[TheForge] Concrete forms OT, but important... for me anyhow.

[Paul Sperbeck]

Have you priced out insulated concrete forms? At least you would have 
the insulation when you are done...

In our area of the country there are a number of companies that used 
aluminum forms. They set and remove them and pour the walls, but our 
primary basement wall construction is concrete block.

There are also the forms that use 2" pink foam panels,  these are a 
'system' so I don't know how difficult it would be to emulate them, but 
again you have the 'R' value when the dust settles...

As to your original question, I can't see where the the slighly reduced 
capacity would matter, yours is a one time use vs the industrial 
practice of using it until the plies separate   :-)

see table 2:

https://duckduckgo.com/l/?kh=-1&uddg=http%3A%2F%2Fwww.socomi.com%2Fimg%2FPDFs%2FAPA%2FAPA_LoadSpanTables.pdf

paul


On 08/10/2014 07:20 PM, Andrew Vida wrote:
> The excavation under the house is now more or less complete.  I 
> removed about 400 yards of clay from under and just outside the house.
>
> The house is now standing on 18 high strength stilts that I fabricated 
> from drill string.  It is a weird sight, what with all that daylight 
> coming in from under the old footings.
>
> My question is this: would 5/8 plywood suffice for concrete forms? The 
> tallest section to be poured is about 8 feet, about 4 feet wide.  The 
> rest is averaging about 5 feet.  I will be using 12" snap ties, on 24" 
> centers with two layers of 2x4 criss crossing per the usual practice.
>
> I was going to use 3/4 OSB, but am now having some second thoughts 
> because of the tongue and grooved edges.  3/4 ply is painfully 
> expensive, 5/8 being notably less costly.  My concern here is whether 
> the 5/8 has the strength.
>
> The damned lumber for the forms is almost as $$ as the concrete itself 
> and the wife is having a heart attack at the costs.  I'm trying to be 
> as efficient with the money as possible, but do not want to make the 
> mistake of using insufficient materials.  A blow-out would be very 
> bad, as you might surmise.
>
> One other question: because I am forming to the irregular bottom of an 
> existing footing I was going to rough-trace the profile onto wood, cut 
> with a scroll saw, and fit it that way.  Has anyone here done anything 
> like this before and if so, how did you build to the footing?  Since I 
> have couple hundred tons of clay handy, I was thinking I might use it 
> as a sealant to close up the little crannies at the top.
>
> Thanks much,
>
>     -Andy

paul
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