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Establishing guidlines for what are acceptable foundation variations and working with those to provide strong, air-tight first floor for my new home.
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I am really bummed. I typed in this long message and submitted it and it didn't show up. No matter, here goes again.
My wife and I are planning construction of a 1500 sq. ft. ranch. We will be the general contractors but have little building experience BUT we're are reading and asking questions like mad. Basically we want to get good subs and let them do there work but we also want to be in a position to know what to expect. We also expect that we as one-time home-builders will act like seasoned contractors (if that's possibleJ).
First, we want to know what reasonable expectations we can place on our foundation sub. My father-in-law (FIL) say's that to expect less than 0.25" variation is too stringent. He's a concrete man of 50+ years so I will take him at his word even though this seems large to me. Beginning with that variation, a discussion of shimming, double sills and sill seals ensued. First off, FIL said that the stuff that passes for sill seal today might as well be toilet paper. He said, just get 1.5" of fg insulation and stuff it between the sill plate and the foundation. Doesn't sound right to me but what the heck do I know anyway. I'm still wet behing the ears.
Having read an old FH on installing square sill plates, I asked about using double sills to overcome what seems to be a yawning 0.25" gap. He says "That's just a waste of money." What the heck do I know. So I say "so then do you scribe the stringer and joists" He says, "Heck know, just run a powah planah over the sill plate to level it out." EESH! Could he be right???
So what is the bottom line in all this? I would like to know first of all what deviations in the foundation are reasonable to expect/not expect? How to deal with the inevitable dips and humps which are out of spec? What type of sill seal to use? When and when not to use double sills, etc.
Mind you, I don't plan to do the installation, though I would truly love to, I just want to be able to handle and direct these inevitable situations with poise and dignity without getting duped in the process.
Thank you all for the incredible discussion in other threads. This is a great source.
-michael form Iowa
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Michael,
A good foundation sub is a must. If the foundation is right the rest of the house will be much easier to build and eliminate the framers passing the buck back to the foundation crew.
A 1/4" may be o.k. for some walls and devistating for others. If you have a 60' wall that varries 1/4" it would most likely not cause problems. If you have an 8' wall it may cause problems. If the wall is parallel to the joist you can scribe to rim joist. If perpendicular to the joists, you can use shims. Keep in mind that if you are using 2x10s or 12s, they can varry up to a 1/8" or so in height.
As for sill sealer, I must admit that I use it but I don't think it acts as a great seal. I use it to bridge the small dips and humps on top of the foundation wall. You should handle air sealing with spray foams, air barriers, caulk and insulation.
Again I must stress the importance of a good foundation. Make sure it's square and level and your house will be off to a good start.
Good Luck!
kcoyner
*Micheal after reading your concern about .25 tolerances in the foundation and the chit chat about the sill gasket material and subsequent sealing, I'll keep it short.Hire a construction manager.Picture one of us taking the place of your family doctor and come on in.
*Yes, our neighbors acted as GCs and were VERY involved in the planning/const. of their nice house, but they also hired an experienced contractor to act as a "foreman" of sorts. He knew how to manage subs and was willing to let the owners handle pulling permits, cutting checks, absorbing risk of unforeseen difficulties & other hassles a GC deals with (a whole LOT of work). His help was important -- for example they had to fire one sub. Foreman = no monkey business. However much you learn about building techniques, it would be hard to know how to do the oversight part on your first try.Any experience out there with the EPDM sill gaskets? (If you do a search, i think you'll find more here on this.) I'm interested in and impressed by EPDM's many capabilities in general... The sill gasket acts as a capillary break, too. It may also me a good place to consider some termite protection.
*Michael,Such an easy question to answer....Don't hire the "subcontractor." Go look at their work...If you it meets your approval...you're golden.Jack : )ps-Make sure the crew that did the approved work does your work...Put it in writing.ps-ps-I have never had to shim a foundation ever...Concrete is almost self leveling...If they can't get that right, then you're in big trouble...S walls and lots of other things go wrong...like leaky basements and cracking walls and settling and oh so much more.
