Wednesday, November 14, 2007

Piggies (Pig's Feet & Snap Ties)

This post may be quite boring to most of you but I have been wanting to put it up for some time now after studying my hits on Site Meter. I get a number of hits for people searching on how to use snap ties and pig's feet etc. and that is a lot of the type of form work we have been doing on this job so I thought it might help some to put up some photos and explain a little. I like doing form work because it is a little like sculpture. The forms themselves can be very artistic, if done well and neatly, with the repetitive elements and shapes. It seems odd to a lot of people to spend so much time building something, sometimes weeks, and then to tear it all back down again.
So, OK, in this photo you can see where we have formed up one side of the wall completely. The whalers (the horizontal 2x4's) and stiff backs (the vertical 2x4's) are all on etc. All those small rods sticking out from the wall are the snap ties. For standard forming you would drill (5/8" hole) your plywood on a 16" grid pattern for the ties. Remember to start 8" off the edges though so that when you butt 2 pieces of plywood together, you have 16" between ties. This works for walls up to 16" thick. Now, there are tons of variations on tie spacing and even using all johnny clamps or all pig's feet but this is the most common method.

Normally, you run 2 johnny clamps, then a stiff back etc. but this can vary too. The johnny clamps hold the whalers and the pig's feet hold the stiff backs. When you get your plywood stood up and nailed off plumb to the rat sill, stick your ties through the holes (short tails for where the clamps go and long tails for the stiff backs) and put your johnny clamps on (loosely fastened). Next, lay your whalers in the clamps. You will have to take your hammer and give them a good whack. Make sure to let enough of them run wild on the ends to lock your corners. You may need to add some temporary bracing now to help the wall stay plumb. Now, stand your stiff backs up. you just sandwich the long tails of the snap ties between two 2x4's and slip the pig's foot on the button of the tie. Tighten the pig's foot down. I usually toe nail the stiff backs on opposite sides at the top and bottom whaler because the pig's feet can loosen up. Some bosses will curse you for this though. Also, alternate the direction of the pig's feet (see photo) and drive an 8 penny nail in that little hole in the foot. This helps hold the stiff backs together also. Generally, you do not nail the stiff backs to one another.
This is a view from on top of the wall looking down into it. Those little cones on the ties hold the plywood a prescribed distance apart. You can sort of see how the tails of the ties are used to hold the hardware. This part of the tie stays in the wall after it is poured. The tails are designed to break off when you wreck the forms, thus the name "snap ties".
This is the wall almost completely done. The carpenter is locking the corners. To do that, you simply lay another, shorter whaler across the ends of the whaler held by clamps and nail it off where they cross. Make sure this whaler is up tight! Two nails at each cross point and make sure that these short whalers run wild also by about 6" as you are now going to add 2 vertical 2x4's in this corner you have just made. This has been done on the left side of the wall. You nail these 2x's in an "L" shape in the corner, 2 nails at each whaler, both sides. The concrete will be pressing outward on the whalers and these corner locks hold the crossed whalers and keep them from moving outward. So, they must all be as tight to one another as possible. This is a very simplified lesson so if I did not explain something clearly, please ask me to clarify. Oh, yeah, after all this you still have to add the turnbuckles and plumb the wall etc. It is easier to do this just after you get the whalers and stiff backs on but before you have everything tightened down and locked off. Generally, every stiff back gets a turnbuckle to get a nice, straight wall.

The house is progressing slowly. I grouted some more this evening but am still not finished with the shower. The house is wearing on me a lot lately. I am having trouble finding a proper control for the ceiling fans. That has been a frustrating ordeal and I guess what I get for ordering industrial fans instead of residential. The house gets invaded everyday by wasps. There are usually 20-30 wasps in the house every time I go down and open up. I have no idea where they are coming from. Everything seems to cost $1,000. The shower, the heat, the siding etc. I seem to keep coming up just slightly short on all my material; tile, grout, paint, plywood. The water is still muddy; I must get another filter. That's another $500.00. I should not complain at all though. So many people have done so much to help me. I've just been working almost every day for over 2 years now to build this house and I'm really getting tired but I just need to suck it up and keep going. It's just one thing at a time.

10 comments:

Woody said...

Next time you see the tall switchman ask him to get you a can of the wasp spray that the railroad has laying around. He should be able to get you a can...it works great.

edifice rex said...

Hey, OK Woody! I'll do that. Hehe, give me a chance to talk to Mr. Handsome again.

Walter Jeffries said...

Pigs feet? Pigs feet? Did I hear... Oh! :)

edifice rex said...

Hey Walter! Yeah, and sometimes we use cat heads too!

Rurality said...

Oh I'm so glad you'll never have to see that retaining wall we poured at our old house.

There was a show on the other night about reinforced concrete... I was surprised that the first use was actually by a guy making planters in the shape of big vases.

Tossing Pebbles in the Stream said...

Good form work is a work of art!

I was involved with building and pouring the foundations for a bridge up the road.

It got really tricky pouring concrete in -25 to -30 C. It was all wrapped in "blanket" tarps and propane heaters ran all the time to keep it warm. Living near by i got to go up at 2:00 am to make sure the propane didn't go out.

edifice rex said...

Yes, it is Philip! Well, we have never had to pour at -20 but we have poured when it was getting down in the 20's and 30's here so, been there and done that with the heaters and such. Usually floor slabs for high rises and we would put the heaters on the floor below and drap those blankets over the sides. Very toasty inside these "rooms". We always used kerosene heaters though. Wonder if that is a regional thing?

homie said...

well atleast u got my good side lol.

edifice rex said...

Hey Homie! Yeah, yours and Head's too!

Ron said...

Thanks for the info, Annie. I only wish I had read this before we decided not to do poured walls for our root cellar. Maybe next time. :)

Ron