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columbiascgw

Flat roofs

columbiasc
13 years ago

Since we were talking about foundations, let's take that discussion and flip it over! What is it with architects and flat roofs or low pitched "slab" roofs? It seems to me that an awful lot of "architectural" houses incoroporate flat roofs or low pitched roofs into the design. You see this in many of Frank Lloyd Wright's designs and in designs going back to the 60's up through today's modern and avante-garde designs.

But on a practical side, I have never seen a house with a flat roof that didn't eventually leak. I have talked to many roofers over the years that feel the same way. So if they are flawed, why continue the infatuation?

Scott

Comments (20)

  • flgargoyle
    13 years ago
    last modified: 9 years ago

    That's a really good question, and another one of my pet peeves. (I seem to have a lot of them!) I've seen so many failures of flat roofs, and yet they still build them. I worked in a place with a flat roof, and it was a never-ending battle with leaks. Same with one of the roofs at my church. I can't imagine the small amount of money saved on the building could possibly cover all of the repairs over the years, not to mention the damage inside.

    I have a favorite flat-roof failure story, and it actually happened. In CT, they built a huge arena for concerts and sports. The construction method was interesting: They built four big columns at the corners. The roof was built on the ground, and then jacked up, using the 4 columns. As designed, this huge roof was supposed to have a 4' crown, which isn't much over the many acres the roof covered. By the time they built it, and jacked it up, all of the crown was gone; the roof was virtually flat. Why they didn't stop and fix it right then and there, I don't know. On top of that, they hung the lights and massive speakers from the center of the roof. One winter, we had a heavy snowstorm, followed by heavy rain. The added weight made the roof sag, and all of the snow and rain ran to the center, making things worse. About two hours after a basketball game, the roof failed spectacularly. Had this happened earlier, tens of thousands of people would have been inside that building!

    Aside from the practical aspects, I think low pitch roofs are ugly. Our old house here in FL had a 2/12 pitch- ugh! There's been a return to steeper roofs in most areas, mostly for aesthetics, I believe. The old-timers in New England knew their stuff with the typical 12/12 cape roofs. The steep roof helped shed snow, kept the rain out using less-than-ideal roofing materials, and created some room upstairs for the kids' bedrooms. All this in a compact footprint! To me, that makes more sense than a sprawling ranch with flat roofs that have to be 100% waterproof under all conditions.

    About the flattest roofs I can stomach are some of the Prairie Style and Bungalow houses. Somehow, they managed to make a low pitch roof look good.

  • User
    13 years ago
    last modified: 9 years ago

    Jay and Scott, roof pitch is on my mind now, and I am glad to see input from other folks.

    One of the latest ideas for my derelict cement block garage is to have one side of the roof, that facing south, almost flat, but not quite, so that it can be planted a la midwest sodbuster roof, although this is not dug into the side of a hill or anything. This is the latest thinking, because I was planning a translucent/transparent Lexan roof for a greenhouse below. Someone on Greenhouses forum advised me the place was not oriented properly for that. However, I still wish to keep my larger tropicals inside and overwinter tender plants in this half of the redone structure. In the other half, I want a soaring roof almost the 12/12, which will intersect the low half way up, and have the Lexan panels at the join be vertical, and a real LOFT above the foundation room. And in that space below, a 48" deep Endless Pool for exercising my aging bones. It would also humidify the entire space. And I could have a spiral stair to the loft where I'd sit in my ivory tower and meditate. Before I die, I really want to have a fantasy space, and not leave this mortal coil never expressing the natural child within me.

    What I'm bringing to the table is the question about,"What will it take to make a successful good draining low roof able to hold up the weight of wet dirt and plant life? A rubber liner? And what kind of support structure?

    Some of the homes in the southwest are low pitched. They have the tiles arranged up/down/up/down across the roof, which forces all the drainage in one direction, even with a low pitch. Maybe low roofs need better roofing materials and maybe the standing seam metal roofs are one modern material that could achieve that. But not with stadium sized buildings! How in the world did the authorities allow such a hazardous design to be built for a public arena?

