When running EMT on a flat roof, such as a commercial shopping center, what do you use to support the EMT? Do you use wood? Do you use those special support blocks? Those support blocks seem so expensive for what they are... But by the time we buy 4x4's cut them up, take them to the site, etc, not much of a savings, plus it looks cheap.
What are others doing?
If you're talking about on top of the roof, then yes we use the support blocks. Expensive, but what can you do. They work well, easy to use, and once all the pipe is down they don't generally go anywhere.
I always specify Roof Top Blox for conduit installations on flat roofs.
I saw those one time doing a search and couldn't find them next time. Plus I thought you had to use the unistrut which added to the cost. Now I see you can strap directly to the block.
RTB is the way to go.
Thanks
Roof support blocks are typically used but EMT outdoors? IMC is code required in most areas.
I don't think IMC is required outdoors. NEC 2011 article 358 states when EMT is used in wet locations, all supports, straps, screws etc shall be corrosion resistant.
This is in the USA (not sure where you are located)
Support blocks as mentioned are the best. However if you do use wood blocks I would recommend 2x6. Make sure that you run the grain with the conduit if not the wood will split after a year. You will also need to apply roofing sealant to prevent them from sliding around. I do that for the support blocks as well. If it's a rubberized roof make sure that you let them know you are going to put roofing sealant down.
Obviously when you use EMT it needs to be in conjunction with rain tight fittings.
One more things out the support blocks, they can be very useful when you need to go up and over something. Because they make different heights but you can also add an additional layer of strut to raise them.
Good luck it's going to take a long time no matter which way.
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