I looked at a job today, the building exterior was originally cement block and now it has a 2" thick foam board(exterior thin skin, Styrofoam behind) covering it. I need to split an existing service into 2 separate ones. My concern is that how does one go about properly supporting conduit along the building exterior.If you push hard enough(by hand) you can indent the material, I'm afraid even using uni strut and straps for conduit will collapse the foam.Anybody deal with a building finish like this in the past?
Styrofoam type building exterior.
- Thread starter nizak
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- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
I have not done it, but anchors in the concrete and long threaded rod to the unistrut comes to mind. With a nut on both sides of the unistrut so you are not compressing the foam.
For conduit only, back to back clamps surrounding the conduit and the same two nuts on all thread might be justified.
Hopefully the downward force on the rod will not bend it too much or torque the anchors too hard.
For conduit only, back to back clamps surrounding the conduit and the same two nuts on all thread might be justified.
Hopefully the downward force on the rod will not bend it too much or torque the anchors too hard.
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SceneryDriver
Senior Member
- Location
- NJ
- Occupation
- Electrical and Automation Designer
Place concrete anchors with female threads in the block. Use bolts of the appropriate length to pass through the unistrut and the depth of foam to thread into the anchors. Use fender washers and appropriate lengths of 1/2" EMT as standoffs/spacers. The bolts will place the EMT in compression and the foam will see no compressive forces. Caulk appropriately to seal the wall from water infiltration. Anchor your conduits to the unistrut as normal. Threaded rod with nuts would also work, but using bolts means fewer parts; threaded rod is more forgiving to variations in set depth of the anchors.
SceneryDriver
SceneryDriver
- Location
- Massachusetts
You are dealing with EIFS. http://en.m.wikipedia.org/wiki/Exterior_insulation_finishing_system and it sucks.
As detailed as scenery drivers idea was, GDs as well it is virtually impossible to pull off with a concrete block building. You will have no idea if you are drilling into a joint, a solid rib or a hollow. It also would burn up tons of labor if you have many to do.
I would try to avoid running pipe on it if at all possible. There is also the issue of water intrusion but with a block building underneath that may not be a big deal.
When there are no other choices I have used strut to spread the load, paintable adhesive caulk on the entire surface of the strut along with whatever hardware I can make work. Don't over tighten. The adhesive is to just keep the strut from sliding with the hardware holding the weight.
For me I can generally use long 1/4" toggle bolts as most times I have a type of wallboard behind the EIFS.
Good luck.
As detailed as scenery drivers idea was, GDs as well it is virtually impossible to pull off with a concrete block building. You will have no idea if you are drilling into a joint, a solid rib or a hollow. It also would burn up tons of labor if you have many to do.
I would try to avoid running pipe on it if at all possible. There is also the issue of water intrusion but with a block building underneath that may not be a big deal.
When there are no other choices I have used strut to spread the load, paintable adhesive caulk on the entire surface of the strut along with whatever hardware I can make work. Don't over tighten. The adhesive is to just keep the strut from sliding with the hardware holding the weight.
For me I can generally use long 1/4" toggle bolts as most times I have a type of wallboard behind the EIFS.
Good luck.
SceneryDriver
Senior Member
- Location
- NJ
- Occupation
- Electrical and Automation Designer
Practically any concrete anchoring system would work for the given conditions - toggle bolts, red hats, lead shields, etc... - what's important is to keep the compressive forces off the styrofoam. That's where the lengths of EMT come in. I agree though; it's going to be labor intensive no matter what.
SceneryDriver
SceneryDriver
Another option is to anchor a 3" - 4" piece of deep Ustrut on to the concrete and install another piece of Ustrut on it. Basically double up on your Ustrut, that should give you a 3" standoff.
But I am not sure if you are allowed to notch the styrofoam??
But I am not sure if you are allowed to notch the styrofoam??
- Occupation
- Licensed Electrician
Iwire is right this stuff is a building version of The Blob; touch it and it just keeps getting yuckier and yuckier.
Stay away from it as much as you can, get to know a good painter and stucco guy, talk to the owner about the extra work, good luck.
Stay away from it as much as you can, get to know a good painter and stucco guy, talk to the owner about the extra work, good luck.
J.P.
Senior Member
- Location
- United States
Is the block poured full of grout? Most walls are it seems.
I'm doing two schools made out of 15" fox blocks. 2-1/2 polystyrene sandwiching poured in concrete and lots of rebar.
To attach equip I slot the foam with a keyhole saw or battery powered grinder.
Put in however much pre-made double strut I need anchored with readheads.
You could use hollow wall anchors if needed. But I'm betting a exterior block wall is poured full.
I have a hilti hammerdrill that makes concrete my Bi@tch
I have a battery powered makita hammerdrill that makes me concretes Bi@tch
Depends on the day which one I feel like being......
I'm doing two schools made out of 15" fox blocks. 2-1/2 polystyrene sandwiching poured in concrete and lots of rebar.
To attach equip I slot the foam with a keyhole saw or battery powered grinder.
Put in however much pre-made double strut I need anchored with readheads.
You could use hollow wall anchors if needed. But I'm betting a exterior block wall is poured full.
I have a hilti hammerdrill that makes concrete my Bi@tch
I have a battery powered makita hammerdrill that makes me concretes Bi@tch
Depends on the day which one I feel like being......
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Thanks for the ideas. When I originally scoped the job I stupidly checked the building exterior make up on the opposite side of where I was going to be doing the work.
I assumed the whole building was finished the same, NOT! When I attempted to start fastening I found that there was a 5" space, 2" styrafoam, SOMETHING about 1/4" thick, then approx. 3" more space, then actual block.Have no idea what the physical make up of the building is behind the foam.
Ended up setting a disconnect and running thru the basement as opposed to outside.Cost me a bit more for material but saved countless hours of labor.
I assumed the whole building was finished the same, NOT! When I attempted to start fastening I found that there was a 5" space, 2" styrafoam, SOMETHING about 1/4" thick, then approx. 3" more space, then actual block.Have no idea what the physical make up of the building is behind the foam.
Ended up setting a disconnect and running thru the basement as opposed to outside.Cost me a bit more for material but saved countless hours of labor.
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