    The old builders of cathedrals used butresses to fortify the walls and thus the roofs of the buildings. Transfering load all the way to the ground. Oh sigh, how I wish I could have been an architect! Or a civil engineer.

  • TxMarti
    13 years ago
    last modified: 9 years ago

    I would guess the reason is cost. We lived in a duplex with a flat roof and while it never leaked while we lived there, it had in the past. We also bought a house with an almost flat roof addition. Leaked like a sieve. The reason for that roof was because of the roofline it attached to. I still think there could have been a better way. But that was the easy way.

  • columbiasc
    Original Author
    13 years ago
    last modified: 9 years ago

    ML - I have heard of these grow-roofs or "green roofs" and they are gaining popularity. In my untrained opinion, the only roof system that would do what you are suggesting AND maintain watertight integrity would be a solid concrete slab roof. Something along the lines of a single slab of pre-stressed concrete.

    A friend of mine's father-in-law (recently deceased) was involved in a company in the Florida Keys that was building homes that were made entirely of pre-stressed concrete panels that were manufactured off-site and transported to the building site and assembled. I am told the bridge tolls, which are based on weight, are quite expensive. They are supposed to be hurricane proof. All window and door openings are in place at the time of the pour. It's an interesting concept. I don't know all the details so I don't know how they insulate these homes, but it is still an interesting technique.

    Dwell Magazine, one of the few magazines that regularly features smaller homes, also leans heavily toward the flat-roofed, modern architecturally styled homes. I still say we need our own magazine. One that features real, liveable homes like Kiki's or Jeff's Basic Personal Structure, www.verysmallhome.com, not arcitechturally unique, expensive to build, design statements.

    Oops, there I go straying again. I guess I digressed from flat roofs and I suppose I should have included the small home angle when mentioning flat roofs in my original post. My apologies to the censors.

    Good luck on the grow roof!

    Scott

  • desertsteph
    13 years ago
    last modified: 9 years ago

    their spouse, brother, son etc owns a roofing company...

    maybe all of them do!

  • emagineer
    13 years ago
    last modified: 9 years ago

    Think pueblo style homes in NM. I would bet that over 90% are flat roofs. You can't see them because the adobe walls go up a foot or more and are usually of some design which takes your focus away from "flat". Actually those walls may even be higher, swamp coolers are the norm on roofs there and you can't see them. I had a new home there with a flat roof and actually never thought about problems. But they do have to be checked yearly for any voids in the sealing done.

    We do have a lot of flat roofs here in the area I live. Most are early modern design, very large homes. Hadn't thought about their roof design with our normal possibility of having 2' of snow. They must be built like iron.

  • User
    13 years ago
    last modified: 9 years ago

    Emagineer, good observation about the pueblo style in NM.
    I'm thinking it is all possible, even the adobe, much less the flat roof, because rainfall is scant. Where rainfall is greater than 60 inches a year, as in Mobile, adobe would be out of the question. But the Spanish tile on the roof, over whatever it is they use for sealing the roof against the weather, would work fine with a low slope.

    And Scott, I have a couple of books I'm studying on the mechanics of the "green roof" concept. They use them all the time in Europe. They are touting them for big cities with flat roofs that contribute to the higher temps for the cities in general. So the living or green roof is a way of lessening the city heat gain. In fact, there is a credit given for designing and building a living roof on new buildings these days. I think it would be a great idea even in the southwest where they have minimal rainfall. I do not know how that works exactly, but grasses are wonderful plants and can make such a big difference in their environments. By the way, they also include "living walls" in the mix.....where cables and other handholds are provided for VINES to grow up a screen a little removed from the walls exposed to major sun and heat. It also works to dampen noise levels. I'll look up the name of the books I'm reading and post them for you.

    And I have no idea what a swamp cooler is. Is it some kind of flat surface which allows evaporation of water? Does it have a shade cloth over it?

    With the soaring temps in all parts of the world, even Moscow, a little creative thinking is required. Somehow I think doubters must accept that the earth is warming up with our excess hydrocarbons in the atmosphere. How long can people deny it? I think we need to learn to use our architecture to protect us from a rise in average temps. And work to decrease our dependence on petroleum...including plastics.

