Dear PoP – Roofdeck Suggestions


“Dear PoP,

Loved the post on the basement dig out. I think a lot of your readers would love to see a post on the costs associated with building a rooftop deck. There are a lot of great rooftop decks in the city. Are there architecture firms and/or contractors that specialize in rooftop decks? What are their fees? What unexpected costs do folks run into when building a rooftop deck? On the eve of winter weather, it is nice to consider enjoying nicer seasons on a new rooftop deck!”

Does anyone have any roofdeck photos they can share? If so please email me at princeofpetworth (at) gmail (dot) com. But in general does anyone know how cumbersome/expensive the process is to install one?

22 Comment

  • I’ve always thought about putting a rooftop deck on our home. I’ve always thought it was prohibitively expensive. I can’t wait to see the response here!

  • I love those Ohio flags!

  • I think decks are one of the less expensive additions you can do – for example way cheaper to put a deck in your backyard than to put in a patio of pavers. So I think you could put in a basic roofdeck for less than $10,000, but if you have to build stairs to get up there or you also end up popping up to have an interior stairwell to go to your roof, it could start getting pricey.

    I used to live in a condo with a fantastic roof deck. The best things about it:
    – no matter how hot the day there was always a nice breeze that made it comfortable – so usable for more of the year than a ground-level deck
    – no mosquitoes!! That was on top of a 5 story building, but I hope even on top of a 2 story house there would be less…

    • I concur that there always seems to be a breeze on the rooftops, even when the air at ground level feels still and muggy. I’d consider building one if I had a rooftop view of something interesting, but the only thing you can see from my roof is the Eiffel Cellphone Tower!

  • i’ve been thinking about putting a roofdeck onto my two story rowhouse since i bought it. i just figured it would be in the neighborhood of $50k-$100k. i could probably do 30 or so. doable?

  • How can it only be $10K? DC requires full archeticture prints for rooftop structures. That alone will cost $10k.

    • i’d say for a modest roofdeck an architect would charge 2-3k for permit drawings… if there’s not really any demolition i think 10k is reasonable…

  • ah yes the crazy roofdeck with the Ohio flags on Argonne Place.

  • I looked into — ever so briefly — a couple years ago. It’s surprisingly not that expensive, which I guess makes sense in that it’s just fencing and decking added to the existing structure of the home. The quotes I got were 10k at the low end and 15-20k for something with all the bells and whistles or a green roof. That probably assumes existing access to the roof, which would add several thousand more if you had to build it.

    But count me in as somebody who would be very interested in a post a la “digging out the basement” for building a roofdeck — the process and experience of doing it as a homeowner, choices to be made, costs incurred, etc..

  • I looked into it as well. The problem I encountered was structural. My roof trusses, and I would assume a few others in DC as well, were not designed to support the weight of a deck that could have 20+ people. At most, it can handle a big snow load which is not the same as alot of people walking around.

    The other issue has to do with the roof membrane. Unless you can shell out some serious cash for a metal roof, most roofing membranes only last about 20 years. Given the extreme changes in temperature we have here, you probably get less. So if you have a spot on your roof that leaks, it is pretty tough to address with a roof deck over it.

    Sorry about being the Debbie Downer on this.

    • Ahhh, of course. I did just pay to redo my roof. I presume that you’d need to redo your roof before spending the money on the deck. That deck would have to come down before the entire roof is replaced.

  • The photo is indeed from Argonne Pl – and it’s not just the roof deck or flags that is unusual about that house.

    Anyone have info on what’s up with that house?

  • We put a small roof deck on our row house, I took 1 year to get the permits; about a month to get a deck put up. Total cost, $16,000 to $24,000. (16 is a cheap pine, and 24 is for Trex-like engineered plastic wood: It’s not supposed to fade, or need maintenance every few years.

    Details, Our home is not as deep on the 3rd floor as the second: outside the 3rd floor bathroom was a 13x24ish flat roof: We were able to put a deck about 13×16 over the origional house (row home, two brick walls on the sides), but not over the roof of the porch extending from the back wall.

    The 16K included making the bathroom smaller (partitioning off a hall – using a wall with a sliding door.), building steps up to the roof level (~3′ above floor level), adding a few electrical outlets (inside; out), and putting a exterior door.

    We bit at the extra to make all exposed surfaces in an engineered wood; have a lovely deck approved by DCRA; rated for 6 persons.

    • Who did you use? This sounds very much like what I want to do and I’d love to have someone come out and give me a quote.

    • Wow, sounds great. Makes sense getting approved for fewer people – but still not bad. It’s great you could use your 3rd floor to access the deck.

  • If you do this, be very careful. Make sure your roofing material underneath is in good condition, as you will have to remove your roof deck if you should spring a leak. Also, make sure your roof can handle the additional weight of a deck, and make sure drainage is considered. Pull permits and make sure you are dealing with a reputable contractor. This is a structural addition that needs to be done properly to avoid potentially huge problems later on.

  • Just to address a few misconceptions from the posts above-

    Roof decks are normally built (I know, I’ve built them) on beams that run from brick party wall to brick party wall. It doesn’t matter how strong your roof trusses are because you won’t be stepping on them. The deck is suspended over them. Also, although repairing the roof is a little more difficult, a carpenter who has any idea what he’s doing will use wood screws to attach the decking to the beams, and not nails or glue. So when you have to repair a spot on the roof, you can just unscrew the decking in that particular place and repair the roof. You don’t need a metal roof just because you’re putting in a roof deck- a normal rubberized membrane is fine. Finally, architecural plans for a deck shouldn’t cost you any more than $2500, and probably could be had for a lot less. No where near the 10K quoted above.

    I’m a developer and contractor (although I’ve got my hands full and am not taking on any new contracts), and I’d say a good estimate for a roof deck should be about $20-25K, depending on how you access it (spiral steps are about $4k for a 10 ft section, for example). Keep in mind if you have any vents from bathrooms or furnaces you will probably have to reroute them, which can be a bit of an extra expense. Also if you’re in a historic area you will encounter a lot of resistance from neighbors as the deck may be visible from the street.

    Good luck!

    • Dave,

      As an experienced contractor in this type of work, what type of wood have you used for the supporting cross beams on a roof deck ?

      I’ve noticed that treated or wolmanized wood can begin to deteriorate after a few short years and like any wood exposed to the elements outside will have some kind of obsolescence.

    • Dave,

      When are you taking on new projects? It really sounds like you know so much more about this, as you are a contractor in the business. I’ve just bought an old restored house and would like to add a rooftop deck.


  • Dave is right. If your deck is sitting on the roof trusses, it’s not built right.

  • Speaking of building on top of houses, how much does it cost on average to build a pop up? I just assume it costs around 100k, but would love to know a more accurate estimate.

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