Replies

1. 
   mrles | May 13, 2003 08:09am | #1

   I own two different commercial buildings, one is an old convenience store about 50-60 years old.It is a metal frame with cement blocks and brick as the walls. The other is all metal with  a brick veneer over the metal on the front. On both the roof is screwed directly on the purloins and trusses with a thin layer of insulation in between. I've never heard of putting plywood under a metal roof.

   Gods Peace

   les

1. 
   worndark | May 13, 2003 02:54pm | #2

   Thank you for your response. I hadn't heard of using the plywood before either, but didn't want to discount it as a bad idea if it had merit.

2. 
   chairmake1 | May 13, 2003 08:10pm | #3

   I belive that at the top of the block wall a metal strip- 1/4" or 3/8" thk. - is anchored in and the metal joist or girders are then welded to the strip at the spec'ed spacing. The metal roof is installed over the griders/joist with metal clips attached to the joist/girders. This is for a standing seam roof system. If there is to be some insulation under the roof panels then then chicken wire is rolled out - then the insulation and then the roof panels.

   If you are going to use a corrigated type panel or a 5-V crimp panel then a plywood sheet in laid down and then a wax or rosin paper and then the metal roof is nailed or screwed to the plywood.

   In the metal building industry there are "R" and "U" panel configuritions that overlap at the edge and they are screwed down to a roof structure made up of bay frames - 20' to 25' bay spacing - with metal "C" or "Z" purlins over lapped and running the lenght of the building with eave struts that are pre-bent to the slope of the roof - 4 on 12, 1 on 12, and so on -

   So there are many possibilities - but you really did'nt give us enough information to begin with. You will need engineered approved and stamped drawing in order to get your building permit anyway so you should start looking for one.

   Robert

1. 
   worndark | May 13, 2003 11:43pm | #4

   Thanks for the help. I was hoping to find relative merits of various systems before turning this job over to architect or engineer. My previous experiences have told me to know what I want and why I  want it before going to either disipline. Sometimes I have been led astray and ended up with something my customer was not pleased with (in this case that would be me).

3. 
   SawdustSteve | May 14, 2003 10:20pm | #5

   Warren... Just my 'two cents' worth ...   Are you planning to insulate the roof??  I've been in steel sheds during a good rainstorm and it sounded like I was standing in inside a snare drum while Gene Krupa did one of his famous solos.  A metal roof also conducts a great bit of heat INTO the building.  Building codes should specify the size, type and quantity of Hurricane Clips that you must have to anchor the whole roof structure to the walls.  My sisters house in Delray Beach is block construction and wooden trusses for the roof.  I tend to think that anchoring a galvalume roof to wooden beam/ plywood deck would be much more secure than attaching to a steel truss system.  Have you contacted a local architect??  They know the ins and outs of the building codes and will keep you out of trouble.  Also... I really don't know if I would want to be standing under a metal roof during a good thunder-storm.  Local laws should also cover the proper 'grounding' of the roof.   Before you start pouring the slab, have a layer of termite-proofing chemicals sprayed on the ground.  How are you going to bring in the electric / phone / water / cable TV lines into the building.  I assume local codes also call for underground wiring to eliminate exposed wires.  Plan for these items too.  Again an architect knows how deep to go for these services and how far apart the spacing of the different lines must be.   I hope this helps you plan a better (and legal) shop.

   SawdustSteve

1. 
   worndark | May 14, 2003 10:42pm | #6

   Thanks for your input.  I have not contracted an architect or engineer yet, but have been in telephone contact with the Orange County Zoning and Building Code Officials. "AS long as an architect or engineer has sealed those drawings , and it meets 120 mph and FL BLDG CODE any of these methods is acceptable.

   My shop in Ohio was sheetmetal (Butler Building / sheetmetal with insulation below sheetmetal, but had wooden trusses ( 5 in 40 feet with wood purlins between) and no plywood. Structure there was 40 ft x 40 ft with 20 ft clear to eves. Butler doesn't offer similar here in Florida. No snow, but wind I guess.

1. 
   worndark | May 14, 2003 10:44pm | #7

   Thanks for your help.

4. 
   mrles | May 15, 2003 07:09am | #8

   Warren something else you might want to consider is metal studs. When I built my building for my printing plant I went all metal. the only wood are my doors and the frame around them. A termite will starve to death in my building. Just a thought.

   The roofs on both of my buildings are screwed on, hasn't been a problem and I live on the Gulf Coast in Texas, hurricane winds are a problem to contend with here also.

   Gods Peace

   les

1. 
   worndark | May 15, 2003 03:11pm | #9

   I will place the 1 st course of the 8 inch exterior masonry walls as a 12 inch block filled with grout  and 12 inch anchor bolts so that I can place metal studs and channel and wall insulation  to eves at 14 ft. That is good advice and just the kind of thinking that this forum is famous for providing.

   Thank you