  • User
    13 years ago
    last modified: 9 years ago

    Scott, I'm looking in Chapter 3 of PLANTING GREEN ROOFS AND LIVING WALLS, with the title "Constructing Green Roofs."

    Not all of the planted roofs are flat like a pancake, but they are sometimes bowed or arched, just not to a great extent. What I'm reading about it the more DIY project.
    Once I decide what sort of structure is required to HOLD UP such a roof, I will know if I can change my derelict garage to work that way. The author of this book is Nigel Dunnett & Noel Kingsbury, publisher is Timber Press. I have the revised and updated edition. The living walls portion is interesting too, because it uses vines both climbing and trailing (hanging from the roof eaves)....

    On a more technial approach, I bought LIVING SYSTEMS by Liat Margolis & Alexander Robinson. Its subtitle is "Innovative Materials & Technologies for Landscape Architecture." It is published by Birkhauser, with offices in Boston. It uses acid free paper, so it is environmentally conscious all the way! You should see the illustrations in this book, mostly in Europe, roofs on existing buildings and then whole parks with trees built on top of underground garages and such. They are interested in moderating global warming by changing our buildings and communities. I think we will see more of this as the earth continues to warm up with our pollution.

    Anyway, they have flat roofs, and drainage materials beneath the surface, and they use the water runoff to water the living walls which keep the floors of a building from heat gain against the high walls. I had not thought much about shading the walls as well as the roof, but with a tall building, the walls are more square foot exposed than the roofs.

  • spunbondwarrior
    13 years ago
    last modified: 9 years ago

    Hey there Flagargoyle and all!
    I was born and raised in way far south Florida, a long time, like almost 60 years of time ago. My family had already been there long enough to remember and talk about life in far south Fla in the days before "Mr. Flaglers' railroad" (Florida East Coast Railroad, the Ball and Dupont family 'toy") came anywhere near as far south as Dade County, let alone to the "Keys". Back before the Arabian Nights town of Opa-Locka was ever even thought of.
    If anyone has ever been to Opa-Locka, all the old and original houses remaining have (or maybe had) flat roofs. I am unsure of what the place looks like anymore as I understand that things there have changed quite a bit since back when Ed Eschek was the Chief of Police and Mrs Rose was still alive. Before I boogied on off to greener pastures back in 1972.
    What a cool little town it was!!!! And the town hall all spified up for the 1972 let's renominate Tricky Dicky for Pres at the Miami Beach Republican National Convention, what a great time was had growing up in the far south Florida.....
    Anyway, Mommas adopted daddy had been building and buying and selling houses and land for many years, and I remember once asking him why so many "old houses" had flat or barely pitched tile covered roofs, even all the houses in the neighborhood of Grandma's Cousin Ida and Joes' house that no longer exists and was long ago in what is now "downtown" Miami had flat roofs. Oh yeah... And all the houses there built back before and in the 1920's had solar water heaters too
    Anyway, he told me that it was a simple matter of keeping houses cool, you know, back before any but the truly wealthy could even afford to think about room air conditioning let alone "Central" HVAC systems. Back when having the coolness of a terrazzo floor to sleep on, and a sleeping porch too were true blessings. Turns out it's true you know.....
    And at last.... the reason I replied:
    The least summertime solar exposure and attendant heat gain that a building can have comes from having a flat roof.
    OK.... My long winded and ultimately very brief reply is done

    Well, almost....
    Hey gargoyle, you know where Vanderbilt Beach is?
    40 years ago it was a 15 or 20 mile expanse of pine trees and sand where on some weekends we would drive across the Tamiami Trail to go and party till the cows came home.... Nothing there except the occasional Marion County deputy, that all us half stoned and completely drunk party animal guys and gals would all end up pushing and pulling and getting the wayward officer safely back to the road.... Yeah boy.... back when the coolest thrift store anywhere was the one in Fort Myers......
    My daughter says that you can tell when someone is getting old cause they have all these "I remember when" stories. I reckon I'm getting old, real old, rel fast....

  • jey_l
    13 years ago
    last modified: 9 years ago

    Where's the PC in this thread? Just because something is vertically challenged doesn't mean it isn't good.

