Comments on: Ask us: How can I add a roof deck to a 2-unit building?

By: Kerry

Kerry — Mon, 17 Oct 2011 22:34:59 +0000

Well, I’m not the only one with a very late reply.
FYI, residential and commercial structural engineering are pretty different animals. You could hire someone brilliant moonlighting from one of the “big” structural firms downtown (actually, they are small businesses) and they won’t know the pitfalls of existing local construction.
Adding a roof deck can be a very complicated and expensive project in SF. Many folks want to add a hot tub to their 4th floor Russian Hill condo on brick foundations and are upset when I tell them what is involved.

By: Charles Chan

Charles Chan — Thu, 25 Aug 2011 04:06:22 +0000

Roof deck is great in the city.
I’m doing architectural plans for two roof deck projects. One is 4 story 3 units building by Telegraph Hill and the other one is 17 story high rise in Union Square. SF planning department can approve the roof deck over the counter as long as the roof is maintain within allowable built area with railing or parapet not more than 48″. If the proposed roof deck that encroaches on a yard or setback, then all railings are limited to 42 inches tall a notice will be required for immediate neighbors only not the 311 long process. Make sure to read the SF bldg. code Amendment – section 1511.5 about the roof deck requirement, one of the require is that decking material must be fire retardant treated wood such as Ipe wood or 2″ nominal thick redwood.
Lastly make sure that the roof decking system is allowed for roof maintenance or repair. Bison pedestal decking support system & 2×2 ipe wood tile work great to allow flexibility to remove portion of decking for repair.

Check out the deck handout from SF planning website. http://www.sf-planning.org/index.aspx?page=2471

Email me chan@tc-archstudio.com if you need more info.

By: George

George — Tue, 24 May 2011 19:22:28 +0000

Samantha / Mark / Steve:

I am in the Inner Sunset and I too want to build a simple roof deck. Any successes to share?

By: steve

steve — Fri, 18 Feb 2011 20:38:40 +0000

Samantha/Mark,

I am in the sunset and want to build a simple deck too… did you succeed? Did you have to do a 311? Cost? Architect’s name?

By: Samantha Wright

Samantha Wright — Sun, 27 Sep 2009 18:13:26 +0000

Mark – Did you end up buiding a roof deck? I was just starting research on this as I am interested in putting roof deck on my home in the sunset also.

By: darkstar

darkstar — Tue, 11 Nov 2008 21:30:52 +0000

Interesting conversation. I had a similar question, but my home is a two story SFR in the sunset. I’m interested in a roof deck too. My questions are:

Can i get away with one egress from the roof, that goes to the 2nd floor deck?

Also – if i’m not buidling a stairwell penthouse, just a deck with transparent windscreens, and some railings, do i need a 311?

Thanks for any help!

Mark

By: Dede

Dede — Sat, 13 Sep 2008 19:29:09 +0000

@urbanSF,

I watched somebody at the building dept. this very week, a licensed architect, try to negotiate with a plan checker about a second exit requirement when all the conditions (height, area, occupant load, occupancy, etc) called for just a single exit for one unit in a two unit building – and I watched them loose. The plan checker said two exits are always required from each unit in two unit buildings. Somebody who doesn’t fully understand the issues would not continue the fight – and in this case they didn’t. So I stand my comments.

You are absolutely correct in stating that it is a process – and you need somebody who understands the process working for you in making sure your interests are protected.

By: sparky

sparky — Fri, 12 Sep 2008 16:21:57 +0000

urbanSF7,

“Two means of egress” meaning 1 for each unit; of course you need that. If you mean 2-units need 2 each that is not true. The new code is 1. Have I submitted and approved this with the new code; Yes. But anyway we are talking about the egress from the deck, and that would be one. Either from the private unit or from the comman stairs. Have I submitted and approved this: yes.

Do you need rear stairs to the back yard anymore; NO.

LiveSmart, What you described is what my company does; Design/Build. But most generals do not, and since engineers won’t do the architectural drawings, and city needs them, an architect is required. So it’s not really like the water heater scenario.

By: urbanSF7

urbanSF7 — Fri, 12 Sep 2008 15:59:36 +0000

sparky- no disrespect, but I disagree with you on a couple of points.

1. Your reference to “1 flight of stairs” probably means one means of egress. That DEPENDS on several factors. For most single family homes, one means of egress is enough, except for large floor areas. In some cases, yes, you may need 2 means of egress. Each case is individual. For 2 unit buildings, meaning 2 floors of living area over a garage level, you will need 2 means of egress. That’s the code. There are conditions and other issues if you choose to sprinkler the building. (I’m talking new construction here only.) I doubt if we could find a pair of flats with NO stair at the rear of the units leading to the rear yard, (except for completely unpermitted and illegal construction).

2. As for roof decks, depending on many factors, the permit can be easy or challenging to obtain. In many cases you WILL need 311 notification. In some you wont. The planning dept. is pretty clear on those issues. And yes, you are correct about structural costs. As I mentioned previously, for any new live loads you MUST carry the new loads completely down to the foundation.

By: Live Smart

Live Smart — Fri, 12 Sep 2008 15:58:55 +0000

Why do you need to hire an architect to design a roof deck? How much of it needs to be designed? You aren’t designing or building the Taj Mahal.

Jeez, I would think that a structural engineer and a contractor w/extensive experience building roof decks are sufficient — the structural engineer tells you what needs to be done and the limits of what can be done while the contractor can give you options according to your budget.

There are design/build firms in SF who can provide one price to do it all, including gutting and rebuilding 2 unit flats and cut out the middleman. Seems like you should get also get a bid from these folks to get an idea of costs.

A very simple analogy: I needed my standard 40 gallon gas water heater replaced. Called several plumbers (some “hi-end,” some not) who quoted me a price from $500 to $1,600 for identical work. I gave the job to the plumber for $500 and have no problems. Goes to show the huge variances in construction costs.