Fastening Projection Screen to Proscenium Arch

Colin

Well-Known Member
Had a vendor visit to look at installing projection in our proscenium space, and he wants to attach the motorized screen (probably about 22'W) to the underside of our arch rather than hanging from some catwalk-accessible steel just in front of the arch... What do you all think I should insist on in terms of engineering that to make sure this additional, not-originally-designed-for load doesn't bring the whole arch down? I don't know what these things weigh other than enough to hurt. I suppose spreading it over about 30 sq. ft helps.

It's a 1962 cement block wall with a new arch fascia added in later renovation. No idea what's behind that or what damage was done/covered up in the reno (generally, have reasons to not trust that anything is as it should be in the building).

Don't worry and let them do their thing? Engineer's stamp? Install whatever anchors and proof test first?
 
You should definitely get them to explain their intended method of attachment in enough detail to meet your satisfaction and not just take them at their word. There are installers out there who would just drive screws into whatever they find (decorative or not) and hope their check clears before it falls on anyone. There are also installers who would do the work to go through the decorative facing and anchor into whatever is solid underneath. You don't know which kind you're working with until you see some evidence.

Not knowing what your space is like... how are the aesthetics of having it mounted to the proscenium? I would tend to think it would look better up out of the way, and accessibility for future maintenance is always a nice thing.
 
Here's the deal, unless you know what's behind the fascia which includes filled or non-filled CMU, and unless you are positive of the materials, fastening scheme and layout of the material that make up the fascia you should always default to a direct connection to known structure. Requiring a PE stamp might mean nothing at all if they Engineer is not given all the information mentioned above. a PE will engineer what they have. If, as a sub contractor I say, "Hey I need this stamped", and give them a drawings that shows all my rigging points but doesn't show structure they can stamp the drawings and say, "Yep, if properly anchored that won't fail."
I deal with this everyday when approached by folks that say, "Couldn't you just attach it here?" the answer is not unless you tell me what is behind there. Any reputable company should do the verification themselves or require you to hand over confirmed "as-built's".
 
Thanks, so far all sentiments I share (including Ron's sad face). My preference is to hang from the steel we can see and touch, and which elevates the screen to keep a clean line across the proscenium, but we always shorten the opening such that it's all in shadow up there (along with a center speaker cluster) so I'm willing to accept the extra bit of ugly if the vendor's claim about their approach being cheapest and easiest is true. Pretty sure it won't be true once they start doing their homework, and that homework won't result in as-builts for this building - been down that road before.
 

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