Problem with Curling Cedar Shakes (Side Shingles)

I am in the process of reshingling my house on Cape Cod. Until this year I have used Maibec white cedar "Nantucket" R&R extras. As my dealer tells me they can no longer get these shingles, I have switched to Waska. For a novice, these seemed much easier because they were in general much wider. After having done about a 20X4 foot area, I have noticed that many of the shingles have started to curl. They have been in place for no more than two weeks. I have tried to follow the following rules: 2 nails per shingle. Nails in about 3/4 inch from sides. Nails about 6 1/2 from butt. (The exposure is about 5 1/4 and I add 1 1/4 to this.) These were the rules supplied by Maibec which I assume are the same for all cedar brands. While I have not measured the above distances to the millemeter, I have tried to use reasonable care. In any event, I have been equally precise (or imprecise) with the Maibec. Some of these have been on for over three years and the degree of warpage has been a fraction of what I am seeing with the Waskas after two weeks! What is going on? I am reluctant to blame the Waskas, because I can't imagine they're at fault, but I have stopped my work until I get to the bottom of this. Your help is very much appreciated. A couple of additional questions: (1) Other than taking all the shakes off and starting over, is there anything I can do to reverse the curling, or at least keep it from getting worse? (2) What is the best brand of shingle? I don't expect to redo these shingles again in my lifetime and so you can see why I am concerned. BTW, I used Tyvek, kept the shingles dry, and never tried to work in the rain or with wet surfaces Thank you! Frank
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did you place the shingles with the curl facing you? did you put 3 nails in all the shingles wider than 8"?
if you answer NO to either of these questions then that is your problem(s).
*helpful hint* always look at the bend (curl) of the shingle before nailing. it is not supposed to rock. you should have to press in the middle to get it to stay flat against the house.
_\ \ \ | / / / _ ( ' 0 - - 0 ' ) -----ooO----(__)----Ooo----- 3GCPO I'll wait here while you check
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Maibec specifies to use no more than 2 nails no matter what the width of the shingle. As for the curl, I have placed the shingles with the curl facing out. (Shingle appears concave when in place before nailing.) I think I may not have specified the nature of the curl problem adequately. The problem is that the *bottoms* are curling out- there is no "side-to-side" curl problem. In some cases there is a half-inch gap between the bottom of the shingle and the shingle under it!

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