thanks. PS - Things I have already taken into consideration, before anyone goes off the above topics: • Liability: The wall is inside a locked, 6-foot high fence • Weatherproofing: Thompson's Deck Seal will be used • Weatherproofing the holds: A couple large tarps will get fastened to the wall when not being used Thanks again Ryan
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hsvclimber
Jan 31, 2006, 9:26 PM
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My background is mechanical engineering, so I would also get the input of one of the civil (structural or geotechnical) engineering climbers out there, but from the few civil classes I have had, the soil would play a great deal in the stability of the wall. The portion of the wall experiencing the greatest force would be the overhanging wall. In the wall design you described the soil would have to be strong enough to resist the overturning force created by the walls selfweight and the weight of the climber. If the soil is soft, I don't think two feet would be enough support. However if you have the walls at a 90 degree angle as stated the interestion of the two walls would help combat the overturning force. Most wooden fences have posts set in concrete about 18" deep, and from helping my neighbor build his fence the summer in very firm ground, I don't think they could have held up the the kind of dynamic forces produced by climber even if they were set two foot deep at 32" spans, as you proposed.
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ryanwms
Jan 31, 2006, 9:45 PM
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Thanks for the input. Do you think putting the 4x4's on 24" centers would be enough? that would put 5 per 8-foot span. Would 2 feet still be too shallow? The possibility of a 4 foot depth exists, with a 12' post. This would take more effort, obviously, for digging the hole. My girlfriend/climbing partner's father is an engineer, specializing in civil/structural engineering. I am planning to get his help on the project with final designing (and probably sucker him into picking up a shovel and drill) :wink: Thanks again... Keep the thoughts coming!
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soulsurfer
Jan 31, 2006, 9:58 PM
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Hey Ryan, I also have a free standing wall in my backyard. Like the first guy said. The soil will dictate your post depth. My wall is 24 feet wide and 13 feet tall. I have 2 rows of 6 posts per row that are 4"x6"x12'. I felt 4x4's were too small. They are also pressure treated and concreted in the ground around 2 1/2'-3'. One 12' section overhands by about 15deg and the other is around 30deg. I will send a few pictures over so you get an idea of what I did ok. This is my second free standing boulder and I have had no problems.
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kindasleepy
Jan 31, 2006, 10:18 PM
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I may not be an engineer but I have built 3 walls of different sizes, one which was free standing. On general notes, you will get very bored on your planned wall. A flat 8x8 panel is very short and not challenging. Even an extra 2 feet in height will make a BIG difference. Your angles will also become tired very quickly. For good bouldering you need steeper angles, up to 45 degrees. If I were you, I'd build an something in the realm of a 8x10 min to a 12x12 with an adjustable angle. You don't need to sink posts to do this. Basically you build a climbing panel of the desired size, with studs ever 16 inches made from 2x8's. Use good quality 3/4 plywood with t-nuts in 6 inch grid to deck the frame. Bolt the base to two 2x8x12 runners on either side. Use 2x8's from upper corners and bolt along various distances to adjust angle. Our local climbing gym has a portable wall built on this concept. http://www.climerware.com/wall1.htm http://www.chockstone.org/TechTips/Woodie.htm http://www.metoliusclimbing.com/howto.htm Hope this helps. PM or email me if you want more info. Noel
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aarong
Jan 31, 2006, 10:27 PM
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Have you considered pouring a slab first and building off of that? Secure your wood frame to the slab using concrete anchors - build a basic box shape and then build your overhaging walls off of that. Solid.
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ryanwms
Feb 1, 2006, 12:24 AM
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Okay... I am considering some of the suggestions here of building a free-standing wall without cementing it into the ground. First, as was mentioned in my initial post, I was planning on 2 8x8 walls intersecting at a 90° angle, one of these would be an overhang of roughly 15°, not too much, as I am still developing many of my skills with climbing. Now, with the no-concrete method. Let's say I build the wall wider than one 8-foot sheet of plywood. Will the center be strong? Or will the lack of support on the edge of a wall section weaken the structure? The section of my backyard where I am planning to use the wall does not have level ground. It isn't a hill, mind you, but just regular, normal, ground with high & low spots. I'm afraid that the frame with a move-able, non-fixed wall will not sit level, and create a safety hazard. Also, what about the inevitable falls? Won't that be risky with a couple of heavy, solid, dense 2x8's under the spot where you're going to fall?
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ryanhos
Feb 1, 2006, 12:57 AM
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Ryan, You live in Central PA. Your gf's father will tell you that if use cement, the local frost line will dictate how deep you pour. Otherwise you'll come back to your wall after the winter is over and find that your whole wall has shifted. And if you do cement, use Sono-tubes. They save you LOTS of awful cement mixing and pouring. You should be able to look in any college book store (civil engineering section) to find the book with the standard lumber loading tables that will help you calculate just how long your spans, cantilevers and joist widths can be.
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ryanwms
Feb 1, 2006, 1:01 AM
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Okay.. I am thinking more. I like this guy's design: http://www.chockstone.org/TechTips/Woodie.htm The angled wall in back of the "cave" can be put onto a pivoting joint at the top, with some adjustable sliders on the bottom, and the legs that stretch out to support the base of the angle can also have multiple positions put into them. This will obviously eliminate the walls connecting all the way across from the sides to the back. http://www.ryanjwilliams.com/...es/basic_outline.gif http://www.ryanjwilliams.com/images/side_view.gif What do you think of this?
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joek
Feb 3, 2006, 3:35 AM
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i know nothing about construsting a wall, but i would STRONGLY second the advice to make your walls steeper. one of them overhanging 15 deg would be okay (you could put some cool slopers and small crimps on it), as long as the other wall overhangs at least 30 degs or more. an 8x8 vertical bouldering wall will get boring and useless quick. i had a friend with a verticl wall, and it was worthless for training or even climbing for fun. even if you are just beginning, make your wall steeper, but use good holds. as you get stronger (and with an overhanging wall you will) begin to use smaller and smaller holds and make longer moves. not to be negative towards your plans, but if you build it vertical, i think you will regret it pretty quickly. good luck and have fun building your wall. post pics when you are done.
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ryanwms
Feb 3, 2006, 3:56 AM
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Check out the last two posts I put up in this same category. The two vertical 8x8's are a scrapped idea now. I'm going to build a cave with a 10 foot high, 8 foot wide wall that can be adjusted from vertical out to 45 degrees.
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ryanwms
Feb 28, 2006, 1:43 PM
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Just an update, I have already begun (and have nearly completed) construction on my outdoor wall (now has taken the shape more of a cave). Check the post out at: http://www.rockclimbing.com/forums/viewtopic.php?p=1321917#1321917
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reg
Feb 28, 2006, 2:02 PM
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with the leverage created by the 15deg overhang and possibility of more then one climber on the wall, i would use 12' post and put them deeper into the ground maybe not the full four feet available - definitely 3 feet. do you have a frost heaving problem? whats the frost line?
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ryanwms
Feb 28, 2006, 2:12 PM
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Reg - I consulted an engineer on the situation. His recommendation was to sink the posts 18-24 inches, and he also said that due to the construction design and all the cross bracing that would exist, between actual boards and the plywood sheeting, concrete wouldn't even by necessary. Because of the terrain and the way all the heights worked out, I was able to use the ground to support the weight of the back wall.
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