Concrete Formwork

[NathanS]

Can anyone recommend resources on building forms for foundations? I'm having a hard time finding anything. I'm interested in monolithic slabs and how the forms should be reinforced to prevent bulging or a blowout.

Thanks

[nailit69]

The method i've always used if my 1-1/8" panels aren't available is 3/4" plywood over a 2"x4" frame (a short wall basically) with a continuous top plate to tie them together on top and nail them together at the ends, then 2"x4" stakes pounded in directly behind the forms @ 4'-0" o.c. and nailed top and bottom (set everything to grade at this time), then diagonals pounded in behind each vertical 2"x4"... use these to set and nail to a stringline for straightening the wall.  This is usually adequate, the better it's put toghether the less likely you'll have a bulge or blowout... I usually don't have problems until I get over 3' and again... the better it's built, the better it'll turn out.  Think about taking it apart too... don't box any panels into corners or you'll have to cut them out.

A couple other things... spray your forms down w/diesel in a pump sprayer (morning of the pour), have a hose on hand and wash all the spillage off the forms while it's still wet, and get all the big chuncks away from the forms while it's still green... this'll make stripping and cleanup a breeze.

[UK4X4]

here it looks like they have just used a 2 x 10 frame with a small ammount of props and the trench sides its self
https://www.youtube.com/watch?v=Roaz2zn4uW8

[Bob S.]

check to see if you can rent forms locally, might be cheaper