Pure L's Detached Garage Studio

len-morgan wrote:

If you've see Art Garfunkle lately, you'd know he hasn't had that much hair since the 60s! The last time he looked a lot like Larry Fine from the three stooges. len

....."... Dr. Howard... Dr. Garfunkel... Dr. Howard... " ..... :lol:

Is it me or is it the older you get, the less time you have to spare, yet it goes much quicker?? (I just turned 32!) Anyway, I finally got around to sketching up another idea. Sharward suggested 2 gaps (one for each leaf) which makes sense, so I sketched up the drawing below. Keith (or anyone else, for that matter), feel free to chime-in on what you think. Hope all's going well with everyone.

I haven't been following along with your project, but I'm just wondering why there are 2 gaps in the concrete? If the concrete blocks on the new footing is for the outer leaf, and the 3 layers of sheetrock is for the inner leaf.... I don't understand the additional gap for the inner floor.... Maybe I'm not seeing things right... or perhaps I just don't 'get' the whole isolated slab concept. K

Me too; the inner gap isn't necessary. Inner wall frame/wallboard should sit on the inner slab, outer (sand filled) blocks should sit on a WIDE, DEEP, separate footing. Inner ceiling should rest on inner wall frames, outer ceiling/roof on the blocks... Steve

I'm probably misunderstanding something. (That's usually the case). When I posted this: Keith said this:

sharward wrote:

Ahhh, OK, I see what you're trying to accomplish. You don't want to do it that way. You need to have your gap between your leaves in order to have any hope of reducing or eliminating flanking across the slab or ground. So, rather than one fat foundation, you need two foundations -- one for each leaf. --Keith :mrgreen:

I think Keith understood my dilemma: I would like to keep the "existing slab" (see the pic above) for cost reasons. The problem is that this slab is only 3.5 inches deep and, obviously wouldn't be able to handle the weight of the wallboard/inner ceiling. Basically, what I'm trying to accomplish is to not have to pour a whole new main slab. Steve, would it be possible to put both the wallboard leaf, 12" gap, and concrete blocks on the same large, deep footing?

I don't think I ever said you need "two gaps." What you need (if you're aiming for an isolated slab) is a gap [/b]between[/b] your leaves. Just one. --Keith :mrgreen:

Actually, Rod covers this in his book -- how to salvage an existing slab and still make it isolated. It's a lot of work though. You have to eliminate about two feet around the perimeter and dig down so that you can pour a deeper, reinforced footing. --Keith :mrgreen:

If your existing slab had/has walls, are you sure you don't already HAVE a footing/"haunch" around the perimeter? Or were the walls set on a separate footing OUTSIDE the slab you plan to keep? Let's get this cleared up BEFORE it costs you more than necessary... Steve

Thanks for the reply, Steve. As it stands, the walls are set on a separate footing OUTSIDE the slab that I would like to keep (it's labeled "existing slab" here): The "footing" now, however, is hardly a footing......It's about 12" wide and 6 inches deep. The old building has multiple instances of wood-to-ground contact, as can be seen here: I've actually just finished the chapter in Rod's book regarding the salvaging of an existing slab. Doesn't really apply to me though as I will have to pour a whole new footing on which--ideally--my concrete walls and the wallboard leaf, both, sit on this new slab/footing. What I really need to find out is: a) Is this possible? b) How big and how deep must this new footing be? (In order to withstand the concrete-block walls AND the drywall leaf). Thanks, again. Attached is a picture of the corner of the building. You can see the crappy "footing" it stands on. I just realized that the picture is tilted at an angle making it a bit difficult to get a perspective. It is the corner of the building though. EDITED for idiocy. My apologies if you read this before and it was confusing. It was when I re-read it, anyway.

I'm bumping this because I just edited my post above. Sorry if anyone read it and got confused. When I re-read it a minute ago, I realized it was very confusing. :oops:

Who's confused? About what? Oops, I just got lost in thought; it wasn't familiar territory... :? OK, all betur now :arrow: Soooo, how tall are you planning your block wall? How tall will the 3-layer gyp wall be, and is this 3 layers of 5/8? What kind of soil do you have? (Nooo, not "dirty" - answers could include sand, clay, rock, loam, etc... Have you decided on a roof/ceiling construction to match your walls and doors, and if so, what? All these will allow you to calculate the total weight that would be resting on your footings - from there, you'll need to involve a local engineer that knows soils, compaction, etc - he will be able to give you a spec for your footings - expect something in the range of at least 24" wide by 8" deep, probably more. Be sure to mention that you intend to FILL the blocks with sand - also, are you still considering the dry-stack, bonded method? That adds a small amount of weight to the calculations too, because there's an extra 1/2" of masonry product on EACH SIDE of the block wall. HTH... Steve

Yikes. :-( That's a horrible foundation. If I were you, I'd leave that garage structure alone and use it as a garage or a workshop of some kind. Then I'd build a new accessory building on the property. Do you have the space for that? Would your municipality allow that? Seriously... I see so many headaches trying to salvage anything in that building, including the new slab that was poured. --Keith :mrgreen:

Well, I'm still working on saving that one slab....... :? The rest will be demo'd for sure. Unfortunately, I don't have the space for another building and sooner or later something will have to done with this garage as it's slowly falling apart.

