I have heard two different features on a house called a widow's walk. One is a flat roof, usually over a porch that has a balustrade assembly around it and is only accessible by a window. The second is a flat at the peak of the roof with a balustrade assembly. This flat normally has no visible access. For this discussion let's talk about the second. If this is not your case than ask again and we'll talk about the first, for the two are different.  I must start by saying I'm sorry but I can not come up with a pre-made package from which you could make a widows walk. As for design ideas, my daughter put together two collages for you (Images Below) showing both examples of wood and iron balustrades. There are also a couple of wrought iron fences that would work for a design.  A balustrade is the complete assembly made up of newels (the large posts that connect to the structure), a bottom rail and a handrail ( the two horizontal members), and the balasters (the decorative pieces  between the two rails from newel to newel. This is what you will have to design.

One interesting thing... I drove around my hometown of Eureka, looking for widow's walks. Now Eureka has 1700 historically significant buildings and although I didn't see them all I spent an hour and only found ONE widows walk, and that was one that I did for the customer! Now the point is that there were many roofs that originally had them but it seems that that is the first detail to go. So we must examine why. Looking at the roofs closely it seems that it is too hard to re-roof around these elements so they are just removed.  The point of this is that when you design your balustrade make it such that it can be removed for re-roofing and re-installed without hassle or damage. You see I learned something from doing this Q&A! Thanks for the question ...... Eric    

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