    Come to think of it, I have yet to see a pitched roof that doesn't leak after a while either.

    Your example of Falling Water is perfect because in Autumn it becomes falling leaves. Leaves along with the acorns and other airborne seeds that do not slide off pitched roofs as easily as assumed and if you insist on gutters it makes the situation worse.

    Both styles have their advantages and disadvantages but a flat roof really outweighs the pitched roof in many aspects. That is why there is by far more acreage of flat roofs (footprint not surface area as a pitched roof always has more surface area to cover the same footprint) in the world than there are pitched. Many have been neglected for years and years yet still don't leak. There are even single roofs measured in acreage that are flat and zero that are pitched aside from similar subsidized monstrosities as mentioned above (Hartford Civic Center). Both styles of roof require maintenance and a flat roof is much easier to maintain. For some a 4 pitch is like a dance floor but for the majority it is like Pike's Peak even if it is but a few feet off the ground. Pitched roofs look nice as they have a bit more character and offer a majestic facade but for the most part are a lot of wasted space and energy in most structures that have them especially if it s a truss roof as is becoming more common these days.

    The living roofs are not a new idea or concept but are being marketed differently these days and presented to a different group of people. We now have "systems" available that have been approved by the society of acronyms that will allow you to use them provided you design it as they say with materials of the manufacturers they approve but who will take no responsibility when they fail and we have to pay well above market value for their "services". They are extremely expensive to build, of very poor design and require a lot of maintenance. Drainage is not what you want and retention and recirculation, wether mechanical or natural, is what you need on a living roof. Something you don't want either is pecan, oak or coconut trees growing unless they were intended and placed by design but if you don't have easy, safe and comfortable access they will grow and destroy your roof. ML will tell you about some tree roots that lifted and broke the slab in her Derelict Garage and I could write volumes about trees, vegetation and even moss that have destroyed roofs and massive concrete and steel structures. No matter where you go in the world when the trees are higher than the roofs you will find them growing there but when you provide access to and put a feature on a flat roof that draws the occupants to it they are usually better kept than any other roof.

    Flat roofs offer more versatility and elegance. Let's see you relax on a barcalounger on your 12 pitch because you have nowhere else to put one or because the views are spectacular and see if you are of the same opinion then.

    Either way it comes down to design, materials and workmanship. In todays world none are worth writing home about as we live in a land of rules and schemes. None of which are really intended to protect the person who just wants a place for their stuff, to raise a family or relax after having done so and enjoy the changes of seasons and smell a few flowers. We shouldn't have to be a world of architects and engineers but those self appointed keepers of the codes should know better and be required to do the jobs that we pay them for.

  • flgargoyle
    13 years ago
    last modified: 9 years ago

    One problem with flat or low-pitched roofs here in FL is that with the houses being built on a slab, there's precious little room for A/C ducts. Our old house had a 2/12, and you had to slither like a snake to get around the 'attic'. I would think with all else being equal, a flatter roof might be able to withstand a hurricane better, though.

    From an engineering stand-point, there's nothing wrong with a flat roof unless it's really flat- like inches of pitch. Then you get into trouble with low spots that hold water. A few feet of pitch will prevent that, and the difference in cost is pretty minimal.

    For me, though, it's a matter of aesthetics. Having grown up around capes in New England, and the even steeper Victorian-era homes, flat roofs just look 'wrong' to my eye. YMMV....

  • User
    13 years ago
    last modified: 9 years ago

    Spunbondwarrior, love the tales of the old days, but you know, I'm old enough to have been your babysitter. However, civilization comes slower to some parts of the country, and that is often a blessing.

    Then Flgargoyle, your observations on retrofitting ductwork into a low-roofed house are point well taken. I had to add ductwork to my old MoccasinLanding cottage in July one year, and I truly felt for the guys doing the job. Up in the big cities, they like the "loft" look of exposed ducting and piping, and I'm thinking it is an honest look not to be scorned. Much easier to get to them for any maintenance, and less chance of damage inside the living space too. I think the key here is to have the ceilings high enough that the innards of your home systems soon disappear from your awareness.

