Flat Roof specifications

[amateurdesigner]

hi, does anyone know how to create a flat roof and what are different layers materials..and thickness that make up the flat roof?

I am making the flat roof with parapet walls (I ALREADY KNOW HOW TO MAKE PARAPET WALLS) so I am just inquiring about the flat roof and its components.

thanks!

[David J. Potter]

Here is a place to start: http://en.wikipedia.org/wiki/Flat_roof

The exact layering and support structure is the province of the State Licensed Engineer and depends upon the design of the building, the local weather stresses it must withstand, dynamic and dead loads it must bare.

Since I am not an Architect or Structural Engineer and the variables and diversity possible in Architecture I cannot give you a "Typical" answer other than to say you design your building, share your design with a State Licensed Structural Engineer and he or she will then tell you how they want it layered, designed and built.

My advice is to study available material on the subject, visit some construction sites where these exist or are being built, observe and ask questions of those experienced in creating them to advance your own knowledge and understanding.

DJP

[Jay M]

Samantha,

Too vague an answer. If it is residential new construction I imagine you would want TPO or EPDM. There are other options it depends on if there is going to be traffic etc on it (roof deck). When I was a commercial roof estimator I would use Firestone details for our submittals. Here is a link to their site and details.

http://firestonebpco.com/roofing/

[amateurdesigner]

@David, thanks for the link and information. I was not thinking about the different climates which would yield different types of construction methods of a flat roof.
I was hoping for a general solution, but no worries, I will dig into it.

@Jay M, thanks for the link also. Yes this will have traffic on it..as a rooftop deck. Can you give me an example of how a rooftop deck would be constructed in south florida?

I would imagine that first it would be a flat roof truss, then waterproofing materials.. and then a top layer of concrete all on a slight slope? Just looking for a "general" idea so that I can create a quick visual in Chief.

thanks!

[Curtis Johnson]

Samantha:

I would suggest you subscribe to two construction magazines that have good articles on all sorts of construction for new and existing homes. They are: The Journal of Light Construction and Fine Homebuilding. As you may be aware, Fine Homebuilding magazine can often be found in home centers, book stores and magazine racks in other stores. JLC needs to be subscribed to. You may also want to consider purchasing all their magazines on DVD. I think this would be a very good investment for you.

You may also want to get a good home drafting book. I have one called "Architectural Drafting and Design" by Alan Jefferis and David Madsen that is jamb packed with excellent information on creating construction plans for new homes. There is some information that applies to commercial buildings in the book as well. The book isn't cheap if purchased new but if you search the Internet, you can often find some decent deals. I have the 5th Edition and I think there is at least one newer addition than mine. I believe I paid $90.00 for mine and it was new ... that was several years ago. Check it out ... I think on some sites you may be able to look at the index to see what the book covers.

Searching the Internet sometimes yields some excellent articles or technical information and from time to time, some good CAD details on how to build things. Sometimes Chief Architect has some good information on how to do things in their Help Database articles or in their video archives. Good luck.

[JJohnson]

I would imagine that first it would be a flat roof truss, then waterproofing materials.. and then a top layer of concrete all on a slight slope? Just looking for a "general" idea so that I can create a quick visual in Chief.

thanks!

Then it's more than just a roof, it's a deck and will need stronger framing, like a floor.

Use tapered joists, determine size and spacing from a span chart, for slope.

Use 3/4 " subfloor for ply, not roof sheathing which may be 1/2 ".

Some water proofing can be left exposed or can be tiled over http://universalprotectivecoatings.com/

[lbuttery]

Samantha:

yes, Amazon in particular has a zillion used books for very low cost

I usually look for the prior edition and with cost + shipping can usually get them for under $10

if I really like the book I will then consider getting the latest edition

I have a massive construction/architecture library based on these cheap books

I also bought the entire collection of Fine Home Building in paper back to 1981
then about a year later the whole collection was offered on DVD
so I have that and someday will try to sell or donate the paper copies

I also have the JLC collection on DVD

both magazines are incredibly informative, especially for someone who has zero
background in construction and architecture

there are also a zillion informative websites

it is imperative to read and learn every day - every single day

Lew

[Curtis Johnson]

Samantha:

Here's a link to Amazon for the book I recommended:

http://www.amazon.com/Architectural-.../dp/1435481623

I don't remember for sure but I may have purchased my book on drafting book on ebay.

Here's the link to the JLC website:

http://www.jlconline.com/

Here's the 1st page from the JLC website when I did a rooftop deck search:

http://www.jlconline.com/search.aspx?query=rooftop+deck

Here's the link to the Fine Homebuilding website:

http://www.finehomebuilding.com/

Here's the 1st page when I did a search for rooftop deck on the FHB website:

http://www.finehomebuilding.com/sear...a.x=14&sa.y=11

Lew is right ... there's a ton of information to be found on the Internet with good searches and sometimes a little persistence to keep looking.

[Curtis Johnson]

Samantha:

I forgot to mention that if you subscribe to the JLC magazine, you can read, download and save their articles (pdf files) from the Internet without paying any extra for that service. The FHB magazine, however, charges an annual fee (@$20 or $30 ±) for the ability to download their articles from the Internet. FHB usually has a little more content in their magazines but they both are good magazines to get for anyone involved with home construction.

[alan11]

@Curtis Would the Journal of Light Construction and the Fine Homebuilding magazine be applicable to residential construction in the UK where we tend to build the external walls in facing brick and blockwork (with cavity between) ? I'd like to invest in a good reference set and just want to be sure that it would be relevant to UK building methods.

Regards Alan

[Curtis Johnson]

Alan:

Both magazines and the drafting book are tailored to construction methods commonly used in the US. I haven't seen the 6th edition of the book so I don't know what new things may have been added to it. I can't help but think there are some similarities in construction methods used in the UK vs. here. Fortunately, Chief is a program that is quite adaptable to many different construction methods as evidenced by the number of Chief users that post here on ChiefTalk from all around the world. If you could post more information on construction methods you employ in the UK, I might better be able to address your question.

[amateurdesigner]

@JJohnson, thanks for the information how where do I select "tapered joists"?

@Curtis, thanks for all the links! It is more than I can handle

@ REED, yes it is a learning process..thanks for the inspiration.

[JJohnson]

I do not think the program can provide tapered joists, but you just call them out on
the plan drawing *( text box with arrow pointing to joists )

Something like, " 2 x 12 joists 16 " o.c., tops sawn to taper for 1/4" per ft. slope."

As others have pointed out sizing and spacing of these would be specified by
an architect or structural engineer. Unless the span table calls for 2 x 8 and
sawing a 2 x 12 would leave no less that the depth of a 2 x 8 when done. A plan
checker may be ok with something like that

To show a tapered joist in a cross section view you can use the CAD tools and draw it so.
To show a tapered joinst in a 3D camera view, you make one from a polyline solid.

There are several ways to get there.

Hope this helps.

[Ron Ravenscroft]

hi, does anyone know how to create a flat roof and what are different layers materials..and thickness that make up the flat roof?

I am making the flat roof with parapet walls (I ALREADY KNOW HOW TO MAKE PARAPET WALLS) so I am just inquiring about the flat roof and its components.

thanks!

My Suggestion would be; Hire a professional if you don't have the training to make the decision.

[JJohnson]

My Suggestion would be; Hire a professional if you don't have the training to make the decision.

Trollism Ravenscroft

Get Thee under the bridge !

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