I have to hang a 4'x30' banner between two buildings that have Dryvit System facades. Here's a diagram of my best guess...
I'll go as deep in as I can (6-8"?) but I need to figure out what kind of anchors to use. I'll also be using some sort of water-based epoxy both in the anchor holes and on the back of the aluminum strip bracket.
Anyone ever done this or have any recommendations?
Thanks ahead of time.
Posted by Bruce Bowers (Member # 892) on :
Pat,
EFIS has no supporting strength that would be required to do what you are looking for. That banner is going to weigh a lot and is going to have some wind force against it.
Underneath that EFIS is nothing but Styrofoam sheathing. Maybe you could find the studs but most of the installations of EFIS I have seen has metal studs underneath.
Personally, unless the client would be willing to sign a release of any responsibility, I wouldn't be doing this install. Too many things to go wrong.
Posted by jimmy chatham (Member # 525) on :
behind most dryvit there is a piece of plywood behind the styrofoam that the dryvit attaches to. then a hollow wall
Posted by bruce ward (Member # 1289) on :
i have seen there is plywood also. if it were me it would require climbing up behind this facade and using bolts and large fender washers to reinforce what this banner will need to support it
alot of responsibility on this job. i would also have 2nd thoughts about it
Posted by Si Allen (Member # 420) on :
This sounds like a disaster waiting to happen!
Bruce touched on the problem.
These buldings are normally structural steel framed and thin plywood attached to 'tin can' studs. Then styrofoam is glued to it and finished with Dryvit!
Very nice looking, very well insulated... but... NO STRENGTH! Unless there is a structural member that you can attach to... a good strong wind will rip the banner off, and probably a large chunk of the wall!
Evere seen an over the street banner like this bend the light poles that it is attached to?
Posted by Jeff Ogden (Member # 3184) on :
Pat...I agree with both Bruces...you can't anchor with just the foam. You have to get back to the studs. If they are not placed where you need to attach, then you need to span across 2 studs with something like angle iron, and bolt through the whole wall with allthread or some other threaded device.
If there is a crawl space behind the wall then that would be great. If not ...good luck. I would suggest to the customer that they make permanent mounts if they ever plan on doing this again.
Posted by Dana Stanley (Member # 6786) on :
I too would find the studs underneath. Usually steel studs. Getting behind the wall if possible is the best way, but you may be able to use a good quality stud finder if you cant get behind. Holes in the banner to relieve wing pressure are a essential in this situation too.
Toggle bolts would be a better choice than wall anchors too.
[ November 17, 2008, 12:05 PM: Message edited by: Dana Stanley ]
Posted by Brent Logan (Member # 6587) on :
Si, we made a 40' over the street banner one time that took down 2 light poles just as you described. It's a wonder somebody wasn't killed. The customer was a large midwest bank and the person in charge didn't want those ugly wind holes covering up their logo. Luckily we weren't in charge of the out of town install and avoided any liability.
Posted by Dale Feicke (Member # 767) on :
I'm with the others, Pat. There's going to be a tremendous amount of wind load on a banner this size. I'd try to find a flat place on the building to put it up against.
There's too much possibility of damage to the building or passers-by, and people will sue for anything.....not worth it.
Aside from wind slits, I noticed Fellers had some mesh banner material that might work in a wind situation like this.
Posted by Tony Vickio (Member # 2265) on :
I agree with the above that this is not a simple install. I would call Mary at Britten Media. They do all the specialty banners (very large) for most of the sporting events & NASCAR. They know how to install & what type banners are available. Britten Media Posted by Dave Sherby (Member # 698) on :
I wouldn't touch that job. I'd have a building contractor that knows their stuff put anchors in for a banner like that. Wind vents or mesh banner? Won't help that much. Wind vents only reduce the wind load by the size of the holes. Add up the square inches of the holes, reduce the banner size by that same amount of square inches and that is how much you've reduced the wind load, not much. Mesh banners reduce the wind load by only 15%.
Posted by Bruce Bowers (Member # 892) on :
Wind slits DO NOT alleviate enough wind load to warrant their use. This is a fallacy! Do not buy into the theory that this will work. The damage done to the banner is far from the good done. Do the math... cutting all those slits will open up 20% open area? That is not enough to keep this banner from destroying something.
Mesh banners are better but still suffer from wind load. They also do not look as good as they look washed out.
I know that there is plywood behind EFIS. It is thin sheathing that has little strength. It is also attached with lightweight screws that are strong enough to hold the sheathing but not enough to bear that kind of wind load. Good luck trying to crawl up behind it. Hahahaha! Even when you can, there is little to stand on.
I would walk away from this one. Seriously.
Posted by Gene Golden (Member # 3934) on :
Pat, Between all of those responding, there are probably 200 years of sign experience speaking - actually 300, I just noticed that Si responded
None of us feel to comfortable with this. Tell your customer your concerns and be truthful. Sometimes it is necessary to refuse a job, as painful as that may be in these tough economic times. But the consequences may be even more painful - even if the customer "signs off" on it.
By the way, in your installation assembly, I would comment that you actually placed the eyebolts where the panel was the weakest... at the ends of the panels, where they are most likely to bend. I would have placed another couple of bolts ABOVE and below the eyebolts. I would also put TWO (one in each corner) to "triangulate" with the eyebolt. The same with any other support bolts... but I STILL recommend against this particular install.
[ November 18, 2008, 10:11 AM: Message edited by: Gene Golden ]
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