    Then there is Jey_L. I am so glad that you are hanging with us. I am feeling more inclined to consider a flat roof for the derelict garage. ...which, by the way, I will soon be inclined to identify in a positive way as TEAHOUSE. This identifier has personal significance to me.

    Sorry to nix the idea of a Barcalounger, but years ago I swore I'd never allow a recliner into my house. However, the idea of a lookout atop the Teahouse appeals to me.
    Even an exterior staircase from the back side of the building would work. Positioned there, no issues with breaks in the flat nature of the roof. I like the first design better, if it was a continuous flat roof. I'm not yet willing to give up on the living roof concept. For all those years the Swedes, and the midwesterners had earthen roofed buildings. And no modern systems to speak of. Maybe grass on the roof. Strong enough to walk on, grow wildflowers maybe, grass definitely. And I'm accustomed to pulling up seedling trees after every rain when the soil is soft. It is figuring the strength required to support the load on the foundation, the walls and the roof/rafter/beams that I'd need to know. My DH is quite good at that if I could come up with a workable design simple enough, economical enough, that we could afford to pay for it outright.

  • jey_l
    13 years ago
    last modified: 9 years ago

    My daughter says that you can tell when someone is getting old cause they have all these "I remember when" stories. I reckon I'm getting old, real old, rel fast....

    You're still a spring chicken. When your story of "I remember when" is about what you did this mornin' then you know your getting old. For me, though, it's a matter of aesthetics. Having grown up around capes in New England, and the even steeper Victorian-era homes, flat roofs just look 'wrong' to my eye. YMMV....

    Ah yes... But the view from the ground is quite a different perspective. It is aesthetics. They are works of art. IMO second only to Gothic. It's an odd comfortable feeling that you will be impaled by a spire before you hit the ground. It is a shame that our technology and knowledge could make such masterpieces common place but have instead put them farther out of reach. A good many Victorians in NE were actually quite similar to Sears homes. They were affordable kits for the DIYers carriage houses and all. Many of them also have flat roofs throughout but we don't notice them as such as we just see them as balconies. Sorry to nix the idea of a Barcalounger, but years ago I swore I'd never allow a recliner into my house.

    Couldn't agree more. Wouldn't want one on my roof either. I wouldn't want you to give up on the idea of a living roof either but I am considering affordability and the enjoyment factor. Will see you on your other thread.

  • fixizin
    13 years ago
    last modified: 9 years ago

    Most of the "leak like a sieve" horror stories are due to architects and contractors who ignorantly transfer the same materials and methods that are successful with pitched roofs onto flat roofs, and/or eschew the practical for the "artsy". One of the many reasons I consider Frank Wright an overrated interior designer and architectural poseur is the sheer lack of durability displayed in his many "works". He seems to have been unable take into account such everyday effects as, I dunno, SUN and RAIN, lol! An expensive custom home should NOT be significantly (even STRUCTURALLY) degraded by such obvious factors in just a decade, or three. FLW, pffff... puh-leeze do not use his so-called roofs as an example of proper design...

    That said, flat roofs are a signal element of tons of International and Modernist styles I absolutely love. I understand the charm of an 18th Century New England village, but I want to live in OUR time--Mies for me. (Better to be a flat-roofer than a flat-Earther, lol.)

    Even a slight 1/4" per foot slope does wonders to avoid ponding, yet still feels dead-level to walk, dance, or lounge on. See LockDry aluminum decking... try putting that on your 4:12 or even 2:12 roof.

    As for adding central A/C to pre-1959 homes, that's what ductless mini-split units are for.

    In general, a pitched roof is "finis", done, closed to all future activity, while a flat roof (esp. of concrete construction) is a blank canvas with all sorts of "later-on we're going to..." possibilities... e.g. decks, solar power/heating, roof lawns/gardens, atrium, ANOTHER STOREY, etc.

    Flat roofs have their place and purpose, but like a fireplace, it has to be put together correctly, or... it's Mr. Bill time--Oh NO! =:O

  • User
    13 years ago
    last modified: 9 years ago

    Fixizin, you make some good points for the flat roof. So many options....so few places to restore!!!