In that case, I wouldn't salvage anything. Think of how much better you'll sleep, knowing that the ground was prepped properly and the slab and its footings are reinforced with steel. I just think there's not enough jackhammering photos on this Web site, dammit! ;-) Seriously. Start totally fresh. You'll be glad you did. --Keith :mrgreen:

sharward wrote:

Ahhh, OK, I see what you're trying to accomplish. You don't want to do it that way. You need to have your gap between your leaves in order to have any hope of reducing or eliminating flanking across the slab or ground. So, rather than one fat foundation, you need two foundations -- one for each leaf. --Keith :mrgreen:

I'd like to know why this wouldn't work: Basically, the first leaf (the double-drywall w/green-glue leaf) would rest on the inside-edge of a very large footing as opposed to the outer-edge of the inner slab (in this case the "existing slab" in the picture). This wall would surround the existing slab that I'm trying to keep. This first leaf would then be surrounded by 12" of airspace on all sides and then, finally, by 8x8x16", sand-filled, concrete blocks. The ceiling would be scissor trusses that rest on the outside, concrete blocks. I'm not too sure yet as to how the inner, drywall leaf would best be connected to that ceiling. I would just like to know why this (my pictured scenario) would or would not work. As it stands, I'm not seeing how this could be much different----sound-control wise---- than having the drwall leaf on the outer edge of the inner slab (again, called "existing slab" in the picture). I do understand, however, that one would be faced with having to do something about the exposed gap. Unsightly to say the least. Thanks.

Let's clarify something: the goal of an isolated slab is not simply to separate the slab of the loud room from the outer leaf -- it's to separate all inner leaves from all outer leaves. In your drawing, your inner leaf wall is on the same foundation as outer outer leaf wall. The sole plates of your outer leaf and inner leaf walls are attached the same "beefy" foundation, and this "shared foundation" defeats the purpose of having an islated slab in my opinion. --Keith :mrgreen:

I think you've got a point, Keith. Not too long after I posted that, I realized that it was kinda weird. I've just re-read the section on underpinning the current slab in Rod's book. It looks like that will be the way I'll have to go. You just might get your jackhammer photos anyway! (For reinforcement-testing of the slab, of course. Then, to "clean" away the concrete-bits to get to the rebar). Does anyone have experience in hiring a "team" to do jackhammering? I'm not too well-versed in the art of sub-contracting.

The jackhammering is much, much easier than seems. The electric 60 pound hammers are actually pretty easy to operate. I stressed about it for days before finally just biting the bullet and doing it. Really, it's no big deal, and was actually kind of fun! :twisted: Still, I think you should consider just blowing out the entire slab and starting fresh. You can have a beautiful one-piece slab when you're done -- so beautiful that you can consider doing an acid stain and using it as your finished floor -- a look of marble. Then you won't ever have to worry about the new concrete separating from the old concrete. Or, maybe I just want some company. ;-) :lol: --Keith :mrgreen:

Thanks, Keith. I'm not too sure about acid-staining the slab, etc........I'll probably treat the floor with some kind of flooring eventually anyway. This existing slab has no moisture problems whatsoever. The existing footing, however? I can't say the same for............it's gotta go. So I just sketched up a cutaway/side-view plan for the new footings and walls. Lemme know what you think. Remember, this is how things currently are (looking down): Gracias!!!

The 12" air gap will actually be about 16" when you factor in the depth of the studs on your inner leaf. Not that it's a bad thing -- if you can afford the space, then make it so. The farther apart the leaves, the better the isolation. I wish I could afford three feet like Steve's going to do (eventually)... :roll: You will want to pour your new concrete on top of a rigorously prepared compacted base. I used 3/4" crushed granite, hand-tamped, then machine tamped. Rod Gervais recommends a base of sand as I recall in his book (which is what I probably would have done if I had the benefit of the book before I prepped my soil). Your new "beefy footing" isn't very beefy, according to that drawing. It looks like it's only about 6" thick. It should be a minimum of one foot, and possibly much deeper. I believe you have to go deeper than the frost line. This is critical due to frost heave: "Frost heave is created by the freezing and thawing of water in the soil. Ground surface movements of 5-15 cm are common and movements of as much as 30 cm have been observed during a freeze-thaw cycle. Differential frost heave can cause severe distortion of structures which may not return to their original position at the end of the thaw season because the underlying voids have been filled with soil or trapped water." (Source: http://www.north-rthn.org/FactSheets/94_214.html) Your existing slab doesn't have rebar in it -- does it? Assuming it doesn't -- how do you intend to get rebar into the existing slab? --Keith :mrgreen:

Hey Aaron! Wake up! You've got a studio to build! Chop, chop!! 8) But seriously... Where have you been, many? We miss you around here... :roll: --Keith :mrgreen: