sojay_gw

flat roof pitfalls?

sojay
15 years ago

I am about to put an offer on a house that has a flat roof with zero overhang. There are signs of leaks on the ceilings, and this will be a major negotiating point after the inspection. We really love the house and definitely want to buy it, but are we walking blindly into a nightmare? What are some of the pitfalls with flat roofed houses? Would it be enough to request that the roof be resealed before closing, or would you make sure you are in control of the details and get it done after closing allowing a reduction in price? Any special systems you'd recommend?

Comments (19)

  • Don_
    15 years ago

    The words flatroof/leaks almost go hand in hand. I would wait for more posts if I were you.

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  • JRRR
    15 years ago

    Flat roofs don't have to be a problem, especially if they're drained well. The inspector should have experience with flat roofs and the particular roofing material. If not, get one who does. The recommendation of the foam roof is good. They add effective insulation value.
    A flat roof with no overhang, heh? Does it have downspouts or parapets with scuppers?

  • ventupete
    15 years ago

    If you really like the house, I wouldn't treat the flat roof as a deal breaker. Flat roofs can be made leak free, but they do not last as long as pitched roofs and require periodic maintenance (including keeping the roof drains clear of debris).

  • sojay
    Original Author
    15 years ago

    Actually I don't see any downspouts, but I haven't been up on the roof. Here's a pic:
    {{!gwi}}
    The climate is in the south, meaning not much snow, but lots of rain. I was there in a downpour, and the rain washed down the walls.

  • jeniferkey
    15 years ago

    How pretty. Maybe it has drains that go down the walls and out at the bottom (that's what we did). Or it slopes a bit to one side or the other where we don't see scupper holes.
    Jennifer

  • jakabedy
    15 years ago

    We had a flat roof on a sunroom (well, sloped a bit to one corner for runoff) and the main problem was the flashing where it met the main house/chimney. Or shall I say, the lack of flashing. Once that was fixed, no problem.

    As for a WHOLE HOUSE flat roof, I would consider getting an experienced roofer ALONG WITH your inspector to look at the thing. I know I had a great inspector when we bought our latest house, but he had a disclaimer about the roof (80-year old concrete tile). Had I been smart and had more time, I would have had a specialty roofer look at it as well. But, he could get in the attic and see that the roof structure was in good shape (just wouldn't climb on the roof) -- I don't know that that is possible in your case.

  • brickeyee
    15 years ago

    The most reliable flat roof is EPDM membrane. When installed correctly the roof should have a life of at leat 30 years.
    For smaller areas factory seamed can be used, for larger areas field seamed is required.
    EPDM is very common in commercial roofing (stores, shopping centers) and it can be hard to find an installer for a small home job, but they are usually out there.
    Firestone is one of the big material manufacturers, but they are mainly interested in commercial applications. The basic methods transfer directly however.

  • sojay
    Original Author
    15 years ago

    Thanks, everyone, I'll follow your suggestions.

  • higginsx
    15 years ago

    Did you have a home inspector on this?? What does he/she say??

  • andee_gw
    15 years ago

    I, too, fell in love with a house with a flat roof and bought it with my "eyes open". And then my eyes were opened! The house is somewhat large with 2-ft. eaves; no attic space. The original 35-year old roof was built-up asphalt type. The inspector said to start considering a replacement.

    New asphalt type roofs are said by some to be inferior to the old ones because the source of the material used is thought to be inferior. Nonetheless, some of my neighbors with the same style house have replaced theirs with the built up type.

    I decided on a membrane roof. It costs a fortune (any flat roofing job does). Be prepared. I had a couple of estimates that were in the same range. I went with a well-known reputable company with experience in flat roofs. The did a good job, except.... The roof's drainage is now completely different than before. Before, the rainwater drained through most of the available downspouts. After the new roof, it all drained through one spout. Actually, since it couldn't all go down one spout, it ran off in waterfalls on the lowest parts of the roof. The roofing company did a bit of mounding up at the most critical spots, but 5 years later it is a mess. I've run plastic spouts on the top roof to un-used downspouts (there is a flat roof on top of a flat roof where the high-walled living room is). I have rotting fascia boards. Since the house is on a hill, my down-hill neighbor spent an entire season complaining to me about my drainage going on to his property (I don't blame him -- it was horrible). He had a drainage system constructed in his yard to contain my run-off!

    The moral here is to plan your drainage when you plan on re-roofing.

  • inox
    15 years ago

    Did any native culture ever build structures with flat roofs, except of adobe in the desert?

  • rosecottagelynn
    15 years ago

    Insurance. Insurance companies don't like flat roofs, as i found out when shopping for homeowners insurance for my house with part peaked, part low-slope (not even flat) roof. Many of them will not cover flat roofed residences at all. Check around!

  • paulines
    15 years ago

    Beautiful home, sojay! We have the glass block elements, too, in the kitchen and over the main staircase. Here's our home (in New England, no less). We do have a very slight pitch towards the back of the home where the downspouts are located.

    {{!gwi}}

  • grittymitts
    15 years ago

    30 years of property mgmt taught me that flat roofs equal trouble! One 210 unit multi-family community had 93 roof leaks. Previous owner had been sold foam type roofing which had broken into pcs & floated about in the roof "pond"
    Northern or Southern part of the country was the same- except ice dams up North in scuppers during winter caused 2" of ice formation on roofs resulting in whole roofs being severely damaged by freeze & thaw cycle. Of 41 bldgs on one particular property, over half were severely damaged... over half a million for re-roof and interior repairs! Installation of heat tapes prevented future icing but that wasn't cheap either & required monitoring.
    You couldn't give me anything with a flat roof.

  • sojay
    Original Author
    14 years ago

    well, well... here we are a year and a half later. We bought the house and absolutely love it. The seller (and original builder) is a reputable roofer, it turns out, so that was reassuring.

    BUT, now we all of a sudden after excessive rain have substantial leaks, but only in one room. The downspouts go down through interior walls (which gets really loud during downpours). My suspicion is that the issue is related to us not thinking of cleaning the drains.

    But now the damage is done and something has to be done. Does a patch job ever work on a flat roof? Should we get the whole roof redone or would it always come back to haunt us?

    An architect friend has suggested adding a completely new pitched metal roof over the flat roof part (which is about a 3rd of the house) to match the rest of the roof, but I love the existing look, so I'm a bit reluctant (not to speak of balking at the cost). But there are other issues which could be adressed the same time. There are no overhangs, rain washes down the walls and horisontal rain manages to get in over the top of the windows (we are seriously exposed to the elements here, as the western exposure is waterfront), so our architect friend recommended at the same time as adding a new roof, to add 2-ft overhangs over the windows, sticking out from the wall. It would be a nod to the local vernacular and wouldn't take too much away from the contemporary look, he says, but I'm not convinced yet, although I see the practical worth of it, and I do love the look of those old southern farmhouses with differing degrees of roof pitches.

    So, my question is 2-fold, practical and aesthetic.

    here's the other side of the house:
    {{!gwi}}

  • jakkom
    14 years ago

    Without overhangs you are risking a lot of water leakage developing around the window frames (don't ask how I know this, LOL).

    On the downside, you want to make sure that your expensive new pitched roof with its extended overhangs has proper drainage, either with gutters or some other system. An overhang right over that pretty second story-patio can be a real disaster if that patio wasn't pitched correctly. Your home is beautiful, BTW!

  • jimrac
    14 years ago

    Here is my 2 cents,,,after having experienced leaks with a low sloped (2/12) and skylites on a portion of our home in CT. We had roll roofing installed previously, didnt care for it. Went with 40 year, thickest arch. shingle they made, had a thick ice and water barrier undelayment installed, with step flchings for skylights,,and finally a beautiful, long lasting, nioce looking section of the roof. countless people warned me to not go with a shingle.

    But anyways, your home, the overhangs would might resolve some of the problem, but I personally feel would change the character and appearance of the home,,,,,and as to patching sometimes yes, and sometimes no, the hard part is blending in the newer portion with the existing..You solve one problem but create another.
    If anything, if a pitched roof is added,,,I would think a steeper pitch would be more pleasing to the eyes.

  • bornaroofer
    12 years ago

    I have been installing, repairing and inspecting flat roofs for over 20 years. If its a membrane roof system it probably can be repaired and provide years of service if done properly.
    The problem is getting a good flat roofer.
    If its an asphalt system and its old or improperly installed it may need to be re roofed as repairs only last a few years on these systems.
    A membrane roof especially epdm has a life of 30 years at least if properly installed and maintained.