Steel Deck topping

[mes7a]

Hi,

If you just want to use steel deck as raining shed instead of thin metal or plastic roofing. Is it possible to just use some kind of say insulated panel over the steel deck or even plastic roofing material over it.. or do you have to top it with concrete? But this would be so heavy.. what other ways to top the steel deck.. which do you use?

Also what are the advantage of using steel deck as material to shed rain rather than thin metal roof? Won't it be overkill? Perhaps you use steel deck to avoid robbers from axing his way into the house via the thin metal roof or jogging above? what else why choose steel deck?

And what are the common gauges of it that is used for just rain roofing.. for walking, and for parking?

 

[structSU10]

metal deck with no concrete is a common roof in the US. the metal deck allows you to span and carry roof loads (snow, maintenance, etc) much easier than any old corrugated metal or plastic decking would allow. it also can work as a diaphragm from lateral loads.

 

[mes7a]

metal deck with no concrete is a common roof in the US. the metal deck allows you to span and carry roof loads (snow, maintenance, etc) much easier than any old corrugated metal or plastic decking would allow. it also can work as a diaphragm from lateral loads.

But how do you waterproof it from rain? unless you mean the steel deck is itself the waterproof surface by applying waterproof paint to the surface? Or do you have to cover it with other membrane and what are these? Thanks.

 

[mike20793]

They just apply a waterproof membrane and use flashing around the edges, penetrations, etc. Try looking up TPO roof membrane.

 

[mes7a]

They just apply a waterproof membrane and use flashing around the edges, penetrations, etc. Try looking up TPO roof membrane.

What would happen if you just apply epoxy primer to prevent the steel deck from getting rusted.. and not applying anything else (because it would add to the cost a lot)?

And what is the problem you guys encountered with Long span roof. How many percentage is this used in the US versus steel deck?

 

[structSU10]

It depend what you are doing, but usually insulation and a membrane roof are added to the top of the deck. You want some kind of insulation for your roof, and putting on top of the deck is easier than on the underside.

What do you mean by long span roof vs steel deck?

 

[mes7a]

What do you mean by long span roof vs steel deck?

The following is called Long span roofing in Asia.. don't you use it elsewhere? We use it in 99% of building in our place.

If you don't use it in your country (no?). What do you use as roof besides steel deck?

 

[Guastavino]

That looks like what we would call standing seam metal decking. The Pre-engineered metal building folks use it, but I think just for gravity loads. I don't think they count on it for lateral loads. They use "bagged" insulation that drapes between purlins.

Not sure what your goal is, but look up the SDI (steel deck institute) or vulcraft if you want to see structural decking that is used for roofs. IT is NOT a waterproof decking, it is a structural deck. For roofs, they often top it with rigid insulation and a TPO membrane.

 

[mes7a]

That looks like what we would call standing seam metal decking. The Pre-engineered metal building folks use it, but I think just for gravity loads. I don't think they count on it for lateral loads. They use "bagged" insulation that drapes between purlins.

Not sure what your goal is, but look up the SDI (steel deck institute) or vulcraft if you want to see structural decking that is used for roofs. IT is NOT a waterproof decking, it is a structural deck. For roofs, they often top it with rigid insulation and a TPO membrane.

My goal is just to have a roof that can shed rain. So I guess the standing seam metal decking will do. I now understand why majority in my place use it. Because a steel deck is much more expensive.. with bigger beams and rafters.. and the steel deck itself more expensive and the waterproof membrane even more expensive.. and the price would become like 7 times that of standing seam metal decking. Thank you.

 

[BUGGAR]

That looks like our standard "corrugated iron panels", though with colors. Typically lapped one corrugation for walls, and two corrugations for roofs. This used to be covered in the AISC Manual. Overlap the seams away from prevailing winds. These are typical industrial type rain sheds. Look at films taken during high wind events and you can see these panels flying all over the landscape.

 

[darthsoilsguy2]

i've seen hundreds of steel roof decks that support insulation to which TPO roofing or EPDM roofing is attached.
i've seen a few steel roof decks that have roofing boards attached and waterproofed, then insulation and ballast.

 

[hokie66]

The picture is not standing seam roofing, but rather corrugated steel roofing. It is one type profile of steel roofing, widely used in commercial, industrial, and residential construction in Australia. It is roofing, not "roof deck", and is not used for diaphragm action. It is screwed through the crowns to purlins or battens.

http://www.lysaght.com/roofing

 

[mes7a]

The picture is not standing seam roofing, but rather corrugated steel roofing. It is one type profile of steel roofing, widely used in commercial, industrial, and residential construction in Australia. It is roofing, not "roof deck", and is not used for diaphragm action. It is screwed through the crowns to purlins or battens.

http://www.lysaght.com/roofing

In your estimation. How much heavier is a steel deck versus corrugated lightweight steel roofing? In our place.. most steel deck are poured with concrete cover and only used if you will use it as parking and not as ordinary roof. So in Australia.. what reason people use steel deck vs the lighter corrugated steel roofing? And is membrane really very expensive?

Also for moment frames without any shear wall or brace framed.. what would be the benefit of roof diaphragm and diaphragm action of the steel deck?

 

[hokie66]

Steel roof deck of the kind used in North America is not used in Australia to my knowledge. We do use a lot of steel form deck for concrete slabs, some composite and some not. We don't tend to use roof diaphragms, but rather uses diagonal bracing where required to distribute load to the stiff vertical elements.