*Jack, oh Jack, oh Jacki "...Concrete is almost selfi leveling..."b . . . NOT!!!sorry buddy but your waaaay out to lunch on that one. . . have another toke!!! Your friend-Patrick
*Now, someone was going to explain how to read a concrete loading ticket, or whatever they're called. i understand that "real" concrete can get pretty complicated with different mixtures, additives, and air entrainment. I think Michael is dying to hear about all this. (BTW, I'm just a Quikrete/Sakcrete kind of guy.)
*Patrick, oh Patrick, oh Pat, my buddy, o'l pal,If you work with the likes of those that can't get concrete foundation walls level, better you than me...I don't work from that poor a starting point...never did, never will.Concrete's not rocket science to level,Jack : )
*Jack oh my Jacki " Concrete's not rocket science to level, "Truer words were never spoke, but it is just as surelyi tick as a brick and won't be after levellin' itself boyo!!!And most concrete levellers that I've met couldn't even spell rokit psyence.Gettin' a head start on Saint Paddy's dayYer 6 generations removed Irish buddy-Padreigh
*Gentlemen, oh gentlemen. Using wood shim stock to shim a sill plate is a NO-NO. Stay away from fiberglass sill sealer. I've never used the bubble pac that FredL likes. Í'd recommend EPDM gasket for sill sealing. GeneL.
*Good question Andrew.Most concrete bills will contain the volume ordered, volume on board, time of loading, time of arrival at site, time unloaded. There will be information on concrete mix as to the strength of the concrete, the size of stone and slump. Additives are noted, such as air, calcium, platisizers, etc.Time is important, because the length of time the load is being mixed has a dramatic effect on the concrete, nothing worst than a hot load.Concrete mix could be in psi or Mpa, slump could be in inches or mm.air and calcium are in %.Air is used when the concrete is exposed to freeze thaw cycles. Calcium is cold weather additives and plastisizers are to enhance the concretes flow around steel bars and intricate formwork. Kinda like the formworker's vaseline.Hope that answers some of your questions.
*Mike,
Joseph FuscoView Image
*3" !!!!!!!
*Joe. Some may be uncomfortable with 1/4-inch. But if you specify 1/4-inch you'll be lucky if you get it. Why not specify 1/8-inch and be glad if you get 1/4-inch? GeneL
*Michael,Whatever you can to to make sure that you start with a good foundation will make the rest of the job go better. It's worth your time to design well and shop around for a good concrete sub. Check with builders in your area who have a good reputation and see who they use.I worked on a job where the specifications called for no more than .01' (about one eighth of an inch, there are 96 eighths in a foot) variation in a slab across any given 10' run, and no more than .01' from one side of the pour to another. This was a government job, and the specs were admittedly a little tighter than usual. The point is, this can be done. If a concrete sub takes the time to shoot his forms and grade pins with a transit, and has competent finishers, you should be able to get a very accurate result.We've been talking about slabs that are out 1/4" and so on -- a critical factor is how much horizontal distance this happens over, and where in the slab or stemwall it happens.A badly botched pour can be very hard to correct. It can be even harder to get a sub to do anything about his mistakes, regardless of what your contract says. What you're after here is a good job, not an argument with someone after the fact. We'd all like to think that everone is going to do what theyre supposed to do, but I hear that there are people out there who don't play by the rules. Think about this as you write the contract language for your concrete sub, i.e. if he doesn't do what he said he'd do, what are you really going to do about it?Don't try to save money on your foundation. You'll never be sorry for having the job done right.
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Michael,
Don't worry too much about close tolerances with the foundation. Any decent framer can easily correct a bad foundation with the sill. I expect to spend an extra hour or so compensating for the foundation, it's to be expected.
I also suggest you hire a manager, foreman, overseer...
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Establishing guidlines for what are acceptable foundation variations and working with those to provide strong, air-tight first floor for my new home.
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Gene,
Joseph Fusco
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