Concrete pad - Forms question

[jgrinn]

We always use utility sheeting.......depending on your radius you might not even need to relief / back cut to get your desire shape. Utility sheeting is one by (1X nominal in varying widths) in white pine and is inexpensive, durable and with the right amount of pins it can be used by itself. Hardboard is weak and will need to be at least doubled and will blow up when exposed to moisture. I doubt you will find utility sheeting at a big box store.....a lumber yard most certainly. It is also known as roof sheeting in some areas.

We use sheeting also. As Whitey stated, you may have to relief cut on the back if it is a tighter radius.

 

[EddieWalker]

I use quarter inch plywood and rip to the thickness needed. Basically whatever is the cheapest, thin plywood available.

Eddie

 

[skipro3]

Yes! 3 ply 1/4" plywood should bend pretty tight. You might have to wet it a bit and that should make it bend easier.

 

[rimshot]

1/4" Plywood and masonite, it's all good and so is piece of sheared metal from the plumbing and heating shop. Have them shear you a 4" strip and get it bit long so you can try the arc atthe straight form with different radius to see what you like. Just overlap what you do not need. You won't get any differential in thickness where the radius meets the straight form with the tin strip as opposed to using a thicker materiel. A couple of stakes strategically placed and you can use an edger to finish the flatwork.

rimshot

 

[CurlyDave]

I was amazed to discover how nice a form OSB makes. And, the many small wood chips leave a very pleasing pattern on the concrete, especially if you use a vibrator. No excuse not to, HF sells them pretty cheap these days.

Rip lengths at the proper height, and the make shallow saw cuts in the back perpendicular to the curve for really tight curves.