  • fixizin
    13 years ago
    last modified: 9 years ago

    Options indeed... here in HVHZ-land, some would say options are limited... but I say options are channeled towards better strength-to-weight ratio solutions... there's the longstanding "commercial" building pre-cast pre-stressed solutions, e.g. double-tees and hollowcore plank, reliable and proven cast-in-place (CIP) systems like Hambro D500 and Speedfloor (both being used in more and more SFRs), and newer stuff like ICF-formed planks (Lite-Deck, AmDeck, etc... favored by DIYers and smaller builders), and really new stuff like Aerated Autoclaved Concrete (AAC) slabs (haven't seen any used in real life yet).

    Now I realize that in most areas of the USA such concrete roof/deck systems are "prohibitively" expensive, but in my locale, where they are used everywhere--by every contractor--from the cheapest strip malls and auto repair bays to mid-rise Class A office space and multi-story parking garages, the costs are only a few points above wood-truss + concrete tile, and often come back in terms of reduced insurance premiums.

    A tiny bit of slope, and the right "goo" in the seams, and you'll never have a leaky concrete roof, even without a topping... though most do get a membrane and/or thin concrete topping.

    PS: discovered a modest SFR recently with a "zig-zag" FOLDED-PLATE concrete roof! Very cool look, and no doubt very strong!... and it's in foreclosure... hmmm... I'll keep an eye on it.

  • User
    13 years ago
    last modified: 9 years ago

    Fixizin, if you have photos to illustrate some of the things you talk about, we could stay with you and follow the meaning. I'm willing to think outside the box with materials, and keep trying on different kinds to see what will work best (esthetically and financially) when we restore our now-derelict garage.

    I was originally totally against a flat roof as an option for it, but now I am open to suggestion. Undoubtedly it needs structural reinforcing to hold up any weighty roof system. It needs more thickness in its slab too, even if only to raise it above the normal rain depth of the surrounding back yard. And to hold the weight of anything we might place on it. It would no longer be a garage, but a studio/plant house/pool house/part time aviary for parrots.

    I'm seeing a zig-zag folded-plate concrete roof as one which channels any rainfall in one direction, and by having the folds, it also, like corrugated galvanized metal, increases its strength in that direction. It sounds very interesting, and I'd love to see a picture here next time you drive by it.

  • fixizin
    13 years ago
    last modified: 9 years ago

    Moccasin, I gather from your MyPage and postings that the garage in question is in Mobile, AL, i.e. coastal hurricane zone? If so, 'cement block garage' probably means STEEL-REINFORCED concrete block, aka 'CBS' (concrete block stucco). Is the block exposed and visible on the interior of your garage? Do you see a poured concrete bond beam (aka 'tie beam') running the perimeter at the top of the walls, to which the roof is tied? If so, that beam is tied to the slab via several rebars and poured columns running down through the cavities in your block walls. VERY STURDY construction.

    Regardless, the extensive mods you've described above will doubtless require the structural analysis and blessing (official seal) of a Civil Engineer--money well spent.

    Anyway, while your existing garage may or may not be strong enough to support a concrete roof, you have to remember that the self-weight of the roofing system subtracts from the added dead- and live-weight of whatever people, plants, solar panels, and temporary structures you add later.

    While I'm partial to concrete, I'm thinking pre-fab wood trusses and the standing seam metal roofing you mentioned above would be more than strong enough, and probably the lowest weight/sq. ft... yes, wood-frame CAN meet hurricane codes...

    Checkout the Gulf Coast 'company' town of Seaside, FL. The whole municipality was essentially built by one developer. It's an entirely wood-frame community--the only concrete is the slabs. Even the multi-story structures are wood-frame w/ metal roofs. They meet all Florida Building Code stds. for HVHZ, and fared well in Hurricane Ivan, and the other bad Gulf hits, 2001-2005. Needless to say, the wood framing makes extensive use of steel straps/brackets. Simpson Strong-Tie and Hilti Corp. come to mind.

    ... if you have photos to illustrate some of the things you talk about, we could stay with you and follow the meaning.

