Hi! I have a couple questions. First, I hope to put a concrete retaining wall at least eight feet tall all the way across a sloped lot that is thirty feet wide, essentially so we can use the space under a deck, which is at this point mostly a slither-space, particularly at its uppermost point.
The lot is situated very near to where the opening scene from a famous novel would have taken place. I will be building the forms for this tall wall out of plywood, and I was hoping I might cast passages from this opening scene right into the wall. So I guess I have several questions…
Can you cast the reverse impressions of letters right into ordinary concrete? Do you know of a source for such reverse letters? Ideally they would be made of wood, or something that can be tacked and glued to the forms and hold form release, and absorb a thumping. Also ideally they’d be beveled, so I could get ’em out! Also, provided there are no typos, can I come and work for the Taunton Press?
My other question is unrelated. The house is nearly one hundred years old and has never had even a teaspoonful of concrete under it, which is the real reason for this concrete orgy and will constitute by far the greater part of this job. The first floor over the crawl space, though, is tongue-in-groove subfloor over two-by-six joists on what looks like more than 16-inch centers — probably two feet. It is exceedingly “crunchy” when you walk on it, and from below you can follow the progress of anyone overhead, even down to the housecat, to the point of distraction. I most likely will be doing this foundation in keyed sections and doing the shoring myself, then sealing off the joists from underneath with firerock. So, while I’m at it, is there anything I can do from underneath to strengthen and silence the floor? Also I plan to do a suspended ceiling afterwards if possible, but what is the best kind of insulation I can put in the joist bays for the purpose mainly of deadening sound?
Thanks, y’all…this is my first ever posting, so it sort of feels like a message in a bottle. Send help!
-Lito
Replies
As to the letters in the concrete...it's done all the time. You could buy letters, if you can find the size and font you want. Or you can either make or purchase thin strips of wood, maybe 1/4 to 1/2"" wide and 1/4" thick, and then cut & paste the letters onto the backside of the plywood form. Before the pour, spray with form release agent (or silicone spray) and they should come right off with the plywood. Be careful when you mark any layout lines on the ply because some things will transfer to the concrete...a pencil line will work ok. Use small tacks or liquid nails, and be aware that any bumps you see or create will show in the finished product, and since the letters will be recessed, it will be difficult to clean them.
Do it right, or do it twice.
Sounds like an ambitious project. Have you ever formed and poured a tall concrete wall before? You'll need to pay attention to detail if not. Do you understand how to design a retaining wall with drainage and buttresses?
Is this Peyton Place you are speaking of? Give us a hint what novel. Please?.
And pardon my rudeness, Welcome to BT
Excellence is its own reward!
Edited 6/9/2003 8:08:24 PM ET by piffin
Hiya! Yes, I've been a part of exactly one big foundation project using plywood forms, snap-ties, and "cowbells." The footings were poured with keyways and a couple feet of steel sticking up, and by the time I came aboard we could nearly build 'em by numbers (exactly, in fact, as per the article in "The Best of Fine Homebuilding" series written by Arne Waldstein).
As for the inspiration, think California bildungsroman, with maybe estuarine beginnings...
Sounds Michner to me but I guess we'll have to get Theodora inhere to interpret....
Excellence is its own reward!
As to the noise from the floor, the crunching as you put it. There are two ways i can think of to improve the situation.
1.) You can install solid bracing perpendicular to the joists at 16"OC. That should significantly improve the stiffness of the floor. If you install perlins for the drywall that will keep the floor joists from twisting at the bottom, but it won't solve the problem.
2.) Depending on the length of you floor joists you may consider installing a system of piers under the house or add piers in problem areas if there are already some holding up the floor. If your in sandy or silty soil I would highly recommend using a wide footing under each pier. If the soil is fairly stable then you can probably just do a small footing. The inexpensive way to do acoomplish this is to pour a footing and then use a screw jack column, or if you want to go with a more substantial system you can use CMU. If you use CMU I would recommend filling the CMU with a lightweight grout (non-shrink grout works great for this purpose. It literally pours in and cures in about the same time as concrete). Its a bit of overkill but will garauntee that the pier will never fail due to movement of the CMU.
You have the benefit of seeing what we can't so you can make the best decesion as to the method. I just thought of a third way to deal with your floor.
3.) You could use a 2x12 in order to maximize your span for columns. I believe you can span 20'-0" with the 2x12, maybe more than that. Look up the span tables to be sure but I think that is right. (You could also use an LVL joist or even steel if you really want to maximize your span) Run the new joists perpendicular to the existing joists. If you then put a footing down you can attached the screw jack column to the bottom of the 2x12 and span the recommended distance to support the floor above. Make sure your floor above is level or the outcome will not be what you expect. You can level the floor above with additional columns placed along the new joist if necessary. You could also us CMU here as well, depends on your preference.
Now for insulation you should definitely use fireblanket insualtion to deaden sound. Sound attenuation blanket is basically the same thing. The idea is to prevent the transmission of air through the material which standard insulation will not do.
I kinda got lost in the reference of the location of the drop ceiling but I will explain my assumption and if it's wrong I apologize. I have assumed that you are installing drywall to the floor joists above and are then installing a drop ceiling below. Based on that information I will continue. If you are trying to minimize sound from above use fire blanket insulation between your joists. If you are installing drywall over the top of the joists then run RC metall channel purlins for the drywall. (sound travels both by the transmission of air and through vibration of the structure. The metal RC channel will absorb a huge amount fo your structural noise and you fire blanket will abosorb the air transmission of noise.
If you are using drywall under your house I would recommend Dens Glass by Georgia Pacific, or Aquatough from USG. Dens Glass is a water resistant drywall material covered with yellow, fiberglass paper. It is warranted for 6 months of direct weather exposure and 5 years for product defect. Aquatough is cementitous drywall product warranted for 12 months of direct weather exposure and 10 years of product defect. Both are great products and either would do well in your situation. They are both about the same price as fire rated drywall, and well worth the little bit of extra expense.
The Aquatough sounds like Durock but its not even close. It's a newer product mainly used in commercial work. I spoke with a USG rep a year ago and he said that they had a panel of Aquatough they built at their lab in south Florida that had been exposed to the weather for 2 years so far and no failiures. It's heavy duty stuff but you can use drywall screws made for wood and they work fine.
Good Luck!
Here's my 2cents. With a caulk gun and several tubes of construction adhesive or caulk, write a mirror image of your passage on the back(inside) of your form. Moisten a finger and shape your bevel and clean up any goofs before they dry. Spray the whole thing down with silicon or spray wax before concrete goes in. Make sure to get the air out of the form, so the concrete gets in tight around the letters. Should look just like an old tombstone, with the beveled etchings. You gotta give us an opening line or two!
Big Sur?
or maybe some Steinbeck? Give us a line atleast!
Edited 6/10/2003 12:32:36 AM ET by ccr
Valley of the Dolls?