i find that pvc doesn't work well for me here in Ohio. when it gets below freezing it cracks really easy under the snow load. the cost was alot more too, i can build one of these frames for about $55.00, if i built a similar pen out of PVC (2") with the extra fittings i end up well above $100.00. the pvc would be lighter to move though. in any of these designs i look for something i can move by myself. i have one i made out of sawmill lumber, its 3 feet tall (4 feet at peak) the sides are about 1x10 on the bottom and 1x6 on the top. that one is to heavy for me to move without wheels.I do the same thing, but I use PVC and zip ties which seem stronger than wood and staples. I leave a "hatch" on the top so I can reach in and get them.