    >Hollow-core plank being installed on (cast-in-place? walls) single-family residence... in Illinois, no less!... watch your toes, lol... : (copy/paste URL)

    http://heartstonebuilders.com/images/CRW_9190.jpg

    >RE: FOLDED PLATE roof... while this method would definitely give you the most STYLISH garage in town, it would seem to be contrary to your desire to have a useable surface, since it is basically like having MULTIPLE PITCHED ROOFS in series:

    http://populuxebooks.com/blog/media/houseplan1.jpg

    http://parkimperialsouthps.com/wp-content/uploads/2010/06/17.jpg

    http://www.columbia.edu/cu/gsapp/BT/BSI/SHELLS_BM/concrf-1.jpg

    >Double-tees joined to concrete walls: (copy/paste URL)

    http://www.cpci.ca/images/sectionpics/products_systems/dt_2.jpg

    PS: Note the CRANES req'd for pre-cast concrete solutions... reportedly a significant cost factor.

    Here is a link that might be useful:

  • User
    13 years ago
    last modified: 9 years ago

    Thank you for your input, Fixizin. VERY interesting.
    I was watching what the GContractor did with the foundation he made for my recent HOUSE bumpout, consisting of a walkincloset and a tub alcove. They dug down about a foot or so (no freeze in Mobile to speak of), and then laid the rebar in a web, and inserted vertical rebar as well. Then they poured the cement in that trench, burying the rebar but with the about 24" high verticals sticking up at intervals. Over that they placed cement block and filled them with cement too. Then the structure was built over that. They added the long threaded rods from the base plate with huge square washers at the bottom of the first wood framing member, and it came out at the top with another nut and washer at the top, essentially tying the whole structure to the ground and the foundation. With the rafter tails, where they intersected the top of the exterior wall, they had those straps further securing the roof to the walls. I was taking pictures of this for my DH, who was not here during the building phase. He is a retired engineer.

    I'm not a technically educated person, so I do not know what terms to use communicating with contractors or engineers. Your references are helping me with my education.

    Now to the derelict garage. It was a home built job is my impression. Tree roots destroyed the poured slab floor. And managed to mess up two of the four walls at the weakest point where windows were located. There was nothing reinforced as far as we can tell. No metal. Because this is really close to the south property line, we will not be tearing it down....grandfathering comes in handy at times, you know. We cut down the trees that WE own, so that helps. But there may be future problems with the neighbor's trees as they grow. I do not know if a steel plate vertical in the soil would deter the destructive power of oaks, sweetgums, and yew trees or now. But I'm thinking about it.

    I'm not thinking precast concrete for the roof, but I will let my DH take over with that design. We may well wind up with an Irish cottage roof, as homage to his Irish heritage. He is first generation Irish. I'd love to own an Irish cottage, even if it served as my plant house.

    Thanks for pitching in here, Fixizin. It takes me a while to get things done, but I frequently work through to completion.....

  • fixizin
    13 years ago
    last modified: 9 years ago

    OK... finally clued into your related threads, w/ pics, and your need to grandfather at least the "footprint" of the outbuilding; not sure about AL, but in FL and some other states I'm familiar with, you can "grandfather" or "renovate" while retaining VERY little of the original structure... an experienced (and politically-connected) Gen Con is indispensable in these things. ;') CAN be done. Generally, if you never get a permit to "demolish" anything, you're not building any "new" construction, just "repairing", lol.

    Also of note, is that you don't plan on doing LOUD obnoxious activities in this tea house, which would infringe on the spirit of the new setbacks, thus getting a "variance" is possible too, though usually requires neighbor(s) to sign off.

    I'd say the fact you have 2 out of 4 walls as "sound" puts you in good shape; the slab will have to be repaired, and may end up with a (leak prone?) "joint" in it, depending on how it was tied to the footer... not sure.

    e.g. I'm now following a beachfront motel-to-condo "conversion" in which out of 2 long-axis 2-story CBS walls, and 2 short-axis 2-story CBS walls, only 1 story of ONE of the short walls was retained. I believe the slab was sound, but it was a COMPLETE rebuild, but qual'd as a much easier to approve "renovation".

    PS: What is an Irish Cottage roof? I've been to the Emerald Isle, and saw every type of roof, incl. the VERY traditional peat/sod arrangement! THEE original "green" roof!

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