Roof top support

[HoosierSparky]

I have only been able to find references in the NEC for where supports should be for conduit, but none for acceptable means of support such as redwood blocks or some listed device. Is there a specific code section that addresses this?

 

[HoosierSparky]

I have only been able to find references in the NEC for where supports should be for conduit, but none for acceptable means of support such as redwood blocks or some listed device. Is there a specific code section that addresses this?

If at first you don't succeed, get a bigger hammer.

 

[cowboyjwc]

A lot of times it's up to the AHJ what they will allow and sometimes it's up to the building owner or the roofing contractor. Some don't want anything run on the roof and others have a system that you have to use.

Most contractors, carpenters included, do not install pressure treated lumber correctly. It's only pressure treated until you cut it and then you're supposed to seal the ends again.

I can't get back to look but I thought your location was AZ and I know that several cities there only allow RMC on the roof.

 

[jumper]

Most contractors, carpenters included, do not install pressure treated lumber correctly. It's only pressure treated until you cut it and then you're supposed to seal the ends again.

I use this stuff for sealing the cut ends of PT wood. It is nasty, but it keeps the inspector happy.

 

[HoosierSparky]

I've usually seen the redwood blocks used in the past, heck, I've used them. Them problem and question with using them is that they develope "checks" over time and the screws used to attach the fasteners loosen.

A lot of roofing contractors in AZ don't like to see wood blocks used. They are hard to fasten correctly to the roof, especially foam.

What I have been trying to find is some reference in the NEC. I am thinking I may have to find and apply code from the IBC or some obscure ANSI "white paper".

 

[chris kennedy]

I use these.

 

[cowboyjwc]

I use these.

I don't think you'll find a code reference, but I am see a lot more of these ones that Chris posted.

 

[jumper]

I use these.

Those are cool!

 

[jeremysterling]

A lot of roofing contractors in AZ don't like to see wood blocks used. They are hard to fasten correctly to the roof....

??????


How hard is gravity?

 

[RyanA]

I use these.

Those are almost all that we use here. Of course, you are supposed to adjust everything on a roof per t310.16(B)(2)(c).

 

[HoosierSparky]

??????


How hard is gravity?

The blocks need to be fastened to the roof. It can be done either with an approved adhesive, screws or nails. Some adhesives are not compatible with some roofing surfaces. Nails and screws create penetrations to the membrane and then creates a new liability for the electrical contractor.

 

[Jlarson]

I use these.

I use those, (or ones from manufactures that make similar ones), cinder blocks, or PVC with the conduit one or two hole strapped to it. But never have I used wood, it doesn't hold up.

 

[HoosierSparky]

Thanks all. I am going to have to allow the wood to be used. I do like the alternative method better, but until there is code to back it up...........I get wood.